Protection against welding splashes: semi-automatic inverter welding and the use of special solutions

When performing welding work, spattering of the electrode metal and its sticking to the surfaces of the parts being connected or the seam are very often observed.

When accepting welding work, depending on the degree of responsibility of the structure, adhering drops of metal may be perceived as a serious defect.

Welding spatter protection is a definite concern for new welders. To prevent splashing, it is necessary to follow the technology and use protective compounds.

Methods of protection against adhesion of welding spatter

When performing welding work, spattering of the electrode metal and its sticking to the surfaces of the parts being connected or the seam are very often observed.
When accepting welding work, depending on the degree of responsibility of the structure, adhering drops of metal may be perceived as a serious defect.

Welding spatter protection is a definite concern for new welders. To prevent splashing, it is necessary to follow the technology and use protective compounds.

How to hold a semi-automatic burner correctly?

Burner

held at an angle of 60°, the wire should be directed towards the seam. In this case, it is extremely important to constantly maintain a distance from the surface to the nozzle of about 5–10 mm.

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Reasons for appearance

Welding spatter usually occurs at the moment the arc is ignited, while the current is at its highest. When the electrode touches the connected parts at the moment of a short circuit, the metal of the electrode, subjected to an electrodynamic shock, scatters and settles in drops in the form of balls on the surface.

In some cases, welding the droplets to the base metal can be very strong. The defect is clearly visible. It can be removed by cutting off frozen drops or grinding with special tools.

In addition to this case, welding spatter most often occurs when welding semi-automatically using single-phase current during power surges.

The amount of spatter increases greatly if welding is performed on a rusty and dirty metal surface.

Thus, the main causes of welding spatter are:

poor quality electrodes;
incorrect choice of welding mode and parameters;
low quality of preparation of products for welding;
lack of protection of the product from sticking.

By eliminating all or part of these problems, you can ensure high quality work with a minimum amount of welding spatter.

Impact of equipment and technology

To protect against welding spatter, first of all, you need to pay attention to the use of high-quality equipment and electrodes. Good results can be achieved by using inverter semi-automatic machines.

When operating, these devices produce a very even current, which allows you to obtain a stable arc.

The cost of inverter semi-automatic machines reaches high values, but more expensive equipment does not always completely eliminate welding spatter.

Improvement in welding quality also occurs when switching to the use of three-phase current.

Working in a gas environment almost completely eliminates welding spatter. To do this, use a mixture of argon and carbon dioxide in proportions of 95% argon to 5% carbon dioxide.

When choosing parameters, you need to pay attention to the value of the welding current. It is its overestimated value that contributes to the formation and scattering of molten metal.

Electrodes must be used in accordance with the welding mode, their characteristics must correspond to the properties of the materials being welded, which provides protection against the formation of splashes. The use of wet, damp electrodes, as well as rods with cracked or peeling coating is not allowed .

When preparing products for welding, they should be thoroughly cleaned of dirt, rust, and soot. Oily parts must be degreased. The cutting of seam edges must be carried out in accordance with the requirements of the work technology.

By following the above tips, you can significantly reduce the amount of splashing. But small splashes still form, sticking to the metal.

If the design or structure is of a low degree of responsibility, and strict requirements are not imposed on its appearance, one could stop at using these measures. Otherwise, you have to eliminate the consequences.

Non-stick paste M-WELD

M-WELD's non-stick paste is designed to protect welding machine torch nozzles from deposits caused by splashing molten metal. The paste is economical, simple and easy to use. It is also used for processing tips. Forms a heat-resistant coating on their surface, as a result of which welding torches last much longer.

The paste is applied to the burner and the part in a heated state (whereas sprays are applied only to cold elements), which ensures uniform distribution of the non-stick composition. The nozzle is lowered into the paste and removed after a few seconds. After work, to prevent clogging of the nozzle, the burner should be held for some time above the container with the nozzle down.

M-WELD paste is also used for processing various production equipment and tools. In this case, it is applied with brushes.

Non-stick paste from M-WELD is environmentally safe, does not ignite, and does not have a toxic effect on the human body.

Anti-caking agents

Sometimes removing splashes of molten metal is impossible using mechanical methods, that is, cutting down or grinding. Problems arise due to the location of the seam in hard-to-reach places.

In this case, the surfaces of the parts to be joined by welding are pre-treated around the weld area with means to protect against welding spatter. Such products are a paste or liquid against the adhesion of molten metal.

Currently, there are many different means of protection. The retail network has ready-made products from the BINZEL, ESAB, E-WELD, and INDUSVAR brands.

