How to properly weld with electrodes on aluminum

How to properly weld aluminum with electrodes?

The peculiarities of aluminum welding cause certain difficulties when joining this metal. The developed technologies, to one degree or another, make it possible to combat this and achieve positive results. The quality of aluminum welding using an inverter cannot be compared with argon arc welding or other Al joining technologies.

However, in domestic conditions it is unlikely that suitable equipment will be found.
The master may have at most a home welding machine at his disposal, be it an inverter or a DC transformer. Reasonable questions arise: is it possible to weld aluminum with an inverter at home, how to do it correctly and what materials are required for this?

What a welder needs to know

According to experienced welders, electric welding of this “winged” metal without argon can be no worse than argon.
Those craftsmen who talk about the mediocre quality of the weld and poor weldability using this method either did not weld aluminum with an electrode at all, or approached this method incorrectly. Please note the following recommendations:

The butt connection is the most acceptable. People try to avoid T-type and overlap types of welded joints due to the high probability of slag flowing into the gaps, which causes corrosion.
After welding, the seam is washed with water to remove slag;
Preparing aluminum before welding is mandatory. Removal of oxide film, protection from its re-formation;
Welding of massive parts with a thickness of more than 3 mm is accompanied by cutting the edges at an angle of 60° with a V-shape.
Preheating of Al before welding to 150-250 °C.

Do not forget that technically pure aluminum is welded better than its alloys containing magnesium and manganese (duralumin, silumin).

That is why you should choose the right welding electrodes depending on the chemical composition of the alloy.

Electrodes for aluminum

The most common brands of electrodes for welding aluminum alloys: OZA-1, OZA-2, OZANA-1, OZANA-2, OK96.20. Electrode rods are made from welding wire and coated with a mixture of chloride and fluoride salts. The coating thickness is no more than 0.30.5 mm per side.

Electrodes for aluminum OZANA-2

Let's consider a more detailed purpose of each electrode.

OZA-1 - for parts and structures made of technically pure aluminum A0, A1, A2, A3. Welding with preheating along cleaned edges.
OZA-2 – for welding casting defects and surfacing aluminum-silicon alloys AL-4, AL-9, AL-11.
OZANA-1 - welds technically pure aluminum with a thickness of products more than 10 mm. Preheating at a temperature of 250-400 C.
OZANA-2 – for AL-4, AL-9, AL-11 alloys, surfacing and welding of casting defects. Can be used as a connecting material for products made of duralumin and silumin.
OK96.20 – aluminum-manganese alloys AMts; aluminum-magnesium alloys AMg2; AMg3; AMg5; AMg6; aluminum-silicon alloys AL-4; AL-9; AL-11. Suitable for duralumin

Aluminum electrodes are more expensive than conventional electrodes and are very hygroscopic, i.e. they absorb moisture from the surrounding air.

Aluminum welding technique with coated electrodes

Aluminum welding with an inverter is carried out with direct current of reverse polarity, preferably in the lower position. The point is not even the high fluidity of aluminum, but the welding speed, which increases 2-3 times compared to steel.

The electrode melts very quickly and you simply cannot make a seam in a vertical position, much less in a ceiling position.

Important! Electrodes should be calcined before welding.

The electrode should be held predominantly in a vertical position or slightly tilted. Move the end of the electrode in the direction of the seam. Welding is performed in one pass on a short arc, without lateral movements.

The chemical elements of the coating create increased electrical resistance of the welding seam, and therefore create obstacles when re-igniting the arc. They try not to make the seams long.

In case of arc breakage, the slag crust from the crater and the end of the electrode should be removed and overlap the previous one by at least 1 cm to avoid the formation of pores when filling the crater.

Upon completion of welding, the weld seam must be cleaned and washed with water to avoid corrosion.

Welding modes with aluminum electrodes

Conclusion

The toxic smoke released during welding, as well as the high cost of electrodes and their capriciousness in storage, will not make this method more popular than MIG or TIG. It is used, as a rule, in cases where it is impossible or inappropriate to use gas equipment.

We recommend! Methods for monitoring welds and joints

Source: https://rem-serv.com/kak-pravilno-varit-alyuminiy-elektrodami/

Electrodes for welding aluminum products at home

Electrodes for aluminum welding are metal rods that are coated with a specialized mixture. They are rarely used in large enterprises. With their help, aluminum is welded at home, in small workshops, and in fairly complex work outside production facilities. The use of such electrodes makes it possible to avoid the appearance of a film of oxides on the metal. It makes welding very difficult.

Main features of aluminum electrode welding
How to weld aluminum with an electrode
The most common types of electrodes
Making electrodes at home

Main features of aluminum electrode welding

It has long been known that welding aluminum parts is very difficult. Scientists explain this by the presence of a poorly fused film of oxides on them. In order for welding to be of the highest quality, it is necessary to thoroughly clean the surface to be joined from dirt and oxide films.

To effectively clean the aluminum surface , before welding, any organic solvent or alkali bath is often used. Treatment in an alkali bath is considered the most effective method for cleaning aluminum products. Making such a solution with your own hands is quite simple.

For an alkaline bath you need:

no more than a liter of water;
50 grams of sodium carbonate;
30 grams of liquid glass;
50 grams of trisodium phosphate.

The solution, which was obtained by mixing these components, must be heated to 70 degrees. After this, it is worth placing metal products in it.

After cleaning and degreasing the products, you must proceed to the next stage. It consists of removing the oxide film . If this condition is not met, it will be very difficult to weld such parts, and their connection will be unreliable and of poor quality. To remove the oxide film with your own hands, you can use files, metal brushes or a grinder. After this process, the surface of the welded products is additionally coated with a solvent.

After completing all work on preparing the aluminum, it is necessary to begin welding the products. An inverter and the use of specialized electrodes for welding aluminum are most suitable for this purpose. To ensure a good burning arc and an excellent welding seam, the electrodes should be heated in an oven at a temperature of at least 210 degrees. The average warm-up time should be about 3 hours.

To weld aluminum, it is worth using a reliable direct current source with reverse polarity. When using special electrodes for welding aluminum, it is necessary to select the correct current strength. Experts recommend that its strength be about 28 amperes per millimeter of electrode diameter.

It is worth considering one more point that allows you to achieve high-quality and reliable welding seams. It consists in the fact that before welding the product is heated using a gas burner. The maximum temperature to which aluminum products should be heated depends very much on their size. The higher this indicator, the higher the temperature it is necessary to heat aluminum products.

The quality of the welded seam of aluminum products also depends on their cooling rate. The connection will work better if you cool it slowly. Such technical methods make it possible to perfectly alloy aluminum when welding at low currents, to avoid deformation of the welded products and the appearance of crystallization formations on the seams.

Welding of aluminum parts is carried out in this order:

Before starting cooking, if you need to weld products of large thickness, the joint should be heated with a gas burner.
The seam made must be thoroughly cleaned of slag.
Treat the cleaned seam with water at a temperature of at least 50 degrees.
After complete cooling, the welding seam is cleaned of remaining slag with a metal brush. When this is not done, the remaining slag on the weld can cause it to fail quickly.

