How to cook aluminum with a semi-automatic for beginners

How to choose?

The main purpose of the welding wire is to fill the weld formed in the process of joining metal structures. In simple terms, additives reduce the loss of base metal products. The main thing is to choose the right additive. Welders claim that there are only two rules to follow when choosing a quality welding wire.

The additive material must be identical to the composition of the product to be welded.
That is why, when choosing a wire, it is extremely important to get acquainted with its composition. For example, for welding on cast iron, it is better to use a solid wire of the appropriate thickness.
However, this list may also include substances harmful to human health, namely sulfur and phosphorus.

Accordingly, the welder must exercise the utmost care when working with such an additive.
The melting point of the additive must be lower than that of the structure to be joined. The high melting temperature of the wire can damage the weldable structure, leaving burn-out spots on the metal.

When choosing a wire according to the marking, you need to pay attention to several nuances:

• the diameter of the welding consumable must be identical to the thickness of the metal;
• the additive should not even have a hint of rust, paint and other chemical compounds;
• the finished weld should be free of slag, cracks and even minimal pores.

2 Operational features

Welding carried out with the use of flux-cored wire is now widely used.

This is due to the undeniable advantages of this consumable. For example, when carrying out conventional flux-cored welding, some difficulties may arise associated with the impossibility of directing the electrode to a hard-to-reach welding spot.

In addition, monitoring the seam formation process will also be difficult. Quite often, such difficulties arise in the process of semi-automatic welding.

This welding method has many advantages.

Unforeseen difficulties can also arise when the process is carried out using protective gas, for example, the gas flow can be disturbed by a draft.

Under these conditions, it is most expedient to use the so-called flux-cored wire. This is due to the fact that this product combines such positive qualities of electrodes as:

• alloying;
• high degree of protection;
• metal deoxidation;
• high level of performance.

In addition, flux-cored wire does not need a gas cylinder, additional hoses, reducers, flux equipment and, in fact, flux.

When carrying out the welding process, it is possible with a considerable degree of ease to produce the direction of the electrode to the groove.

In this case, there is a good opportunity to observe the process of forming the resulting seam.

2.1 Types of flux-cored wire

The design of the presented consumable can be of several types:

• simple;
• tubular;
• with shell folds;
• two-layer.

Bends are created so that the wire has the required degree of rigidity. In addition, the folds prevent unauthorized pouring of powder during the squeezing of the material by the feed rollers of the semiautomatic welding machine.

Flux-cored wire construction (sectional view)

The powdery filler contains a mixture of ores, ferroalloys, chemicals and minerals.

Its immediate task is to reliably protect the metal from exposure to air, ensure the stabilization of the arc discharge, deoxidation, alloying and formation of the weld structure.

According to the classification of the composition of the product, there may be:

• rutile;
• rutile organic;
• rutile fluorite;
• carbonate-fluorite;
• fluorite.

For their intended purpose, products are divided into two types:

1. Self-shielding - they weld without additional gas shielding.
2. Products for welding in carbon dioxide environment.

When using wires with self-shielding properties, the welding process is greatly simplified. This is due to the disappearance of the need to use bulky gas cylinders.

If flux-cored wires are used, which are in an environment of carbon dioxide, then the mechanical characteristics of the seam will be significantly increased.

2.2 Features of welding technique

The presented flux-cored wire when welding involves the use of a semiautomatic hose.

Since the weld will be constantly available for review, the technology for welding butts and fillet joints is practically indistinguishable from welding using consumable electrodes.

There are times when the slag formed on the upper edge of the surface of the resulting weld can enter the gap that was formed by the two edges.

When welding, which consists of several stages, all already formed seams are intensively cleaned in order to get rid of excess slag.

It is known that flux-cored wire does not have high parameters of mechanical strength and rigidity.

For this purpose, it is imperative to use a special mechanism that provides continuous automatic wire feed. The mechanism provides a limited increase in the compression ratio using feed rollers.

2.3 Semiautomatic welding using flux-cored wire (video)

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Welding of stainless parts with a semiautomatic device

Welding stainless metals requires a special approach to the cleanliness of the edges to be joined and their preparation for work. When working with thick metal, it is necessary to remove the edges at an angle of 45 ° to 60 °, and clean the joints with an angle grinder. In addition, with the help of solvents, it is necessary to degrease the welding place, and the parts must be fixed with a gap of 1.5 mm to ensure the most complete penetration through the entire thickness of the metal. Then it is necessary to adjust the supply of inert gas or gas mixture, taking into account the thickness of the workpieces.

