Soldering with hard solder with a blowtorch. Solder for soldering copper. Preparation of equipment and tooling

Soldering stainless steel is a rather laborious process, but at the same time there are no big difficulties. Alloys containing up to 25% nickel and chromium alloy with each other quite simply. Moreover, these alloys can form strong bonds with other metals, with the exception of magnesium and aluminum alloys.

But you need to pay attention to the fact that some nickel-plated alloys when heated to a temperature of 500-700 degrees. They can form carbides, their level of release depends on the duration of soldering, so the procedure time must be reduced.

The resulting carbides are significantly reduce corrosion resistance of stainless steel. In order to minimize the precipitation of carbides, titanium is added or an additional heat treatment is carried out after soldering. Under the action of hot solder (tinol), the riveted stainless material can crack, so soldering occurs after annealing, without the use of loads during soldering.

The choice of solder for stainless steel depends entirely on such characteristics: steel composition, soldering conditions. It should be noted that products that are made in corrosive conditions must be soldered using silver tinols, where nickel is in the composition in a small amount. Copper, silver-manganese, and chromium-nickel solders are used during soldering in dry conditions.

As a flux for stainless steel today most commonly used borax. It is applied to the joint in powder or paste form. When the borax melts, the rest of the metal gradually heats up until a bright red heat (850 degrees) is formed. When this temperature is reached, solder is injected into the joint.

Removal of material adhering to the stainless surface after soldering is done by washing the soldered product in water, or using sand blowing. Hydrochloric or nitric acid, which can be used in cleaning, is highly undesirable at this stage of working with stainless steel, as they corrode the base metal along with the solder.

Perhaps everyone knows that House master constantly encounters domestic difficulties that he needs to resolve on his own. But it often happens that you need to do the work related to the processing of stainless steel with your own hands. Therefore, this will require certain skills, abilities and knowledge. You will also need to acquire some materials and tools. Here list of everything you need:

Now that you have decided on the soldering tool, you need to find out the steps for performing the actions:

• To process stainless steel, you must first take care of the presence of a flux and an electric soldering iron with a power of 100 watts. You need to know that it makes no sense to choose a more powerful soldering iron for processing stainless steel. The flux is ordinary soldering acid. Also, do not forget to always have tin-lead solder on hand.
• When all necessary tools and the materials are ready for soldering, you can start work. First you need to clean the junction of stainless steel: this can be done with sandpaper or a file. Upon completion of the cleaning of the working areas, it is necessary to apply soldering acid, followed by processing. If the processing fails (the solder does not stick to the surface of the stainless steel), then you need to re-manipulate the soldering acid on a thoroughly heated surface, then perform the processing again.
• In the case when you made a second attempt, and it was not successful, and the solder lags behind again, then the stainless steel working surface needs to be cleaned with a special brush that you can make your own: you need a piece of pipe with a cross section of 5 mm, where you place thin wires pulled from a metal cable . Now, apply acid to the soldering place, and then bring the brush and soldering iron here at the same time. Then start working with two tools. It should be noted that this process is very helpful in removing the oxide film from the surface of the stainless steel.
• When the parts have been removed, start soldering stainless steel using a soldering iron and flux.

Details heated with a gas burner or a tinned soldering iron tip. While working with the burner, it is necessary to ensure that there is not much oxygen in the flame, because this causes the stainless steel to oxidize. This can be determined by the color of the fire (it should be blue), if the color is pale and the fire is weak, then this indicates an excess of oxygen. To warm up the connection, the burner must be moved smoothly.

Touching the metal periodically with solder, determine the quality of the temperature reached. Heating is sufficient when the solder is melted not by the flame of the burner, but by touching the metal.

Then the solder is immediately applied to the part where the joint needs to be made, while the parts continue to be heated so that the solder, melting, slowly filled the gap completely. In the case when there is not enough liquid solder in some area, it is heated more than other places, and the solder flows into it by itself. A clear sign of high-quality soldering is the leakage of excess solder from the joint.

Working with hard solders

Soldering stainless steel is excellent with a fluid, liquid, fluxed solder with a low melting point and high capillary characteristics. This solder is quite elastic, has excellent deoxidizing properties, which are very useful when working with stainless steel.