How to weld aluminum with an electrode

Aluminum parts can be welded using different types of electrodes . These include carbon, tungsten and graphite electrodes. To choose a specific type, you need to consider some factors. First of all, this is the cooking method that will be used.

Welding, performed using manual arc technology , involves welding aluminum with a carbon electrode, and sometimes with a steel rod with a specialized coating, which is an additive. Such cooking is carried out using direct current with reverse polarity. It is most often used when welding thin aluminum products, when reworking defects that were found in aluminum castings. For cooking using this technique, inverters are used.

Arc welding , performed using automatic technology, has proven itself very well when butt welding aluminum products that have a thickness of no more than 5 millimeters.

The electrode is an ordinary aluminum wire, and welding is done under a submerged arc, which has a low conductivity of electric current. This flux consists of carboxymethylcellulose mixed with plain water.

After mixing, it is ground using a sieve and heated for more than 6 hours at a temperature of about 300 degrees.

Welding with shielding gases , which requires aluminum wire, is used for welding products of medium thickness. To ignite and maintain the welding arc in normal condition when working with such equipment, you need to have tungsten electrodes.

Such cooking can be done automatically or manually. For this purpose, a pulsed or immersed electric arc is used. Such a cooking arc, created using a tungsten electrode, is distinguished by its good stability, which makes it possible to obtain reliable and durable seams.

With this method it is also better to cook with an inverter.

Plasma cooking is characterized by high speed of work and occurs using tungsten electrodes and special aluminum wire. This type of welding requires an alternating electric current source. The maximum diameter of tungsten electrodes reaches 1.6 millimeters. Argon, sometimes mixed with helium, is used as a shielding gas for this type of cooking.

The most common types of electrodes

There is a huge selection of electrodes on the market that are used to weld aluminum products, but there are some brands that are most often used.

The OK alkali-salt grade welds technical aluminum, and sometimes parts with admixtures of magnesium and manganese. Such electrodes are highly hygroscopic, which is why they must be kept in rooms with the lowest level of humidity. The OZANA grade is necessary for welding or surfacing of products of almost all types of aluminum.

The OZA grade is made from aluminum welding wire. They are used for cooking products made of aluminum or its alloys with silicon. The UANA grade is necessary for welding parts from casting and wrought aluminum alloys.

EHF electrodes are tungsten electrodes for welding aluminum, and welding with their use is done in a protective environment of argon gas.

These electrodes provide very poor quality ignition of the electric arc, which is why they are not popular among specialists.

Making electrodes at home

Electrodes that are used for welding aluminum products are quite expensive. That's why many welders want to make them themselves. You can find a large number of videos online that describe in detail the process of producing electrodes for aluminum and its alloys at home. In order to make them, you should use the detailed description below.

Aluminum wire with a diameter of no more than 4.5 millimeters, cut into pieces of 30 centimeters. To make a coating for electrodes, you need to grind simple chalk and mix this powder with liquid glass.

This entire mixture must be made completely homogeneous and the prepared pieces of aluminum wire must be coated with it. A similar coating of chalk and liquid glass should be applied to the aluminum wire in a layer of up to 2 millimeters.

Next, the manufactured electrode is dried until its entire surface is completely hardened.

By following these simple instructions, you can make good electrodes for welding aluminum products with your own hands, and numerous videos from the Internet can help with this. Even despite such a simple production method, such electrodes are capable of welding aluminum products with great efficiency and obtaining good welds.

Source: https://instrument.guru/osnastka/elektrody-dlya-svarki-izdelij-iz-alyuminiya-v-domashnih-usloviyah.html

How to weld aluminum using electric welding - Machine tools, welding, metalworking

Date: 06/17/2015
581
: 42

Quite often there is a need to weld aluminum. This material has high electrical and thermal conductivity, relatively light weight, and its alloys have excellent mechanical properties. But welding aluminum is a rather difficult process. Not everyone can do it.

Diagram of a semi-automatic machine for aluminum welding.

But you should also take into account the correct electrodes for aluminum and how to weld it correctly.

Features of working with aluminum

Table of characteristics of electrodes for welding.

Cooking aluminum is quite difficult, as it has certain properties:

The surface of aluminum sheets has an oxide film, which begins to melt only at a temperature of 2044 ° C, but the metal itself begins to “work” at a temperature of 660 ° C.
It is quite difficult to make a solid seam on aluminum due to the fact that this metal easily oxidizes, resulting in the formation of a refractory film on the droplets. Therefore, when working with this metal, care must be taken to ensure that there is no air in the environment. For this purpose, electric welding using argon is used.
When welding, aluminum spreads very much, so during the process it is necessary to remember about heat-dissipating pads.
When aluminum is welded by electrodes, crystallization cracks form. This causes the seams to weaken significantly. Such splits are formed due to the presence of silicon in aluminum. And pores are formed due to hydrogen, which also leaves the metal when heated.
During welding of seams, a defect occurs such as deformation of the shape during the hardening process. This is due to the fact that this metal has a high linear expansion rate.
For aluminum metalworking, a current is needed that is 1.5 times greater than that needed for welding work with other steels. Although if we compare the temperature indicators for melting, then aluminum metal has a lower temperature.
Aluminum may also contain unknown alloys. And this, in turn, can lead to difficulties with the choice of electrodes and modes.

How to cook aluminum correctly?

Arc welding diagram.

Today there are three main options for welding work on aluminum:

The AC TIG mode, intended for welding in an inert gas environment, is carried out with a tungsten electrode.
The DC MIG mode is intended for inert gas environments, but is already carried out semi-automatically with automatic wire feed.
MMA mode, during which welding occurs with coated consumable electrodes and in the absence of shielding gas.

First of all, it should be remembered that in order to perform high-quality aluminum alloying, it is necessary to take care of the oxide film. For this purpose, direct or alternating current is used, but with reverse polarity. Thus, cathode sputtering occurs, under the influence of which the film is destroyed. If the current is directly polar, then this will not give any effect.

What is the best way to prepare aluminum?

Scheme of argon-arc welding of aluminum.

Before starting welding work, the aluminum surface must be carefully prepared for this process. To do this, a number of works must be performed.

First of all, the surface joints and the surface as a whole are degreased and cleaned. There should be no dirt, oil or grease left on the surface of the aluminum being welded. For this purpose, use acetone, white spirit, aviation gasoline or some other similar solvent.

It may be necessary to trim the edges. This is done if the thickness of the aluminum sheet exceeds 0.4 cm. In other cases, the metal is left as it is. But there is a case when aluminum is covered with electrodes, then it is not touched if it is not thicker than 2 cm. If you have to deal with aluminum thinner than 1.5 mm, then you should take care of the flanges.

Next, the oxide film is removed. To do this, using sandpaper, a file or a metal brush (wire diameter no more than 0.15 mm), the edges of the parts to be fused (at a distance of 2.5-3 cm) are cleaned.

Aluminum welding method using coated piece electrodes

Main characteristics of coated electrodes for aluminum welding.

