What is rad in welding

Argon arc welding

Electric arc welding in a shielded gas environment is used when it is necessary to isolate the process from interaction with atmospheric air. The most popular and effective is the inert gas argon. The process using it is called argon arc welding or, in common parlance, argon welding.

It is used for welding products made of aluminum, titanium, copper, stainless steels - metals and alloys that actively oxidize or contain elements that are actively oxidized by atmospheric oxygen.

Why is argon used - its comparison with helium

Argon, as already mentioned, is an inert gas. It does not react chemically with anything, which is especially important at temperatures above a thousand degrees Celsius in the welding zone.

Another inert gas, helium, has a similar property. It costs much more than argon, so it is used only in special cases. Argon has a specific gravity 38% greater than air. Due to this, it well insulates the welding site and protects it from oxidation.

Helium under similar conditions requires the supply of gas under high pressure to the high-temperature zone and, accordingly, a higher consumption of protective gas.

Due to the different ionization potential, the voltage of an argon arc is lower than that of a helium arc. Its heat generation is less, which means the penetration zone is smaller and the cross-section of the weld is smaller. Unlike helium welding, argon welding forms a long and narrow finger-shaped seam. At the gas-liquid interface, argon has a higher surface tension. As a result, the seam bead is higher with sharp transitions from the base metal to the seam.

Features of the weld seam in argon arc welding

The greater the angle between the surface of the base metal and the weld, the greater the stress concentration in the welding zone. If the joint has sufficiently high requirements for equal strength, it is necessary to grind off the seam bead after welding

With the correct choice of electrode material or additive, welding mode and method of protection, the weld metal is usually softer than the base metal due to a smaller amount of impurities. To ensure strength, it is required that the “soft” zone be as narrow as possible. Welding is more difficult to perform technologically, but avoids the need to strengthen structural elements at the joint.

There are two main technologies used for argon arc welding: TIG welding and MIG welding.

TIG – non-consumable electrode welding

The arc burns between a refractory tungsten electrode and the workpiece. The filler metal rod is fed into the welding zone manually.

The non-consumable electrode welding process has its own characteristics. It is better to ignite the welding arc with straight polarity, when the electrode is the cathode. It is given a sharp sharpening at an angle of 45 - 55 degrees.

This is necessary to obtain a narrower welding arc and narrow the penetration area. The narrower the zone you need to get, the sharper the sharpening should be. It is not recommended to light an arc on the metal being welded, so as not to melt or contaminate the tip of the electrode.

It is better to perform this operation on an auxiliary carbon (graphite) plate.

The polarity of the process should be selected depending on the metal of the parts being welded:

• Stainless steels are better welded with straight polarity.
• Aluminum and its alloys - on reverse or more often on alternating current. This is due to the fact that when the cathode is a part, refractory oxide films formed on the surface of aluminum are better removed from the welding zone. But when the cathode is a part, instability of the emission spot appears because the combustion zone of the welding arc moves to the cold area. Therefore, not just alternating welding current is needed, but high-voltage pulses during periods when the cathode is located on the part.

The welding torch with a tungsten electrode is held at an angle of about 80° to the seam, back to the direction of movement. Filler rod - in front perpendicular to the electrode.

There must be a gap between the parts being welded. The exception is when the parts lie on a copper or steel substrate. Argon is supplied through a nozzle surrounding the welding electrode.

Unlike the usual zigzag or crescent movements made by a coated electrode, tungsten is carried out in a straight line, without deviating from the seam line. This is necessary so that the area of ​​molten metal does not leave the zone protected by argon. The speed of the welding process should not be high so that argon has time to penetrate through the gap between the parts being joined to the back side of the weld.

It is important to maintain a stable distance between the electrode and the workpiece. This is necessary for constant voltage and heat generation of the welding arc. The size of the penetration area, the shape and quality of the weld directly depend on this.

The process must begin 10 - 15 seconds after the supply of argon, so that the molten metal is guaranteed to be protected from interaction with atmospheric oxygen.

At the end of the process, the welding current should be reduced gradually to avoid the appearance of a crater at the end of the seam.

After the arc goes out, argon must be supplied for another 10–15 seconds until the metal cools below the temperature of active oxidation. If possible, it is better to finish the welding process outside the parts being welded.

Vertical sutures are applied from bottom to top. The nozzle is positioned obliquely to the seam so that the argon jet is directed upward. The filler rod is located above the nozzle. If possible, protective screens should be provided to contain the argon gas at the welding site.

There is automatic welding with a non-consumable electrode. In this embodiment, the filler metal wire is fed into the welding zone automatically, and the arc between the tungsten electrode and the workpiece is ignited by applying a high voltage pulse.

MIG – semi-automatic argon arc welding with consumable electrode

Instead of a tungsten electrode, welding wire is fed through the torch.

In automatic mode, before igniting the welding arc, argon is supplied similar to the process with a non-consumable electrode. Next, voltage is applied to the wire, and the wire itself moves to the area where the seam begins. Contact occurs, the wire heats up, its end breaks off and is energized, and an arc is ignited. The arc length can be adjusted automatically or by self-regulation. Welding is carried out in similar modes.

At the end of the seam, the voltage supply gradually stops, the arc goes out, leaving no crater. After 10–15 seconds, the argon supply stops.

In semi-automatic mode, it is recommended to light the arc outside the welding zone on the auxiliary part, and then move the arc to the beginning of the seam. If this is not possible, first purge the torch with argon and then a live wire into the protected area.

In both cases, the argon arc process requires a room protected from drafts so that the gas protection of the molten metal is not compromised.

To ensure the argon arc welding process, a certain set of welding equipment is required:

Source: https://kabel-house.ru/remont/argonodugovaya-svarka/

Technology of manual argon arc welding with a non-consumable electrode - All about insulation and energy efficiency

Argon arc welding is a modern technology that not only improves the quality of metal connections, but also significantly simplifies working with refractory metals such as titanium, copper and aluminum. Let's talk in more detail about what argon welding is and talk about its advantages and disadvantages.

A special feature of this technology is that welding occurs in an environment of protective inert gas argon.

This improves the quality of the metal connection and provides the highest possible protection against oxidation.

Argon is supplied to the burner under high pressure and, completely blocking the working area, does not allow oxygen to penetrate into the metals being joined, preventing the formation of rust.

If previously this technology was available only to professionals, today, with the advent of relatively simple and universal-to-use welding machines, anyone can perform such work.

