At what temperature does solder melt?

How solders differ in melting temperature - Welding Profi

Soldering is often used to join metal parts together. This type of switching is used in various areas of everyday life and production. Often the work is carried out by home craftsmen or radio amateurs.

The method is relevant when repairing computers, televisions and even refrigerators. To obtain a high-quality and airtight joint, work skills, low- and high-melting solders, and fluxes are required.

Their choice depends on the material of the elements being processed.

A variety of metal alloys are used as soldering materials. However, there are compositions consisting entirely of metal. In order for the connections to be of high quality, the solder must have certain properties.

Any materials must have high wettability - a phenomenon in which the bond strength between solid and liquid substances is higher than that of the liquid.

At high values, the liquid spreads over the surface, filling the smallest cavities. If the solder does not sufficiently wet the metal, it cannot be used for soldering.

For example, lead is not used to work with copper, otherwise the result will be a low-quality compound.

There are two temperature limits. The first is the one in which the most fusible elements begin to melt during the soldering process, the second is when all the solder becomes liquid. The interval between these indicators is scientifically called the crystallization interval.

If the switching point is in such a temperature range, the soldering can quickly fail even under minimal load. This is due to the fact that the connection has high resistance and fragility. It should be noted: until the solder has completely hardened, you cannot have any impact on it.

Materials used

Often tin is used for soldering with the addition of other components. Solder can contain various materials. For example:

• Tin. It is a soft material whose melting occurs at +231.9 °C. The metal is dissolved in hydrochloric and sulfuric acid. Most organic acids have no effect on it. At room temperatures it does not oxidize, but at temperatures below + 18 °C (especially below -50 °C), the crystal lattice is destroyed, as a result of which the color changes to gray.
• Lead. It is very often used in solders due to its low fusibility. Pure metal without foreign impurities is soft and easy to work with. Oxidation occurs only on the outer part, which comes into contact with air. Easily soluble in acidic and alkaline environments containing organic matter and nitrogen.
• Cadmium. Popular in the production of low-melting solders in small quantities together with lead or bismuth. The metal in its pure form is toxic and melts at + 321 °C. It is often used to prevent corrosion.
• Bismuth. One of the most fusible materials, melts at +271 °C, dissolves in nitric and heated sulfuric acid.
• Antimony. Refractory material, melting begins at +630.5 degrees. Does not oxidize under the influence of oxygen. Very toxic, gives the solder a glossy appearance.
• Zinc. Brittle gray-blue metal, melting is achieved at +419 ° C. Oxidation occurs upon contact with oxygen. It is used for solders that are used in conditions of high humidity, protects the soldering area with an oxide film, and easily dissolves in acids.
• Copper. Its highest melting point is +1083 degrees. It does not interact with air, but in a humid environment its top layer oxidizes. Often used in the production of refractory solders.

Types of solder

All types of solders are divided into high-melting and low-melting solders. The latter are in demand in the production of radio equipment, soldering of electronic elements, as well as for tinning radio circuit boards. Melting is carried out at temperatures not exceeding +450 degrees. Such materials are based on zinc, lead, tin, etc.

On an industrial scale, POS - tin-lead solder - is in demand. If the composition contains bismuth or cadmium, the name contains the letters B or K.

The number at the end of the marking indicates the proportion of tin in relation to lead - the lower this value, the stronger the solder. Marking with the letter F indicates the presence of flux in the composition.

In recent years, due to environmental standards in Europe, lead-free materials have become more often used in their composition.

The most common domestic products and their scope of application:

• POS-18 - often used for tinning.
• POS-30 - soldering of steel, as well as copper and their alloys.
• POS-50 - production of high-quality soldering in radio electronics.
• POS-90 - tinning of parts before gilding or silvering. Do not use for processing installations that operate at elevated temperatures.
• POS-40 and POS-60 are the most in demand in radio electronics. For switching brass and shielded plates, material marked 30 is used. Products containing flux are used for mounting radio components and are produced in the form of wire 1-3 mm thick.

Refractory solders are mainly used on an industrial scale for joining hard metals. Melting point - from +450 to +800 degrees. The composition contains magnesium, copper, silver and nickel. These solders are highly durable, but due to their high performance, they are not used in domestic conditions. Release form: ingots of various shapes.

