Is it possible to weld aluminum to copper?

Welding copper and copper alloys with metals and alloys of other groups

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The aluminum-copper phase diagram indicates that in this system there are a number of chemical compounds that are stable at room temperature: θ-phase (Al2Сu), η-phase (AlCu), ξ2-phase, δ-phase (Al2Сu3), γ2-phase (AlСu2 ), γ-phase (Al4Cu9). They have high hardness and low ductility. At room temperature, copper has relatively low solubility in aluminum, despite the similarity in the crystal structure of these metals.

In comparison with the combination of aluminum with other metals (for example, Ni, Fe), the interaction of Al with Cu is characterized by high growth rates of intermetallic layers and a short latent period. For each method, there is a fairly narrow range of values ​​of technological parameters of welding modes and temperature-time operating conditions of the bimetallic joint.

Operation of the Al + Cu bimetal is allowed at a temperature not exceeding 400 °C in order to avoid intensive growth of the diffusion layer and a sharp deterioration in mechanical properties. When heated above the specified temperature in the aluminum + L96 compound, as it increases and the sample is held for longer, a δ-phase is formed, which diffuses into the brass, resulting in the appearance of a γ2-phase and an α-solid solution.

Saturation of the δ phase on the other side of aluminum leads to the formation of the θ phase.

Due to the fact that there are fairly ductile alloys of the Al-Cu system containing up to 7% Cu, and bronze alloys with an Al content of up to 10%, it is promising to conduct the fusion welding process when the copper content in the weld does not exceed 6-8 %.

Cold welding is used mainly for local cladding of aluminum parts with copper (current-carrying elements of transformers, busbars, current leads to electrolyzers) by spot welding, producing butt joints of wires, busbars and other elements of compact sections. The material of the blanks is technically pure copper and aluminum.

The cold rolling method is used to produce bimetallic sheets and strips (card and roll rolling). The degree of compression during rolling welding is 60-75%.

Due to the need to create a directed flow of metal in the joint zone, this specificity of the process imposes certain restrictions on the ratio of the thicknesses of the initial workpieces. In this regard, it is difficult or not at all possible to obtain sheet material with a thickness of more than 4 mm and a small thickness of the cladding layer. For the electrical industry, layered material with a minimum thickness of copper coating of 0.1 - 0.8 mm is obtained.

There are no fundamental restrictions on the sizes of sections when butt welding, except for the capabilities of the equipment itself. In reality, elements with a cross-sectional area of ​​up to 1000 mm2 are welded. The preparation and welding technique does not differ from the general technological principles of cold welding.

With this welding method, the formation of intermetallic compounds is excluded, since the process occurs without preheating.

Friction and ultrasonic welding are used for a wider range of welded aluminum and copper alloys. The main feature inherent in these methods is that, due to their specificity, undesirable products of the interaction of materials (intermetallic compounds) are continuously evacuated from the joint zone. When friction welding copper with the AMts alloy, an intermittent narrow (∼ 1.5 μm) zone of intermetallic compounds is observed on the sections.

In ultrasonic welding, the connection is made with an overlap at points or a continuous seam. Due to the specifics of the process, the thickness of the workpiece from which vibrations are applied is limited to a value of the order of 1.2–1.5 mm due to hysteresis losses in the thickness of the material.

Diffusion welding produces high-quality joints when welding Cu with Al and some of its alloys with the maximum possible limitation of heating temperature, welding time and when using barrier sublayers and coatings. Zn, Ag, Ni can be used as the material of such layers.

Fusion welding can only be carried out when the aluminum is mainly melted. This can make it possible to obtain metal in the weld with a limited (6-8%) copper content, which provides an optimal combination of properties of the joints. The main ways to solve the problem: the use of shot glass-shaped cutting of edges, reducing the risk of overheating of the metal at the root of the weld, alloying the weld metal with Si, Zn, and the use of barrier sublayers.

Electrolytically applying a zinc layer with a thickness of about 60 microns to the copper edge during argon arc welding makes it possible to reduce the copper content in the weld to 1% and reduce the length of the intermetallic layer on the copper side by 3-5 times (to 10-15 microns).

The edge of the copper billet is cut at an angle of 60°. The introduction of Zn through an additive during submerged arc welding leads to the fact that the copper content does not exceed 12%, and the amount of zinc in the weld can reach 30%.

The connections obtained in such cases fail when tested on aluminum far from the seam.

Electrolytic deposition of a layer of tin or zinc on the copper edge when welding metal of small thickness (3-8 mm) makes it possible to obtain high-quality joints, since the coating layer, which acts as a barrier, also creates a layer in front of the moving wave of liquid metal, facilitating wetting of the surface with molten aluminum .

The use of more severe welding conditions (higher than necessary for welding aluminum) helps to obtain satisfactory joint quality. As the welding speed decreases, the transition of copper into the weld increases, and the time the contact zone of materials remains at the temperature of intensive growth of intermetallic compounds increases. It is recommended to select the heat input from the ratio q/v=(18.8—20.9)δ, where δ is the thickness of the material being welded.

The electrode displacement towards more thermally conductive copper should be (0.5-0.6)δ.

Welding copper with titanium

A feature of the metallurgical interaction of Ti with Cu, which influences the conditions and the very possibility of obtaining compounds between them and the quality of the connection, is the ability of these metals to enter into chemical interaction with the formation of intermetallic compounds Ti2Cu (39.88% Cu), TiCu (57.0% Cu ), TiCu3 (79.92% Cu), give low-melting eutectics at a copper concentration of 66 and 43% with a melting point of 855 and 955 °C, respectively. Titanium and copper form a system with limited solubility and eutectoid decomposition of the β-phase. The maximum solubility of copper in α-titanium and β-titanium is 2.1 and 13.4% at 990 °C. The solubility of Ti in Cu at 400 °C is 0.4%. Therefore, under fusion welding conditions, when the material of both workpieces is in a liquid state, intermetallic compounds and low-melting eutectics will inevitably appear in the weld metal during crystallization. The latter circumstance is associated with the risk of cracks. The materials under consideration differ sharply in melting temperatures and other thermophysical characteristics.

