How to choose polarity when welding with an inverter

Reverse and direct polarity when welding with an inverter - Ice advice

Business October 10, 2017

When welding a structure using direct current, it is important to know that the quality of the seam will depend largely on the settings of the machine. An important nuance is that in addition to the current regulator, it is necessary to select the correct polarity. There can be only two types - direct and reverse polarity when welding with an inverter.

What does straight polarity mean?

In order to achieve a high-quality seam when welding various steels, it is important to know which polarity is suitable for the material that needs to be processed. The general essence of welding with an inverter is that the machine must have “+” and “-“ sockets. Depending on which socket the ground will be connected to and which the electrode will be connected to, the polarity will depend.

Direct polarity is connected in this way: a ground is added to the positive socket, and an electrode is added to the negative socket. It is important to know here that the type and polarity of the current will be determined by the existence of the anode and cathode spots. During straight polarity welding, an anodic spot, which is hotter, will form on the workpiece side.

What does reverse polarity mean?

With reverse polarity, it is logical that the connections of the ground and the electrode are swapped. That is, an electrode is connected to the positive socket, and ground is connected to the negative socket. Here you need to understand that when connecting the sockets in this way, an anode spot will also form, but it will appear not on the side of the workpiece, but on the opposite side from it, that is, on the electrode.

Important note! Connecting the polarity manually is carried out only when welding with an inverter, that is, in the presence of direct current. When carrying out the same process, but on alternating current, the polarity is changed up to hundreds of times per second independently. Therefore, the connection method does not matter.

As you can see, the difference between direct and reverse polarity when welding with an inverter is that the anode spot will form in different places.

Source: https://LEDsovet.ru/obratnaia-i-priamaia-poliarnost-pri-svarke-invertorom/

Polarity when welding thin metal with an inverter

[Welding sheets of thin metal with an inverter] allows you to quickly and efficiently produce a metal product.

Thin-sheet material is a material with a thickness of up to 5 mm; it is often used in the production of blanks for cars, motor boats, as well as for the manufacture of pipes, various hull structures, etc.

The main problem when welding thin sheets of metal is the high probability of damage.

The reason for this may be careless movement of the welder, as a result of which a burn may form on the workpiece.

In addition, welding of thin metal, carried out by a person without experience, may turn out to be of poor quality due to non-compliance with the technology.

Since the welding process is performed by an inverter exclusively using low current, even a slight gap in the working distance between the part and the electrode should not be allowed.

Otherwise, a break in the electric arc cannot be avoided. Therefore, it is not recommended to start welding thin sheets with an inverter without knowledge of the process features.

Next, we suggest that you familiarize yourself with a step-by-step lesson, specially created for novice welders, with which you can learn how to properly weld thin metal with an inverter semi-automatic machine.

Step-by-step guide to welding thin metal with an inverter

Welding thin metal requires, like any other welding process, to have protective clothing on hand: a special welding helmet, gloves and outer clothing made of rough fabric, but in no case should you wear rubber gloves.

Step one

We adjust the welding current and select an electrical conductor that will allow it to operate as an inverter.

We take the welding current indicator based on the characteristics of the metal sheets being joined.

Typically, the manufacturer indicates the current strength for specific cases on the inverter housing.

We use electrodes for inverter arc welding with a diameter of 2-5 mm. Next, insert the electrical conductor into the holder and connect the ground terminal to the workpiece.

To prevent sticking, do not bring it to the part too sharply.

Step two

Welding thin metal using an inverter machine begins with igniting the arc.

Using the electrode, we pointly touch the line to be welded a couple of times at a slight angle, which will activate it.

We keep the electrical conductor from the product to be welded at a distance that will correspond to its diameter.

Step three

If all of the above was done correctly, you should get a high-quality seam joint.

At the moment, there is scale or scale on the surface of the weld, they need to be removed using an object, for example a hammer.

The following video for novice welders will demonstrate how to properly connect thin sheets of metal with an inverter.

How to control arc gap?

The arc gap is the distance formed during welding between the elements being connected and the electrode.

It is imperative to maintain a stable size of the specified distance while operating the inverter.

If you weld thin metal with an inverter and at the same time maintain a small arc gap, then the welded seam joint will be convex for the reason that the main part of the metal does not heat up well.

If you weld thin metal with an inverter semi-automatic and at the same time keep too large a distance between the electrical conductor and the workpiece, then such a large gap can interfere with weld penetration.

The electric arc will jump, the deposited metal will lie crookedly.