The MMA mode is intended for welding when dealing with metal thicker than 4 mm. But this mode has a number of negative aspects, namely:

With this type of work, the seam is not of very high quality, so its surface will have porosity.
In addition, during electric welding there is a strong spattering of metal, which is also not very safe.
After completing the work, the resulting slag is very difficult to clean off, and if you do not get rid of it, corrosion will form on the surface of the aluminum.

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But with all this, coated electrodes work both on ordinary aluminum and on its components. Previously, OZA-1 and OZA-2 electrodes were used for welding work, but today UANA and OZANA have replaced them. These electrodes are designed for all types of aluminum alloys. The first electrode works with metal of technical purity, and the second - with aluminum-silicon alloys.

When welding aluminum in MMA mode, direct current with reverse polarity should be used. In this case, 25-30 A of current should flow per 1 mm of electrode diameter.

To achieve optimal welding quality, the metal is heated to at least 250-300° C. But if more massive parts are used, then this figure increases to 400° C.

The process of heating and gradual cooling helps to obtain good fusibility of materials using a weakened current. Also, this method of operation does not lead to the formation of crystalline cracks and reduces warping.

If you are dealing with large parts, it is better to use local heating.

You should know that welding work with an aluminum electrode is carried out 2 times faster compared to others, since they melt faster. As a result, the welding speed increases.

In the event of an arc failure, the crater and the working end of the electrode receive a layer of slag.

And it will already interfere with “igniting” the arc. Experts advise that in order to avoid such a nuisance, all welding should be carried out in one fell swoop, without interruptions, within the same electrode. Moreover, work on aluminum does not require vibrations with a transverse electrode, as would be done when working on steel.

To help improve the quality of the seam, the finished joint is cleared of slag, washed with hot water and cleaned with a steel brush. In this way, debris will be removed from all microcracks, which could later lead to corrosion.

Since coated electrodes and welding with them have many unpleasant features, this method is used quite rarely. Instead, argon welding is preferred.

Method of electric welding with a tungsten electrode in an inert gas environment

Electrode position during welding.

AC TIG mode is very popular. This method provides high strength values, and the seam has a very aesthetic appearance.

To carry out such metalworking, tungsten electrodes (cross-section - from 1.6 mm to 5 mm) and special filler rods (cross-section - from 1.6 to 4 mm) are used.

To achieve a high-quality effect, argon or helium is used. The main thing is that both gases are of maximum purity. The oxide film is destroyed by an arc powered by alternating current. In many ways, the quality of work performed is influenced by correctly selected equipment and its configuration.

For proper metal melting, it is necessary to maintain an inclination angle of 70-80° between the surface and the electrodes, and a 90° inclination is required for the electrode and filler wire. It is necessary to ensure that the length of the arc is no more than 1.5-2.5 mm.

When welding correctly, the torch goes behind the filler rod, not in front. This ensures seam protection. The filler rod operates in a reciprocating motion. Under no circumstances should lateral movements be used.

To remove heat, a steel or copper lining is used, which acts as a radiator. The weld pool is used in small sizes. During welding, the welding current and inert gas must have a directly proportional flow rate.

Argon is supplied 5 seconds before the arc is ignited, and turns off 7 seconds later after it has gone out.

Semiautomatic aluminum welding method

Aluminum welding with direct current.

The DC MIG mode is performed using a special impulse device, which helps to cope with oxide oxide with the help of a high voltage pulse. This method has a high level of weld quality, since during melting, drops of aluminum are “driven” into the weld pool. But the cost of such equipment is very high.

To perform MIG welding, you must remember the following technical features:

Aluminum alloys and its alloys do not tolerate direct current with straight polarity.
If resistance is observed in the sleeve, the aluminum wire will curl into loops, since it is softer than steel. To avoid such trouble, you need to stock up on a four-roller feed mechanism, a short sleeve and a Teflon liner for it, which helps reduce resistance.
To prevent the aluminum wire from getting stuck in the current collector, it is best to select a tip whose diameter will exceed the size of the hole. As an alternative, there are special conductive tips marked “Al”.
We should not forget about the correct feed speed of the aluminum wire so that it does not have time to completely melt. Aluminum is a very soft metal, so it melts much faster than steel.

Homemade DC welding machine with your own hands

It should be remembered that no matter what mode is selected, the grade of wire must be selected for the working material. In order to carry out all the work efficiently, it is advisable to initially become familiar not only with the aluminum welding technology, but also with all the equipment that will have to be used during this process.

Source: https://stanki-info.com/kak-varit-alyuminiy-elektrosvarkoy/

Electrodes for aluminum, welding at home with an inverter

The unique properties of aluminum as a metal result in serious difficulties in welding work with it. These difficulties are understandable, and methods for solving them are known. In order to choose the most optimal working technology in a particular “aluminum” case, it is necessary to understand the properties of this extremely interesting and capricious metal.

There is no escape from working on it: no metal can compare with it in popularity, the automotive industry alone is worth it. Aluminum is widely used in aviation, space and many other industries.

At the same time, this metal is extremely capricious in welding work; it is one of the most complex materials, requiring a differentiated approach to each technological case. Aluminum electrodes are a key element for obtaining high quality welds.

Why is aluminum difficult to weld?

Welding aluminum using a TIG inverter.

It's all about physics and, in particular, melting point. Aluminum itself melts at very low temperatures, not exceeding 650°C.

Unlike other metals, it does not change color when heated, making it very difficult to tell when parts are ready to form a weld.

All this would not be so scary if the oxide film, which forms on the surface of this metal at lightning speed, did not interfere with the process.

Film behaves completely differently. Firstly, in order to melt it, the temperature must be raised to 1750°C. Secondly, the oxide is much heavier than the metal itself, so during welding it is immersed in it and thus solidifies. A simple and elegant solution to problems with oxide film is to thoroughly clean the surfaces of aluminum workpieces - this is one of the mandatory requirements in aluminum welding.

Aluminum gets along well with other metals and forms alloys for a wide variety of purposes, sometimes with diametrically opposed properties. These alloys are also not without problems. There is a high risk of cracks when working with them. This occurs due to the metal's insufficient tensile strength when it is in a partially liquid and solid state at the boundary temperature range. As a result of shrinkage stress, parts are deformed during the cooling process in the form of cracks.

Types of electrodes for aluminum

OZA is made from aluminum wire and is used for pure aluminum and aluminum alloys with silicon.

Features of aluminum welding using argon arc welding.

OZA – 1 are suitable for almost any aluminum alloys and surfacing. These are consumable electrodes on aluminum made of a metal rod and coated with salt. The diameter can be very different. In operation, you need to use direct current of reverse polarity. Used for workpieces with edge thicknesses ranging from 3 to 16 mm. Preheating of parts to a temperature of 250 – 400°C is mandatory. The consumption of OZA-1 is quite high: two kilograms of electrodes are consumed per kilogram of metal blanks. The composition of the weld is complex: more than half nickel, copper, manganese, iron. After completion, be sure to rinse the seam with heated water, then clean it with a wire brush. The disadvantage of these consumables is the difficulty of welding in a vertical position, which can create an unnecessary side arc. As a result, you can only work in the lower position.
OZA – 2 – highly specialized consumables for aluminum alloys with silicon. Salt coating. The consumption is the same: two kilograms per kilogram of metal.