Due to the indicated metallurgical and physical characteristics for this pair of materials, pressure welding processes have the greatest prospects. The use of welding methods in the liquid phase is possible provided that only the copper workpiece is melted (welding-soldering mode) with a limited duration of contact of the melt with the solid metal or using intermediate inserts that act as a barrier.

Diffusion welding without the use of intermediate barrier layers is possible in a narrow range of conditions and produces connections with low strength. To obtain an equal-strength connection, layers of vanadium, molybdenum, and niobium are used.

When welding OT4, VT14 with copper Ml and bronze BrKh0.8, interlayers of Mo and Nb with a thickness of 0.1-0.2 mm are used in the form of foil or a sprayed layer. In the latter case, after deposition on Ti, annealing is carried out in vacuum at a temperature of 1300 °C for 3 hours.

The use of these materials is due to the fact that they form solid solutions with Ti, but do not form brittle phases with Cu. In diffusion welding, the best results are obtained when using radiation (furnace) heating. Heating temperature 950-980 °C. Duration 0.5-5 hours.

Higher temperatures and durations apply to oven heating.

Fusion welding is carried out by melting only copper. The use of hard modes helps to reduce the contact time of the melt with solid titanium.

Electron beam welding under severe conditions produces joints with satisfactory mechanical properties only on thin sheet workpieces.

When argon-arc welding, preliminary plasma spraying of a copper coating 0.15–0.25 mm thick onto a titanium edge, displacement of the electrode from the axis of the joint towards Cu by 2.5–4.5 mm and cutting of the titanium workpiece at an angle of 45° slightly improves the conditions weld formation, but do not completely prevent the appearance of intermetallic compounds. With subsequent heating of such a compound to 400-500 °C, the strength and ductility sharply decreases.

A radical solution for fusion welding is the use of Nb or Ta inserts. Electron beam welding produces joints with high ductility (bending angle 180°). With ADS, this figure is 120-160°. Impact strength at the level of 700-800 kJ/mm2. When testing welded joints, fracture occurs along the boundary with the copper alloy.

Welding copper with refractory metals

Copper and molybdenum are mutually insoluble, but liquid copper is able to wet its surface. Therefore, to obtain a joint of this combination of materials, welding-brazing, diffusion and electron beam welding have been used. In the electronics industry, the method of pouring molybdenum rods into special mandrels in a vacuum with molten copper and then manufacturing machining parts from the resulting workpiece has become widespread.

Welding Cu with Nb is complicated by significant differences in melting points and thermal conductivity and different reactions to the presence of hydrogen. Therefore, only Nb with a low hydrogen content is suitable for fusion welding. Nb with Cu forms limited solutions. At 950 °C, 2.2% copper dissolves in Ni.

In argon arc welding, the tungsten electrode is placed above the copper edge with a slight excess above the edge of the second workpiece (about 0.2-0.25 mm). In this case, electron beam beam is shifted towards the copper workpiece by about 0.75 times its diameter.

The welding process is critical to the accuracy of assembly and the location of the heating spot on the product. In case of deviation - lack of penetration, burns, undercuts. Due to its high thermal conductivity, the melt quickly crystallizes and released gas bubbles can be recorded in the seam.

This defect is eliminated by re-melting.

Welded joints made by argon arc and electron beam welding are equal in strength to the base material (destruction during testing occurs along copper) and are quite ductile (bending angle 120-180°).

Welded joints between W and Cu, made directly by diffusion welding, have low strength. The Ni sublayer makes it possible to obtain welded joints with a strength level of up to 133 MPa (welding temperature 700 °C, welding pressure of about 15 MPa, welding time 15 min). At the same time, the fatigue strength of the connection significantly increases under thermal cycling conditions.

Source: https://www.autowelding.ru/publ/1/1/svarka_medi_i_mednykh_splavov_s_metallami_i_splavami_drugikh_grupp/2-1-0-191

Semi-automatic copper welding technology at home

When the conversation turns to welding copper, it is necessary to understand that this metal has unique properties. Namely: excellent ductility, high thermal and electrical conductivity, highest corrosion resistance. Plus excellent aesthetic qualities.

Therefore, copper is used today in a variety of fields. And since everyone has to meet with it often, there is a high probability that a large circle of people will be interested in the process of welding this metal.

Therefore, the question of whether copper welding can be carried out at home is of interest to many today.

Features of copper welding

It should be noted that the purer the copper, the better it welds. But besides this, the following factors also influence the quality of the process.

• Like many non-ferrous metals, copper begins to oxidize when it comes into contact with oxygen. Oxide is a thin heat-resistant film that interferes with the welding of copper workpieces. Therefore, at the preparation stage, the oxide film must be removed in different ways.
• Copper has a very high linear expansion coefficient. It is one and a half times more than steel. Therefore, when cooling, severe shrinkage occurs. It is this factor that negatively affects the quality of the seam, in which cracks appear during shrinkage.
• When heated, copper absorbs hydrogen and oxygen. The first forms pores inside the metal after cooling. The second oxide is on the surface.
• With sudden heating and cooling, the structure of the metal changes. From fine-grained it turns into coarse-grained. And this is an increase in fragility in the welding zone.
• The thermal conductivity coefficient of copper is seven times greater than that of steel. That is, when heated, the metal quickly melts, and when the temperature decreases, it quickly becomes solid. An abrupt transition from one stage to another causes the formation of defects inside.
• Fluidity of copper. This figure is 2.5 times more than that of steel. At high temperatures, and this is sometimes required for welding thick workpieces, complete penetration on one side is almost impossible. Therefore, welding of copper and its alloys is carried out using double-sided technology. When the seam is completely welded on one side, and the weld seam is finally formed on the back side. By the way, it is the fluidity of copper that complicates welding in a vertical and overhead position.
• Before cooking copper, you need to understand that the strength and ductility of the material decreases with increasing temperature. Up to +200C these indicators are still normal, but with an increase their value decreases sharply. For example, when heated within 500-550C, ductility practically drops to zero. Therefore, there is a high probability of cracks appearing inside the weld. At a high current value, you should not carry out a two-layer filling of the gap between the workpieces to be welded, even if the parts are thick. We must try to do everything in one pass.