A correct and stable distance will allow you to obtain a high-quality seam joint; however, it is necessary to weld thin metal with an inverter, as mentioned above, with a gap corresponding to the diameter of the electrode.

Having gained experience and the ability to control the inverter welding arc length, you will be able to achieve optimal results.

Due to the electric arc, which is fed through the gap and melts the base metal, a weld pool is formed. It also helps to move the molten metal into the weld pool.

Features of the formation of a weld seam

If you move the electrode too vigorously during the welding process, then all that can be achieved is a deformed joint.

This fact is explained by the fact that the line of the weld pool is below the level of the base metal, and if the penetration of the arc into the base metal is strong and fast, it pushes the pool back, resulting in a seam.

That is why it is necessary to control that the welding seam line is located on the surface of the metal sheets.

A high-quality seam can be achieved through circular and zigzag movements of the electrode along the surface to be joined.

When moving in a circle, it is recommended to monitor the level of the connection, distributing the weld pool as evenly as possible.

When performing zigzag actions, you need to monitor the formation of the seam line alternately in three positions: from one edge, on top of the weld pool, from the second edge.

Here we should not forget that the weld pool moves with heat, which is very important when changing the working direction.

If there is a lack of electrode metal, an undercut is formed - a narrow groove in the base metal along or along the edges of the weld, appears as a result of the lack of metal to fill the pool during transverse movement.

To prevent the formation of such a side recess or undercut, it is recommended to monitor the outer boundaries and weld pool, and, if necessary, adjust the width of the groove.

The welding pool is operated by the force of the electric arc located at the tip of the electrical conductor.

Do not forget that when working with a welding product at an angle, the pool will not be pulled, but will be pushed.

Therefore, a vertically positioned electrical conductor allows for less convex welding joints.

The process is explained by the fact that at this time all the thermal energy is concentrated under the electrode, the weld pool is pushed to the bottom, melts and is distributed around.

When the product is slightly tilted, all the force is pushed back, causing the weld to float up.

If the electrode product is tilted too strongly, the force is transferred towards the suture line, which does not allow effective control of the bath.

To achieve a flat seam connection, the electrical conductor is tilted at different angles.

Source: https://MyTooling.ru/instrumenty/poljarnost-pri-svarke-invertorom-tonkogo-metalla

Polarity when welding stainless steel with an electrode

Direct and reverse polarity when welding with an inverter (or any other welding machine) sets the tone for the entire work process and the correct choice of this parameter directly affects the quality of the welded joint. With reverse polarity, “minus” is applied to the metal parts, and “plus” is applied to the electrode. In the case of direct polarity, the opposite is true. And this is just one of several features that need to be taken into account when welding. But today we will focus on reverse polarity.

In this article we will talk in more detail about reverse polarity when welding. You will learn what reverse polarity is, under what conditions this type of current direction is selected, what equipment is used when working with reverse polarity, and how to set up the device to get the job done efficiently and quickly.

general information

What is reverse polarity in welding? Reversing current polarity is the process of applying a positive electrical charge to the electrode and a negative electrical charge to the metal part being welded.

In this case, the heat is distributed in the reverse order: the electrode significantly overheats, but the part, on the contrary, does not warm up at all.

For this reason, reverse polarity in arc welding is used in special cases when there is a high chance of deforming the metal at high temperatures or a very neat seam is required. Due to exposure to high temperatures, the metal easily warms up, the seam is formed quickly and evenly.

Reverse polarity is simply necessary when welding stainless steel, thin metal, alloy and high-carbon steel, aluminum and other alloys that are easily subject to overheating. For example, a current of reverse polarity is a mandatory satellite of electric arc welding using flux or welding in an inert gas environment. You simply won’t be able to deposit metal well if you use, say, argon arc welding and set straight polarity.

Many beginners still wonder why some jobs use reverse or direct polarity when welding with an inverter? We will try to explain in more detail. Reverse polarity is used in work, since when the arc burns, areas with a high concentration of anodes and cathodes are formed at the end of the welding rod. In this case, the temperatures differ significantly; the anode region can be hotter than the cathode region by 700 degrees Celsius!

Based on this, it is not difficult to guess that with reverse polarity, a huge amount of heat is released, which contributes to high-quality welding of the metal. If this indicator is important for welding a particular metal, then reverse polarity is used. Direct current direction is used in all other cases.