Depending on the characteristics of the metals and equipment being connected, two types of electrodes are used: non-consumable and consumable.

Of the non-melting materials, the most widely used technology is the use of tungsten wire, which makes it possible to obtain strong connections between two dissimilar metals.

But consumable electrodes can be used in manual and semi-automatic welding, when metals that are identical or similar in their refractoriness characteristics are joined.

Operating principle of welding equipment

Welding equipment consists of the following elements:

• the welding machine itself, which has an open circuit voltage of at least 60 volts;
• an oscillator that increases the mains voltage to a level of 6,000 volts;
• a power contractor responsible for supplying voltage from the welding machine to the torch;
• ceramic burner;
• devices for blowing the welding zone;
• a cylinder with argon or other inert gas;
• filler wire and non-consumable electrodes.

Manual argon arc welding is not particularly difficult. The metals to be joined are cleaned and prepared, and the operating mode is configured and selected.

Next, the welder lights the torch, after which the gas supply to the immediate welding area begins. The elements to be joined are melted with a gas torch and the electrode or welding wire is carefully dropped into the joint area.

The only caveat is that the supply of protective gas should be turned off approximately 10-15 seconds after turning off the burner.

The following classification of argon arc welding modes will allow you to select the correct electrodes and equipment.

• Automatic, using non-consumable AMA electrodes.
• RAD welding with electrodes with markings for manual work.
• Arc-argon automatic, using consumable electrodes AADP.

How to choose the right mode

The quality of your work depends on the correct choice of electrode thickness and current strength.

Remember: the thicker the metal being connected, the larger the diameter of the tungsten electrodes used, and accordingly, the higher the current.

In the operating instructions that come with the device, you can find all the data on the current strength and diameter of the electrodes, depending on the thickness of the parts being connected.

The most popular today are AMA and RAD welding. But professionals who need to perform a large amount of work use powerful, fully automatic units.

With a long welding arc, a wide seam is formed with a small penetration depth. This may cause the connection to deteriorate. In this case, it is recommended to keep the non-consumable electrode used as close as possible to the joints of the parts being welded.

To make deep and narrow seams, the longitudinal movement of the torch and electrode must be maintained. In this case, lateral movements should be avoided.

The non-consumable electrode and filler wire must be in the welding zone and completely covered with argon. This will protect the weld from exposure to nitrogen and oxygen.

The filler wire is fed evenly and smoothly, since fast and sharp wire feeding will lead to metal spattering, which will affect the quality of the weld.

The presence of a convex or rounded shape in the weld indicates that the connection was not made properly. In this case, surface penetration is not enough.

The filler wire should be fed in front of the torch, while holding it at a slight angle, which will ensure a minimum weld width and excellent metal penetration.

It is not recommended to stop the supply of inert gas immediately after welding is completed, as the anti-corrosion protection of the joint may be affected.

The joints of the parts to be connected should be degreased and cleaned before starting work.

Advantages and disadvantages of this technology

The advantages of RAD technology include the following:

• Argon provides high-quality protection of the seam from oxidation.
• All work is performed at a relatively low temperature, so the welded products retain their shape and size.
• The thermal power of the arc is at a high level, which can significantly reduce operating time.
• The procedure itself is simple, so anyone can learn it.
• It is possible to combine metals with different characteristics.

Among the shortcomings we highlight the following:

• It is recommended to perform this work indoors.
• Certain difficulties may arise with the correct configuration of the equipment.

Source: https://myecoteplo.com/tehnologiya-ruchnoy-argonodugovoy-svarki-neplavyaschimsya-elektrodom/

Argon welding (argon arc) - technology and equipment

[Argon welding] is one of the most popular types of modern welding. Most often, this technology is used in relation to aluminum, as well as products made from it.

Thus, argon welding is considered the optimal method for aluminum. It is well known that the above material is quite capricious both during contact with oxygen and when heated.

In the latter case, its surface tends to be covered with a thin film. The nuance is that argon is characterized by such properties (chemical) that practically eliminate contact with oxygen particles of the heated metal.

This is possible due to the displacement of argon by its oxygen pressure.

Argon welding diagram

In addition, the argon arc welding technique is also used when welding other metals: cast iron and titanium, steel and copper, as well as some others, including silver, gold, etc.

The popularity that argon arc welding enjoys today is easily explained:

• Firstly, it is high quality.
• Secondly, considerable durability.
• The third absolute plus is the availability of machines for welding work.

Let us clarify that when working with reliable equipment, the seam turns out to be virtually invisible.

This feature actually plays an important role not only for the appearance of the resulting product, but, first of all, for its strength.

Argon welding is indispensable when it is necessary to weld difficult-to-join metals.

The value of such a technique lies primarily in experience and quality, as well as in savings. Moreover, the latter is possible in a variety of areas. Not only money is saved, but also effort and nerves, which you will agree is also very important.

Argon welding technology

In everyday life, we can most often find argon welding when repairing the disks of our favorite swallow.

Argon welding of disks, when eliminating small cracks on this part, is simply irreplaceable (of course, performed with professional equipment using innovative high-quality materials).

Argon welding technology has practically nothing in common with such a device as a soldering iron. The main element of the torch is a tungsten electrode. To be clear, tungsten is an extremely refractory metal.

Its melting begins at 3410°C, and boiling at 5900°C. The uniqueness of this metal is that even when red-hot, it is also hard. When welding, tungsten requires a negligible amount (hundredths of a gram per 1 meter of weld).

If we consider in this aspect tungsten electrodes, which are doped with oxides of rare earth elements, then they are even more durable.

Today, the market offers tungsten electrodes with a wide range of chemical compositions.

For example, it is no secret that various oxides of rare earth metals are added to pure tungsten in order to improve welding technology and welding characteristics.

It can be cerium, lanthanum, yttrium, thorium, and zirconium. Whatever electrode is chosen, it is usually surrounded by a ceramic nozzle, and argon (an inert gas) is blown out of it during welding.

Let us clarify that the first attempts to weld aluminum without argon ended with the metal starting to burn, becoming covered with oxidation, and the electric arc was immediately interrupted.

What were the inventors able to achieve, and what does argon welding of aluminum represent today?

A simplified process looks like this. First, “mass” is supplied to the part using special equipment (welding machine), just as with conventional electric welding.

IMPORTANT TO KNOW: Argon welding technology in video tutorials

Argon arc welding with a non-consumable electrode occurs in the following way: the “mass” is supplied to the part being welded, similar to conventional electric welding.