According to the method of application, they are divided into:

produced in the form of liquids packaged in canisters and bottles. The protection is applied by brush or spray through a spray bottle;
produced in the form of aerosols in special bottles;
in the form of pastes, packaged in metal or plastic jars with a wide neck for ease of use.

Each product must be used in accordance with the manufacturer's instructions.

Very often, experienced welders use their own compound recipes, developed over the years, to prevent the adhesion of spatter.

As a means of protection, you can use a solution of chalk in water. It is desirable that the consistency be close to paste. Using a brush, this solution is used to cover the part around the future seam, but the edges themselves must remain clean.

After welding work, it is necessary to thoroughly clean the surfaces of the seam and metal from the applied product. Many anti-splash formulations include oils, greases, and other substances that significantly reduce the adhesive properties of the coating.

If necessary, surfaces must be degreased, which improves the quality of further processing of products and structures.

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Non-stick spray Ceram Stak

Using advanced nanotechnology, M-WELD specialists have developed an innovative ceramic-based spray. It contains tiny ceramic particles and a special binder. When applied to the surface, the spray forms a white film that dries within 5 minutes. This non-stick composition is recommended for use in automatic and semi-automatic welding, as well as in plasma and laser cutting of metals. It can withstand temperatures up to +1500°C, and differs from other similar products in that it provides more stable and long-lasting protection for the metal.

Ceram Stak is applied to a pre-dried and degreased base. The can must be shaken for one minute before use and periodically while spraying. This spray has excellent lubricating properties, prevents premature abrasion of surfaces and their deformation, therefore it is used as a lubricant in high-temperature conditions (electric ovens, work tables, etc.).

The inverter splashes when welding

How to reduce metal spatter during welding? This question is especially relevant for those surfaces to which high demands are placed - rubbing, or external ones, those that will subsequently be painted. The cardinal solution is to use protective chemicals, but with the help of other solutions you can achieve good results. We consider some of them below.

If welding spatter appears more frequently and there is more of it than usual, check the welding machine. The most common culprits for spatter associated with welding machines are:

low quality of welding current (current surges);

worn out nozzle or current tip;

quality of the welding machine.

Generally, a better quality machine means less splashing. It is almost impossible to avoid them on single-phase non-inverter type equipment. But welding inverters can significantly improve welding by stabilizing the characteristics of the welding current.

A worn-out nozzle or current tip does not provide a high-quality arc, which reduces the quality of the seam and increases the number of sparks. These consumables need to be replaced as soon as the first signs of wear are noticeable.

High-quality welding materials

The amount of spatter is significantly influenced by the consumables that the welder uses in his work: electrodes, gas, flux. Reduce excessive sparks in the following ways:

welding with powdered flux;

welding with special grades of flux;

use of a protective environment from a mixture of carbon dioxide and argon;

refusal of electrodes with rutile coating.

Proper preparation of material for welding

Thorough cleaning of the surface and removal of rust helps reduce the amount of splashes. Treatment with special compounds, which both reduce the number of sparks and protect the welded surface from the adhesion of splashes, helps dramatically.

Special welding technique

To reduce metal spatter, experienced welders advise reducing the arc length, bringing the electrode as close as possible to the surface to be welded. You can also get rid of spatter by switching to TIG welding, however, this will increase the cost of welding and increase the time spent working with the part.

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Why does the electrode stick when welding with an inverter?

1. Why does the electrode stick and how to deal with it

Today almost everyone can buy a welding inverter; prices have dropped to 4 thousand rubles. However, buying a welder is not so bad, since you need to be able to use it correctly.

The sound of proper semi-automatic welding

When learning MIG / MAG welding, it is important to listen to the sounds made during welding and, of course, control the welding process visually (through a darkened mask). When welding correctly, a semi-automatic welding machine produces a sound reminiscent of frying meat in a frying pan. This "hissing-buzzing" sound indicates a good balance between wire feed speed, gas flow and voltage settings. Solidified spatter on the nozzle or tip of the welding torch impairs the flow of shielding gas, poor contact of the ground clamp, poorly cleaned welding area, all of these can impair the formation of the welding arc, and will be reflected in the welding sound. You can also read the article “how to set up a semi-automatic welding machine” for a better understanding of the correct settings of the machine before welding.

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Why does the electrode stick and how to deal with it

Electrode sticking to the metal surface during welding is the most common problem among those who first set foot on the thorny path of an electric welder. And although most modern inverters have a magical “Anti-stick” function, it still will not save you from a short arc or its incorrect ignition.

In addition, this function will be of little help if the welding electrodes are very damp. How to dry electrodes at home was described earlier, in previous issues of the construction magazine SAMASTROYKA.