Fluxes and their application

The quality and strength of soldering, the neatness and evenness of the seam directly depend on the correctly selected flux.

When heated, a thin film should form between the materials and the solder, enhancing the adhesion of the latter to the metal. The lower the flux melting rate, the higher the quality of work.

In addition, these values ​​should be lower than those of solder. Today two types of materials are produced:

• Active. They often contain acids (hydrochloric, orthophosphoric). They have a good effect on greasy deposits, but poor cleaning of the commutation area leads to corrosion over time. People try to use drugs rarely in everyday life, especially for radio electronics. This is due to the fact that they destroy PCB and also cause burns when they come into contact with the skin. In addition, the fumes released during operation have a toxic effect on humans. The most popular fluxes are ammonia, phosphoric acid and borax.
• Passive fluxes help remove fat deposits. Prominent representatives are wax and rosin. These are organic, non-corrosive substances necessary for soldering radio components. Recently, the use of materials marked LTI for switching with low-melting solders has become in demand. In addition, it is possible to solder lead, iron, stainless steel and galvanized metals. The composition contains alcohol, rosin, etc. Minus: under the influence of temperatures, vapors release substances harmful to health. The only exception is the drug LTI-120, which does not contain hazardous elements.

There are many different types of fluxes. The most popular of them:

• Pine rosin. The simplest and most accessible type. It has low current leakage rates and is a passive type. Due to its popularity, it is available for sale. Used in a wide range of works, dissolved in a mixture of alcohol and glycerin.
• Orthophosphoric acid. It is a chemically active compound. Used when working with oxidized metals, nickel-plated steel. At the end of the work, be sure to clean the soldering area with soda solution. This is necessary to extinguish acid activity and prevent corrosion of the metal.
• Soldering acid. Needed for soldering nickel, carbon steel, copper and brass.
• Soldering fat. It can be active or neutral and is used for oxidized elements of ferrous and non-ferrous metals. Neutral can be used to work with radio components, active is not.
• Borax. Suitable for soldering steel, copper and cast iron at high temperatures.
• TAGS. Made on the basis of glycerin, it is used for radio installation; after finishing the work, it is necessary to treat the areas with alcohol.
• Fluxes ZIL. Designed to work with steel, brass, copper.
• Active FIM fluxes. Suitable for working with oxidized platinum or silver. The composition contains phosphoric acid, so washing with soda solution is necessary.
• FTS. A product that does not contain rosin. Used for soldering radio components without smoke.
• Tinol paste is a chemical product intended for soldering with a hot air gun.

Types of soldering irons

A soldering iron is a tool that is used for soldering and tinning, for heating flux and elements, melting solder, etc. The working part of the device is called a tip; heating occurs from a blowtorch or electric current.

Typically, the electrical power of such tools is 30-40 W; they are designed for repairing and installing electronic devices.

But when working with semiconductor equipment, this product can cause unacceptable overheating. To prevent such situations, it is advisable to purchase a low-power unit with ratings of no more than 15 V.

Soldering irons come with both periodic and constant heating. The latter are divided:

• Electrical. They have a built-in heating element that operates from an outlet, battery or transformer.
• Gas. Equipped with a built-in burner, fuel is usually supplied from a cylinder with liquefied material. An external source is rarely used.
• Liquid fuel. They are similar in design to gas ones, but are heated by the combustion flame of liquid fuel.
• Thermal air. The work is carried out thanks to a stream of hot air. The principle of operation is similar to a hair dryer, but in this case a thin air stream is used.
• Infrared. Heated by a source of infrared radiation.

Devices with periodic heating are hammer and end-type. They are presented in the form of a massive tip attached to a metal handle, the length of which ensures the safety of work. Heating is carried out from external heat sources.

There are different types of solders and fluxes that are suitable for working with specific metals. Having understood the features of the drugs, choosing the right material will not take much time and will not cause difficulties.

Source: https://fgpip.ru/harakteristiki/kak-otlichayutsya-pripoi-po-temperature-plavleniya.html

Solder melting point: basic properties and types of composition, how it melts, what it can consist of

To connect various metal elements together, a special alloy called solder is often used. The low melting point of solders (a table with this indicator can be found in various methodological literature) allows them to be used in everyday life and industry. It is worth considering that not all metals can be joined together by soldering. Let's look at the types of solder, its composition and some other features in more detail.

