We select electrodes for a welding inverter

For a novice welder, the choice of electrode can be a problem: there are more than two hundred brands with different properties, purpose and characteristics. And about 100 marks are suitable for manual electric arc welding with inverter devices. It is impossible to tell about all of them, yes, to begin with, it is not necessary. Just briefly characterize the main types and about which electrodes for inverter welding are more suitable for beginners. We will also discuss what diameter to take and what to set the current for welding metal of different thicknesses.

What is an electrode and what is the coating used for?

The electrode is a piece of metal wire with a special coating - coating. During welding, the core melts from the arc temperature. At the same time, the coating burns and melts, creating a protective gas cloud around the welding area - a welded bath. It blocks access to oxygen contained in the air. During the burning of the coating, part of it passes into a liquid state and covers a thin layer of molten metal, also protecting it from interaction with oxygen. So the coating provides a good quality seam.

The welding electrode consists of a core and a protective coating

The welding electrode consists of a core and a protective coating

Any electrode before the beginning of welding is inspected: the coating must not have chips. Otherwise, you will not achieve a uniform warm-up and quality seam. Also pay attention to the tip of the electrode: the thickness of the coating should be the same on all sides. Then the arc will go out in the center. Otherwise, it will be shifted. For welders with experience, this is intrepid, but for beginners can create tangible problems.

It is necessary to monitor the moisture of the coating. Some of them with very high humidity are ignited very poorly (for example, SSSI). In connection with this "capriciousness" of the coating, they should be stored in a dry place, ensuring, if possible, a sealed package. You can put the box in a bag, and even put a few bags of salt in there, which are in shoe boxes.

You do not need to buy wet electrodes: you can dry them, of course, but their characteristics will decrease at the same time. If it still happens that the electrodes are damp, they can be dried in a conventional household oven at low temperatures (they are usually indicated on the package). The second way is to put it in a dry, well ventilated room for a long time.

The coating (protective coating) of electrodes can be: basic, rutile, cellulose and acidic

The coating (protective coating) of electrodes can be: basic, rutile, cellulose and acidic

Types of coating and their characteristics

There are only four types of coatings:

  • Basic.
  • Rutile.
  • The sour.
  • Cellulose.

The main (SSSI) and cellulose coating is suitable only for DC welding. They can be used on critical seams: they create a strong, elastic seam, resistant to shock loads.

Electrodes for welding more than 200 marks, about 100 of them can be used for manual electric arc welding

Electrodes for welding more than 200 marks, about 100 of them can be used for manual electric arc welding

The other two (rutile and acidic) can work in welding with both alternating and direct current. But the acidic coating is very toxic: it is possible to work indoors only if the workplace is equipped with forced draft.

Rutile coating has a greenish or blue hue, the electrodes are lightly ignited. They are well lit even if the inverter has a low idling voltage (for a reliable ignition of the main coating requires a good current-voltage characteristic, how to choose an inverter welding machine, read here.). When welding with rutile electrodes (MP-3), the metal does not spatter almost, but there is a lot of slag and it leaves uneasy: it is necessary to work with a hammer.

Perhaps you will be interested in how to weld an arbor from a metal pipe or how to make a shed on a frame from a pipe.

How to choose electrodes for inverter welding

First of all, the composition of the core is selected: it should be similar to the type of metal to be welded. In the household, structural steels are most often used. That's the same wire and should be electrodes. Sometimes you still have to cook stainless steel. Then the core should also be of stainless steel, and for high-alloy and heat-resistant materials made of metal with the same characteristics.

Do all the work on the house or at the construction site can be using only a few brands of electrodes:

  • MR-3
  • SSSI 13/55
  • ANO 21
  • OK 63.34

They are recognized by many of the best electrodes for beginners who work with inverter welding machines: they are easier to work with, at the same time, they allow you to weld quality seams even in the absence of significant experience. Below are the characteristics and general application of those consumables, which many experts regard as good electrodes for the inverter. In any case, they are often recommended to novice welders for gaining experience.

Electrodes with rutile coating MR 3

This is perhaps the most popular among the newcomers welding electrodes for inverters: SSSI 13/55

This is perhaps the most popular among the newcomers welding electrodes for inverters: SSSI 13/55 (To increase the size of the picture, click on it with the right mouse button)

Most often beginners are advised to start mastering welded seams with MR-3 electrodes. They are easily ignited, even with a not very good volt-ampere characteristic of the welding machine, give a good protection of the welded bath, allow you to easily control its position. If the electrode is not ignited, then calcine it at a temperature of 150-180 ° for 40 minutes.