As mentioned above, the easiest way is to weld pure copper without impurities or deoxidized copper, which contains only 0.01% oxygen.

And since such copper is rare, its alloys are mainly used in industry, it is recommended that welding be carried out in shielding gases or fluxes with filler materials that include deoxidizing agents. Namely: silicon, manganese, aluminum and other additives.

By the way, copper welding with (melting) electrodes can also be carried out. The only thing is that the rod contains the deoxidizers mentioned above.

Manual arc welding of copper alloys

In general, copper arc welding is often used, especially at home. The feasibility of application depends on the speed of the process. In this case, semi-automatic or automatic copper welding can be used.

Copper welding technology is as follows.

• The edges of the workpieces being joined are cleaned from contamination, for which any solvent is used.
• Then the oxide film is cleaned off using iron brushes, sandpaper or other abrasive tools.
• Next, the electrode welding process itself is carried out.

But since the thickness of copper parts can vary widely, the welding mode itself will differ. For example, to connect workpieces with a thickness of 6-12 mm, it is necessary to cut the edges so that a V-shaped gap is formed.

In this case, the angle between the edges should be within 60-70°. If double-sided welding is used, the angle can be reduced to 50°.

The gap between the parts is created by shifting the workpieces so that a gap with a width of 2.5% of the length of the weld itself is formed between them.

If the parts are not moved apart, then it is necessary to tack them. Tack welding is carried out by incomplete welding of the seam with a length of 30 mm every 300 mm. In this case, a gap of 2-4 mm should be maintained. When welding copper with an inverter, reaching the tack, it must be removed by knocking it down with any impact tool. Because double penetration of copper will lead to a change in its structure and the appearance of defects inside the weld.

If the metal being welded has a thickness of more than 12 mm, then it is better to use X-shaped cutting of the edges, and, accordingly, double-sided welding. If for some reason it is impossible to use this cutting, then you can use a V-shaped one. True, you will have to completely fill the gap, which will take more electrodes and time.

Useful tips

• It is better to weld butt joints on pads, which will lower the temperature in the welding zone and prevent metal from flowing through the gap. Here you can use steel, copper, graphite and other linings. The width of the lining is 40-50 mm.
• Before welding copper with an electrode, it is necessary to heat the edges to 300-400C.
• The rod of electrodes used for welding copper alloys must be made of copper or bronze with alloying additives (silicon, manganese, etc.).

Manual argon arc welding

Welding copper with argon is another option for joining copper workpieces. For this purpose, direct current of direct polarity, a tungsten non-consumable electrode and filler material made of copper, bronze or copper-nickel alloy of the MNZHKT brand are used.

Before starting work, the edges of the joint are heated to 800C. Welding is carried out from right to left, the filler rod is in front of the torch. The arc is short.

Welding with carbon and graphite electrodes

This type of welding of copper alloys is rarely used. Carbon electrodes are used when connecting workpieces up to 15 mm thick, graphite electrodes are larger than this value. Welding mode:

• The current is constant.
• Polarity is straight.
• The filler rod is not immersed in the weld pool. Distance 5-6 mm.
• The process is carried out in a protective flux. It is applied to the filler rod, which is pre-dipped in liquid glass.
• The gap is 0.5 mm.
• An asbestos or graphite lining is used.
• Copper up to 5 mm thick is welded without preheating.
• Welding must be done in one pass.

Welding copper and aluminum

These two metals can be welded in two ways: resistance welding and locking. In the first case, it is necessary to take into account that aluminum material has a lower melting point than copper. Therefore, when joining, you need to take a longer aluminum billet to correct for melting.

When welding, it is recommended to blow the welding zone using nitrogen. Air will not flow here; it will immediately form an oxide film. If copper and aluminum tubes are welded, they must be placed on the rod, joining at one point.

A lock joint is when a flat piece of copper is placed on a plate of aluminum. In this case, the copper billet is welded around the perimeter. In this case, the width of the seam should be equal to the thickness of the copper plate. The process is carried out using graphite inserts, which will form the joint seam.

Cooking copper with steel is difficult, but possible. For this, the same methods are used as when welding two steel workpieces. The only thing you need to pay attention to is the different melting temperatures of the metals. Therefore, when forming edges, it is necessary to make the steel edge longer (3.5 times) and thinner, so that during the welding process the thin metal begins to melt faster.

If welding is performed with carbon electrodes, then the process is carried out using direct current of direct polarity. The length of the arc is 14-20 mm, its voltage is 40-55 volts, and the current is 300-550 amperes. Welding is carried out in a protective flux, which has exactly the same composition as when welding copper alloys. The flux itself is poured into the gap between the workpieces.

Sometimes there are situations when you need to weld a copper stud to a steel part. To do this, you need to use reverse polarity; the process itself is carried out under flux without preheating the edges. Steel studs are poorly welded to copper parts, so a copper ring is put on the stud for tension, which is welded to the copper workpiece.

These are the methods of welding copper alloys and workpieces that are used today in industry and in home workshops. Be sure to watch the video posted on this page of the site.