Presettings for a semiautomatic device are made based on the following proportions, namely:

• with a metal thickness of less than 1 mm, a wire of 0.6-0.8 mm is used with a feed rate of 150 m / h and a gas flow rate of 6-7 l / min;
• metal with a thickness of 1.5 mm is welded with a wire 0.8-1 mm in diameter at a speed of 150 to 200 m / h and a shielding gas supply of 6-8 l / min;
• stainless steel 2 mm is connected with products with a diameter of 1-1.2 mm, speed 200-250 m / h, gas flow rate from 7 to 9 l / min;
• for stainless steel 3 mm, use a wire of 1.2-1.4 mm, at a speed of 250-300 m / h and with a gas supply from 9 to 11 l / min;
• for parts over 4 mm thick, a wire of 1.4-1.6 mm is required when moving above 300 m / h, and gas is supplied at a flow rate of more than 11 l / min.

The arc voltage depends on its length and is set from 19 V to 30 V with an experimental selection, as well as the stickout of the electrode. On a number of high-end MIG / MAG inverters, there is an inductance adjustment mode, which determines the penetration depth and the width of the weld.

The presets are advisory in nature and are selected individually depending on the composition of the metal, wire type, gas mixture and welding speed.

After the selection of the wire for welding with a semiautomatic device applied to the material of the workpieces, it is necessary to place the drum on the shaft and insert the wire into the feeder. Then adjust the travel speed, which is usually related to the strength of the welding current, the higher the speed, the higher the applied value. The last stage of preparation for work is to adjust the parameters of the gas mixture, adjust the voltage and inductance.

It is important to follow the instructions for use of the semi-automatic inverter and follow the safety rules for welding.

Semiautomatic aluminum welding technology

The quality of the weld obtained depends on many factors - the apparatus used, the filler material, the quality of argon (in argon-arc welding), the skills of the welder. How to weld aluminum with a semiautomatic device? Depends on the model of the device, but whatever it is, it is necessary to perform the following actions:

preparation of workpiece surfaces. Remove all kinds of contamination with a rag. Next, you need to remove the oxides. They are removed using a metal brush, an angle grinder and etching with special solvents and reagents. At the same time, they adhere to such rules. The brush should not press hard on the product and cleaning is carried out in only one direction. The remains of etching liquids must be removed using acetone solvents or rinsing. For products with a thickness of more than 3 mm, the edges are cut. Groove angle 60 0;

heating. Carried out in ovens or with a burner. This is especially true for workpieces with different thicknesses. Warm-up temperature should not exceed 110 0С;

setting up the device. Regardless of the type of device used, the wire diameter, tip diameter, current and voltage are selected. Most often, they use special tables that are available in the instructions for the product. The most advantageous are devices of the pulse type, equipped with a special program. The welder only sets the current value, and the microcontroller selects the rest of the parameters in automatic mode;

determine the position of the torch and the speed of the welding process. It should be located at an angle of no more than 20 0 to the vertical, welding is carried out at high speed only from right to left

Particular attention must be paid to the end of the seam. It is welded, going back 20 mm, without turning off the welding arc.

The welding result is influenced by the qualifications of the welder and his skills. He must use protective equipment - a mask, respirator, overalls, shoes and gloves. The welder should not have open areas of the body, since it is possible to get burned from ultraviolet radiation.

A few words about the causes of marriage. Most often, after welding, burn-throughs, cracks, and an incorrectly welded crater are found. Cracks occur due to a violation of the technological process.

When the heating temperature is exceeded, the alloy expands, and if slow cooling is not ensured, then rapid compression occurs, which leads to the occurrence of cracks and ruptures. The use of heat-dissipating pads will ensure the quality of the welding. Also, unfair preparation of the product for the welding process also negatively affects the quality.

Semi-automatic welding machine for aluminum welding is a device that allows you to increase labor productivity. Its use will be effective if all the requirements of the device manufacturer, which are indicated in the passport, are taken into account. Therefore, it is necessary to carefully study the instructions and follow its instructions.

Selection and configuration of equipment

Semi-automatic welding machine for aluminum

Welding of aluminum with standard MIG machines is conditional, i.e. you can cook with it, but you should not expect a good result.

The optimal solution in the selection is a semiautomatic device for welding aluminum with a pulse mode. The pulses break through the oxide film, reduce overheating of aluminum and reduce the likelihood of burn-through.

DC pulsed aluminum welding

Synergic pulse-arc devices equipped with a special program make the task even easier. The welder needs to decide on the choice of alloys to be welded and select the appropriate program. Next, set the current value with the push-button regulator.The selection of the rest of the parameters is carried out by the microcontroller automatically.

I would like to note that these semiautomatic devices are not a cheap pleasure and are justified in professional use. At home, it is quite possible to do with equipment without fancy programs, however, the quality of the weld will be incomparable.