Also be able deal with brass, copper and some other materials. Soldering with such hard solders is very well suited for stainless steel. Stainless steel does not contain cadmium, and the percentage of silver here is 30%. Processing the material with hard solders gives good results, making it possible to obtain a durable and high-quality fastening of metals.

Solder HTS528 can cope with copper, brass, nickel, bronze, stainless steel, and other metals. Along with other hard solders today, this tinol is the most in demand. The solder looks like a rod treated with red flux. Bar size about 45 cm., and the mass is 20 gr. The melting point is 760 degrees.

How to choose a flux for soldering

Small items are soldered with adjustable benzo-air burners (this method is more suitable for jewelry). Larger parts are best soldered with acetylene. The same applies when choosing a flux for stainless steel, since this metal is very picky about the flux. Flux for stainless steel from 10% calcium fluoride, 20% boric acid, 70% borax.

For small stainless steel parts, you can prepare a flux composition that includes 50/50% boric acid and borax. This flux must be diluted in water, then applied to the part, when it dries, the solder will adhere perfectly to the metal surface.

That is, the soldering area is not pickled, but only cleaned with sandpaper. Copper does not spread well over the surface of steel, so it is better to use brass L 63. For better soldering, you can also use silver and brass, making solder from them.

There are many people who, so to speak, "ate the dog" in their work with soldering. And they share their personal experience gained in practice, giving helpful advice:

• A soldering iron is best chosen with a non-flammable tip.
• An electric soldering iron is needed with a power of 60-100 watts. The most optimal soldering iron 100 watts. A less powerful soldering iron will not be able to heat the metal.
• Orthophosphoric acid serves best as a flux.
• It is desirable to use tin-lead rods as solder. You can also use tin in pure form. It must be said that it is better to solder utensils with tin, since pure tin does not contain lead in itself.
• When working with soldering, it is necessary to use personal protective equipment.
• Soldering must take place in a well-ventilated and open area.

Common mistakes during soldering

If a mistake is made during preparation, selection of materials, or during the soldering process, the solder may not flow over the surface and not hold the parts together. It happens that the parts before soldering were insufficiently cleaned or poorly warmed up. Often this happens with large products. The tip of the soldering iron after any session must be well cleaned, and in order to be able to carry out jewelry work, its tip must be sharpened from time to time.

To get a quality connection, you should not solder stainless steel with pure lead or use rosin. If the solder is made of tin, then working with it can be quite difficult due to its weak consistency. If the tin does not melt more than to the state of warm plasticine, then most likely it will not hold the connection, constantly breaking and crumbling. The optimal condition of the tin for fastening is if it looks like a liquid.

High-quality solder, which is laid according to all the rules, can only scratch but not separated from the stainless steel soldering area. In order not to spoil the connection in the future, after soldering, the product must be allowed to cool at rest. When the joint has cooled, it is cleaned of flux and solder, which remained at the edges, and then thoroughly washed with soap.

As with soldering with soft solders, before soldering with hard solders, the soldering points are cleaned of dirt and fatty substances, the parts to be soldered are tightly adjusted to each other. The soldered seams are cleaned mechanically and chemically.

The assembled and fitted parts at the soldering points are coated with the appropriate flux, depending on the metal being soldered and the solder.

Solder mixed with borax is applied to the seam, and the product is heated to the melting point of the solder in various ways: with a blowtorch, on a furnace, in a furnace. The seam must be soldered evenly along the entire length.

When soldering with silver or brass solders, the latter are applied to the heated place of the seam or injected into the preheated seam. If the solder does not disperse along the seam, flux is again poured onto it.

After soldering, the flux remaining on the seams is removed by short-term boiling for 10-15 minutes in a solution containing 10% caustic soda, 5% machine oil and 85% water.

The soldered and boiled product is thoroughly washed in water, wiped with a dry cloth and dried.

If necessary, the soldered product is tested for tightness.

An example of brazing a tee joint. A tee connection (Fig. 228, b) consists of a coupling, a branch pipe and three outlet pipes. Soldering is carried out with copper-zinc solder PMTs-54.

In preparation for soldering, the parts to be joined (coupling, branch pipe and outlet pipes) are cleaned at the soldering points, degreased, assembled into a knot and tied with steel wire. In mass or serial production, special devices are used to connect parts during soldering.