By the way, when working with direct current of reverse polarity, the electrode burns out much faster than when working with direct polarity. This is again due to excessive heating of the rod. So be prepared to overuse components. If you are using alternating current, then the choice of polarity is not relevant at all, since the direction of the current will constantly change during operation.

So, let us repeat: polarity is set only when working with direct current. Reverse polarity is used when welding special, easily deformable metals, when the seam needs to be formed quickly and efficiently.

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Welding with reverse polarity current cannot affect the properties of the electrode used in the work. A large amount of heat passes through the rod, which means that the part itself heats up very quickly, the metal is easily and deeply boiled, and there is practically no spattering (especially when welding with flux).

Is it possible to change the polarity directly during operation if the welding inverter (or any other type of equipment) has such an option? You can, of course, try this method as an experiment, but we will not recommend it to you. This is simply not necessary.

But sometimes there are situations when you started working with the wrong polarity and suddenly discovered this, so you want to set other settings. Try to finish what you started without changing the polarity (unless the requirements for the weld are very high). Yes, the electrode will stick, but you have to live with it.

If the seam should turn out to be of high quality and beautiful, then it is better to start the work again, setting a different polarity.

Polarity selection

Let's spend a little more time choosing the correct polarity. In addition to the metal itself, it is important to consider the electrodes or wire that you use in your work. The choice of direct or reverse polarity when welding depends on the type of coating.

If you work with a carbon electrode, then connecting in the opposite way is undesirable, since such rods quickly collapse when overheated.

If you use a wire that does not have any coating at all, then it will melt without problems even with straight polarity, but when used with alternating current it will not even heat up.

The choice of polarity is also influenced by what kind of seam you want to make, what size and shape it should have. When working with constant and reverse direction, the seams are well fused, the welded joint is narrow and shallow, since the welding process does not last long due to high temperatures.

Equipment

Welding with reverse direct current is carried out only on welding machines designed for such work. Choosing a welding machine is a very important topic, so in this article we will tell you only the most important things.

First of all, your welding machine must be able to work with different modes and feed wire at different speeds.

So you can weld with argon or carbon dioxide (this is very important when welding stainless steel), but you cannot weld with flux-cored wire, since this requires straight polarity.

With the help of reverse polarity, it becomes possible to use semi-automatic welding equipment in your work. Here the holder and ground are connected to “plus” and “minus”, respectively. Due to this, the flux burns out gradually and completely, and the welding itself occurs in the resulting gas cloud.

Instead of a conclusion

Choosing polarity when welding with DC is not an easy task if you are a beginner welder.

You need to take into account all possible nuances related to the type and thickness of the metal, the electrode or filler wire used in the work, and also successfully select a welding machine with the set of functions you need.

All this seems like something very complicated, but believe me, with experience you will set up the device and select components without even thinking. Study a lot of theory and don't forget to put it into practice.

Source: https://rem-serv.com/polyarnost-pri-svarke-nerzhaveyki-elektrodom/

How to choose the right current when welding with an inverter - Metalworker's Handbook

You bought a welding machine and want to learn how to weld with an inverter for beginners.

There is no need to be afraid of difficulties! The inverter machine is easy to use; anyone without experience or knowledge can master the welding process in a short time.

Equipment, equipment, safety precautions

Safety precautions. Welding production is associated with electrical voltage, or in common parlance - current. The current is invisible, but can kill a person.

We check the welding cables for serviceability and connect them to the inverter equipment. Return cable with a clothespin on metal to the negative connector. Cable with electrode holder to connector +. We insert the electrode into the electrode holder.

When connecting the device to the network, visually evaluate the current-carrying cables for serviceability. After making sure that the cables are in good condition, we plug in the plug into the socket and the toggle switch on the device, having previously set the current regulator to the lowest value. If the cooling fan starts working smoothly, without crackling or noise, then everything is fine.

Metal weight. When connecting heavy structures, take precautions. If multi-ton products collapse, they can lead to death or disability.

Equipment. Welding production involves high temperatures. The welder must have:

canvas mittens (gaiters);
robe (special suit);
mask with a light filter;
respirator for work in confined spaces;
boots with rubber soles.

Gaiters are used when welding at heights, when arms are raised up, and mittens in other cases.

https://www.youtube.com/watch?v=edwILvaxWls

Other accessories:

welding machine;
hammer;
brush;
electrodes.

Electrodes are selected according to the metal (carbon content, additives) and diameter, depending on the thickness of the metal and the technical characteristics of the inverter.