Alkaline salt OK.

This type includes brands 96.10, 96.20 and 96.50.

Consumables 10 of Swedish production ESAB are used in the argon-arc method and are the most preferred option in this technology. Their feature is a coating of a new composition from a mixture of chlorine and fluorine salts. As a result, the arc is smooth and stable without metal spattering. The seam is of high quality and aesthetically pleasing. In operation, preheating of workpieces is preferable, but not required. Unlike OZA-1, heating does not affect the quality of the seam; it only helps to reduce the consumption of expensive electrodes. Another positive difference from OZA-1 is the ability to carry out welding work on vertical surfaces. The consumption of electrodes is significantly lower due to the characteristics of the coating and thin wire as a rod, which reduces the overall cost of this technology. The weld seam is characterized by high hardness.
OK 96.50 is very popular in mechanical engineering for automotive engine parts, installation of a wide variety of building structures and correction of casting defects in aluminum alloys. The composition is an aluminum electrode: the rod is made of aluminum, silicon and iron with four thickness options. The current is applied constant with reverse polarity. Coating with an alkali-salt composition allows you to form a protective crater to neutralize the oxide film. Preheating of workpieces is very desirable; the optimal temperature is 250 – 300°C.

Brands of electrodes and areas of application.

Two grades of the OZANA type: OZANA - 1 for surfacing or welding of four grades of aluminum A0 - A3 and OZANA - 2 for welding aluminum alloys AL4, AL9, AL11. Perhaps the most popular consumables of all: they make it possible to form an even arc and a high-quality seam. You can also work in a vertical position, unlike other types of aluminum welding.

OZANA – 1 are designed specifically for working with parts and surfacing of pure aluminum. The coating is made of a salt composition, the rod is made of an alloy of aluminum, silicon and iron. Coating allows you to cope with the oxide film and stabilize the melting process. The current used is constant, reverse polarity. Consumption is slightly lower compared to other consumables: 1.7 kg per kilogram of surfacing. The seam is of very high quality with pronounced anti-corrosion resistance. Preheating of workpieces depends on the thickness of the edges. If it is more than 10 mm, heating to 200°C is recommended. If the edge is thinner than 2 mm, it is necessary to make a preliminary beading of the edges along the intended seam. These consumables must be heated before use for 30 minutes at a temperature of 150°C.
OZANA – 2 is an updated version of OZANA – 1.

UANA - special consumables for working with alloys that are easily deformed.

EHF - tungsten tips for welding in argon.

A special property of aluminum electrodes is their extremely high hygroscopicity; they manage to extract all the moisture possible from the air. Hence, you need to remember about the special conditions for their storage - in moisture-proof packaging and only in strictly dry rooms.

We cook with an inverter without argon

Welding aluminum at home with an inverter is quite possible, and here again the right electrodes will help us - special consumables for aluminum. Of course, the quality of seams using argon arc welding is disproportionately higher than with methods without argon, but for home work, equipment for working in argon is too expensive. Amateur craftsmen most often have only a basic welding machine at their disposal.

Tungsten electrodes for aluminum welding.

Home welding of aluminum with an electrode requires knowledge and implementation of the following recommendations:

Seam connections should only be made butt. Other types such as tee or lap welds are not suitable for aluminum due to the risk of slag flowing into the gaps. This subsequently leads to corrosion.
Cleaning the seam after melting is as important as cleaning surfaces before work. The best way is to rinse the seam with water.
It has already been written here about removing the oxide film before welding, but repetition would not be superfluous: this action is too important.
Finishing the edges of metal workpieces is also extremely important. It all depends on the thickness of the edges. If they are thicker, for example, 3 mm, the groove should be formed at an angle of 60° in a V-shape.
It also doesn’t hurt to preheat the workpieces before welding. In this way, you can at least slightly “even out” the imbalance of low melting point and high heat conductivity.

The rules for choosing consumables are the same and depend on the chemical composition of the alloy - welding aluminum with an inverter in this matter is no exception. Let us immediately note that pure aluminum is welded much easier and better than its alloys. An important factor is the considerable price of aluminum electrodes.

Welding torch device.

The rods of the most popular ones are made of wire coated with a mixture of chlorine or fluorine salts in a very thin layer. A number of brands of electrodes are designed this way, each of them having its own precise purpose with the most detailed details of use.

Electrodes for welding aluminum with an inverter are as follows:

OZA-1 for welding with mandatory heating before the process for workpieces made of pure aluminum with cleaned edges.
OZA-2 for surfacing aluminum alloys with silicon and sealing defects obtained during casting.
OZANA-1 for welding pure aluminum with an edge thickness of more than 10 mm with preheating up to 400°C.
ShchL96.20 for aluminum alloys with manganese, magnesium, silicon, duralumin.

An inverter for aluminum welding can be of various modifications. Semi-automatic machines are more often used, but electric arc machines are also quite suitable.

Homemade consumables for aluminum

Since purchased aluminum electrodes are not cheap, home craftsmen have come up with ways to make consumables.

Brands of electrodes for welding aluminum structures.

Homemade electrodes for aluminum welding are produced using simple technology:

Cut into even pieces 30 cm long from aluminum wire with a diameter of no more than 4 mm.
Prepare a coating or coating from crushed chalk, which must be mixed with silicate glue and mixed thoroughly. Dip the aluminum rods into the mixture.
The coating layer should be approximately 1.5 - 2.0 mm. Dry until the layer is completely hard.

Once again about cleaning

Cleaning requirements are set out in the instructions for each type of aluminum electrodes as a mandatory component of the technology. Oils, greases and small metal particles should be removed with the utmost care. To minimize the risk of scale and high porosity, the edges must be perfectly smooth and clean.

Source: https://tutsvarka.ru/vidy/elektrody-po-alyuminiyu

Tips for welding aluminum with electrodes

[Welding aluminum with electrodes] requires special conditions.

In this case, it is important not only to correctly carry out the welding process with electrodes, but also to select suitable electrodes.

The price for this service is not too high, but many people choose to do their own electrode welding at home.

If you have never welded aluminum yourself before, then before starting work you should find out how this process occurs, as well as the rules that need to be followed in order for aluminum welding to be carried out correctly.

Process Features

Welding, even at home, must be carried out in compliance with safety precautions.

It is very important, for example, to insulate the wires before starting work to avoid the risk of electric shock.

Rubber boots will also help you protect yourself from electric shock; you can put them on before starting the process.

To protect yourself from burns, you will need special gloves and a mask designed for welding. The price of protective equipment is not that high, and work without it is prohibited.

The DIY process can only be carried out in a room where there are no flammable objects. This applies not only to furniture, but also, for example, to wooden floors.

While working, you should keep a fire extinguisher or at least a container of water nearby to quickly neutralize an unexpected situation.

It is best to work with aluminum outdoors, but if this is not possible, then before starting, the room where work with the inverter will take place must be ventilated.

This is necessary because during operation gas compounds that are dangerous to humans will be formed in the air.

The unique properties of aluminum alloys determine the peculiarities of the process of working with it.

For example, aluminum can be melted at low temperatures, plus it has high thermal conductivity (on average three times higher than other metals).