When soldering this compound, borax is used as a flux, which is heated and dried over low heat before soldering, since raw borax during soldering, swelling with bubbles, bursts and splashes along with the solder. Dry borax is mixed with solder and stored in a box. A mixture of borax and water, used to coat the seams during soldering, will be placed in the second box.

The tee connection is soldered first on one side, then on the other. First, the left end of the coupling is soldered with a drain tube inserted into it (Fig. 228, c), while the connection is held obliquely by the right end (Fig. 228, d). Then they proceed to soldering the tee coupling with nozzles (Fig. 228.5), then solder the right end of the connection, holding the product by the left end in an inclined position (Fig. 228, e).

After that, the soldered joint is turned over and the final soldering of the seams is carried out on the other side.

Soldering a tee joint is a rather complicated process, as it involves heating the joint to a high temperature, at which it is easy to burn it. To avoid this, heating is carried out evenly throughout the soldering point, for which the connection is moved relative to the flame, or vice versa.

When the borax begins to melt and becomes liquid, the solder will begin to melt along with it, the spreading of which must be monitored. If the solder collects on one side, then that side is hotter. In this case, the other side is heated so that the solder goes along the seam.

If heating does not give a positive result, add more solder with borax.

When the solder fills the solder joint, remove the flame from the tee joint. Having finished soldering, the product is allowed to cool down gradually, after which the quality of soldering is checked and any defects are eliminated.

This type of connection is popular in various areas of life and production. Most often they are used by radio amateurs and home masters.

Soldering can help out both when repairing a computer, TV, radio equipment, and in industry, repairing refrigerators. Soldering is good at creating a tight joint. And some materials are simply impossible to connect in another way.

Not all metals can be joined by welding. And in order for the soldering to turn out to be of high quality and tight, work skills are needed, good tools and related solders and fluxes.

The compositions and types of solders and fluxes are selected in accordance with the materials from which the materials to be joined are made. For example, aluminum needs a completely different flux than copper. Consider the main properties of solders, their applicability, features of use.

Basic properties

Various metal alloys are used as solder. There are alloys on one pure metal, usually tin. The metals that make up the solder differ from each other in different parameters.

wettability

Any solders for soldering must necessarily have the wettability property, otherwise the parts to be joined cannot be connected by high-quality soldering.

Wettability is a phenomenon in which the reliability of the bond between the molecules of a solid with a liquid is greater than that of a liquid. In the presence of good wettability, the liquid diverges over the surface, while filling all its cavities. When the solder does not sufficiently wet the metal, it is not used for that metal. Pure lead is not used for soldering copper; it does not wet copper.

Melting temperature

Regardless of the type of solder, for any type of solder, the melting point should not be higher than the temperature of the parts to be soldered. However, it must be greater than the operating temperatures of the materials so that the solder does not melt during operation of the soldered device.

There are two temperature thresholds in this question. The first is the temperature at which the melting of the most fusible components of the solder just begins, and the second is when all the solder has turned into a liquid. The interval between these two values ​​is called the solidification interval of the solder.

If the place connected by soldering is at a crystallization temperature, then the place of soldering can quickly collapse, even from a small load, since the connection will have an increased electrical resistance and fragility. During soldering, you need to know that until the solder is completely hardened, you can not apply any loads to it.

Solder properties

Any composition of the solder should not contain substances that are toxic to humans, above the norm. Solders for soldering must have the properties of thermal stability and electrical stability. When choosing a solder, the thermal conductivity of the solder and its thermal expansion are taken into account. They should be level with soldered parts.

Types of solders

All solders for soldering are divided into hard and soft. The melting temperature of hard solders is more than 450 degrees, and soft solders - up to this value.

Solders for soldering: soft

The most popular of these are alloys of tin and lead with various percentages. To give special properties to solder, auxiliary components can be added to it. Cadmium and bismuth are used to reduce the melting point. Antimony increases solder strength.

Solder on tin and lead have a low melting point and low strength. It is better not to use such solder for critical parts. If you have to solder soft solder parts subject to severe stress, it is recommended to increase the soldering area of ​​the parts.

The most popular soft solder steels are from POS - 18 to POS - 90. The numbers in the marking indicate the percentage of tin in the solder. These brands of solders are used in the manufacture of appliances, as well as electronic devices. POS-90 is used for soldering parts that are further electroplated. POS-61 is used for soldering precision devices, especially critical parts made of various materials. They carry out the soldering of brass, copper, when connection strength and increased electrical conductivity are needed.