Inverter Welding Basics

For beginners, experienced welders advise attaching the holder cable to the body, pressing it with the elbow of the arm and wrapping it along the forearm (from the elbow to the hand), and taking the holder in your hand. This way the shoulder joint will pull the cable, and the arm and hand will remain free. The method will help you manipulate your hand with ease.

Correct placement of the cable on the forearm. You should not work with bare hands.

If you simply take the holder in your hand without wrapping the cable around your forearm, then during the welding process your hand will get tired and wrist movements will cause the cable to dangle. Which will affect the quality of the welded joint.

How to cook using inverter welding correctly? We set the welding current on the machine according to the diameter of the electrode, the type of connection and the welding position. Setup instructions are available on the device and the electrode pack. We take a stable stance, move our elbow away from the body (no pressing), put on a mask and begin the process.

For beginners, it is better to start welding with an inverter with metal workpieces larger than 20 cm.

It is known that a beginner, putting on a mask and lighting an arc, stops breathing, trying to boil the entire length of the workpiece in one breath. With short products, you will develop the habit of cooking in one go. Therefore, practice on long workpieces, learning to breathe properly when welding.

Workpieces (plates) on the work table can be placed in a horizontal plane - vertically towards you or horizontally, it makes no difference.

At the beginning of welding, place the electrode clamped in the holder at an angle of 90 degrees (perpendicular) and move it towards the seam by 30-45 degrees. Light the arc and start moving.

If welding is performed at an angle backwards, then the tilt of 30-45 degrees goes towards the seam.
If the connection occurs at an angle forward, then the electrode is tilted away from the seam.

The distance between the surface to be welded and the electrode is 2-3 mm, imagine that you are running a pencil along a sheet of paper.

Please note that when welding, the electrode decreases as it burns - gradually bring the melting rod closer to the surface at a distance of 2-3 mm and maintain an inclination angle of 30-45 degrees.

How can a beginner learn to weld with a welding inverter?

First we learn to light and hold an arc. Feel the edge when to bring the electrode closer to the surface to be welded during combustion so that the arc does not interrupt.

The electrode is ignited in two ways:

tapping;
chirping.

The new electrode ignites easily. A slag film appears on the working rod, preventing ignition. You just need to tap longer to break the film.

To facilitate arc ignition, inverter devices have a built-in Hot Start function.
If a beginner quickly brings the electrode closer to the surface, the Arc Force function (arc force, anti-sticking) is activated, increasing the welding current, preventing the electrode from sticking.
If the melting rod gets stuck, the Anti Stick function cuts off the current, preventing the inverter from overheating.

: What is arc force on a welding inverter and how to use it.

It is better for a beginner to first learn on a thread seam; the electrode is held smoothly, without oscillatory movements.

After mastering thread technology, proceed to welding metal with oscillatory movements. Which are used on thick metal for heating, holding the electrode at a certain point using movements - herringbone, zigzags, spiral or your own method.

Types of oscillatory movements

At the beginning of the connection, we carry out several movements from left to right, forming a weld pool and go along the seam making oscillatory movements. The angle of inclination of the electrode is 30-45 degrees. After passing, we beat off the slag with a hammer and clean it with a brush. Take care of your eyes, wear glasses.

Tip: at the end of the weld, make oscillatory movements to the sides and move the electrode towards the deposited metal. This trick will add beauty to the welded joint (get rid of the crater).

: how to weld corner joints, butt joints and overlap joints.

Seams are divided into:

single-pass (one pass replenishes the thickness of the metal);
multi-pass.

A single-pass weld is performed on metals up to 3 mm. Multi-pass seams are applied for large metal thicknesses.

Welders check the quality of the seam with a hammer - they strike next to the seam. If the seam is smooth, without irregularities, then after the impact the slag flies off completely, there is nothing for it to catch on. It is important to select the correct temperature regime: an overheated seam (hot) will break, an underheated one - there is a risk of lack of penetration.

The current is selected based on the diameter of the electrode, in theory 30 A per 1 mm of electrode diameter.

Direct and reverse polarity when welding with an inverter

Let's consider polarity when welding with an inverter. With a DC connection, the movement of electrons is constant, which reduces spattering of molten metal. The seam is of high quality and neat.

The device has a choice of polarity. What is polarity is the direction of movement of electrons depending on the connection of cables to equipment connectors.

Reverse polarity when welding with an inverter - minus on the workpiece, plus on the electrode. The current flows from minus to plus (from the workpiece to the electrode). The electrode heats up more. Used for welding thin metals, the risk of burn-through is reduced.
Straight polarity - minus on the electrode, plus on the workpiece. Current moves from the electrode to the workpiece. The metal heats up more than the electrode. Used for welding thick metals from 3 mm and cutting with an inverter.