So, here are the most common reasons why the electrode may stick while welding metal:

1. Raw electrodes - the design of the electrode is very simple, it is a metal rod on which a special coating made from a special powder is applied. So, this very coating, if it is damp, becomes the main problem when igniting and holding the welding arc. It goes without saying that to eliminate this problem, you need to calcinate the electrodes at a temperature of 110 degrees, about half an hour.

2. Incorrectly selected electrodes for welding. Experienced welders know that there are specific electrodes for welding with alternating and direct current. If you mess this up, the electrode will stick to the metal surface all the time, and, alas, you will never be able to achieve a stable arc.

3. Incorrect ignition of the electrode. Many novice welders make the first mistake, which is precisely related to incorrect ignition of the arc. If the electrode sticks when the arc is ignited, try tapping it on the metal and immediately moving it to the side a certain distance to maintain the arc.

4. The inverter settings are incorrect. Before you pick up an electrode holder, you should read in more detail about the arc welding process. Here it is important to take into account the thickness of the metal being welded, on which the diameter of the electrode and the current strength for normal operation of the welding machine depend. If the current strength is set too low on the inverter, then it will not be possible to obtain a stable arc; it will go out all the time, and the electrode, accordingly, will stick to the metal surface.

5. Arc too short. You should begin learning the basics of welding by igniting the arc and holding it in a stable state. You can find out what the arc length should be from the relevant literature. However, this is precisely the second problem of novice welders, which is associated, first of all, with the lack of the necessary experience.

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Spatter during manual arc welding with coated electrodes and ways to reduce it

Over the past 20 years, in industrialized countries, the share of metal deposited by manual arc welding has decreased by almost 3 times. There is reason to believe that in the near future the share of manual arc welding (for deposited metal) in industrial countries will stabilize at 15-25%, and in the world as a whole the decline will be mainly due to developing countries and China. The predominant use of this welding method in construction (at least 85-90% of the total volume of welding work) will continue in the coming years.

Spattering during manual arc welding with coated electrodes

This determines the following advantages of manual arc welding with coated electrodes compared to mechanized arc welding methods:

— the ability to weld in very inconvenient and difficult to access mechanized welding methods;

— simplicity and low cost of equipment compared to mechanized welding methods;

— the ability to monitor the welding process and high maneuverability of the process, ensuring the execution of short and long seams of any shape in various spatial positions;

— welding with coated electrodes allows you to obtain weld metal of almost any composition due to alloying through the coating without expanding the range of wire;

- is the main method of welding in field conditions during the installation of main and field pipelines, despite the existing proven mechanized methods of welding in shielding gases.

However, along with the advantages, this welding method has disadvantages that reduce the effectiveness of its use: low productivity compared to mechanized welding methods; dependence of the quality of the welded joint on the qualifications of the welder; different rates of melting of the electrode at the beginning and end of the process (since the current flowing through the electrode heats it up and the resistance changes); large losses of metal due to waste and spattering, cinders, in total amounting to 10-20% of the mass of the rod.

The main reasons for the ejection of metal droplets from the welding zone include:

— unstable nature of metal transfer, when the force separating a drop from the electrode is directed away from the bath and the drop is thrown beyond its boundaries; transfer instability can be caused by the conditions of arc discharge development and metallurgical factors, in particular the intense occurrence of chemical reactions;

- local explosive release of gases in the volume of metal, caused by metallurgical reactions and leading to the release of metal particles from drops or, less commonly, from the bath;

— destruction of the bridge of liquid metal formed during the transfer of metal with short circuits as a result of a sharp increase in current density when the bridge narrows; spattering largely depends on the dynamic characteristics of the current source;

— insufficient stability of the welding process.

The intensity of metal spattering depends on many factors:

— type of electrode coating (constituent components of the electrode coating) and the condition of the surface of the base metal edges;

— characteristics of the power source (the work has established a relationship between the dynamic characteristics of the power source and losses due to spattering of the electrode metal);

- values and ratios of welding mode parameters, etc.

There are no exact data on the magnitude of spatter during manual arc welding with coated electrodes. We can only divide the existing brands of electrode coatings into three groups: with large, moderate and small spatter. Thus, there is clearly insufficient data on the issue of spatter during manual arc welding with coated electrodes.

This paper presents a research methodology for determining the loss of electrode metal due to waste and spattering during manual arc welding with coated electrodes.

Losses due to waste and spattering are determined by the formula

where Qp is the amount of molten electrode metal, g; Qn - amount of deposited electrode metal, g.