POS-40 is used for non-critical parts that do not require special accuracy. The soldering area can be heated to a high temperature value. POS-30 goes well with brass and copper, as well as steel alloys.

Hard solders for soldering

Among hard solders with a high melting point, there are two groups: copper and silver alloys. To copper species solders include solders based on zinc and copper, which are well combined for joints designed for static loading. These alloys are brittle and should not be used for soldering materials subject to shock or vibration.

Other types of solder

There are other types of solder that are rarely used. They are necessary for soldering rare metals, or for special special conditions. There are nickel-based solders that are used for parts operating at high temperatures or made of stainless steel. Gold solders are used for vacuum tubes. Magnesium solders are also available.

Release form

Solders are available in various forms and packages. More often, solders are made in the form of wire, foil, or powder or tablets. There are also granular solders, solder pastes. The shape of the solder is selected depending on the type of soldering zone.

Aluminum soldering

Aluminum parts are connected by soldering, using special solders. Aluminum soldering is used in industry, domestic conditions.

In general, soldering aluminum is considered a difficult job. This happens when the type of solder is chosen incorrectly. They take the wrong solder, which is intended for other metals. The reason for difficult soldering is the formation of an oxide film, which does not allow good wettability of aluminum.

To solder aluminum part, solder containing zinc, silver, copper, aluminum and silicon is used. In the trading network there are many solders with such components in different proportions. When choosing, it should be taken into account that the highest corrosion resistance and joint strength is achieved by solder with a significant zinc content.

Aluminum can also be soldered with conventional lead and tin solder, but this requires high-quality surface preparation, which includes cleaning with a stainless steel wire brush. When soldering, you need to use an active flux. But this method is rarely used.

Aluminum soldering is carried out at high temperature. The most used solders for aluminum soldering are aluminum-copper-silicon compounds.

Copper soldering

Copper is the easiest to solder. Almost all types of solders are combined with it. Both soft fusible solders and solid types, as well as alloys of tin, lead, silver, zinc, etc.

Any soft solder is suitable for repairing a computer or TV. Hard solders are used for soldering pipes, plumbing, and refrigerators. By following these simple rules, you can get good results.

Soldering stainless steel

For soldering parts made of stainless steel, experts recommend using a solder consisting of lead and tin. A good result is obtained with solder containing cadmium. Zinc-based soft solders can be used.

They cannot be used in conjunction with low-alloy steels, as well as carbon alloys. The best solder for stainless steel is pure tin solder, especially if the solder will be in contact with food.

When soldering in a dry place or in an oven, manganese with silver, pure copper or solders on nickel and chromium are used. During soldering under corrosive conditions, silver-based tinols with a part of nickel are used.

Soldering steel

An effective solder for joining steel parts is POS-41. Other brazing solders can also be used, but they are not quite suitable for this purpose. Zinc-based solder does not mix well with steel, especially low-alloy and carbon alloys.

How to make your own solder

To prepare solder with your own hands, the constituent parts (usually lead and tin) are weighed on a scale. This mixture is melted in a crucible on a gas burner. The molten composition is stirred with a metal rod.

Melting is carried out in a ventilated room, in compliance with safety measures, that is, they put on glasses, an apron, gloves.

Types of fluxes

No soldering is complete without flux, just like without solder. It is a chemical that dissolves and absorbs oxides. The flux protects the metal from oxidation and promotes wetting of the parts to be joined.

For the process of soldering with solder based on tin and lead, a flux based on hydrochloric acid or zinc chloride is used. Ammonium chloride or borax can also serve as a flux. These fluxes are active. Passive fluxes consist of rosin, oil, petroleum jelly and other similar substances.

For example, a hydrochloric acid solution can be used with soft solders. With steel, copper and brass, zinc chloride is used. Fatty substances are able to dissolve ammonia. For soldering aluminum alloys, a mixture of tung oil, zinc chloride, and rosin is used as a flux. Phosphoric acid also has its uses.

When connecting copper products, various tools and equipment are used, without which the soldering process would not be possible. The main tool is a soldering iron. In addition, you can use a gas burner or special ovens.

At home, it is preferable to use the soldering of copper products, this option is the simplest and fastest in comparison with cooking. In addition, you do not need special equipment, which will be bonded. Subject to all terms and conditions technological process, you can get a strong and reliable connection of the elements, increasing the resistance to various loads.