The welder, if manual argon arc welding is meant, holds a torch in his right hand and a wire (additive) in his left hand.

Argon welding process - diagram

When welding aluminum, naturally, an aluminum analogue or special alloys are used. The burner is turned on by pressing a button, then current and gas are supplied.

An electric arc occurs between the tip of the electrode (non-consumable) and the workpiece. It plays the role of the main tool, and melts the part, and the filler wire.

Actually, it melts both the edge of the required part and the filler wire, thereby forming a welding seam. In fact, after finishing the work, the 2 halves of the part turn into one whole.

How argon welding works is clear and, at first glance, there is nothing complicated about it. The technology has long been adopted, and its effectiveness has long been proven. But this is only at first glance.

Carrying out argon welding requires an experienced welder and a reliable machine with both good performance and excellent characteristics.

It will also take a lot of time to get better at this matter.

When welding in protective gases by fusion, a powerful electric arc is used as the main tool.

Electricity in the arc is converted into heat. In atmospheric conditions, the welding zone must be reliably protected from saturation of the weld metal with nitrogen and atmospheric oxygen.

lesson:

Shielding gases, which are supplied through the nozzle, displace air and thus protect the weld pool and electrode.

Filling the gap between the edges to be joined (when cutting the edges) into the melting zone is carried out by an additive for argon welding or electrode wire.

The operating principle of argon welding with a non-consumable tungsten electrode in shielding gas.

It is this that prevents aluminum from burning. The welding site is protected by argon.

Argon welding is a hybrid of electric and [gas] welding. From the first one she received an electric arc, and from the gas one she received a similar welding technique.

Next, we will consider what equipment and welding machines are required by GOST argon arc welding.

Equipment and welding machines

GOST number 5.917-71 suggests the production of torches of the RGA-150 type with a weight of 0.35 kg for the highest welding current of 200A with natural cooling for analogues with a width of 0.8-3.0 mm for argon welding with a non-consumable electrode.

It also involves the production of RGA-400 torches for the highest welding current of 500A with a weight of 0.625 kg with water cooling for electrodes with a width of 4.0-6.0 mm. There are also requirements for ceramic nozzles for such welding.

Let us recall that the ceramic nozzle for argon arc welding is the so-called consumable part of the torch, which is responsible for the quality of the gas protection process (local).

There are different types of nozzles based on their shape: cylindrical, conical, and profiled. It is no secret that the larger the ceramic nozzle, the better protection it can provide.

Typically, when working indoors, cylindrical or conical analogues are used, but when working outdoors, profiled or cylindrical models of nozzles with a larger hole (outlet) diameter are used.

Note that elongated nozzles are used, as a rule, in hard-to-reach places.

Types of equipment

Let us clarify that argon welding, depending on the level of mechanization, is divided into several types:

• manual;
• mechanized;
• automated;
• robotic.

IMPORTANT TO KNOW: Methods and methods of welding aluminum

Accordingly, the equipment for argon welding and, of course, the cost of argon welding will be different.

[Types of equipment by type:]

In manual welding, the torch for argon arc welding is moved, and the welding wire is supplied by the welder himself, and welding work is carried out using tungsten electrodes (non-consumable).

In the mechanized form, the welder holds the torch, but the wire - filler rods for argon-arc welding - are fed mechanized.

In the automated form, both the movement of the torch and the wire feed are completely mechanized. Here there is no longer a welder, but an operator.

The latter is not needed if robotic equipment is used for argon arc welding

Welders

Let's consider equipment, or rather welding machines for argon-arc welding, which are used when performing work in inert gases.

They are divided into:

• special;
• universal;
• specialized equipment.

If we consider a universal welding machine for argon welding, then it is mass-produced and is most in demand by consumers.

Inverter welding machine for argon welding

In most cases, such welding is performed in production conditions at specially equipped workplaces called “welding stations.”

Installations using a tungsten non-consumable electrode in an argon environment are equipped with the following elements:

• current source - direct/alternating;
• a burner or a set of the latter, designed to work with different currents;
• a device that provides initial excitation of the arc or stabilizes the arc of current (alternating);
• equipment that controls the welding cycle, as well as its protection;
• a device for compensating or regulating the direct current component.

Today, new methods of argon welding are known, which were created with the aim of expanding the range of thicknesses of materials being welded, increasing productivity in obtaining permanent joints, as well as improving penetration.

Nowadays, pulsating current work is considered innovative. During a current pulse, the metal melts, crystallizing during a pause.

The arc moves at a constant speed or in steps, and these movements are synchronized with current pulses (welding).

At the same time, effective penetration is ensured in all (spatial) positions without exception, and insensitivity to small defects that are acceptable during assembly.

This reduction in current prevents overheating of the metal, and therefore deformation is ultimately virtually eliminated.

Heating of the wire (filler) is also used. Let us clarify that this technique significantly affects productivity and therefore buying an argon welding machine that uses such an improvement is the dream of many.

A fairly effective way to obtain seams without undercutting at high speeds of metal welding is the simultaneous use of several tungsten electrodes.

Nothing special is needed to implement these types of process. All that is required is standard equipment for argon welding and so-called additional blocks.

Source: https://rezhemmetall.ru/argonnaya-svarka-argonodugovaya-texnologiya-i-oborudovanie.html

Technology of manual argon arc welding with non-consumable electrode

Argon welding is a technology that is very popular at the moment.
This is due to its availability, as well as the ability to work with high and low alloy steels and non-ferrous metals. If there is a need to weld a critical structure or difficult-to-cut metals, such as aluminum or titanium, then you cannot do without argon welding. Advantages of argon arc welding:

• High-quality seam;
• Durability of connections;
• Availability;
• Reasonable cost of work;
• Aesthetic appearance of the seam.

What is argon arc welding

Argon-arc welding is a welding method applicable for welding metals using an electric arc and gas (argon). An electric arc melts the metal of the part being welded, as well as the filler rod, forming a seam.

Argon is an inert gas that plays the role of an insulator, preventing the entry of oxygen and other gases that interact with the weld pool.

When oxygen enters the place where metals are welded, it causes severe oxidation, affecting the quality of the weld, and some metals can even ignite from such a reaction.

Due to its inertness, argon itself does not react and does not allow oxygen to react with the metal in the weld pool, which is why the gas is supplied before the arc is ignited and continues to be supplied for some time after welding is completed.

