Solder for brazing copper, aluminum, brass, steel, stainless steel. The composition of the solder for soldering. The types of solders for soldering

When you need to securely fasten together the various solid compounds, most often to do this, select soldering. This process is common in many industries. I had to solder and house masters.

This operation helps not only when out of order the TV or computer for repair, you must replace the blown chip or chip. Using this restore process refrigeration equipment, industrial system. Soldering helps if you need to obtain a sealed connection. In addition, some materials simply cannot be connected differently. Aluminum, copper, brass will not be able to connect by welding. To get quality and reliable and tight connection, you need to have not only good equipment and special skills, but suitable consumable materials - solders and fluxes for soldering.

Alloys, solders and choose the types of flux depending on the materials that have to work. For example, when operation with aluminum products requires a different flux, different from what is suitable for copper or silver. Below we describe the main characteristics of each of them and choose the best option for work.

Solder for soldering: key features

As it is used in various metal alloys. There are also formulations based on pure metal. In order to use of a solder, it was possible to create high-quality compounds, these materials must differ in some qualities.

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Wettability

First of all, any kind of solder needs to have excellent wettability. Without this capability, solder the parts simply can not reliably contact each other. What is wettability? This is such an interesting phenomenon, when the strength of the bonds between the solid particles and liquid is higher than that of liquid molecules. If there is wetting, then the liquid will spread on the surface and gets into all cavities. So, if the solder soldering is not wet, for example, copper, then it cannot be used with this metal. Soldering it does not use lead in its pure form. Its characteristics wetting very low and we cannot rely on the high quality of the connection.

Melting point

Whatever kind of solder, the temperature at which it begins to melt must be below the melting point of the solder materials. Also it should be higher than the working temperature of the parts.

Speaking of the melting temperature, imply two points. This is the value at which the fusible components will begin the melting process, and the minimum, where the alloy will become liquid. The difference between these two temperatures is called the interval of crystallization. If the soldering is within this difference, even a small mechanical load on detail can completely destroy the structure of the solder. In this connection, will mark the high fragility and resistance. Remember: do not in any way affect the connection until the solder soldering is not fully crystallized.

Important properties of solders

Whatever type and kind of alloy, with whatever material he's utilized, it should not contain heavy metals or any other toxic substances above the established norms. The solder composition corresponds to material details. Otherwise, it will not be able to get reliable connections. Will experience excessive brittleness.

Any solder, regardless of type and purpose, must be thermostable. Also solder soldering must have electrostimulation. Consider the coefficients of thermal expansion and thermal conductivity. They should not differ significantly from the values that apply to soldered products.

Types of alloys

All existing grades for this operation are divided into soft or low-melting, where the melting point is 450 degrees Celsius, and solid. Here it is much more than the above value.

Soft solder

One of the most popular and common are considered tin-lead alloys with different content of components. In order to give the material the required characteristics, the composition of the solder for soldering can be added various additional ingredients. For example, bismuth and cadmium are used to reduce the melting temperature. The addition of antimony allows to increase the strength of the solder joint.

The Alloys of lead and tin have low melting temperature and low strength. They should not be used for parts, the operation of which implies a serious burden. Also not recommended for these alloys, if the operating temperature of the parts will be above 100 °C. If you have loaded soldering details soft solders, you should try to increase the area of contact of the two products.

Among the most popular soft materials can be identified, PIC-18, PIC-30, PIC-40, POS 61, POS-90. The numbers here are not just. This is the percentage of tin in the alloy. In industry it is often used in the manufacture of electronics, instrumentation. In everyday life they canto combine the different parts: schema TV's, microwaves, electric kettles and other small appliances.

Use soft solders

POS-90 is designed to work with the details, which are then processed by electroplating technology. POS-61 can be used for repair of precision equipment. Also the alloy is suitable for joining parts of high responsibility from a variety of materials. POS-61 is proven as a solder for soldering of copper and brass. The solder will be suitable when it is necessary to achieve durable connections with a high degree of electrical conductivity.

POS-40 are widely used for operations with non-critical and inaccurate details. Therefore, the working area can be heated to high temperatures. POS-30 is suitable for brazing copper or brass, steel alloys and iron.

Solid

Among the refractory alloys are widely used and distinguish between only two groups. This is mainly copper or silver alloys.

The first group include alloys of copper and zinc. They are well suited for those links, which will affect only the static load. The fragility of these alloys do not allow to apply them to the nodes that will experience a shock or any vibration.