When buying a universal welding semiautomatic device in the price range up to 40 thousand rubles, designed for welding non-ferrous metals, incl. aluminum, you can take a closer look at the following models:

• Svarog REAL MIG 200 (N24002)
• Svarog PRO MIG 160 SYNERGY (N227)
• Svarog PRO MIG 200 SYNERGY (N229)
• Grovers MULTIMIG 200 SYN
• Aurora PRO OVERMAN 180

Semi-automatic wire

When welding aluminum with a semiautomatic device, certain requirements are imposed when choosing a welding wire

Important points to pay attention to:

• the melting temperature of the wire should be comparable to the temperature of the metal being welded. Less spread - the welding process is easier;
• optimal wire diameter 1.2-1.6 mm;
• larger diameter - easier feeding into the welding zone.

Common types of aluminum welding wire are ER4043 and ER5356. Designed for welding and repairing products made of aluminum and its alloys with a silicon content of no more than 5%.

Welding modes for ER4043 and ER5356 wires

ER 4043 Aluminum Welding Wire

Welding torch

The welding torch uses a Teflon guide to reduce the friction of the wire. It is desirable that the sleeve for aluminum welding is intended only for welding aluminum and not too long - 3 m.

Push-pul- torch

The contact tip must be designed for welding aluminum (in addition to the wire diameter, the AL marking is stamped on them); simple ones used for welding ferrous metals and stainless steel are not suitable. This is due to the strong expansion of aluminum during heating. The diameter of the hole should be about 0.4 mm larger than the diameter of the wire, and at the same time not too large to ensure good electrical contact.

It is difficult to use an aluminum wire with a diameter of 0.8 mm due to the ductility of the metal and the complexity of broaching. The solution to this problem can be the use of a Push Pull welding torch. A special built-in mechanism will improve wire feed and allow longer torch length.

Wire feeder

Due to the increased ductility and softness of aluminum wire compared to steel, the feeder must have a number of features, such as:

• four-roller feeder. It is necessary for uniform pressing of each pair of rollers;

• feed rolls with U-grooves specially designed for aluminum wire.

Shielding gas

The most commonly used shielding gas is argon, which has a good cleaning effect and good penetration into the weld pool. When welding aluminum alloys with a high magnesium content, mixtures of argon with helium are used as a shielding gas (up to 75% helium in the mixture). Such mixtures prevent the formation of magnesium oxides.

Here the question may arise, how to cook aluminum in an atmosphere of carbon dioxide or without gas at all, because argon is quite expensive?

The cheaper carbon dioxide used for welding low-carbon steels will not work in this case. CO2 is an active gas, it will protect the weld pool from air, but at the same time it will react in aluminum, preventing the formation of a strong joint. Therefore, in this case, it is the inert gas that is used.

Welding with a semiautomatic device without gas is possible using a special flux-cored wire that protects the weld pool.

Safety engineering

The use of protective equipment is a prerequisite for welding.It is imperative to use a respirator mask, protective mask, special clothing and footwear to protect against the glow of the welding arc and splashes of molten metal. Acrid white smoke emitted from aluminum welding provokes coughs and headaches.

Particular attention should be paid to protecting exposed areas of the body from the effects of UV radiation. when welding aluminum, it is much more intense than when welding other metals

If you try to weld in "shorts" and in a "T-shirt", the effect of the solarium is provided to you already after 30 minutes.

Semi-automatic welding of aluminum is not comparable in quality with the use of TIG, however, it is more than compensated by the significant productivity. It is an excellent solution for hardfacing or filling large gaps. In industrial conditions, the use of semiautomatic devices is most expedient due to the volume and high speed requirements. The use of industrial devices and the high qualification of the welder allow achieving excellent results.

Advantages

• Additional use of flux and its calculation in a certain proportion is not required;
• The welding process becomes better and the percentage of rejects decreases;
• Wire use becomes simpler and more efficient;
• Many negative nuances of difficult-to-weld metals fade into the background due to correctly selected additional consumables;
• The connection is accelerated, as the flux cored wire allows it to come into contact with the base metal more quickly;
• For automatic devices, this is one of the best options, which guarantees a more reliable connection;
• There is no risk that any extra elements will get into the molten seam with the flux.

Preparation of surfaces to be welded

Cleaning aluminum before welding is the key to a successful joining of parts. Stainless steel brushes or pickling solvents and reagents can be used to remove aluminum oxides.

Metal cleaning rules:

1. Do not use a brush that has been used to clean any steel such as stainless or carbon steel.
2. Do not press hard on the brush - with strong pressure, oxides penetrate the workpiece.
3. Cleaning with a stainless steel wire brush is carried out in one direction only;
4. If etching liquids are used, care should be taken to remove them from the surface of the workpiece before welding with acetone or solvent.

Stripping aluminum before welding

Varieties of wire for semiautomatic devices

The selection of welding wire for semiautomatic devices should be carried out for a specific type of metal to be joined. The use of an additive consumable material significantly improves the quality of the seam, prevents the formation of pores and irregularities in the joint.