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The polarity is indicated on the pack of electrodes; these instructions will help you correctly connect the wires to the equipment.

Welding thin metal with an inverter

The essence of connecting thin plates comes down to selecting small-diameter electrodes and adjusting the welding current. For example, for metal with a thickness of 0.8 mm, electrodes with a diameter of 1.8 mm are used. The current on the inverter is set to 35 A.

Technology occurs in intermittent movements. Watch a video showing how to join thin plates in detail.

How to cut metal with a welding inverter

To properly burn a hole in a pipe, we set the current on the device to 140 A for a 2.5 mm electrode. We light the electrode, placing it in one place to warm up the metal and press it in. We move the electrode to a new place, warm it up and press it in. Gradually, we cut a hole in the pipe.

Pipe cutting

When cutting, it is better to place the plate vertically so that the molten snot flows down. If you cut in a horizontal position, icicles will harden at the bottom of the cut. That's all the tricks!

Beginners are tormented by the question, which polarity of wires is better when cutting with an inverter?

When cutting with electric welding, straight polarity is preferable. The melting zone is narrow but deep.
With reverse polarity, the melting zone is wide but shallow.

It is not recommended to cut with electric welding (metal melts from the cut zone). It’s better to take a grinder and cut off the desired piece.

Source: https://ssk2121.com/kak-pravilno-vybrat-tok-pri-svarke-invertorom/

Welding thin sheet metal with an inverter for beginners - how to weld with an inverter, what polarity to weld iron with, machines with wire

06Dec

articles

In this article for novice welders, we will talk about welding electrodes for welding thin sheet metal and how to properly weld iron with wire from an inverter. Working with thin-sheet material is aerobatics, so you need to learn all the nuances and features of welding.

How to carry out the procedure with thin-walled products

Structures with small walls are very common. This is the car body, various containers, pots, etc. In a factory setting, the operation is carried out using a special machine with a CNC control panel.

But what to do at home if you have a plane on your hands with a width of 1 mm to 1.5 mm? An electrode of size 1.5 is very rare in stores; on the counter it is much more common to find a conductor of 2 or 3 mm in diameter. But according to the unspoken rule of welders, the nozzle must be thinner in cross-section than the workpiece.

But 0.8 mm products simply do not exist, and one-and-a-half mm products are so difficult to work with that their use is rare. The best option is

Technology: how to weld thin metal with an inverter

Inverter equipment is considered more preferable because the generator produces high-voltage direct current, which is easy to regulate. They can be used to work with thin-sheet alloys without burnouts or deformations. To avoid them, you need to carry out the procedure as quickly as possible, do not linger in one place, and carry out the guide only once.

The second technological rule is to reduce the current strength to a minimum. To do this, it is important to have a device that can smoothly change the indicators. At the same time, its voltage at idle should not be lower than 70 V.

To avoid damaging the geometry of the workpiece, watch the joints. They must be thoroughly cleaned of corrosion. Then you need to secure the samples with strong clamps and make several connections every 5-7 cm. Then you can proceed to the main action.

Selection of modes and conductors: at what polarity and with what electrodes to weld thin metal

If you choose between a transformer and an inverter machine, we give preference to the inverter, because it is easier to set parameters on it. Any sheet not exceeding 5 mm is considered a thin-walled material, but problems can only arise with workpieces up to 3 mm. We offer a table, we recommend that you use it as a guide:

Sheet thickness, mm	0,5	1	1,5	2	2,5
Diameter, mm	1	1 – 1,6	2	2,5	2 – 3
Current strength, A	10 – 20	30 – 35	35 – 45	50 – 65	65

These are recommendations, but each specialist can choose the necessary modes through experience. With such wires or conductors, you need to remember that they melt very quickly, so they are led very quickly.

The right technology: how to weld thin metal using electric welding

The width of the workpiece does not affect the three main stages:

Preparation;
welding;
sanding, cleaning seams.

Preparatory work

It is necessary to remove all contamination, especially attention should be paid to the place to which the mass of the welding machine is attached. Rust can be removed with sandpaper. If the product is galvanized, then you can clean the surface with a grinder, or cook directly over the zinc - the substance will melt at the moment of heating.