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Aluminum is used in almost all areas of life, since it is a very convenient metal to process, however, in the process of welding it with your own hands, you may encounter some difficulties associated with the increased oxidation of the material.

During operation, a film forms on the surface of aluminum, which can only be melted at a very high temperature, much higher than what is permissible when working with this type of material.

At the same time, processing aluminum alloys with fluxing materials is impossible, since this material does not have the necessary chemical properties.

Therefore, independent welding of aluminum is carried out using a gas burner or arc welding. Before starting work, you need to thoroughly clean the surface.

You can use scouring pad, baking soda or gasoline for this. After processing alloys, the metal surface must be rinsed with clean water. Cleaning will help protect the aluminum from corrosion.

To work with aluminum, you will need a special flux designed specifically for working with this type of alloy.

Flux is designed to dissolve the oxide that forms on the surface of aluminum during operation. You can buy it at a hardware store, the price is low.

In this case, the oxide dissolves at the temperature that is optimal for processing this type of metal.

It is best to purchase solvents that contain lithium chloride or lithium fluoride - this alkali metal is most effective at dissolving the oxide.

It is also important to choose the right filler material and find out what its price is before starting work.

It is used to ensure that aluminum hardens properly and, after shrinking, strong seams appear on its surface. In this case, the surface of the material will remain smooth.

With the arc welding method, the choice of torch is very important.

It is best to consult with a knowledgeable person before purchasing, but you can focus on a value that is 1 value below that required for working with low carbon steel of the same size, and the price in this case is not so important.

Arc welding requires special shielding gas to be supplied to the work area.

Due to the mixing of oxygen with nitrogen, the metal can deform: become brittle or acquire a porous structure.

This also happens in cases of contact with a graphite electrode, arc or aluminum itself.

Gas is necessary not only when working with aluminum, but also with other metal compounds and metals.

Inert gas is often used as an additional gas: it not only protects the surface, but also removes slag, metal residues and other elements that appear during the work process.

When choosing a gas, you should focus, first of all, on the type of metal you will be working with, in this case aluminum.

IMPORTANT TO KNOW: Instructions for welding aluminum with argon for beginners

It is best to focus on argon and helium - these are the inert gases most used in welding non-ferrous metals, and this combination is perfect for welding aluminum.

Do-it-yourself welding

To carry out independent work, you will need a number of auxiliary items: the most important element is a welding machine capable of performing argon-arc welding.

You will also need an argon cylinder, aluminum wire, an oscillator and a gas torch.

Selecting wire for welding is a very important step before starting work.

The price of the material is approximately the same, so you need to focus not on it, but on the aluminum properties: you need to evaluate how suitable the wire is for working with them.

Before starting work, you need to protect the metal at the joints. This is best done with a stiff steel brush or other similar tool.

After cleaning, these places must be additionally treated with previously purchased flux.

Cleaning aluminum alloys is necessary in order to remove the oxide film and then work with the metal surface itself.

The second stage of welding is working with a gas torch. It must first be heated to a suitable temperature and then treated with it in the places where the seams were made.

To mix alloys, you need to apply additional tungsten welding electrodes to the seams and melt them under the torch - this way, the rods will mix with the aluminum and create a mixture of the necessary alloys.

For home use, the argon-arc welding method is most suitable.

With this method, the nature of the tungsten electrodes is unimportant; tungsten electrodes do not need sharpening; you can purchase both consumable and non-consumable elements.

This welding method is not only effective, but also very convenient, since it does not require flux, which greatly facilitates the work process.

Argon-arc welding with an inverter allows you to weld aluminum even with the help of metal electrodes that do not need sharpening.

If you decide to use the automatic argon-arc method, then you will need a flux that has a special composition and is completely chemically pure.

Another suitable welding method for home work is spot welding.

IMPORTANT TO KNOW: Semi-automatic welding technique in a carbon dioxide environment

But it is less efficient than argon-arc due to the fact that aluminum has high thermal conductivity, as well as due to the very rapid melting process of the material.

Spot welding is performed at high speed, sufficient so that the electrode can be moved at an equal level with the metal.

The next welding method, which you can do yourself, requires an electric drive machine - thanks to it, the metal can be melted continuously and at the required speed.

This is a rather complicated method, and it is rarely used at home, and in general, mostly experienced craftsmen work this way.

It is best to focus on the first welding option, since it is the most convenient, and even a person with minimal experience can perform it.

The last two methods are quite difficult to implement at home, and the popular cold welding is not suitable for aluminum at all.

Melting aluminum is a long process, and it is important to observe safety precautions at all stages of work, because it poses a certain health risk, especially if you have no previous welding experience.

The process of arc welding with an inverter is quite complex, especially at home.

Therefore, if you do not have experience, it is better to turn to a professional, especially since the price for these services today is not too high.

If you want to work with an aluminum inverter yourself, then watch the video with instructions before starting work.

Not all welding methods are suitable for aluminum and its alloys; the simplest is argon-arc. Even a person with minimal experience can do it with his own hands.

You can see in the video what this type of welding is.

Other work methods are more complex, so if you are not a professional welder, it is better to entrust them to a specialist, especially since the price for this service is quite reasonable.

Source: https://rezhemmetall.ru/svarka-alyuminiya-elektrodom-v-domashnix-usloviyax.html

Welding aluminum with a simple electrode

Currently, aluminum is used in a wide variety of fields. This thin and flexible material is often found in vehicle parts, including engine blocks, transmissions and body parts. It is also used to create stainless steel containers for household and industrial needs and many other important everyday items.

If a crack or problematic hole forms in such a structure, it is better to close it using a special apparatus in an argon environment. However, not every average person has such a unit at their disposal, so they have to look for more affordable solutions. One of them is aluminum electrode welding .

To successfully carry out such an activity, it is necessary to acquire a certain set of skills and purchase the appropriate equipment and supplies. The principle and technology of such welding are quite simple, so with the right approach you can learn them in a short time.

Stages of welding activities

Understanding the key intricacies of aluminum welding is not as difficult as it might seem at first glance. Through numerous attempts and experiments, you can achieve successful results and learn such a skill by heart. So, step-by-step actions for high-quality joining of metal products consist of the following stages and features:

If the thickness of the plate being welded exceeds 5 millimeters, it is necessary to cut the edges. To do this, it is recommended to cut the edges at an angle of 45 degrees, although other values are also allowed. It is no secret that the width of the weld seam depends on the size of the cutting angle. If the thickness of the plates exceeds 7 millimeters, then you will have to make a technical gap between each part of two millimeters. If the work object is represented by a crack, then it is widened using a cutting disc and a grinder. Otherwise, the seam will be superficial.
The prepared workpiece is thoroughly heated. A propane-oxygen flame is used to remove excess liquid. The role of the working tool is performed by a cutter or an ordinary can with a household torch. It is necessary to warm the surface to 150 degrees and make sure that the material is dry enough.
After thoroughly warming up, it is necessary to clean the oxide film. In this case, you can use a regular brush to clean the metal. It is important to remove the refractory layer at the beginning of the welding zone. The following actions are carried out using an electrode, the composition and temperature of which can corrode the oxide and re-weld.
Tacks are installed on the prepared product, which secure all parts to be welded. The root seam should be smooth and completely fill the gap. The angle relative to the parts being welded must be at least 90 degrees. This may seem unusual to inexperienced welders, or those who have had to work with carbon steels. However, in this way the molten metal will more accurately fall into the joint. After the surface cools, the slag falls off. Unfortunately, this action is carried out with great difficulty, so you cannot do without a sharp hammer.
The next layers of the seam are applied until the entire thickness is filled.