Source: https://svarkalegko.com/tehonology/svarka-medi.html

Soldering aluminum to copper

Soldering aluminum has always been a rather complex technological process, since its melting point is considered relatively low, and the properties of the connection are not at the highest level.

Soldering aluminum with copper becomes an even more complex and problematic process, since copper is difficult to melt, although it can be soldered normally. Despite the complexity of the process, there is a need for it periodically in various industrial areas and even in the home environment.

Under normal conditions, without any additional means and with standard materials, it will be almost impossible to obtain a high-quality connection without damaging the metal of the workpiece.

DIY aluminum and copper soldering

Soldering copper and aluminum requires a special approach, since even standard solder for soldering aluminum will be ineffective. It is worth noting right away that with aluminum there is a greater conflict with copper, since the soldering process with steel is better.

Many craftsmen use this when creating complex connections.

The need for such soldering arises both when connecting pipes or other large parts, and when connecting wires, which from the technical side is easier, simpler and faster, since there are no large loads on the final product.

DIY aluminum and copper soldering at home

Advantages

• Allows you to make complex connections required by operating technology;
• There are several different ways to carry out the process, which differ markedly from each other;
• Gives the master extensive experience and the ability to work with any type of metal.

Flaws

• High percentage of defects after completion of the process;
• Soldering aluminum-copper requires a large number of different additional materials, many of which are highly specialized, without which it is impossible to obtain a high-quality connection;
• Sometimes it is necessary to select steel couplings of the same diameter as the pipes being welded;
• The soldering process turns out to be very expensive due to the use of fluxes, special solders and other additional means;
• Many of the additional consumables are difficult to access, as they are not common and frequently used;
• Not every existing soldering method is suitable for a particular case;
• Only a master with extensive experience can cope with the work, and at home this is a difficult process.

Soldering difficulties

The main difficulty in soldering is that metal products made from these materials cannot connect normally, since even when the solder sets, the seam can crack even with a relatively small mechanical impact.

The situation is complicated by the aluminum oxide film, which envelops the solder material, interfering with a normal connection, and also does not melt under the influence of temperature.

Good cleaning and treatment with a solvent, followed by the application of a specialized flux, can help combat this.

Soldering aluminum to copper

Working with copper is also not easy in this case. After all, even solder for soldering copper pipes turns out to be not entirely suitable for such a process. It is refractory, which is what is required for such a metal.

At the same time, aluminum may have a lower melting point, which will cause it to burn out before the solder itself melts. Thus, brazing aluminum to copper turns out to be quite problematic.

Solder for melting aluminum may not be suitable for copper, as it turns out to be too fusible, but this is a more suitable option, since many craftsmen, especially when working at home, use silver solders.

Possible methods of soldering aluminum to copper

Soldering aluminum and copper at home and in production can be carried out in the following ways:

• Soldering using a coupling. In this case, a steel part is inserted between the metals, so that both copper and aluminum are soldered on different sides of the steel in more convenient ways, which helps to obtain a reliable connection, since they interact with steel and other alloys much better than with each other.
• When using special solders. Modern developments, for example, such as the Castolin brand filler material and specially developed fluxes for it, help solve many complex issues. The big disadvantage of this method is the high cost of consumables and low prevalence.

Solder for welding aluminum to copper

• Surface soldering. In this case, a socket is made from aluminum so that a copper tube can fit into it. The edges of this socket are sealed with low-melting solders, covering most of the surface of the copper pipe to increase the joint area.

Materials and tools

Regardless of whether you need to solder aluminum to copper wires, pipes or sheets, you will need:

• A burner (gas or gasoline) or a soldering iron, depending on the conditions under which all this is carried out;
• Solder that will be suitable for the chosen method, since soldering through a steel coupling requires consumables that will be designed for soldering with steel;
• Flux selected for solder to improve interaction with different metals;
• Steel, or some other alloy, coupling, if this method is chosen;
• Tools for fixing workpieces and cutting sockets.

Step-by-step instruction

1. All metal products that will take part in soldering are fully prepared. This includes cutting the edges, preparing the socket, mechanical treatment with a brush and solvents to remove all existing deposits and formed films.
2. The parts are then securely fixed so that there is no movement or displacement during the process.
3. At the next stage, the ends of the parts should be treated with flux.
4. Then you can begin direct soldering.

   If the method through the coupling is chosen, then it is first soldered to one workpiece, for example, a copper pipe. Then you need to take time to cool and check the quality so that there are no cracks or crevices. Only after this should you begin connecting with the second part, which is carried out in exactly the same way, but with the help of other consumables.

5. After completing the procedures, allow the seam to cool and check the completely finished product for defects before putting it into operation.

"Important!

When choosing consumables, you need to pay attention to the strength of the resulting connection, which is especially important when working with pipes that are operated under pressure.”

Mode table

Type of solder	Soldering mode	Maximum strength of alloys, kgf/mm2
AMts	AMg6	D20
P-300-A	440°C, 20 minutes	11	22	–
P-425-A	12	20,8	20,8
34A	550°C, 20 minutes	9-10	–	28,8
B-62	510°C, 15 minutes	12	–	23,8

Safety precautions

Work should be carried out only in well-ventilated areas, since fumes from fluxes and solders can be harmful to humans. When using a gas burner, it should be as far away from the fire source as possible. There should be no unnecessary objects or flammable items in the workplace.

Source: https://svarkaipayka.ru/tehnologia/svarka-alyuminiya/payka-alyuminiya-s-medyu.html

Welding copper to aluminum

Soldering aluminum has always been a rather complex technological process, since its melting point is considered relatively low, and the properties of the connection are not at the highest level.

Soldering aluminum with copper becomes an even more complex and problematic process, since copper is difficult to melt, although it can be soldered normally. Despite the complexity of the process, there is a need for it periodically in various industrial areas and even in the home environment.