Basic properties of the alloy

When considering the temperature at which tin melts for soldering, it should be borne in mind that not only this indicator is taken into account. The materials used for soldering are characterized by the following properties:

1. Wettability. To ensure a high-quality connection, the alloy used must have a high wettability index. This concept means increasing the reliability of the connection between molecules of solid materials. At a high index under consideration, the molten substance disperses over the surface, filling all the cavities.
2. Electrical conductivity. In most cases, soldering alloys are used to produce various microcircuits. With high electrical conductivity, the resulting connection does not create additional resistance during operation. If the conductivity is too low or the resistance is too high, the contacts created begin to heat up.
3. Melting temperature. The main criterion when choosing an alloy is that it must melt at a much lower temperature than the metals being joined. In this case, the melting temperature of tin solder will differ significantly from the corresponding indicator of other solder. The same alloy can melt at different temperatures, it all depends on the chemical composition. The presence of impurities causes an increase or decrease in fusibility. The melting point of POS-40 solder is 238 degrees Celsius. There are also refractory solders, which require a special device to heat.

It is important to consider the temperature at which tin-lead or other solder melts. This is due to the fact that when the base material is heated to critical values, the structure is reconstructed and it changes its basic performance qualities.

Types of materials used

The alloys used can consist of various chemicals. The classification is carried out as follows:

1. Soft or fusible. The most popular compounds are tin and lead, as well as their various types. In order to give special properties to the alloy, various elements are added to its composition. An example is that cadmium and bismuth can be included in the composition to significantly reduce the melting point, for example, to 61 degrees Celsius. It is worth considering that the strength of such alloys is low. This point does not allow obtaining reliable connections; the alloy is only suitable for carrying out work on connecting contacts. It is important to monitor the temperature to which the soldering device heats the alloy. It is not recommended to allow liquid metal to boil, as this may lead to a change in its basic properties.
2. Solids are represented by two groups of alloys: copper and silver. To absorb a small static load, an alloy of zinc and copper is often used, which allows you to obtain a very high-quality connection. Gold can also be used as solder.

A variety of companies produce solder, for example, Harris Corporation. The release form can be very different: from foil to wire of various sections.

Application of flux

As the temperature of the material increases, graphite may precipitate. Almost no soldering process takes place without the use of flux. Such a chemical substance avoids the formation of oxide, which deteriorates the quality of the resulting compound.

There are quite a large number of varieties of flux:

1. When using soldering based on tin and lead, a flux based on hydrochloric acid or zinc chloride is often used.
2. Ammonium chloride or borax can be used as a flux.
3. With soft alloys, a solution of hydrochloric acid or zinc chloride is often used.

When working with aluminum alloys, many use a flux based on zinc chloride, rosin and tung oil.

In conclusion, we note that the soldering process can take place at very different temperatures. For domestic use, materials are chosen that melt at low temperatures, which allows the use of conventional equipment during operation. If you wish, you can prepare the solder yourself. However, such a process is very difficult to implement, since it requires precise dosing of all elements, involves heating them to a high temperature and removing harmful impurities.

Source: https://obrabotkametalla.info/splavy/temperatura-plavleniya-olovyannogo-pripoya

Refractory solder melting point

Solder is a metal or mixture of metals used in soldering to join parts together. Typically, alloys based on tin, copper and nickel are used. Tin-based solder is included in the group of low-melting solders.

And the melting temperature of the solder here does not exceed 450 °C. These compounds are widely used to work with radio equipment.

Solders based on tin and lead are very common; they are widely used in our metal industry: the abbreviation POS.

To assemble homemade devices of the simplest design, the most common solder POS-61 or similar is sufficient. The alloy can be obtained from an old printed circuit board from an electronic device and assembled with a soldering iron from the soldered contacts.

Types and characteristics of solders

They are soft (low-melting) and hard. For installation of radio equipment, low-melting materials are used, with a melting point of 300−450 °C. Soft solders are inferior in strength to hard solders, although they are the ones used for assembling electrical appliances.

Low-melting alloys are usually an alloy of lead and tin primarily. There are few alloying elements.

Impurities of other metals are introduced to obtain certain characteristics:

• plasticity;
• melting point;
• strength;
• corrosion resistance.