Preparatory actions

Regardless of the welding conditions - industrial or home, you need to properly prepare the edges of the workpiece . Such an action consists of the following processes:

The surface of the part that will be welded (as well as the surface of the filler material) is thoroughly cleaned of dirt, oil and grease. To degrease the surface, white spirit, acetone, aviation gasoline and many other solvents are used.
The preparatory stage also includes such actions as cutting the edges of welded parts, which is performed only when absolutely necessary. If you do not use coated electrodes when welding, then edge cutting is carried out when the thickness of the parts being joined exceeds 4 millimeters. If the thickness of the aluminum alloy exceeds 20 mm, then the use of electrodes is indispensable. If aluminum sheets up to 1.5 millimeters thick can be welded, then their ends are pre-flanged before joining.
As mentioned above, immediately before welding, the surface of the part must be completely cleaned of the oxide film. In this case, it is common practice to use a high-quality file or a bristle brush to clean the metal. In some cases, a thin layer of oxide film is also removed using special chemicals, such as caustic soda, gasoline and others. When treating with caustic soda, the workpiece must be thoroughly rinsed with running water .

Equipment and electrodes

Pay attention to the list of the most necessary tools and accessories . In most cases, the operation is carried out using a conventional inverter.

This device has a convenient design, so it is easy to move or move around the workshop. The polarity is set in such a way that the “plus” is placed in the worker’s hands, and the “minus” affects the workpiece.

In this case, you need to get a 220 V outlet.

When choosing electrodes, you should give preference to specialized models such as UTP 48 or similar analogues. They can have different diameters and be selected taking into account the thickness of the metal. The composition of consumable raw materials also has some hygroscopic properties, so it must be pre-dried to ensure a better connection .

According to experienced specialists, electric welding of such flexible metal without the use of argon is sometimes carried out as well as with argon welding. If someone dissuades you from such a decision, arguing that it is of poor quality of the final seam and poor weldability, do not believe it. Most likely, he approached the method incorrectly or never tried to weld aluminum using an electrode .

To avoid irreparable mistakes and unpredictable troubles, it is enough to follow a number of recommendations and rules:

The butt joint method is considered the most promising. Other types in the form of a T-weld or lap welded joint are impractical, since they increase the likelihood of slag flowing into the gaps, which will cause a corrosion reaction.
After welding operations, the seam is washed with water to clean the workpiece from slag.
Immediately before processing, the material must be properly prepared. To do this, remove the oxide film and prevent its appearance in the future.
When welding massive parts with a thickness of three millimeters or more, it is necessary to separate the edges at an angle of 60 degrees with a V-shape.
Primary heating of aluminum is carried out at 150−250 degrees Celsius.

Do not forget that technically pure aluminum can be welded much better than alloys containing magnesium or manganese . We are talking about duralumin or silumin. However, products made from pure material are practically not used, so some difficulties may arise during welding.

Reasons for deterioration of metal weldability

If you encounter any difficulties or unpleasant moments during the welding process, you need to take into account many unique properties of the metal :

The key difficulty of heat welding is the presence of an oxide film, which can only be melted under the influence of temperatures of 20440 degrees Celsius. Melting of the metal itself begins at a lower temperature - from 660 degrees.
Drops of the molten part appearing in the welded zone are very quickly covered with a refractory oxide film, which prevents the formation of a continuous seam. To protect the workpiece from this phenomenon, the welded area is protected from contact with ambient air using argon.
Molten aluminum is characterized by high fluidity, and this significantly complicates the further formation of the weld pool. For this reason, work is carried out using additional heat-dissipating pads.
Aluminum contains dissolved hydrogen, which is directed outward after the molten metal solidifies. As a result, this causes the appearance of pores and crystallization cracks in the seam. In addition, alloys of this metal are characterized by an increased concentration of silicon, which also causes cracks to appear as the product cools.
Aluminum has a decent linear expansion coefficient. Because of this, significant shrinkage of the metal may occur during solidification, which causes a number of serious deformations of the parts being connected.
Welding of pure aluminum and its alloys is carried out under the influence of high values of welding current. Metal is characterized by high thermal conductivity. Also, when welding, it has become common to use currents with lower strength.
Welding parts made of this metal is considered difficult in cases where it is not possible to determine the exact grade of the alloy. In this case, you have to spend a long time and diligently choosing the appropriate welding mode and methods used.

Anodizing aluminum with steel

Anyone can learn all the intricacies of welding aluminum with an electrode. All you need to do is be patient and willing to set aside a few hours of your time to study the relevant material and guidance. In this case, you will be able to perform many important operations at home, without seeking help from qualified employees .

Source: https://varimtutru.com/svarka-alyuminiya-prostym-elektrodom/

DIY electrodes for welding aluminum

Aluminum electrodes for welding are metal rods coated with coating. The coating protects the metal from oxidation and improves the quality of the weld. They are practically not used in large workshops and factories, since their efficiency is not enough to perform large volumes of work. But such electrodes are widely used by home craftsmen.

A carbon electrode is often used to weld aluminum. In this article we will tell you everything you need to know about aluminum rods and explain in detail how to make your own welding electrodes.

Features of welding aluminum at home

Anyone who has welded aluminum at least once in their life knows that this is a very difficult task. There is an oxide film on the surface of the metal, which makes the welding process difficult. Do-it-yourself aluminum welding electrodes can solve this problem.

But before you start, you need to thoroughly clean the surface. Remove contaminants and carry out comprehensive preparation of the metal for welding. This will improve the quality of the seams and they will last longer.

For high-quality welding of aluminum parts, you need a welding machine that produces direct current and is connected in reverse polarity. If you are using electrodes for aluminum arc welding, then pay attention to the current strength. This parameter should be set to a small value.

Follow our recommendations to get the job done efficiently:

If you need to weld thick parts, then the approximate location of the seam must be properly heated before welding. This is done using a regular gas burner.
Be sure to clean the seam of slag and pour boiling water over it.
Once the grout has cooled, clean it again using a stiff brush. Do not disregard this advice, as remaining slag can promote corrosion.

THIS IS INTERESTING: What types of welding are fusion welding

Popular brands of electrodes

As we mentioned earlier, a carbon electrode is often used to weld aluminum. But besides this, there are a number of brands that are no less popular among beginners and experienced welders. So, what electrodes can you use for welding aluminum with your own hands?

OK brand rods

These electrodes are manufactured by ESAB and are marked OK. We recommend using models 96.10, 96.20 and 96.50. Yes, they are not universal, but with their help you can weld technical aluminum or manganese-based aluminum alloys. These aluminum electrodes for welding at home have shown themselves to be on the positive side, but keep in mind that they require special care and strict adherence to the expiration date.