Under normal conditions, without any additional means and with standard materials, it will be almost impossible to obtain a high-quality connection without damaging the metal of the workpiece.

Soldering copper and aluminum requires a special approach, since even standard solder for soldering aluminum will be ineffective. It is worth noting right away that with aluminum there is a greater conflict with copper, since the soldering process with steel is better.

Many craftsmen use this when creating complex connections.

The need for such soldering arises both when connecting pipes or other large parts, and when connecting wires, which from the technical side is easier, simpler and faster, since there are no large loads on the final product.

We perform copper welding at home

Welding of metal parts is a technological procedure that makes it possible to obtain permanent connections by forming a bond between intermolecular and interatomic particles of the material under significant heating until melting and plastic deformation. Spot welding of copper at home is used, as a rule, to join many metals and their alloys in all industrial fields, even medicine.

To carry out welding work, different energy sources can be used: friction, ultrasound, electric arc, electric current. Modern technologies are so advanced that work related to welding joints of metal structures can be performed not only in industrial enterprises, but also in the field, on reservoirs, under water, even in space.

But, as in any type of activity, there are nuances, advantages and disadvantages, requirements for the safety of work, etc.

Thus, when organizing welding work at home with workpieces made of copper, aluminum, brass, and stainless steel, it is necessary to follow the established precautions.

This type of activity is particularly dangerous to human health: there is a danger of damage to the organs of vision by ultraviolet radiation, contact with molten metal on the skin, electric shock, etc.

Copper Gas Welding Technology

Gas welding of copper at home is the most common technology used in domestic conditions. The resulting weld using this technique is highly durable. It is thanks to this parameter that gas welding is in great demand among home craftsmen. To connect copper products at home, you need to have on hand:

• Welding machine
• Gas-burners
• Gas cylinders (acetylene)
• Copper wire
• asbestos

Some advice from experienced welders

• If the thickness of the copper product is no more than 1 cm, the connection can be made with one torch.
• If the thickness of the copper sample is more than 1 cm, it is necessary to use two burners at once, the second will serve for heating.
• To reduce the outflow of thermal energy in this case, additional asbestos sheets will be needed.
• When welding copper products, it is recommended to use electrical wire made of copper, previously cleaned of paint and varnish insulating coatings.
• Cleaning must also be carried out on the welded edges of the products. This condition should not be neglected, since the possibility of cuprous oxide formation depends on it.

All necessary conditions for preliminary preparation for welding work have been completed. This means you can proceed directly to connecting the prepared copper products.

Recommendations

• You should try not to overheat the heated sections of the connection that are located close to each other.
• The concentrated flame must be directed perpendicular to the seam directly to the edge of the wire.
• The wire should melt before the edges of the product. The cooking process continues until the entire seam is completely formed.
• It must be remembered that stopping an unfinished connection can lead to overheating of some areas of the product, resulting in cuprous oxide and the formation of cracks.
• The completed weld must be forged.
• For small thicknesses of products, the wire must be kept cold.
• If the thickness of the product is more than 0.5 cm, then the wire must be heated to a temperature of 200 degrees. Higher temperatures are also allowed, but not more than 500 degrees, since the grain of the metal will form, which will subsequently become quite brittle.
• The welded, forged seam must be brought to a temperature of 500 degrees and cooled instantly.

At this point, the connection of copper parts can be considered complete.

Argon-arc welding of copper samples

Argon-arc welding at home is performed using welding equipment using direct current, non-consumable tungsten electrodes. The procedure is reminiscent of soldering products: the electrode is heated to a high temperature. As a result, the copper begins to melt.

With this welding technique, it is important to instantly cool the areas being joined. Argon-arc welding involves the use of argon and copper filler wire, which is pre-cleaned from the paint and varnish insulating coating.

Copper welding: area of ​​application of technology

Argon welding is used to repair structures made of copper. It has proven itself to be quite effective when performing welding work in hard-to-reach areas.

Argon-arc welding is quite in demand at manufacturing enterprises, and if you have the appropriate equipment, it can also be successfully used in domestic conditions.

If you have inverter welding equipment and special fusible electrodes, the procedure for joining copper samples can be carried out using the technology of welding steel products. There are practically no fundamental differences in this case.

But, with this joining method it is much more difficult to make a vertical seam than a horizontal one.

What you need to know about electrodes used for welding copper parts

To ensure a high quality weld, it is recommended to use electrodes coated with a special compound. Such a coating is necessary for the production of slag formed with metal oxides. It will prevent air from coming into contact with the weld.

The coating fills the voids formed during welding of parts due to burnout of components and subsequently introduces new components into the seam. This coating contributes to better stability of the electric arc.

The slag layer produced by this coating will slow down the cooling of the molten copper, causing more gases to escape from the weld.

Electrodes used in the welding process are divided into two types:

• melting - wire made of copper, steel, aluminum, cast iron is used for their production;
• non-melting - synthetic graphite and electrical coal are used for their production.

When choosing electrodes, you need to look at their color:

• yellow electrodes are intended for samples made of heat-resistant, corrosion-resistant steels;
• red - used for electric arc welding of copper products;
• gray – for blanks made of non-ferrous metals;
• blue - designed for connecting heat-resistant components.

Welding brass structures

Welding brass at home is a rather complicated procedure, since brass contains zinc, which evaporates when heated, as a result of which the product loses its original strength.

Brass itself is an alloy with zinc. The technology for joining parts made of brass is considered difficult due to the evaporation of zinc at high temperatures; this chemical element instantly oxidizes, resulting in the formation of a toxic, refractory oxide. Therefore, welding of brass samples should be carried out in specially equipped places equipped with an exhaust hood; welders should work in respirators.

Basic requirements for welding brass

• Cleanliness of the process when using argon-arc welding. Before starting work, the products are thoroughly cleaned to a characteristic metallic shine on the surface.
• There should be no oxides on the surface of the parts being welded; if present, they must be removed. Nitric acid is used for this. After this cleaning is completed, the product is washed in hot water and then dried.