Argon welding is carried out by two types of electrodes: consumable and non-consumable.

1. The melting electrodes cause the arc to ignite and at the same time act as solder. There is an extensive classification of such wire, divided by size and composition.
2. Non-consumable electrodes are made of the most refractory metal - tungsten. When the device is operating, the electrode provokes the ignition of an arc, the temperature of which is 2000 degrees, and tungsten itself begins to melt at 3600 degrees or more. Such a rod is needed solely for igniting the arc and maintaining it; the filler metal is supplied manually. Non-consumable electrodes are divided according to thickness, length and composition of the alloy suitable for a particular metal and welding method.

Variety of welding technologies

1. TIG - tungsten electrode welding with manual supply of additives;
2. MIG is a mechanized argon arc welding system with a consumable electrode supplied automatically.

There are other varieties, but they are designed for working with high-precision products and industrial work. We’ll talk about what argon welding technology looks like, applicable at home.

Both devices have the main advantage - ease of operation, and every novice welder will be happy with them. In this article we will take a closer look at the first method.

Equipment for argon arc welding with non-consumable electrode

Manual argon arc welding with a non-consumable electrode requires the presence of special equipment, consisting of a power source, a gas installation, if necessary, a wire feeder and a number of other systems.

Each system has its own purpose and its own characteristics, so to carry out quality work you will need:

• argon arc welding voltage source – separated by transformers and inverters. The latter are more convenient to use and versatile; they are a source of direct and alternating current. The inverter can be used in almost any environment in an apartment, country house or garage. Inverters operate from a three-phase network and conventional 220V. It is best that argon welding is universal and insensitive to voltage changes.
• the torch is the main working element, the design of which may vary depending on the chosen welding technique. There are burners for consumable electrodes and tungsten rods. The use of argon welding with wire feed requires the presence of a special torch.
• nozzle - the tip of the torch, which regulates the accuracy of the protective gas supply and a number of other parameters. Since this element works in close proximity to the weld pool, it is exposed to high temperatures. The optimal material for the nozzle is ceramic.
• oscillator – a system for igniting arcs without contact with the surface being welded.
• gas cylinder with reducer. The volume of the gas container directly affects the frequency of refueling and, accordingly, the time off from work. Reducer – regulates the flow of argon during welding.
• additional accessories. This includes basic personal protective equipment, which is essential when working with tig argon arc welding. Also, the accessories include a welding table. This element greatly facilitates the welder’s work. After all, it allows you to rigidly fix the parts being welded, is equipped with a gas exhaust system, and good lighting. The right welding table will protect your workshop from fires caused by splashing sparks.

Consumables

When welding with a tungsten electrode, special filler rods are used to fill the welded joint

Material intended for use in installations with automatic supply of welding material. Like rods, they are divided into groups according to their composition, applicable to different types of steel, and have different thicknesses.

The main consumable material is gas, or rather a gas mixture. Due to its high cost, pure argon is rarely used; welders often use a mixture of argon and carbon dioxide or helium. The gas, as well as the thickness of the wire, and its composition are selected based on the type of metal and its thickness.

Hoses, fittings

If all the work is carried out permanently, then the set of hoses and connections should be enough for a long period, but given the specifics of the work, these elements often wear out and require replacement. During field work, hoses are one of the first consumables. They tear, get burned, very often you need to add length, and so on.

Features of welding with a tungsten electrode

Argon welding with non-consumable and consumable electrodes until recently implied a certain education of the welder. Without the knowledge acquired in educational institutions or special courses, it was very difficult to independently carry out welding work.

But, with the development of technology and the introduction of systems useful to users, argon arc welding technology has become available to the masses. Considering the prevalence of this equipment, it can easily be counted among the rest of the household appliances that are found in almost every garage.

But if welding in argon is so simple, then how to weld with argon?

This welding method differs from the usual for most inverters with electrodes in the use of gas, the principle is the same as that of a protective coating, but this is only at first glance. In fact, the welding method has a number of features and nuances, not complicated, but necessary:

1. If we work with a tungsten electrode, then it is located as close to the metal as possible, but does not touch the steel. An oscillator or special materials are used to ignite the arc.
2. The distance between the electrode and the metal must be constant. Otherwise, the arc may begin to jump, penetration decreases, or metal burning begins. The area of ​​action of the shielding gas also changes, which can lead to oxidation of the weld.

A very important point is the direction of movement. Unlike working with electrodes, there is no need to oscillate. The burner moves smoothly along the seam.

Tig welding modes

1. The welding method involves protecting the seam from oxygen using an inert gas - argon. Therefore, the welder must ensure that the weld pool does not escape from the gas cloud. It is forbidden to start welding before the gas has been turned on. After finishing the work, the burner is held in the last position, and gas is supplied for another 5 - 15 seconds. For better effect, argon is supplied from both sides of the connection.
2. The wire feed speed should be constant; it is worth avoiding jerky feeding of solder. If the wire is fed automatically, then the optimal parameters can be found in special tables. When feeding solder manually, everything depends on the welder himself. The rod must be fed at the correct angle, in front of the torch and strictly in the direction of movement of the seam.
3. Gas consumption is a constant value prescribed in GOSTs. There you can find the optimal balance between argon and other impurities.
4. Setting the current is one of the most difficult points, after working with the burner. This is especially true for novice welders. The main idea is that you should not adjust argon arc welding modes manually without experience. To properly configure the device, you need to resort to standard schemes. To do this, you need to know the thickness of the steel and its composition. The table fully presents current settings, voltage, current type, polarity and other parameters.

Attention! For each type of metal being welded, the equipment settings will be different.

How to cook using argon arc welding

The successful application of argon arc welding technology lies in three things:

• The first is the correct settings of the entire system. Unlike electrode welding, where it is enough to select the current strength, here we will need to carefully study the capabilities of our system, the part to be welded and select the recommended settings.
• The second point of success is the steady hand of the welder. Even if we set everything up correctly, but did not maintain the distance from the electrode to the workpiece or did not feed the rod correctly, we cannot count on a high-quality seam.
• The third pillar of success is the workplace. Here we can sit comfortably on our own, firmly fix the workpiece, place all the necessary consumables nearby, ensure good ventilation, while avoiding drafts. Drafts or strong gusts of wind are the only thing other than the welder himself that can impair the quality of the work.