Rods brand OZA

In principle, such electrodes for welding aluminum with your own hands can be made, since they are based on simple aluminum wire. These rods are used for welding pure aluminum or its silicon alloys.

UANA brand rods

These are very highly directional rods used for welding cast aluminum alloys. They are practically not used in home welding, but we could not include them in our list.

EHF brand rods

EHF are tungsten electrodes; they must be used when welding with argon. It is difficult to make such electrodes for aluminum with your own hands, but if you have the opportunity to purchase them, be sure to try them in your work. Yes, with their help it is difficult to strike the arc correctly, and professionals often do not recommend such electrodes. But if you learn to hold an arc with such rods, then you will not have problems with all the others.

Manufacturing instructions

It doesn't matter what brand of electrodes you need to purchase, in any case it is not cheap.

Especially for beginner welders. We have found a solution to this problem and suggest you make the rods yourself. There are many videos on the Internet in which experienced craftsmen explain the technology for making materials for welding. We also decided to share our instructions on how to make homemade electrodes with your own hands. Follow these simple steps:

Prepare aluminum wire with a diameter of no more than 4 millimeters and cut it into rods 20-25 centimeters long. These parameters are usually sufficient, but you can change the diameter and length as you wish. Our base is ready.
Now let's prepare the coating. Grind up chalk (preferably regular white) and mix it with silicate glue (sometimes called “liquid glass” in stores). Mix everything thoroughly until smooth and dip the aluminum rods into it.
Make sure that the coating layer does not exceed 2 millimeters. Leave the electrodes to dry. When the coating hardens, the rod can be used for work.

Yes, such electrodes for resistance welding are inferior in quality to factory products, but they still allow you to perform simple work that does not require increased responsibility and a perfect seam. This instruction may seem too simple, but believe me, electrodes for spot welding on your own can also be effective and will absolutely save your money.

Please note that this is not a factory carbon electrode or zinc electrode, it is not European quality. So test your electrodes first before working on unwanted metal.

Instead of a conclusion

Now you know how to make welding electrodes with your own hands and what features you should consider before getting started. Be sure to try homemade rods and share your experience in the comments, it will be useful for other welders. Also share this article on your social networks. Good luck!

Source: https://svarkaed.ru/rashodnye-materialy/elektrody/elektrody-dlya-svarki-alyuminiya-svoimi-rukami.html

Welding aluminum with electrodes using an inverter: how to weld correctly

As a rule, special equipment and special technologies are most often used for welding aluminum structures and parts. Welding using manual arc welding is quite difficult . But sometimes it is necessary, and we will help you figure out how to weld aluminum structures with electrodes.

When working with aluminum, the following types of welding are mainly applicable:

MMA (manual arc welding of aluminum (see electrodes for aluminum));
MIG (semi-automatic aluminum welding);
TIG (welding of aluminum in an argon atmosphere using filler wire).

We will not touch upon the topic of agro-arc welding or the use of tungsten electrodes. Below we will talk about carrying out welding work with simple manual coated arc welding electrodes .

Aluminum electrode welding (MMA)

MMA (Manual Metal Arc) - manual arc welding with coated electrodes. This method is far from the most effective when working with aluminum products. Disadvantages of manual arc welding:

it is difficult to make an even seam;
the seam may be porous and not very durable;
when the electrode melts, strong spattering is observed;
It is difficult to clean the seam from slag.

And yet, despite the listed disadvantages, there are situations when manual arc welding cannot be done without . MMA welding can be used to connect aluminum structures that do not bear heavy loads . The minimum metal thickness must be no less than the thickness of the electrode (4 mm).

Manual arc welding with coated electrodes is useful at home when it is not possible to use bulky and expensive equipment .

Welding with inverter

Why, if there are no options other than MMA, is it then recommended to weld aluminum with an inverter? Although welding aluminum with electrodes is a rather complicated process, there is a way to make your life a little easier. Aluminum is a poorly weldable metal, so to achieve an even and high-quality weld, you should use an inverter.

Of course, there are other techniques that can be used in manual arc welding: rectifiers, transformers or generators. However, an inverter is the most profitable option due to the following advantages:

High efficiency - up to 95% and above. The high-frequency pulse semiconductor converter completely eliminates inductive losses.
Efficient energy consumption . The inverter automatically turns off when operation stops.
Protection from unstable electrical network . The inverter produces the required voltage regardless of network sags. The pulse converter automatically adjusts to the input voltage and provides the required output parameters.
Precise adjustment of welding current . The current required for specific welding jobs directly depends on the thickness of the electrodes used. The inverter control knob allows you to set the desired value before starting work.
Quick arc ignition . It is quite easy to hit the part with an electrode. The inverter ensures stable combustion of the welding arc.
Convenient to use at home . Inverters, as a rule, have compact dimensions. For comparison, a welding transformer with a power of 8 kW weighs more than 40 kg, while an inverter of the same power weighs less than 5 kg.

Features of the technology

Let's look at the features of aluminum electrode welding technology. Manual arc welding of aluminum is not the most convenient process, so it is important to know and take into account some features of welding.

Selection of electrodes . First of all, you need to select the appropriate type of electrodes. The fact is that some brands have a coating intended only for working with aluminum alloys. Others are used exclusively for welding pure aluminum. Therefore, this parameter should be taken into account. Electrode manufacturers indicate the purpose of a specific brand, so you can easily choose the right one.
Surface cleanliness . When welding with electrodes, preparation of the surface of the structure is of great importance. It should be well processed so that the seam is smooth and durable.
Current _ Aluminum welding is carried out using direct current of reverse polarity. This is due to the fact that an oxide film forms on the surface of this metal. And with reverse polarity, the film is destroyed using cathode sputtering.

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Chemical properties of aluminum

Aluminum is characterized by high solubility of hydrogen in liquid form with low solubility at the crystallization point. This directly affects the quality of welding work. If even a small amount of hydrogen dissolves in the weld metal, the weld may become porous , as the hydrogen will tend to escape.

Another important chemical property of aluminum is oxidation . The combination with oxygen creates aluminum oxide, which forms a kind of film on the surface of the metal. On the one hand, the oxide film reliably protects the metal from corrosion. On the other hand, it becomes an obstacle to welding work . While aluminum already melts at 660.3°C, the melting point of the oxide film is 2037°C.

Mechanical properties of aluminum

The strength, elasticity and elongation of the weld depend on the type of alloy from which the parts are made, as well as on the composition of the electrode. The strength of the welded joint will be quite weak in cold-hardened alloys. To achieve good weld strength in heat-resistant alloys, longer heat treatment times and slow cooling are required.

IMPORTANT! Aluminum has good thermal conductivity, so it is recommended to use heat-dissipating pads when carrying out welding work. This will help preserve the remaining parts of the workpieces from shrinkage and deformation.

Use of alloying components

To improve the quality of the weld, the following alloying additives can be used in aluminum electrodes:

Manganese (Mn) - increases corrosion resistance.
Silicon (Si) - reduces the melting of aluminum, improves fluidity and weldability.
Magnesium (Mg) - gives the metal excellent weldability and good strength. When combined with silicon, it forms a heat-resistant alloy.