When welding parts with argon, a characteristic continuous crackling sound is felt, and the welding arc has an amazing color. This is all due to the presence of zinc in the alloy. During the joining process, brass does not burn out or fly off in separate pieces, as it melts. Experienced welders advise welding brass in separate sections and not melting it in a continuous layer.

When the material melts completely, there is a possibility of burning through the metal.

If it is necessary to weld a crater, then it is recommended to gradually reduce the welding voltage, increase the length of the arc and subsequently move it away from the workpiece.

In the process of such a connection, the seam is filled in full; roasting of the zinc leads to its evaporation, resulting in the formation of defects in the metal.

To reduce the evaporation of this chemical element, it is necessary to increase the presence of oxygen in the flame and use filler materials alloyed with boron, aluminum, and silicon.

Advice! When connecting brass parts, carry out welding work outdoors, do not neglect safety requirements!

Source: https://electrod.biz/hobbi/vyipolnyaem-svarku-medi.html

How to weld aluminum with copper?

Fusion welding when joining such metals is extremely difficult. This is because the composition of the molten metal is almost impossible to control. And the properties of the weld depend on the copper content in its composition.

If the amount of copper is higher than 12%, then the tensile strength is no longer increased. At the same time, the corrosion resistance and viscosity of the metal is greatly reduced. Such connections become quite fragile and prone to defects.

The use of carbon electrodes has virtually no effect and does not improve the quality of welding. These metals can be joined by melting, but only if the melting is primarily an aluminum part. Where possible, a “lock” connection is predominantly used. Read about it below.

"Castle" connection of copper and aluminum parts

To achieve a good welding result, you need to strictly follow the technology, since joining these metals is already quite difficult. The essence of this method is as follows:

• a sheet of aluminum is placed underneath,
• a copper plate is placed on top of it,
• along the perimeter of this lining, a weld is made, the seam should be evenly connected to the lining,
• then the perimeter welds are connected by surfacing.

The resulting connection is somewhat reminiscent of a lock, hence the name.

Welding modes

They are very similar to aluminum welding modes. During processing, direct current of straight polarity is used. Filler rods are products made of cast aluminum with a diameter from 12 to 20 millimeters with a thickness of the aluminum part from 29 to 30 millimeters.

The thickness of the copper product is 10 millimeters. The current strength is allowed in the range of 500-550 amperes, and the arc voltage is 50-60 volts. Its length ranges from 20 to 25 millimeters.

The optimal electrodes in this case are carbon electrodes with a diameter of 15-20 millimeters.

contact welding

This type of processing has found its application in industry for connecting aluminum bars or wires to copper lugs. In the manufacture of cables, welding of copper and aluminum wires using capacitors is used. It occurs in the following modes:

Diameter of welded wire, mm	Capacitor capacity, μF	Capacitor voltage, V	Distance between parts, mm	Upsetting force, N
2,5	256	1100	14	1471
2,8	256	1400	10	1471
2,8	260	1400	15	1471
2,8	380	1350	15	1569
2,8	550	1200	15	1716
3,5	550	1500	12	1569
5,0	1000	1500	14	1716

This type of welding is also used when connecting pipes made of these two metals. Typically, such compounds are in demand in the production of refrigeration equipment. When welding with these metals, it is important to remember that aluminum will melt much faster than copper. It follows that the aluminum tube should be longer than necessary and include allowances for further melting.

During operation, burr may form in the pipe, that is, excess metal that is squeezed out during welding under pressure. To reduce its amount, you need to purge the aluminum tube with nitrogen during operation. The gas pressure should be approximately a quarter of an atmosphere. Blowing with plain air is not recommended, since it contains oxygen, which reacts with copper and oxidizes it.

Before butt welding the tube, it is necessary to settle it by 10 millimeters with thicker walls. This technique occurs on a special mechanism. It is required so that later, when working with the joint, the same diameter of the hole will be obtained after upsetting.

The joint is processed by turning the thickened surface. The work is carried out on a lathe and involves drilling a hole. Preferred welding modes for connecting aluminum and copper tubes with a cross-section of 3-10-30 millimeters and walls of 1.5-4 millimeters can be seen in the table:

Specific settlement pressure, MN/m2	196-216
Precipitation current density, A/mm2	500
Current density during reflow, A/mm2	240
Average reflow speed, mm/s	12-15
Settlement speed, mm/s	100-120
Amount of melting of aluminum tube, mm	8-10
The amount of copper tube plating, mm	2-8
Total settlement, mm	3,5-5
Welding duration, s	1,1-1,2

In the butt fracture, you can see inclusions of aluminum particles in the copper. Reverse inclusion does not occur.

Source: https://varimtutru.com/kak-svarit-alyuminiy-s-medyu/

Technology of welding copper and its alloys with aluminum

Fusion welding when joining such metals is extremely difficult. This is because the composition of the molten metal is almost impossible to control. And the properties of the weld depend on the copper content in its composition.

If the amount of copper is higher than 12%, then the tensile strength is no longer increased. At the same time, the corrosion resistance and viscosity of the metal is greatly reduced. Such connections become quite fragile and prone to defects.

The use of carbon electrodes has virtually no effect and does not improve the quality of welding. These metals can be joined by melting, but only if the melting is primarily an aluminum part. Where possible, a “lock” connection is predominantly used. Read about it below.

How to weld copper to copper: technology and features

Often, when installing structures or repairing copper objects, welding work is required. However, due to its extraordinary characteristics, copper is not as easy to weld as steel. Therefore, not everyone will be able to make a reliable connection. After mastering the technology of welding copper and its alloys, you can easily work with any metal.