In order for soldering at home not to cause difficulties, first of all, you need to take care of the main tools that will be involved in this process:

• pipe cutter;
• beveler;
• pipe expander;
• steel brush;
• steel brush;
• solder;
• burner or hair dryer.

For a tubular device, a method is used when the element is immersed in a composition of salt and solder. The salt acts as a heat source and replaces the functions of the flux. Therefore, no additional flux is needed.

In addition to this method, there are several other soldering options that deserve attention.

Brazing

The most common soldering method at home is brazing copper. This is due to the properties of copper, which melts easily at low temperatures. A soldering iron or a gas burner is quite suitable as a tool.

Soldering copper is a bit similar to the process of welding, but still has some minor differences:

• When soldering parts, an additional solder substance is used, which connects these elements. This is possible due to the properties of solder, which has a low melting point.
• The most common materials for soldering parts use nickel and tin. These are affordable and simple components that are used in most cases. As for industrial use, other types of solder are used for these purposes, but for home use they are quite expensive and, therefore, unprofitable.
• To solder copper products, you must first melt the solder until it reaches the desired consistency in order to apply it to the place where the elements are soldered. After that, you should wait until the connection has completely cooled down.

If all the nuances of the process are performed exactly, then such a connection will turn out to be strong and durable.

Soldering in ovens

Brazing of copper in furnaces is carried out under production conditions. This process ensures uniform heating of the parts, completely excluding its deformation. Tin or an alloy of tin and lead is used as an alloy, a composition of rosin and alcohol, or a composition of their ammonium chloride or zinc, acts as a flux.

When using solder with a silver base, fluxes are used, which are based on compounds from fluorine, potassium and boron. These fluxes are the best way to clean the surfaces to be bonded from the oxide film, this will allow the alloy to be perfectly distributed over the entire surface.

Flux soldering

This procedure has one big minus, this is the performance of a tight bond. Excess flux creates additional foci that are subject to corrosion, as a result of which soldering is performed in neutral conditions or in a reducing gas environment. To solder in nitrogen, the required temperature should reach 750-800 degrees.

vacuum soldering

Vacuum soldering is used for many metals, copper is no exception. Brazing of copper is carried out in specialized furnaces, or containers, which are then placed in the furnace. Despite the sophisticated equipment, this option is considered the most effective by all criteria. The fastening of copper products is done with soft solder, or pure tin. You can use other types, for example, silver alloys, using a flux of a rosin-alcohol solution.

In order to use cadmium solder, it is necessary to prepare a special tool and stock up on the necessary knowledge in this area, because the manufacturability of this material is much lower than that of tin-lead tinols.

Brazing

If the solder does not melt during soldering, do not rush, you must wait for the soldering iron to heat up. After the alloy begins to flow, the heat source is removed, allowing the composition to fill the gaps between the elements on its own. To avoid excesses, it is not recommended to add an alloy, except for excesses, there may be material getting into the part.

If you solder copper using ordinary solder rods, then its volume should be equal to the diameter of the surface to be joined. To roughly calculate the required amount of material, you can bend the rod with the letter G, and attach it to the pipe.

With this technology, the strength of copper does not change, but the mechanical criteria are reduced.

This technology is suitable for those surfaces that will be used with high temperatures. Since for the implementation of this process the required temperature should be 700 degrees, a gas-flame heating option is used.

Readiness for soldering is determined using an alloy rod, which melts at the end of the process.

To increase the quality characteristics of the connection, it is necessary to preheat the solder rod. The advantage of this connection method is the high strength of the seams, as well as their resistance during operation, under the influence of high temperatures. But there is also a drawback, which is the inevitable annealing of copper. It is worth considering that when working with this method, it is necessary to have sufficient qualifications and experience, since a beginner can accidentally overheat the copper, thereby causing it to break.

Pipe soldering technology

To solder copper pipes, you need to prepare a pipe cutter. After the desired piece of pipe is cut off, the outer cut is brushed to remove burrs and roughness. Using a pipe expander, the second section of the pipe is expanded to right size so that one part of the pipe enters the other.

A flux is applied to a pipe with a smaller diameter, and two elements of tr are fastened. The junction is evenly heated, for this you can use either a burner or a hair dryer. Solder is applied to this place, after it is melted, the surface is completely covered by it. As an alloy, you can use soft solder, it will do an excellent job with this job.