Argon welding technology looks like this:

1. We select the material for solder;
2. Install a suitable electrode and nozzle;
3. We configure the device according to the table values;
4. Adjusting the gas supply speed on the reducer;
5. We set the gas supply delay;
6. We press the trigger, gas is supplied, but the arc does not ignite
7. The arc is ignited, we bring the solder and lead it to the burner strictly along the seam;
8. Turn off the trigger and hold the burner until the gas supply stops.

Read more: Why are water pipes humming and is it possible to eliminate the noise?

Useful tips

• If you supply gas from the other side of the seam, this will increase its consumption, but also improve the quality of work
• The oscillator makes it easy to start the arc, and the rheostat helps you finish the seam.
• To reduce the cost of the weld, it is worth using a mixture of argon with other gases.
• The success of working with an argon welding torch using the technology described above lies in constant practice.

Conclusion

Manual argon arc welding is becoming more accessible and cheaper. Today, for the cost of expensive inverters for working with electrodes, you can buy a TIG or MIG welding starter kit.

But keep in mind that the purchased manual argon arc welding is only part of the cost, because for the work you need to constantly buy expensive rods and gas, so for infrequent use the purchase may lose its meaning.

The value of argon welding and technology is that due to the experience of the welder and the quality offered by argon welding, it is possible to obtain a joint that is exceptionally strong and beautiful in appearance.

Source: https://otoplenie-doma54.ru/dom/argonodugovaya-svarka-neplavyashhimsya-elektrodom.html

Operating principle of argon welding

Argon arc welding is a modern technology that not only improves the quality of metal connections, but also significantly simplifies working with refractory metals such as titanium, copper and aluminum. Let's talk in more detail about what argon welding is and talk about its advantages and disadvantages.

A special feature of this technology is that welding occurs in an environment of protective inert gas argon. This improves the quality of the metal connection and provides the highest possible protection against oxidation. Argon is supplied to the burner under high pressure and, completely blocking the working area, does not allow oxygen to penetrate into the metals being joined, preventing the formation of rust.

If previously this technology was available only to professionals, today, with the advent of relatively simple and universal-to-use welding machines, anyone can perform such work.

Depending on the characteristics of the metals and equipment being connected, two types of electrodes are used: non-consumable and consumable.

Of the non-melting materials, the most widely used technology is the use of tungsten wire, which makes it possible to obtain strong connections between two dissimilar metals. But consumable electrodes can be used in manual and semi-automatic welding, when metals that are identical or similar in their refractoriness characteristics are joined.

Classification of argon arc welding modes

The following classification of argon arc welding modes will allow you to select the correct electrodes and equipment.

• Automatic, using non-consumable AMA electrodes.
• RAD welding with electrodes with markings for manual work.
• Arc-argon automatic, using consumable electrodes AADP.

Recommendations

With a long welding arc, a wide seam is formed with a small penetration depth. This may cause the connection to deteriorate. In this case, it is recommended to keep the non-consumable electrode used as close as possible to the joints of the parts being welded.

To make deep and narrow seams, the longitudinal movement of the torch and electrode must be maintained. In this case, lateral movements should be avoided.

The non-consumable electrode and filler wire must be in the welding zone and completely covered with argon. This will protect the weld from exposure to nitrogen and oxygen.

The filler wire is fed evenly and smoothly, since fast and sharp wire feeding will lead to metal spattering, which will affect the quality of the weld.

The presence of a convex or rounded shape in the weld indicates that the connection was not made properly. In this case, surface penetration is not enough.

The filler wire should be fed in front of the torch, while holding it at a slight angle, which will ensure a minimum weld width and excellent metal penetration.

It is not recommended to stop the supply of inert gas immediately after welding is completed, as the anti-corrosion protection of the joint may be affected.

The joints of the parts to be connected should be degreased and cleaned before starting work.

Argon arc welding - what is it?

You are probably familiar with the problem of high-quality welding of special types of metal, such as aluminum, copper or non-ferrous metals. With standard electric welding using electrodes, you will not be able to weld a reliable seam, this is due to the characteristics of the metal and its properties. In such cases, experienced craftsmen are looking for another welding method, and welding in an argon environment comes to their rescue.

What is argon welding and what is the principle of operation? What are the pros and cons of this welding method and how to properly weld metal with argon? In this article we will answer all your questions.

general information

Argon-arc welding - what is it? How does argon welding work? This is essentially the same welding as all the others, the only difference is that the process takes place in an argon environment. Argon is a gas stream that is directed into the welding zone during welding.

Below you can see a diagram of welding using argon. Argon, like any other gas, performs a protective function during welding: it prevents metal oxidation, improves the quality of the weld and speeds up work.

Argon for welding, directed into the welding zone, forms a kind of “Dome”, preventing oxygen from negatively affecting the quality of the seam.

Various special metals, such as titanium, can be welded using argon welding. In this work, you can use consumable and non-consumable electrodes and tungsten wire. Tungsten wire is often used when welding dissimilar metals. Welding is carried out both manually and automatically.

Manual argon welding (RAD welding) is the most common and inexpensive type of argon welding. If RAD welding is selected, it is advisable to use a non-consumable electrode.

There is automatic argon welding using a consumable and non-consumable electrode (labeled AADP and AAD, respectively). We will not claim that manual welding is better than automatic welding or vice versa.

Ultimately, each welder decides for himself which method is preferable for him when performing certain jobs.

Equipment

Several types of welding equipment are used for argon welding. This can be a manual method, when the master holds the torch with his own hands and feeds the wire into the welding zone, or an improved manual method, when the wire is fed using a special device.

There is also equipment with which automatic argon arc welding is carried out. The torch and wire are fed into the welding zone automatically; sometimes the welder does not even need to monitor this process; he can be replaced by a special operator. Expensive industries can use robotic equipment that does not require human presence. A program is pre-loaded into the machine, according to which the robot performs welding.

Now let's get down to business. We will tell you how to weld with argon welding so that the work turns out to be of high quality and durable.

How to cook in argon

What is needed for proper welding? Of course, a little theory and a lot of practice. We will tell you the theory, but you will have to do the practice yourself. The more you practice, the faster you can start doing serious work. In the meantime, let's find out what the technology of argon arc welding is and what needs to be taken into account so as not to make mistakes.

First of all, you need to thoroughly clean and degrease the joints of the parts to be welded. Even if there is visually no dirt or corrosion, you still need to clean the metal surface. While working, try to shorten the length of the welding arc. The fact is that a long arc forms a wide, shallow seam. The quality of this connection leaves much to be desired.