Welding

To make the arc ignite faster, before starting, strip the electrode of the coating to the outermost 5 mm.
You can ignite an electric arc in two classical ways - by striking or tapping.
The weld pool should have an oval shape.
Keep your distance so that the guide does not stick.
If your device has a special anti-stick mode, use it. It works like this: when the nozzle approaches the workpiece, the voltage of the equipment is automatically reduced. If the arc is stretched too much, the reverse process occurs and the current increases. The result is a stable seam even with uneven stitching.
The ideal degree of angle is 60 degrees. It must be done before welding thin metal with an electrode. If you make the indicator smaller, the welded joint will turn out to be convex.
The optimal movement is a zigzag. In this case, the direction from yourself or towards yourself does not matter.
The speed of movement of the handle should be high enough, but at the same time be constant.

Let's watch a video of the process itself:

Working as an inverter

The peculiarity is the use of reverse polarity, that is, the negative is connected to the workpiece, and the positive goes to the conductor. This helps ensure protection against burning and deformation. This is explained by the fact that the electrode heats up faster and stronger than the welding site. It is recommended to take high-quality consumables, preferably foreign-made. Moreover, it should be no thicker than 2 mm in diameter and highly buoyant.

Let's watch a video on how to weld thin metal using inverter welding:

Advantages of welding thin-walled workpieces with an inverter

For professional activities, the advantages of using this type of equipment are:

aesthetic appearance, no punctures;
without deformation and changes in size - they mainly occur due to temperature changes;
there are no burns, therefore there are no unsightly spots;
The voltage is constant, without holes or failures.

The only drawback can be considered uneven operation at negative air temperatures. But almost all welding machines begin to fail.

How to properly weld thin galvanized metal using electric arc welding

This steel has its own advantages in operation. It is quite strong and is little exposed to external influences; in fact, it does not rust. But it also has disadvantages, the most important one being that it is difficult for welders to work with the material. Its surface is covered with a layer of zinc, which is first recommended to be removed using a grinding machine or a simple grinder with a special disk.

The device itself supplies such a temperature that the sprayed substance itself melts faster than the formation of a seam. But when working without first cleaning the edges, you should remember the presence of toxic zinc fumes, which should not be inhaled by humans. Use a respirator and other protective equipment.

It is recommended to brew in a workshop with good forced ventilation, an exhaust hood, or in outdoor conditions.

Problems of how to weld thin metal using electric welding

In fact, any resulting defects do not differ from classic defects among welders. Let’s highlight 4 main defects and rank them in order of popularity:

Burning the workpiece. This is excessive melting of the metal plate until a through hole is formed. This occurs due to incorrectly selected, too high, current strength.
Electrode sticking. This happens due to the opposite reason - the voltage was applied too low. The second option is that the end of the conductor was too close to the surface to be welded. The result is an unsightly plaque that will have to be cut off.
Unwelded seam. This happens often among novice welders. In fear of burning through, they extend the filler wire too far. As a result, the temperature is not sufficient to melt the edges of the connecting materials. The seam is formed only due to the additive. And when cleaning, you can see uncooked spots.
Deformation. The sheet may wrinkle, bend, or become wavy. This occurs due to high temperature conditions.

Conditions that must be observed when working

You need to be careful when choosing an electrode. It should be:

with a diameter not exceeding the thickness of the sheet;
ideal size – 1.6 mm;
inside there is the same alloy as the workpiece;
coating of elements that are considered refractory;
any brand.

You should also use a suitable inverter:

semi-automatic is more profitable than manual arc welding;
The current varies depending on the cross-section of the conductor; adjustment is made within the range of 10 - 15 A.

The advantage of inverter equipment is that the efficiency is much higher (up to 90%) than that of a transformer, and it uses much less electricity.

The design of a welding machine for welding thin metal

This is not a simple piece of equipment. It works with many frequencies and quantities. In order to ignite the arc, two conversions occur - from alternating voltage of 220 V to direct voltage, and then to high frequency.

This diagram shows how an electrical impulse is converted. Below are the following stages of the wave passing through the bridge, capacitor filter, inverter itself, high-frequency transformer, high-frequency adapter and to the welding arc.

In the image below we will see what main elements are on the external part of the device. All indicators, knobs for mode adjustment, and connectors are presented here. This is a classic type of product that is suitable for working with thin sheet steel.

semi-automatic welding. With such an apparatus, a wire of the same material as the base is used as an electrician. It can be the subtlest.