Features of welding copper and its alloys

The difficulty of working with this metal is due to a number of negative properties:

1. High chemical activity, especially when heated, leads to the rapid appearance of a heat-resistant oxide film on the surface. If its particles get into the seam, they will cause cracks to form.
2. Due to the high coefficient of thermal expansion, the welded joint may become deformed and crack when shrinking during the cooling process.
3. When heated, copper begins to be actively saturated with hydrogen, which leaves pores, and oxygen, which oxidizes the surface.
4. Rapid heating and cooling makes the connection brittle.
5. Due to the high fluidity, it is difficult to create reliable vertical and ceiling joints.
6. To compensate for the high thermal conductivity, the work is carried out with a high current. Otherwise, due to the rapid dissipation of heat, sagging, undercuts and other defects will appear.

Electrodes for copper welding

To connect copper without filler wire, consumable electrodes with a special coating are used. When melted, it creates a layer of slag that protects the welding site from contact with air. The additives included in the coating combine with the metal to improve the quality of the seam. The slag layer slows down the cooling of the joint, which helps remove more gases.

Non-consumable carbon and graphite electrodes are used in conjunction with the filler wire required to create the weld. When choosing, you should consider that:

• for manual welding of copper, the coating color is red;
• Gray coated grades are intended for non-ferrous metals;
• blue electrodes are used to cook refractory metals;
• heat-resistant alloy steel with yellow coating.

Preparing parts for welding

Regardless of the method, copper blanks must be cleaned of dirt and then degreased. The oxide film is removed with a wire brush or fine-grained sandpaper using careful movements to avoid deep scratches. It is recommended to complete the cleaning by etching the welded parts and wire in an aqueous solution of nitric, hydrochloric or sulfuric acid. Then rinse with fresh water and dry with hot air.

The edges of workpieces 0.6 - 1.2 cm thick are chamfered so that an angle of 60 - 70⁰ is formed between them. When welding on both sides, it is reduced to 50⁰. If the thickness of the parts is more than 12 mm, the edges are cut in the form of the letter X for a two-way connection. If this is not possible, make a deep V-shaped cut. But filling the joint will require more consumables and time, since copper will have to be welded with a wide seam.

To prevent deformation during shrinkage, a gap of 0.5 - 2 mm is left between the workpieces, depending on the thickness. To ensure that its width remains constant along the length of the joint, the parts are grabbed at intervals of 30 cm. When bringing the seam to a temporary connection, it is knocked down with a hammer, otherwise the joint will have defects at this point.

To prevent copper from leaking to the reverse side, steel or graphite plates 4–5 cm wide are placed under the joint. To compensate for thermal expansion, the parts are preheated to 300–400⁰C. When working outdoors, you will need portable screens to protect from the wind.

Copper welding methods

The negative properties of copper that interfere with welding are circumvented in many ways, using various consumables and equipment. Not all can be used at home, but some are quite affordable.

Welding copper with argon

This method is used to weld copper using a semi-automatic or manual argon-arc method. The work is carried out with direct current of straight polarity. Its value is set on the basis that 100 A is needed for every millimeter of thickness. The value can be adjusted during operation depending on the composition of the metal. When welding copper with argon, the gas flow rate should not exceed 10 l/min.

Copper wires or cable cores, cleared of insulation and varnish, can be used as filler wire. It is fed along the edge of the weld pool in front of the electrode so that when melting the metal does not stick to it. For workpieces less than 0.5 cm thick, preheating is not required.

Most often, copper is welded with carbon electrodes, since tungsten electrodes have to be changed frequently. Workpieces with a thickness of more than 1.5 cm are connected with graphite electrodes. The permissible electrode extension is no more than 7 mm, the arc length is 3 mm. Unlike other methods, copper argon welding can be used to qualitatively connect vertical joints.

Gas welding

This technology does not require complex equipment like argon arc technology. All you need is a torch and an acetylene bottle. To ensure the normal flow of the process, a gas flow rate of 150 l/hour will be required for workpieces up to 10 mm thick, and above 200 l/hour. To slow down the cooling, the workpieces are covered with sheet asbestos on both sides. The diameter of the filler wire is selected equal to 0.6 of the metal thickness, but not more than 8 mm.

Source: https://svarkaprosto.ru/tehnologii/kak-svarit-med

Is it possible to solder aluminum to copper - Metalist's Handbook

The procedure for soldering aluminum elements at home is a very problematic process, which is facilitated by the use of special materials.

The work is complicated by the immediate appearance of a thin oxide film at the stripping site, which interferes with soldering. An additional difficulty is created by the material itself, which has a low melting point (+660 °C).

Using solder for soldering aluminum, special strong fluxes and following technology, you can independently solder almost any aluminum object.

Features and principles of soldering

The low temperature value of metal melting complicates the technological process of soldering, as well as repairing products with your own hands.

Parts very quickly lose strength when heated, and structures reduce stability when the temperature reaches 300 degrees.

Low-melting solders consisting of bismuth, cadmium, indium, and tin come into difficult contact with aluminum and do not provide sufficient strength. Excellent solubility is observed in the metal in combination with zinc, which makes the soldered areas highly reliable.

Before soldering begins, aluminum elements are well cleaned of oxides and dirt. To do this, you can use mechanical force with brushes or use special fluxes made from a potent composition. Before the procedure itself, be sure to tin the areas to be treated.

The tin coating will protect the part from the formation of oxides. In order to reliably solder aluminum products, it is necessary to choose the right heating tool, taking into account the volume of metal being processed.

In addition, the reliability of the connection depends on the alloy chosen, as well as the flux for soldering aluminum.

Soldering methods

Soldering of aluminum products is carried out with an electric soldering iron, a blowtorch or a gas torch. There are three ways to solder various aluminum objects:

• with rosin;
• using solders;
• electrochemical method.