Therefore, when working with a non-consumable electrode, try to make the arc as short as possible, bringing the rod closer to the metal surface. But this may not be enough to make the seam narrow and deep. Move the electrode longitudinally without deviating to the side or performing transverse movements. It is for this reason that the welder must have a “steady hand” when welding with argon, otherwise the slightest deviation can lead to deterioration in the quality of the welded joint.

The filler wire and electrode should only be placed in the welding area. If you constantly move the rod or wire to the side, you will break the protective properties of argon and oxygen will penetrate into the weld pool. The wire should be fed smoothly and evenly, avoiding sudden feeding. Otherwise, the metal will spatter heavily and deteriorate the quality of the weld.

At first, many craftsmen (especially beginners) find it difficult to understand at what speed to feed the wire. Unfortunately, there is no single norm that will solve this problem. Everything is learned with experience, so experiment. The additive wire must be fed at an angle and in front of the rod. These requirements are mandatory. Failure to comply with them leads to the formation of an uneven seam and complicates the welding process.

It is also not recommended to abruptly start or end the welding process, since unnecessary oxygen is guaranteed to enter the welding zone. We recommend feeding argon welding gas into the welding zone for 20 seconds before starting work.

If you plan to finish welding, first remove the wire, then turn off the torch. This process should take about 10 seconds. Also, when finishing welding, reduce the amperage.

If you don't do this and simply remove the wire and torch, oxygen will enter the welding area.

Source: https://crast.ru/instrumenty/argonno-dugovaja-svarka-chto-jeto-takoe

Argon welding

There is a fairly extensive list of metals for which welding in a normal atmosphere is not applicable. Due to the high chemical activity of these metals and alloys in a heated and liquid state, they interact with atmospheric oxygen and oxidize, losing their physical properties.

Aluminum alloysStainless steelsHigh alloy steelFerrotitaniumRed copper sheets

Such substances include stainless and high-alloy steel, non-ferrous and rare metals such as titanium, copper, aluminum. For their high-quality welding, a technology was developed for welding in a protective atmosphere of inert gas, which prevents contact of the weld pool with atmospheric oxygen. Argon is most often used as such gas.

Manual arc welding in argon environment

The technology of welding in an argon environment is complex compared to conventional welding, but it makes it possible to weld metals that are almost impossible to connect using any other method.

Argon welding technology

The basic principle of operation is that welding is performed using an electric arc method in a protective gas atmosphere.

Argon welding

Most non-ferrous metals, stainless steel and high-alloy steel differ from ferrous metals in that when heated they exhibit high chemical activity and interact with atmospheric oxygen, forming oxides and losing useful additives.

This significantly worsens both the properties of the weld itself and the metal in the heat-affected area. The weld becomes weak, and the alloys lose their properties due to alloying additives. The situation is even worse with aluminum and some other light metals - they ignite.

To avoid these unpleasant consequences, welding is carried out in an atmosphere of inert gas - argon, which prevents the interaction of heated metal with atmospheric oxygen. The density of argon is almost one and a half times greater than the density of air, so the inert gas replaces the air in the work area and protects it.

Argon welding can be performed with both fusible and non-fusible electrodes, usually tungsten.

Tig welding technology involves three main methods:

• MMA (RAD) manual, tungsten electrode
• MIG/MAG (AMA) automatic, infusible electrode
• TIG (AADP) – also automatic, fusible electrode

Features of argon welding

Argon welding differs from conventional welding in several ways. The main working tool in the hardware complex is the burner. A tungsten electrode is fixed in the center, and gas flows through a nozzle.

The electric arc heats and melts the metal in the working area, the filler wire, melting, provides material for the weld. The composition of this wire must be selected so that it is as close as possible to the composition of the metals being welded.

The technological process consists of the following stages:

• Mechanical or chemical (and in case of heavy contamination - both) cleaning of welded surfaces and heat-affected zones. It is necessary to clean the surface of a lot of mechanical impurities, oil stains and oxide films.
• The ground wire from the machine is connected to the workpieces being welded. It should be noted that the filler wire is not included in the electrical circuit.
• Depending on the thickness of the parts being welded, the operating current is selected and set at the current source.
• 10-25 seconds before ignition of the arc, gas is supplied to the working area by opening the valve on the cylinder. It is important to remember that you can turn off the gas supply only 5-15 seconds after finishing the next seam.

Argon welding process

• A torch with an electrode protruding 2-5 mm should be brought to the start of the seam, as close as possible to the parts, but without touching them. The best gap at which a neat and reliable seam is obtained is approximately two millimeters.
• The filler wire should be held in front of the torch and moved smoothly along the weld line together. It is very important to insert the wire into the work area carefully and smoothly to avoid metal spatter.
• The arc is ignited without contact between the electrode and the workpiece. To do this, an oscillator is added to the circuit, generating powerful pulses with a voltage of 2 to 6 kilovolts and a frequency of up to 500 kilohertz. These pulses carry out electrical breakdown of the gas layer between the electrode and the mass.

To obtain a reliable seam, you need to choose the right argon welding modes. The key parameters are:

• Alternating or direct current.
• Welding voltage polarity.
• Operating current value.
• Argon supply rate.

Thus, alternating current is used to connect light metals, such as magnesium or aluminum. Repeated reversal of polarity destroys the film of oxides that constantly covers their surface.

Selecting a mode for argon arc welding

The role of the oscillator is not limited to the initial ignition of the arc. When working with alternating current, in order to avoid attenuation of the electric arc at the moment of polarity change, it continues to send high-frequency pulses into the welding circuit.

The operating current is determined based on several parameters:

• The metal or pair of metals being welded.
• Thickness and dimensions of parts.
• Electrode thickness.

To facilitate this choice, there are special reference tables in the professional literature and in the welding machine user manual.

The argon supply rate is set based on the following factors:

• Welding speed and filler wire feed.
• The speed of movement of air masses in the work area.

Gas consumption at direct and alternating current

If there are drafts or welding in the open air, it will be necessary to compensate for the carried argon by increasing the supply. In case of strong gusts of wind, special nozzles with mesh meshes are used to supply argon.

In addition, when working outdoors or in cases where it is not possible to completely clean the surface of the workpiece from contaminants, a small proportion of oxygen (up to 5%) is included in the working mixture to burn out impurities or turn them into slag. This principle is not applicable when working with copper, since as a result of a chain of chemical reactions the seam becomes porous and fragile.