The alloys of copper compounds or zinc based can be attributed to PMC-36 PMC-54. First – this is the perfect solder for soldering of brass or any other copper compounds. The second work for brass parts, bronze or steel.

If you need to connect the two steel parts, then you can use pure copper, brass brands, L-62, L-62, L-68. These brazing alloys of brass allow you to create a more durable and plastic compounds. Copper alloys do not have such characteristics.

Highest quality are alloys of silver. The composition may also contain zinc and copper. PSR-70 – solders for soldering copper, for brass or silver hardware. This item is suitable in the case that the connection must conduct electricity. PSR-65 is used in the production of jewelry, fittings, water pipes. PSR-45 needed to connect those parts that operate in conditions of vibration and shock loads.

Other types

There are also other, less popular solders. They're often used for rare metals or to work in special conditions. For example, compositions based on Nickel is used for products that operate in high temperature regimes. They also solder stainless steel alloys. The brazing alloys of gold are used for vacuum tubes. There are appropriate alloys and for magnesium.

Release Form

Materials and compositions for soldering come in many different forms. So, it may be a wire, a thin foil, pills, powder. In addition, solders are available as paste or granules. The shape depends on how the solder will be supplied to the working area.

Features of brazing of aluminum

The Connection of aluminum parts by soldering is applied in industry and everyday life. For example, frames of modern bicycles are made of aluminum alloy – in extreme drive they are often broken. The question is: what kind of solder should I choose?

It is believed that the brazing of aluminium – a very complicated process. But in fact it is so, if you use materials of stainless steel or of brass, steel, copper. The reason for this – the oxide film. It does not give the desired level of wettability and the base metal does not dissolve.

What is brazing aluminum and alloys on its basis

To the work carried out at the appropriate level, solder for brazing of aluminum needs to contain silicon, aluminum, and copper, zinc and silver. The market today it is possible to find compositions where all these components are in different ratios.

When Choosing a reliable solder, it is important to consider the following. Maximum resistance to corrosion and high strength will have a connection that is made with solder, which contains a lot of zinc.

Also, for aluminum you can apply a compound based on tin and lead. But it is important to properly prepare the work surface to smooth out brush made of stainless steel and the use of active fluxes. But experts do not recommend the use of this element.

Any solder for brazing of aluminum high temp. The best that allow you to get reliable connection-aluminum-silicon and aluminum-copper-silicon.

What to solder copper?

As noted above, it is possible to work the majority of the. Can be used as a low-temperature fusible, and hard solders. Also used compounds based on tin with lead, tin, silver, copper, silver and zinc.

If you need to repair a motherboard of computer or to fix the TV at the cottage, you can use any fusible elements. If you need to solder the fittings on the pipes, or fix the plumbing or a refrigerator, then it will fit only the brazing alloy for brazing copper. So it is possible to obtain a high quality result.

Stainless steel

If you need to connect the parts of stainless steel, the professionals recommend to use bars of tin and lead. Also, suitable materials with cadmium. You can applyfusible alloys based on zinc. However they should not be used with carbon or low alloy steels. The best solder for soldering stainless steel – the composition based on pure tin. In addition, only tin is allowed if the soldering will be in contact with food.

If the work will be carried out in dry or kiln atmosphere, then you should apply the silver with manganese, Nickel-chromium alloys or pure copper (better yet, brass). When soldering is necessary in corrosive environments, use silver tinali with a small part of the Nickel.

Pike

To interconnect two such items easy. Affordable and effective solders for the soldering of steel – the La-41. There is also a POS-60 and others, can be used even pure tin. But zinc compounds are not. Especially when it comes to carbon or low alloy materials.

Fluxes for brazing

During the operation the flux plays a lesser role than the solder. It is a chemical solvent and the absorbent oxides. It also protects metals from oxidation and increases the wetting.

For working with items based on lead and tin as a flux it is possible to use hydrochloric acid, zinc chloride. Also suitable borax, ammonium chloride. It is an active flux. To include inactive rosin, vaseline, olive oil and many other substances.

For example, hydrochloric acid solutions can be used with soft solders. Zinc chloride is used with brass, copper, steel. Ammonia is sleeping perfectly separates and dissolves fatty substances. For aluminium use the composition of Tung oil, rosin, calcined zinc chloride. You can also use concentrated phosphoric acid.

So we figured out what are the solders, and which one is the best to use in different occasions.