Applied in devices with variable (welding transformers) and with direct current (welding rectifiers and inverters). Inverters are usually connected on the reverse polarity (+ on the electrode). Suitable for any type of seam, except for vertical top-down.

For types of welding machines read here. 

Electrodes MP 3 are not capricious to the quality of welded surfaces. They can work even on untreated, rusty and damp parts. Welding is carried out medium (2-3 mm) or short arc.

It is very important for novice welders feature MP3 3: they are well "hold" the arc, they work simply. For this, not all professionals like this brand: they are called Bengal lights. Too softly they boil: for good warm-up slow movements are necessary. That the pros do not like it, the beginners are what they need. Try to start learning welding with MP3. You should do it.

Diameter of the LEZ MR-3 electrode, mm Length, mm Recommended welding current, A Tare weight, kg Price, rub
2.0 250 40-60 A 1.0 146
2.5 300 60-100 A 1.0 120
3 350 70-100 A 1.0 95
4 450 80-170 A 1.0 91
5 450 130-210 A 1.0 91

SSSI 13/55 with basic coating

Preferred electrodes for inverter SSSI 13/55

The preferred electrodes for the inverter SSSI 13/55 (To increase the size of the picture, click on it with the right mouse button)

These are the most widely used and popular electrodes with the main coating. They are recommended for welding carbon and low-alloy steels. Suitable for connections of critical structures. The seams are durable to impact loads and plastic, well tolerated by low temperatures.

The disadvantage of these electrodes is that they are only kindled when the inverter has a sufficiently large idling speed (above 70 V). The second significant drawback: high requirements for the cleaning and processing of welded metals. If the rust, dust, oil or other contaminants remain on the edge, the seam will be porous.

Work with SSSI 13/55 is possible only on DC welding machines, including inverters, with reverse polarity (+ applied to the electrode), and with a short arc (to keep the tip of the electrode closer to the welded surface). The minimum open circuit voltage is 65 V.

The diameter of the electrode SSSI 13/55 (producer of "Mezhgosmetiz) Electrode length, mm Recommended welding current, A Retail price of pack, rub
2.0 250 30-60 A
2.5 300 40-70 A 127 rubles
3 350 80-100 A 116 rubles
4 450 130-160 A 111 rubles
5 450 180-210 A 110 rub

ANO 21

This type of electrodes with rutile coating is designed to work with carbon steels of small thickness. (For welding thin metals, read here.) When using them, the arc is kindled easily (including during repeated ignition), the seam is finely scaly (from waves of small size), the slag is easily separated. Electrodes ANO 21 can be used for welding water or gas pipes.

Try to work on the inverter electrodes ANO 21

Try to work on the inverter electrodes ANO 21

They work with both alternating current and direct current of any polarity. Welding requires heat treatment: they are calcined at 120 ° C for 40 minutes.

Diameter, mm Lower electrode position Vertical position of the electrode Ceiling position of the electrode
2 current strength 50-90 A current strength 50-70 A current strength 70-90 A
2.5 current intensity 60-110 A current intensity 60-90 A current strength 80100 A
3 current strength 90-140 A current strength 80-100 A current strength 100-130 A

Electrodes for stainless steel OK 63.34

If you need to weld stainless steel, try OK 63.34. They can also cook structural steels. This produces a seam with a shallow wave with a smooth transition to the main surface of the metal. The amount of slag is small, it fights easily.

This electrode is well to weld vertical seams and metal 6-8 mm, passing from top to bottom. Suitable for multi-pass welding butt and overlap joints. Works with constant and alternating current of any polarity, minimum idling voltage is 60 V.

Welding electrodes OK 63.34

Welding electrodes OK 63.34

For welding, you still need a mask. To make it easier to work, take a welding mask-chameleon. 

How to choose the diameter of the electrode, how to connect it and how to set the current

Select the electrode brand for the inverter is not all. Even if you have decided, at least three questions remain:

  • what electrode diameter to use when welding;
  • what current to set;
  • to which output "+" or "-" to connect the electrode.