Advantages and disadvantages

The obvious advantages of the method include:

• High quality and durable seam
• The low degree of heating of the workpieces makes it possible to weld structures of complex shapes without deformation.
• The ability to weld materials that are chemically active when heated, which can be difficult or impossible to join in other ways.
• Increased operating speed due to high arc temperature.

In addition to the listed advantages, the method also has disadvantages:

• Complexity of the hardware complex and its settings
• High requirements for welder qualifications and skills

The disadvantages of this technology are:

• use of complex welding equipment;
• the need for special knowledge and sufficient experience in performing such work.

Argon arc welding makes it possible to make strong and durable seams, characterized by high uniformity of penetration of the welded workpieces. It allows you to weld both thin-walled and thick-walled structures made of non-ferrous metals in various combinations.

The use of argon welding allows us to obtain high-quality and reliable welded joints, characterized by uniform penetration of the parts being connected. Using argon arc welding with a consumable electrode, it is possible to weld parts made of non-ferrous metals of small thickness even without the use of filler wire.

Types of welding equipment

Several types of equipment are used for argon welding:

• Manual process - the welder holds the torch and filler material.
• Semi-automatic process - filler material and gas are supplied automatically to the torch, which the master guides along the seam manually.
• A completely mechanized process - there is no person in the work area, the supply of filler material and the operation of the burner are carried out by the operator remotely.
• Robotic process - the operator only enters the program, and the CNC system executes it.

The great advantage of the method is the ability to join materials that are difficult to weld with other methods.

This could be dissimilar metals in production, or a pipe joint in a home heating system.

Argon grades used in welding

State Standard 10157-79 defines three grades of argon for use in welding:

• A - contains 99.99% argon, used for working with chemically active and rare metals, such as titanium or zirconium, and for final welding of particularly important structures.
• B - contains 99.96% argon, used for working with aluminum and magnesium alloys and other materials exposed to gases soluble in the metal.
• B - contains 99.90% argon, used for working on stainless steel, alloyed high-strength and heat-resistant steels, as well as pure aluminum.

Technical characteristics of argon for welding

All argon produced by industry is certified according to one of three grades.

Do-it-yourself welding work

It is quite possible for a home craftsman who has sufficient knowledge and skills in the field of electrical engineering, welding and plumbing to independently assemble a hardware complex for manual argon arc welding.

To do this you will need:

• Transformer with ammeter to monitor operating current.
• A switch, or contactor, that supplies voltage to the electrode.
• An oscillator with an inductive-capacitive filter and a relay for turning it on.
• Argon supply regulator.
• Argon burner.
• Cylinder, reducer and gas hose.
• Tungsten electrodes of various diameters.

Source: https://stankiexpert.ru/spravochnik/svarka/svarka-argonom.html

Features of the technology and operating principle of argon arc welding

Inert gases protect permanent joints of steel alloys at the weld creation stage. For non-ferrous metals, argon-arc welding is a reliable joining method. Especially such capricious materials as aluminum and refractory titanium.

Features and principles

Argon welding technology combines the techniques of gas and arc welding. The difference is the non-participation of argon in combustion and melting . Cutting off atmospheric gases with argon as a zoning element from the metallurgical melting site eliminates oxidation of the melt, combustion in an oxygen environment, and eliminates porosity of seam joints.

Argon welding is carried out in 4 classical ways:

• Manual mode with a non-consumable tungsten electrode with filler wire supply - RAD .
• Automated - the burner is fed automatically by the caliper to the welded edges, the electrode is non-consumable - AMA .
• Automatic welding with consumable electrode (wire) - AADP .
• Mechanized consumable electrode welding - MAWP .

Surface deposition of a metal base, classification:

• Automated surfacing: tungsten electrode and additive - AADN .
• Automatic surfacing with consumable electrode - AADPN .
• Mechanized surfacing with fusible electrode – MADPN .

Effect of pure gases on TIG, MAG

The intensity of the process, when refining the conditions for creating a seam: depth, shape, influence of smoke formation, rate of melt deposition, productivity is regulated by an artificial protective environment. The impact on the arc is twofold: the impact is both positive and negative.

Argon (Ar)

The inertness of argon neutralizes the involvement of the atmosphere in oxidative processes . Suppresses the chemical activity of metals. Low thermal conductivity slows down heat transfer to the environment.

A narrow arc column is formed. Accordingly, the penetration profile is V-shaped: deep and narrowed. The tendency for the seam to be convex and undercut at the boundary lines is a consequence of limiting heat transfer to the outer edges. Argon consumption during welding is 7–8 l/min.

The weight of monatomic Ar is greater than that of air, this keeps the cloud in the welding zone. The polarity is predominantly straight - at reverse polarity, the gas generates a flow of current-conducting electrons akin to plasma. In MAG, pure Ar promotes metal jet transport .

Helium (He)

Light helium is the exact opposite of lazy argon. The penetration profile is wide, due to greater heat input, the arc temperature is higher as the current decreases. Without high-frequency excitation, arc ignition is difficult. Successfully used in welding dissimilar metals .

The atomic weight forces the output operating pressure and flow rate of He versus Ar to be increased by 2.5 times: up to 25 l, except for ceiling joints. The cost of unpurified helium is 4 times higher than argon, purified – 8 times. The electrode material in a pure He environment is transferred in large droplets. In a mixture, helium and argon exhibit better properties .

Technology and equipment

The welding process technology is implemented by Tungsten Inert Gas (TIG) machines with mating metal thicknesses of over 2 mm using a consumable electrode in semi-automatic mode. Or a tungsten electrode for thin materials with filler wire - RAD welding.

Equipping the welding station with main and auxiliary equipment:

• Network energy stabilizing device.
• Semiautomatic inverter type, transformer with no-load power interval 60–70 V.
• Power supply voltage contactor.
• Exciter of high-frequency pulses of oscillatory type to overcome ionization and excite the arc without contact with the surface.
• Set of different types of ceramic burners.
• Tungsten electrodes or additive supply mechanism.
• Gas cylinder equipment with reducing devices.
• Individual protection means.

What is argon arc welding in terms of technology recommendations:

• Holding a short arc to form a narrow weld with deep penetration.
• Straightness of the burner feed along the axis of the seam without transverse movement deviations.
• An external sign of lack of fusion is that the convexity of the seam turns into roundness.
• The filler wire is fed towards the movement of the torch evenly, at an angle for easy control of seam formation.
• Butt welds and flanging of small thickness metals are carried out without the use of additives.