Welding techniques for thin-walled structures

We offer the following technologies that will help avoid the most common defects and simplify the welder’s task:

Overlapping. To do this, place the workpiece not with two edges facing each other, but with one part to cover the other by 1-2 mm. Now the task becomes easier, because burning will take twice as much time, current and temperature, which means you don’t have to worry about leaving a through hole.
Point connection. Such tacks are made every 5-7 cm. To do this, you will need to ignite and extinguish the electric arc each time. But then there will be no deformation and you can be sure of an even seam.
By electrode. This is a rougher and not the most beautiful option, but reliable. The conductor must be completely cleared of coating, then placed along the connection and the material used as an additive.

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Let's sum it up

In the article, we told you how to weld thin metal using electric welding, and also revealed several secrets of the work. To finish, let's look at 2 more videos from professional welders.

Source: http://rocta.ru/info/svarka-tonkogo-metalla-ehlektrodom-kak-pravilno-varit-invertorom-sovety-dlya-nachinayushchih/

How to choose electrodes for welding with an inverter?

If you decide to try yourself as a welder and have already bought a welding inverter, the next step will be to search for electrodes with which the welding will take place.

But which electrodes are best to choose for welding with your inverter?

In this article we will tell you what the diameter of the electrode depends on and how to select the welding current, and we will also tell you what direct and reverse polarity are and what polarity is needed for your electrodes.

Nowadays you can find a wide variety of electrodes on the market. They can be divided by type of coating, by purpose, by coating thickness or chemical composition. The marketing services of electrode manufacturers have developed dozens of selection tables and novice welders are lost in such an assortment.

Of course, you can go the simplest route and try all the suitable ones. This is an option, but you will have to spend both time and money.

How to minimize these costs and choose the right welding electrode? After all, the formation of a correct and reliable seam, as well as the comfort of your work, depends on the choice of electrode.

Rice. 1 - Electrodes

WHAT IS A WELDING ELECTRODE

A welding electrode is a consumable material, without which manual arc welding is impossible. This is a metal rod (core) with a special coating - coating. During the welding process, the rod melts, and the coating protects the seam from exposure to oxygen. The composition of the rod should be similar to the composition of the metal that you are going to weld. Therefore, there are electrodes for welding carbon, alloy, high-alloy steels, stainless steel, aluminum, cast iron.

We will not consider many special alloys, for each of which a special electrode can be recommended. Most likely, you will be dealing with welding structural steel of small thickness and the only distinguishing point here will be the carbon content in the metal.

The choice of electrodes for manual welding depends not only on the metal to be worked with and its thickness, but also on the position in which the welding will take place, and what requirements will be placed on the strength of the seam.

For example, rutile-coated electrodes are not suitable for welding load-bearing structures that are operated at particularly low temperatures, but they produce a very elastic and stable arc, which makes it easy for even beginners to work with them.

TYPES OF ELECTRODES

What types of electrode coatings for manual arc welding exist?

There are usually 4 types of cover:

rutile
basic
sour
cellulose

Rice. 2 — Types of electrode coating

Each of them is designed to solve very specific problems.

Rutile electrodes are ideal for use with direct or alternating current. They light easily and do not splatter metal. The slag separates easily.

Rice. 3 – Rutile electrodes

Rice. 4 – Rutile coating

Rutile coated electrodes work well with devices with low open circuit voltage, for example, with IR series inverters equipped with the VRD function.

Basic and cellulose electrodes are only suitable for DC welding. They are chosen if the most durable seam is needed, for example when installing load-bearing structures. Cellulose electrodes can be welded in all spatial positions.

Fig. 5 – Basic and cellulose electrodes

Electrodes with an acid coating are welded using direct and alternating currents and guarantee easy separation of slag. But their fumes are harmful to the welder, so they can only be used outdoors.

Fig. 6 – Acid electrodes

There are also mixed electrodes that combine the properties of different types. For example, FUBAG's product range includes rutile-cellulose electrodes, which are excellent for welding structures and pipelines. They are ideal for ceiling applications as the coating is based on short slags and ensures that the weld pool is retained in the ceiling.