Video: Soldering copper pipes

Soldering has been known since ancient times. This method of joining metals was common in Ancient Rome, Ancient Greece, Ancient Egypt. Soldering is the process of forming an inseparable connection of metals between which solder is introduced. This molten material fills the space between the two parts, thereby firmly bonding them. After complete hardening of the solder, a strong one-piece connection is formed.

High-temperature soldering of steel is carried out by heating the solder to a melting point above 450 ° C.

There are several classifications of soldering. Depending on the melting temperature of the solder, the process of joining parts can be divided into high-temperature and low-temperature.

High-temperature soldering occurs when the solder is heated, for example, with a gas burner, to a melting point above 450 ° C. This method leads to obtaining bonds that can withstand a large load. During high-temperature soldering, hermetic and vacuum-tight joints are formed that can work at high pressure.

Brazing can be used to join small parts and thin films. This method allows you to bind dissimilar metals. This type of soldering is quite simple to perform.

Joining carbon low alloys

Tools needed for soldering.

Carbon low alloy steels are general purpose steels. They have found wide application due to their low cost in shipbuilding, bridge building, boiler building and other special areas.

Soldering carbon low alloy steel is the simplest process for joining products. To do this, you can use various solders. A chemically unstable oxide film forms on the surface of these alloys, which can be easily restored and dissolved in fluxes.

The connecting element is often copper or its derivatives. Less often, lead or tin-lead binders are used. The reducing atmosphere acts as a protective medium in this process.

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Joining structural steels

Structural steels contain chromium. Examples are corrosion-resistant, heat-resistant or high-strength alloys. The connection of such metals has a number of difficulties. Due to the presence of chromium in their composition, it is very difficult to remove a chemically resistant film. Due to this fact, a permanent connection is obtained using active fluxes. The gas medium in this case is a compound of boron trifluoride and nitrogen (or argon). This process can be carried out in a vacuum.

When carrying out the soldering process, it is best to use certain apparatus designed to control the characteristics and composition of the protective atmosphere, as well as the degree of vacuum. This is quite an expensive piece of equipment. To minimize the cost of these devices, most often special compounds are applied to the surfaces prepared for connection. An example of such a coating is copper, zinc or nickel. These compositions protect steel from the formation of iron oxides on its surface, protect it from burnout of alloying components.

Structural steels should not be joined at temperatures above 1100 ° C. When this indicator is exceeded, ductility decreases in corrosion-resistant steels, in heat-resistant steels, strength characteristics deteriorate, and in high-strength ones, brittleness increases.

Nickel, copper, silver and other metals are most often used as solder in such processes.

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Connection of heat resistant steels

In engineering, heat-resistant alloys consisting of one or more phases are often used. They consist of combinations of nickel-chromium, nickel-iron-chromium or other metals. These alloys are distinguished by increased strength and heat resistance, and are resistant to corrosion.

The process of combining these metals occurs at a temperature of about 1100-1150 ° C. Exceeding this temperature can lead to deterioration in ductility, as well as burnout.

If the alloy contains refractory components, then a stable oxide film is formed on the metal surface when permanent joints are obtained. These dopants must first be removed with acid-base solutions. After that, the metal surface is treated with nickel.

Copper or nickel is used as connecting elements.

The protective environment in this soldering process is a neutral gas environment or vacuum without the use of fluxes.

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Bonding of tool and hard alloys

Tool steels are very strong, hard, low cost and highly available. Due to these positive characteristics, this type of alloy has gained immense popularity in the manufacture of various tools.

Soldering of this type of alloy is carried out in the same way as low-carbon ones. However, at a heating temperature above 200 ° C, the hardness of these metals decreases, and the heat resistance of the material decreases. This drawback is eliminated by adding tungsten to the composition of tool steels. The use of this additive increases the soldering temperature to 550-600°C.

In this case, nickel or ferroalloys will serve as solders. Soldering tool steels should be done by induction using boride-fluoride fluxes. Soldering in salt baths or flame furnaces is suitable for this process.

To join hard alloys, the same fluxes are used as for tool steels, and in this case, copper-zinc alloys with the addition of manganese, nickel or aluminum, less often copper-manganese alloys, will serve as solders. With this type of soldering, a mechanized or automatic method of heating the metal is used.