Argon welding is sensitive to contamination and oxide deposits.

Tungsten electrodes

Tolerance to ultra-high temperatures up to 30,000 C while maintaining tip shape and hardness is enhanced by sputtering with rare earth metal oxides. The marking indicates the chemical composition and the size of the rod.

Products of domestic industry do not always coincide with global requirements. International symbols are standardized, generalized, and include alphabetic, digital and color designations:

• W – initial marking symbol, denotes the dominant metal tungsten,
• WP – base without additives, signal color green,
• The second letter means the addition of ligatures per 1000 parts of the base (0.1%),
• Long electrode size (50–175 mm),
• WC – universal electrodes for both types of current,

Purpose of additives:

• Thorium dioxide (WT) - used for non-ferrous alloys, stainless steel, low-alloy carbon steels, the most popular grade on the list, characterized by increased strength,
• Yttrium dioxide (WY) – maximum current values ​​with straight polarity: titanium, copper, argon welding of ferrous metals,
• Zirconium oxide (WZ) – arc stability at alternating current: copper, aluminum, sensitivity to surface cleanliness,
• Lanthanum oxide (WL) - acts in two subcategories with 1.5 and 2% impurity content; the strength characteristics of the rod and sharpening geometry are maintained at high energy costs at alternating and direct current.

Electrode shaping

Surfacing electrodes with impurities of rare earth metals, depending on the purpose and size of the melting front, are produced in sizes Ø 1–6.4, and have improved properties in terms of:

• conductivity,
• arc formation and arc maintenance,
• refractoriness,
• maintaining a given form.

The configuration of the working end in the form of a sphere, a cone with an angle of 15–1200 affects the quality of the connection when the thickness of the parts changes:

• obtuse angle is beneficial for thin-sheet workpieces, inconvenient for thick sheets,
• sharpness helps to increase labor productivity,
• best arc stability at 600.

The forming method is important: when sharpening by hand, the transverse removal of metal decentralizes the arc . The intensity of the penetration is concentrated along the side edges. The center lacks heat, the uniformity of the seam is disrupted.

Typical sharpening mistakes:

• An excessively sharp angle is an activation of melting, characteristic exclusively for strengthening the connection of thick-walled parts.
• The degree of penetration is the lowest, when the angle is around 150, the sharp-angled electrode burns out faster.
• Sharpening affects the width of the penetration; if the indicator goes beyond the width of the application, it leads to unplanned consumption of the additive and time.
• Asymmetry of the sharpening angle and other defects lead to uncontrolled displacement and wandering of the arc.

Burner

The burner holds the W-electrode and is a conductor of argon. Tool certification is carried out in accordance with GOST 5.917-71 . The nozzles are divided according to the maximum current and the type of cooling.

Burners up to 200 A are air-cooled, collet chucks are designed for a maximum Ø 3. Powerful ones are cooled by running water. Collets clamp inserts up to Ø 6. Current reaches 500 A.

A torch with a consumable electrode works on the same principle: an arc is supplied between the product and the wire. There is no need for a collet. A narrow thermal effect zone and mechanization of the process when welding aluminum and stainless steel are advantageous .

Using an inverter

The selection of an inverter for operation in an argon environment is determined by the tasks and the material of the welding units. The basic selection element is the maximum current value . The reference point is the tabular values ​​of the grade and thickness of the alloy.

The flexibility and adaptability of inverters turn installations into universal equipment. But the presence of the desired functional settings simplifies the work even for an inexperienced welder:

• Switching from direct current to alternating current is designated TIG AC DC; without this function you will have to refuse to weld aluminum.
• The addition of manual MMA mode, semi-automatic MIG, MAG to TIG expands the range of work to infinity.
• An oscillator that provides non-contact ignition of an arc by increasing the voltage by 10–30 times and the frequency by 30 thousand times.
• Control of the rise and fall of the ampere characteristic.
• Anti-stick electrode and hot start.

Procedures for preparing and carrying out work

Contaminants and traces of rust are removed from the joining surfaces, and degreasing is carried out. Aluminum undergoes mandatory mechanical treatment to destroy the oxide film .

The supply of gas protection is adjusted with a lead time of 10 seconds. before ignition of the arc and a delay in turning off the gas flow at the end of the cycle to protect the seam against oxidative reactions. The electrode is held close to the workpiece without contact. A short arc is the key to quality.

During 10-minute cycles, in accordance with the rated duration of the load, regulated breaks are taken . The nozzle is guided along the longitudinal axis of the seam without transverse vibrations. The weld is completed by smoothly releasing the current with a rheostat to fill the recess of the weld pool crater.

The welder's equipment includes a mask with a light filter, heat-resistant gloves that do not restrict movement, a jacket that is resistant to burning by splashes, and closed shoes.

Modes

Reference tables will tell you how to cook with argon for a beginner when welding at home . The completeness of the data will help you determine the basic settings in advance and adjust the modes.

It remains to ensure that the torch is at an angle of more than 800 relative to the workpiece, the tip of the electrode protrudes from the nozzle by 3–5 mm, and hold it 2–3 mm above the workpiece when the arc is excited.

The current load is determined:

• diameter of the electrode (wire),
• types and thicknesses of metal,
• polarity.

Ferrous metal is welded with argon with straight polarity . Gas is supplied in a uniform flow without pulsation.

Features of arc ignition

The start of ignition with stable combustion maintenance is facilitated with a constant current of straight polarity . High-density currents with minimal amperage do not contribute to overheating and failure of the electrode.

Changing the polarity is fraught with an increase in arc voltage. The electrode loses its heat resistance, and the arc itself loses its stability. The positive aspect of reverse polarity is that the bombardment of argon particles with positive charges destroys the oxidation of the welded surface.

The flow of electrons causes the electrified gas to become a conductive plasma . For aluminum welding, this aspect is important. The low melting point and fluidity are overcome by lower currents than when welding steel.

Welding copper is complicated by the need for heating, the addition of deoxidizing additives, and fluxes for critical connections . With a non-consumable electrode, straight polarity is used.

Small diameter wire with deoxidizers is fed semi-automatically at high speed. Productive mode with a stable arc and proper penetration is ensured by reverse polarity.

As the feed speed increases, the melting of the wire changes from fine-droplet melting to jet melting. The seam density is satisfactory, spattering is minimal.