About everything in order. Let's start with which electrode diameter is needed for welding. In general, it is recommended to start from the thickness of the metals to be welded: for small thicknesses, the electrode is taken with a diameter of the same size as the metal. If you are cooking metal 3 mm thick, then the electrodes take the same size. If you cook something thicker, then take 4 mm. But it will be difficult to work with large electrodes for beginners. Begin to master welding with a thickness of metal 3-4 mm. To do this, use electrodes 3 mm, or as the "troika" say.

General recommendations for the choice of electrode diameter depending on the thickness of the metal

General recommendations for the choice of electrode diameter depending on the thickness of the metal

Regarding the way to which output to connect the electrodes. In the technical specifications on the pack, it is most likely indicated for which polarity the electrode is intended. With the return connection to the positive output, connect the electrode, to the negative clip that clings onto the part. With a direct polarity, a plus is placed on the part, and a minus is applied to the electrode. How it looks on the welding inverter, shown in the photo.

Direct and reverse polarity of connection on the welding inverter

Direct and reverse polarity of connection on the welding inverter

What is the difference between these two types of connection? A different direction has a stream of electrons. As you know, electrons move from "minus" to "plus". Therefore, when welding it turns out that the element that is connected to the "+" is heated more strongly. By changing the connection modes, you can control the intensity of the metal heating.

Let's consider some situations. For example, you have an electrode of 3 mm, metal of 2 mm. If the detail of the "+" can get burned. Therefore in this case it is better to use the reverse polarity, at which the electrode will be heated more. If you want to weld the same troika with 6 mm metal, it is better to do this on a straight polarity: so the metal will warm up more deeply and the weld will be more durable.

How to choose a welding inverter read here. Maybe you are interested in building a fence of corrugated board.

Current strength during welding

Generally, when installing the electrode, the welding current for the inverter is set depending on the diameter of the electrode used. In general, there are recommendations on each bundle, but you can do without them: for each millimeter of diameter take 20-30 Ampere current. It turns out a fairly wide range, but then you need to consider how you will put the seam: with or without. For welding without detachment, lower currents are applied, with higher currents with detachment.

What kind of current should be cooked at different electrodes (general recommendations, just select by experience)

What kind of current should be cooked at different electrodes (general recommendations, just select by experience)

For example, for an electrode with a diameter of 3 mm, the calculated current is obtained from 60 A to 90 A. Actually, they operate in the range from 30 amperes to 140 amperes. When welding without detachment, a current of the order of 70-90 A is set, with a separation of 90-120 A. These parameters can "walk" in both directions: depends also on the speed of the tip of the electrode, on the mark and the "fluidity" of the welded steel, on the seam position (for the vertical and horizontal seams they put a little less, for the ceiling - even less).

In general, even the currents recommended by the manufacturer are far from being a requirement. Start with them, and then pick up so that you can work comfortably and the seam is good. You should get a qualitative connection, and the ratio of the current and the speed of motion you will select experimentally. In so doing, be guided by the state of the welded bath. It is your main indicator of quality.

On how to properly cook inverter welding, read here.

Errors that may occur during welding

Errors that may occur during welding

Now you know not only how to choose electrodes for inverter welding, but also how to connect them, what diameter you need them for this job, and how to choose a current for each type of electrode and seam. Now let's talk a little about the holders for the electrodes.

Holders for electrodes

On one of the welding cables there is a holder (holder) into which a welding electrode is inserted. They are of two types:

  • with the trigger button, the electrode is clamped in them automatically when releasing the spring-loaded key, it is released when you press it;
  • threaded - the handle is twisted and untwisted, releasing or clamping the inserted electrode core.

Which one is better? Solve you, but by accidentally pressing the button, you can drop the electrode during welding. Nothing terrible happens at the same time, but it's unpleasant ...

When choosing an electrode holder, it is important to pay attention to the current strength to which it is designed. Choose the maximum parameter that is available for your welding machine.

How to connect the cable to the welding electrode holder with a threaded clip is shown in the video.

The drawback of the clip-holder is that, with time, the spring that presses the electrode core is weakened, the contact deteriorates. We have to put a new one. How to do it on the holder-clothespin look in the video.

It is not difficult to connect the electrode holder for welding. Only there is one nuance: with frequent work, the welding cable is rubbed by its edge. You can, of course, shorten the cable and re-make it, but do not always want to cut off even 10-20 cm. To prevent this from happening, find a hose whose internal diameter is the same or slightly smaller than the outer diameter of the welded cable. Cut off a small piece of it - centimeters 15-inch and cut along. Now you can put it on the cable, pull it up and fix it there.

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