A quantitative indicator of metal spattering is the spattering coefficient Ψ, which represents the ratio of the mass of splashes to the mass of molten metal of the electrode:

In this work, the influence of the brand (composition) of the electrode and welding current on the size and amount of spattered electrode metal was investigated. A VDU-306 UZ rectifier was used as a power source. Welding was carried out in a box to facilitate the collection of splashes.

All resulting splashes were divided into three fractions: with a diameter of 1.6 mm or more, 1-1.6 mm and less than 1 mm. The results of the studies are shown in Fig. 1.

Spattering of electrode metal is accompanied by its splashing onto the surface of the parts being welded during manual arc welding and can reach significant values (see table).

According to the results of studies conducted to determine the complexity of cleaning the surface of welded products from splashes of molten metal, it was found that when welding with electrodes with a diameter of 3 mm, the time for cleaning (manually using a chisel and hammer) is 35% of the welding time, and with electrodes with a diameter of 4 mm - 42 %.

Therefore, the problem of combating spatter during manual arc welding with coated electrodes is no less relevant than during mechanized welding in CO2.

There are two ways to reduce the amount of droplets of molten metal splashed onto the surface of the parts being welded:

— eliminate or reduce the amount of spatter (by developing metal transfer control systems or new welding materials, technologies and welding techniques);

— the use of coatings to protect the surface of the metal being welded from splashes of molten metal.

In Fig. Table 2 shows the results of experimental studies to determine the amount of spatter (the mass of hard-to-remove droplets from the surface of welded parts) during manual arc welding with coated electrodes with and without the use of a protective coating. The experimental procedure was as follows: two plates were welded with coated electrodes with and without applying a protective coating; easily removed drops were collected from the surface of the welded products using a brush, and difficult to remove drops were collected mechanically; The mass of collected and cut droplets was determined by weighing. Protective coatings No. 1 (Patent 2297311 (RF)) and 2 (caustic soda, CBJ, water) were used (see Fig. 2).

Rice. 2. Dependence of the amount of spatter on the welding current during manual arc welding with electrodes UONI-13/45 (a), OK 53.70 (b), LV-52 (c), MR-3 (d) and MR-3 (ESAB) (e) (light columns - uncoated, dark - coating No. 1, white - coating No. 2)

Let's compare drops of molten metal when welding in carbon dioxide and manual arc welding. A drop of molten metal during manual arc welding can be covered with both a protective layer of molten slag and oxides of molten iron - FeO, Fe2O3, Fe3O4, and when welding in carbon dioxide - a drop without coating.

It has been established that the presence of an oxide film and contaminants on the surface of the metal being welded reduces the adhesion strength of the drop to the surface of the product being welded. Consequently, the presence of an intermediate layer between the drop and the surface of the welded product affects their adhesion strength. It is possible to use protective coatings as an intermediate layer during manual arc welding.

1. When determining the losses of electrode metal due to waste and spatter during manual arc welding with coated electrodes of various brands, a relationship was established between the amount of losses and the welding current, which made it possible to select rational welding modes with minimal losses of electrode metal.

2. It has been established that difficult-to-remove splashes are located at a distance not exceeding 40 mm from the joint line.

3. The use of protective coatings of various compositions makes it possible to reduce spattering by more than 2 times, while to effectively protect the surface from splashes, the coating must be applied at least 40 mm from the joint line.

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Communities › Body Repair › Blog › Help. The semi-automatic spits!

Hi all! I'm already exhausted and don't know what to do. In general, I have a semi-automatic BestWeld Master 132A. Does not cook in a protective gas environment. It welds fine with flux-cored wire, but it craps on the seams like a bird, and doesn’t want copper-coated wire in carbon dioxide. When you try to weld copper-plated with carbon dioxide, the welding simply spits out and does not weld anything. You just end up with drops of scale on the metal and that’s it. I've already tried everything, played with the settings, measured the voltage, and changed the polarities. There's no point. I’m already sinning with bad gas... Tell me, who has had this happen!

Welding speed

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Welding speed is the speed at which the electric arc travels along the welding site. It is controlled by a welder.

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The speed of movement of the welding torch must be controlled by the welder and correspond to the wire feed speed and arc voltage selected in accordance with the thickness of the metal being welded and the shape of the seam.

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It is important to achieve the correct welding speed. Too high a speed may cause too much molten metal to splash. Shielding gas can remain in the rapidly solidifying molten metal, forming pores. Welding speeds that are too slow can cause excessive penetration of the welding arc into the metal being welded.

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The speed of the welding torch affects the shape and quality of the weld. Many experienced welders determine at what speed the welding torch should be moved by looking at the thickness and width of the seam during the welding process.

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