With rosin

This option for soldering aluminum objects, wires, cables is used for small parts. To do this, the cleaned section of the electrical wire is covered with rosin and placed on a piece of sandpaper with a medium grain size. The wire is pressed from above with the tinned tip of a heated soldering iron. This action is carried out several times, after which the procedure of soldering the electrical wires itself is performed. You can use a rosin solution in diethyl ether.

In this case, the end of the soldering iron is not removed from the end being tinned, but rosin is added on top. An electric soldering iron with a power of about 50 W is suitable for twisting thin aluminum wires. With an aluminum thickness of about 1 mm, a 100 W soldering iron is required, and parts larger than 2 mm require preheating of the joint.

Using solders

This method is the most common and is used in electrical engineering, in the repair of automobile parts, as well as other products. Before soldering aluminum, the area to be soldered is pre-coated with an alloy and the tin-plated elements are subsequently connected. Pre-tinned parts are connected to each other, as well as to other alloys and metals.

Soldering of elements can be carried out using light alloy solders containing tin, zinc, and cadmium. In addition, refractory materials based on aluminum are actively used.

Why are light alloy compounds used? Because they allow you to solder an aluminum product at temperatures up to 400 degrees. This does not produce qualitative changes in the properties of the metal and maintains its strength.

Compositions with cadmium and tin do not create sufficient contact reliability and are susceptible to corrosive effects. Refractory materials containing zinc, copper, and aluminum-based silicon do not have these disadvantages.

Electrochemical method

This procedure requires a plating facility. With its help, copper plating is carried out on the surface of a product or wire. In its absence, independent processing of the part is used. To do this, apply a few drops of a saturated solution of copper sulfate to the area cleaned with sandpaper. After this, the negative pole of an independent power supply is connected to the workpiece.

They can be a battery, an accumulator, or any electrical rectifier. A cleaned copper wire with a diameter of about 1 mm, located in an insulated stand, is connected to the positive terminal. During the electrolysis process, copper will gradually deposit on the part, after which the area is tinning and dried using an electric soldering iron. After this, you can easily solder the tinned area.

Solders, materials, fluxes

Soldering of aluminum with tin is carried out subject to the use of highly active fluxes, as well as good cleaning of parts of the parts. Such tin compounds require additional coating with special compounds, since they have low strength and poor protection against corrosion processes.

How to solder aluminum elements? High-quality solder joints are obtained by using solders with silicon, aluminum, zinc, and copper. These materials are produced by both domestic and many foreign manufacturers.

Domestic brands of rods are represented by the most used solders TsOP40, which according to GOST contain 60% tin and 40% zinc, as well as 34A (aluminum - 66%, silicon - 6%, copper - 28%). The zinc used gives high strength to the contact area and provides good corrosion resistance.

Imported low-temperature alloys with excellent characteristics include HTS-2000, which provides maximum ease of use.

These alloys are used to work with large-sized parts (radiators, pipes) with high heat dissipation using a heating pad or objects made of aluminum alloys that have a fairly high melting temperature. Novice repairmen can familiarize themselves with the soldering process by watching an instructional video. This will help to avoid many unpleasant nuances during the work process.

In addition to solders, aluminum soldering requires the use of special fluxes containing ammonium fluoroborate, zinc fluoroborate, as well as triethanolamine and other elements. The most popular is the domestic F64, which has increased chemical activity. It can be used even without first removing the oxide film from products. In addition to it, 34A is used, containing lithium, potassium and zinc chlorides, as well as sodium fluoride.

Preparation of products

Reliability, as well as excellent quality of connections, is ensured not only by using the right technology, but also by preparatory work. These include the treatment of sealed surfaces. It is necessary to remove contaminants and thin oxide films.

Mechanical processing is carried out using sandpaper, a metal brush, stainless steel wire mesh or a grinding machine. In addition, various acid solutions are used for cleaning.

Surface degreasing is carried out using solvents, as well as gasoline or acetone. On the cleaned aluminum area, an oxide film appears almost immediately, but its thickness is significantly lower than the original one, which facilitates the soldering process.

Heating tools

How to solder aluminum at home? Electric soldering irons are used to solder small-sized aluminum products at home. They are a universal tool, quite convenient for soldering wires, repairing small tubes and other elements.

They require a minimum of working space, as well as the presence of an electrical network. Repair of large-sized products and welding are performed with a gas torch that uses argon, butane, and propane.

When using gas burners, it is necessary to constantly monitor their flame, which characterizes a balanced supply of oxygen and gases. With the correct gas mixture, the fiery tongue has a bright blue color. A dim hue, as well as a small flame, indicate an excess of oxygen.

Technological process

The technology for soldering aluminum objects is similar to the process of joining parts of other metal materials. The first step is to clean and degrease the areas of future adhesion. Then the connected elements are installed in working position for ease of processing.

Flux is applied to the prepared area, and the initially cold product begins to heat up using an electric soldering iron or a torch. As the temperature rises, the solder bar begins to melt, which must constantly touch the surface of the elements, controlling the heating process.

Soldering aluminum elements at home with an electric soldering iron is done in a well-ventilated room, as hazardous compounds are released during operation.

Using flux-free solder requires compliance with some nuances. To prevent the oxide film from interfering with the alloy getting onto the parts, the end of the rod makes scratching movements along the area where the elements are soldered. This breaks the oxide integrity and the solder comes into contact with the metal being processed.

Destruction of the oxide layer during soldering can be done using another method. To do this, the area to be treated is scratched with a metal brush or a stainless steel rod.

  How to bend a copper tube at home

To ensure maximum strength of aluminum parts in the soldered area, the treated areas are pre-tinned. Compliance with the technology of soldering aluminum elements guarantees excellent quality of the connection, as well as its protection against corrosion.

Source: https://ssk2121.com/mozhno-li-spayat-alyuminiy-s-medyu/