The main advantages of using the additive in welding are presented:

• acceleration of the welding process;
• ease of use in the industrial field;
• a significant reduction in the likelihood of defects due to the lack of additive coating;
• a large selection of consumables, allowing you to select the optimal additive for each specific case;
• low level of slag formation during welding.

Disadvantages of using a filler component when welding:

• the need for constant protection;
• difficulty in storing large skeins;
• difficulty in selecting the optimal diameter of the additive;
• the need to constantly use flux.

Wire grades table.

All types of welding wire are generally divided into:

1. Copper-plated.
   This type of wire is used for welding carbon and low alloy steel parts. Copper-plated steel fillers ensure a good weld and low metal spatter.
2. Powder.
   Additive components of these grades are made in the form of a hollow tube made of mild steel. Deoxidizers and slag-forming substances are placed inside the tank, ensuring comfortable use of semi-automatic welding without shielding gas. Flux-cored filler wires help to significantly reduce slag formation and shorten the processing time of the weld.
3. Solid section.
   This type of wire differs from the usual one in that welding electrodes are made from it.
4. Non-copper plated.
   Additives of this type are used primarily for working with low-carbon steel products.
5. Activated.
   Powder additives used when welding in a carbon dioxide atmosphere.
6. Gas welding.
   For carbon and low carbon steel grades, it is best to use gas welding consumables.
7. Aluminum.
   One of the few wire types suitable for welding aluminum parts. When working with an aluminum additive, the porosity of the welds is low. Such additives are actively used in the shipbuilding and dairy industries.
8. Stainless steel.
   The filler component allows welding stainless steel products and prevents corrosion of the resulting weld.
9. Flux.
   This type of filler wire is widely used for joining medium carbon, low carbon and carbon steel grades. Due to the presence of a built-in flux, such additives can be used when welding without shielding gas.
10. Doped.
    One of the best components for welding in any gas mixture and with any kind of metal.

disadvantages

• Submerged arc welding wire has a relatively high cost, so the cost of the joining process is not always advantageous;
• These varieties are not as common as standard varieties;
• In some cases, the problem of poor weldability is not solved and additional funds are still required;
• The thickness of such material is higher, which complicates the selection of the required diameter for the selected operating mode.

Physicochemical properties

The semi-automatic flux cored wire has good ductility and works well with the machine's feeding system. At the same time, the material has great wear resistance, which makes it easier to move, store and contact with other surfaces. This is done to protect the flux layer from damage. The automatic submerged arc welding wire has a lower melting point than the base metal. The properties of the steel material allow you to work with both low carbon and high carbon workpieces.

Submerged arc welding wire

Improved welding properties due to selected soft metals and the presence of additional elements ensure stable arc burning when using argon arc welding. The material contains a minimum amount of hydrogen and other substances that negatively affect the state of the weld and can cause cracks, pores and other elements of marriage. This leads to the formation of a relatively small slag crust on the surface, so that it can be removed without problems.

Varieties

Submerged-arc welding wire varies in diameter and in the base metal with which it will be welded. Which flux will be used depends on this:

• For steel, the material is separated, depending on the level of alloying, since it can be used for high-alloy steels to replace those elements that are lost during heat treatment. This also applies to welding stainless steel.
• For copper, 08mm flux cored wire, which is designed to work with copper parts, helps to improve the bonding of this refractory metal at normal temperatures.
• For aluminum - when welding aluminum, a flux is required, so this product will be an excellent option to do everything with the highest quality and reduce the likelihood of marriage.

Specifications

Features of choice

0.8 mm flux cored wire is used for the thinnest parts. For other procedures, 2 mm is suitable if the metal is 2-4 mm thick. For production, thicker versions of up to 6 mm are often used

When choosing, you need to pay attention not only to the diameter, but also to the composition, since this is a more important parameter. It should be as similar as possible to the base metal.

It is not necessary to select a flux, since everything is already determined automatically by the manufacturer. For private use in small volumes, it is better to buy welding wire for semi-automatic machines with flux in cassettes, and for large-scale work - in coils.

Welding features

The main feature that welding with flux-cored wire has is the absence of lengthy preparations. The only thing that has to be done here is to bevel the edges of the junction if the metal is more than 4 mm thick, and also to treat with solutions if the metal is prone to the formation of an oxide film. Wire for automatic submerged-arc welding, as well as its other varieties, has everything you need to ensure a quality connection in the area for which it is used.

The main thing here is to correctly set the feed rate, since due to the presence of additional materials, the melting temperature can be noticeably lower than that of non-flux analogs and the base metal. This is well manifested due to the fact that the wire begins to melt without any particular problems, even when working with small thicknesses, does not lead to melting of the metal.