Fig. 7 – Mixed (rutile-cellulose) electrodes

Rice. 8 — Rutile-cellulose electrodes FUBAG

Type of coverage	Purpose	With cooking in positions	+	—
Rutile	For operation on direct and alternating currents. Operate at low open circuit voltage.	All spatial positions except vertical seams from top to bottom	Easy ignition and re-ignition Low spatter Easy slag release	Not suitable for welding load-bearing structures that are operated at particularly low temperatures
Basics	For DC operation.	In all spatial positions except vertical seams from top to bottom	Increased strength welding of especially critical structures	Ignition of the arc and re-ignition are difficult. A fairly high qualification of the welder is required
Pulp	For DC operation.	In all spatial positions. Avoid overheating.	Special strength welding of especially critical structures	Losses due to splashingThe coating absorbs moisture very quicklyRequires special storage and packaging conditions
Sour	For operation on direct and alternating currents.	In all spatial positions except vertical seams from top to bottom	Easy slag separation	Splash losses. Possible cracks in the seams. Harmful to the health of the welder
Mixed (rutile-cellulose)	For operation on direct and alternating currents.	In all spatial positions except vertical top-down	Seam strengthLow consumption	Not suitable for welding load-bearing structures that are operated at particularly low temperatures

ELECTRODE DIAMETER FOR MANUAL WELDING

The next parameter you will encounter when choosing an electrode is its diameter.

In general, in order to select an electrode when welding with an inverter, we must know the type of metal and its thickness because... For each type of metal and thickness, a different electrode is selected.

Experienced welders also take into account the position for welding, the depth of penetration and other nuances, but for starters, the thickness of the metal will be enough for us.

Rice. 9 – Selecting an electrode

POLARITY OF ELECTRODES

Based on the type of electrodes, they can be divided into electrodes that work only with direct or reverse polarity, as well as universal electrodes that work with both polarities. The correct choice of electrode connection polarity simplifies the welding process and improves the quality of the seam. The polarity of welding electrodes is indicated on the packaging.

To perform the vast majority of household tasks, you will use universal electrodes.

The welding inverter has a polarity selection. That is, you can connect the electrode holder to both plus and minus.

There are two options for connecting the ground and electrode holder:

- direct polarity - when the workpiece is connected to the plus, and the electrode to the minus.

- reverse polarity - electrode to positive, workpiece to negative.

The pack of electrodes indicates the polarity in which they are recommended to work.

WELDING CURRENT PARAMETERS

Now that the electrodes and polarity have been decided, all that remains is to select the desired current strength.

The welding current is selected depending on the diameter of the electrode. And the choice of electrode, as we have already written, depends on the thickness of the metal. On the housings of FUBAG devices there are hint tables that will help you instantly select the desired current strength. Once you gain enough experience, you will be able to adjust the amperage to suit your style.

Fig. 10 – Selection of welding current depending on the diameter of the electrode

For example: You plan to weld small metal structures - a fence, greenhouse frame or box. The material for them is small shaped rolled products (angles, profile pipes) and rolled sheets made of low-carbon steel with a thickness of 2-3 mm.

The table shows that three electrodes and a device with a current of up to 130 A (we show IR 160) completely cover this task.

You can also use a simplified formula:

For 1 mm of electrode you need 35-40 A of welding current.

When buying welding electrodes, you need to be sure that they have retained all their qualities. Electrodes are a very specific product and the preservation of their original properties depends on storage conditions and the integrity of the packaging. And the quality of the seam will directly depend on the quality of the electrode.

Before welding, check the surface of the electrodes - they should be free of swelling, scratches and chips, well coated and free of rust at the ends.

If the welding electrodes were not stored correctly and became damp, then when working with them, the quality of the seam will suffer, cracks and pores will appear.

Novice welders often ask: how and in what way to calcinate the electrodes.

At home, or in a summer cottage, electrodes can be calcined in different ways. For example, some experienced welders do this in the oven. Setting the temperature to about 190-210°C, keep the electrodes in the oven for about 20-30 minutes.

In fact, it also depends on the coverage.

Electrodes with rutile coating usually do not need to be calcined, but if they are still very damp, then it is better to calcine them for 1-2 hours at a temperature of 100-150°C. At lower calcination temperatures, the calcination time must be increased.

Electrodes with cellulose coating, as a rule, absorb little moisture. Therefore, they do not need to be heated. As a last resort, they can be heated at a temperature of no more than 70°C, otherwise they may crack.

If electrodes with a basic coating are stored under normal conditions (15°C / 40% relative humidity) and in the original packaging, then they also do not need to be annealed. After unpacking, they can be heated at 50 degrees for 2-3 hours.

It is not recommended to calcinate the same electrodes more than 3 times. Electrodes should be stored in a dry room at a temperature not lower than 10-15 degrees.

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Source: https://store.fubag.ru/tips/kak-vybrat-elektrody-dlya-svarki-invertorom/

What is the polarity on the welding inverter?