Electrodes OK AlMn1 (96.20) containing manganese

Which electrodes are better

A few words about which electrodes are best for welding with aluminum electrodes. For manual arc welding of aluminum structures, consumables from the manufacturer SpetsElectrod of the Ozana-2 brand are often used. Among the advantages of electrodes of this brand:

ensure stable arc burning;
the seam is well formed in any position (including vertical);
slag formations on the working surface are easily separated;
the weld seam has good mechanical properties.

Electrodes from the Swedish manufacturer ESAB of the “OK” series are also widely used. Consumables with alkali-salt coating are optimally suited for welding structures made of technical aluminum, as well as aluminum alloys with manganese or magnesium.

You can read more about choosing electrodes for aluminum welding here.
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Difficulties of the process

Let's look at the complexities of the electrode welding process on aluminum. The difficulty of manual welding of aluminum structures is largely due to the properties of this metal. Below are examples of the main problems that may arise during the welding process.

High metal fluidity . Molten aluminum is difficult to control. With significant overheating, the behavior of the metal becomes somewhat unpredictable. The melt can destroy the layer of solid metal underneath and flow out through the crack. To solve this problem, it is recommended to use ceramic or refractory steel gaskets .
Oxidability of aluminum . The main problem of aluminum products. Combining with oxygen, metal molecules form a dense oxide film. It is stronger than the metal itself and melts only at very high temperatures. Another disadvantage is that the film is a dielectric, so it is difficult to ignite an arc. To solve this problem, you need to thoroughly clean the metal working surface before welding .
High coefficient of linear expansion . Aluminum is quite fragile and has low elasticity. When the metal is very hot, the welding zone puts pressure on the rest of the structure, which can cause cracks or deformation of flat surfaces. To avoid this, you need to control the welding temperature . It’s better to preheat the part to 200-250°C.
When the weld metal hardens, it can crystallize and hot cracks appear . Therefore, it is advisable to add a special filler material. This is especially necessary in cases where several seams are located at a short distance from each other.

Source: https://WeldElec.com/info/kak-pravilno-varit/alyuminiy/elektrodami/

Do-it-yourself aluminum electrodes: how to make, characteristics, features, rules of application

Welding elements made of low-melting metals can be compared in labor intensity to refractory metals. The first and second ones are influenced not only by internal, but also by external factors.

Electrodes for aluminum include various additive materials, which simplifies working with this non-ferrous metal and creates additional protection.

But they are not able to relieve the welder of all the preliminary aspects that must be resolved before starting the welding operation.

Aluminum rods are widely used not only in industrial enterprises, but also in everyday life - a garage, a country house, a small repair shop.

However, using them at home to connect parts with an inverter, you may encounter certain difficulties. And only correctly selected surfacing material and preliminary preparation will help to qualitatively connect the structure.

Technical features of electrodes

The thickness of the parts to be connected is limited by the diameter of the rod, which generally ranges from 4 to 5 mm. Operations with thinner electrodes are fraught with difficulties due to the increased melting rate of the rod.

The latter melts three times faster than steel. Based on this, it is recommended to weld aluminum parts with a thickness of at least 4 mm. The produced length of 3 mm rods is 22-30 cm, 4-5 - 35-45 cm.

The main difficulties that arise during the aluminum welding process are the following factors:

oxide film - formed on the surface of the joined elements, and the first melting temperature is more than three times higher than the melt of aluminum itself - 2,000 ° C;
rapid oxidation of the metal leads to the formation of a refractory film, which complicates the production of a solid seam;
to prevent metal spreading, heat-conducting pads should be used;
the presence of silicon in aluminum alloys promotes the formation of crystallization cracks;
if the operation is accidentally stopped, a layer of slag appears at the end of the electrode and the weld pool, making it difficult to re-ignite the arc;
Due to the high linear expansion rate, the welding bead is deformed during its hardening.

Welding operations with aluminum will require an increase in current strength by 1.5 times compared to other metals.

Performing welding

To ensure a high-quality connection of parts, it is necessary to pre-clean their surfaces from all kinds of contaminants and oxides and prepare the joints. At home, this will be facilitated by various solvents, in production - by alkaline baths.

Among the first to be used are white spirit, technical acetone, xylene and white spirit-based solvents - PC-1, PC-2. The alkaline bath allows the part to remain in the composition for no more than 5 minutes.

You can prepare an alkaline bath yourself, for this you will need:

water - 1 l;
soda ash - 50 g;
technical trisubstituted sodium phosphate - 50 g;
silicate glue - 30 g.

To improve cleaning, the alkaline liquid must be heated to a temperature of 65°. After removing the aluminum workpiece from the bath, you need to clean the ends intended for joining with a metal brush specially designed for this purpose, with fine bristles or a file.

Manual labor can be completely replaced by a grinding machine. After cleaning, the elements should be cleaned again with solvent.

Conductive rods for the welding operation will also require preparation before welding. To obtain a high-quality roller, the electrodes must be kept in an oven for two hours at a temperature of at least 200° C.

The welding operation involves the use of direct current of reverse polarity, with a value of up to 30 A for each millimeter of welding rod diameter. It will improve the quality of the connection by preheating the parts to 300-400°.

The amount of heating is directly proportional to the thickness of the structures being connected. However, if large-sized parts are to be processed, only the ends intended for welding are heated.

The following operations will help ensure a high-quality roller:

the seam is freed from the formed slag crust;
the roller is watered with hot water;
cleaned with a wire brush.

Slow cooling of the weld bead will help prevent warping and crystallization defects during welding.

Electrode selection

When choosing conductive rods for welding aluminum, you need to pay attention to the following aspects:

The composition of the electrode must correspond to the alloy of the elements being connected. Information about the first is indicated by the manufacturer on the packaging and certificate.
The thickness of the consumable material should not exceed the thickness of the workpiece by more than 1 mm. Violating the rule will result in burning through the element.
Welding rods dried more than once reduce the strength of the resulting bead. Welding is performed with carbon, graphite or tungsten electrodes, which is determined by the method of operation.

Kinds

Several types of rods are used for welding operations with aluminum. The main ones are the following groups:

alkaline-salt - OK 96.10, 20, 50, intended for aluminum and its technical category, due to increased hygroscopicity they need protection from humidity;
OZAHA - provide a good indicator of weldability and the resulting bead on different metal alloys, you can weld not only horizontal, but also vertical seams;
OZA - SvA1, 3, 5, 10, for pure aluminum and alloy with silicon;
UAHA - aluminum alloys;
tungsten - using a controlled protective atmosphere.

The main disadvantage of the latter is considered to be difficult arc ignition.

For simple welding operations, aluminum electrodes can be made in-house.

This will require the following supplies:

Aluminum wire ± 30 cm long, 3-4 mm in diameter;
A coating made from crushed chalk and liquid glass.

Apply the paste mixture evenly onto the wire in a layer of 1-2 mm. After drying, the electrode is ready for use.

Source: https://prosvarku.info/elektrody/elektrody-dlya-svarki-alyuminiya