The number in the brand designation indicates the percentage of tin it contains. So, the technical characteristics of POS-40 solder are such that it contains 40% Sn, and POS-60 - 60%.

If the brand is unknown, the composition can be assessed by indirect signs:

• The melting point of POS is 183−265 °C.
• If the solder has a metallic sheen, it means there is a lot of Sn in it (POS-61, POS-90). If the color is dark gray and the surface is matte, this indicates a high lead content, which is what gives the grayish tint.
• Solders containing large amounts of lead are very ductile, and tin imparts strength and rigidity.

Use of tin-lead group alloys

These alloys include the following:

• POS-90 contains: Pb - 10%, Sn - 90%. Used for repairing medical equipment and food utensils. There is little toxic lead, as it should not come into contact with food and water.
• POS-40: Pb - 60%, Sn - 40%. Mainly used for soldering electrical equipment and galvanized iron products; it is also used to repair radiators, brass and copper pipelines.
• POS-30: Sn - 30%, Pb - 70%. Used in the cable industry, for soldering and tinning and zinc sheeting.
• POS-61: Pb 39%, Sn 61%. Like with POS-60. There's not much difference.

Using POS-61, tinning and soldering of printed circuit boards of radio equipment is carried out. This is the main material for assembling electronics. It begins to melt at 183 °C, complete melting at 190 °C. You can solder with this solder using an ordinary soldering iron without fear that the radioelements will overheat.

POS-30, POS-40, POS-90 melt at 220−265 °C. For many radio-electronic elements this temperature is subcritical. It is better to assemble homemade electronic devices with POS-61, whose foreign analogue can be considered Sn63Pb37 (where Sn is 63% and Pb is 37%). It is also used to solder radio equipment and homemade electronics.

Solders are usually sold in tubes or coils of 10-100 g. The composition of the alloy can be read on the packaging, for example: Alloy 60/40 (“Alloy 60/40” - POS-60). It looks like a wire with a diameter of 0.25-3 mm.

It often contains flux (FLUX), which fills the core of the wire . indicated as a percentage and amounts to 1−3.5%. Thanks to this form factor, there is no need to supply flux separately during operation.

A variety of POS - POSSu is a tin-lead alloy with antimony, and is used in the automotive industry, in refrigeration equipment, for soldering electrical equipment elements, electrical machine windings, cable products and winding parts; Suitable for soldering galvanized parts. In addition to lead and tin, the alloy contains 0.5−2% antimony.

As the table shows, POSSU-61−0.5 is most suitable for replacing POS-61, because its complete melting temperature is 189 °C. There is also a completely lead-free , tin-antimony POSu 95−5 (Sb 5%, Sn 95%) with a melting point of 234−240 °C.

Low temperature solders

There are solders designed specifically for soldering parts that are highly sensitive to overheating. The most “high-temperature” among low-temperature ones is POSK-50−18 with a melting point of 142−145 °C. POSK-50−18 contains 8% cadmium, 50% tin and 32% lead. Cadmium enhances corrosion resistance, but at the same time imparts toxicity .

In descending order of temperature comes ROSE (Sn 25%, Pb 25%, Bi 50%), marked POSV-50. T pl. - 90−94 °C. Designed for soldering brass and copper. This alloy contains 25% tin, 25% lead, and 50% bismuth.

The ratio of metals in percentage may vary slightly, and their quantity is usually indicated on the package in the “Composition” column. This solder is extremely popular among electronics engineers. Used when dismantling/installing elements sensitive to overheating.

Among other things, the alloy is ideal for tinning the copper tracks of a brand new printed circuit board.

Source: https://MyTooling.ru/instrumenty/tugoplavkij-pripoj-temperatura-plavlenija

Which solder to choose for soldering: types, brands and characteristics

In the manufacture and repair of electrical equipment, skills in handling a soldering iron are constantly required, and solder and rosin are used for soldering; in the middle of the last century, tin was used for these purposes, but not in its pure form, since this is a very expensive pleasure, and alloys with other fusible materials metals.

Which ones are there?

What is solder and how to choose it correctly - in practice they can be soft or hard . Installation of any radio-electronic equipment occurs using low-fusible options.

Components of unknown origin differ in the following characteristics:

1. The rich shine of the cut indicates a high presence of tin.
2. The predominance of lead guarantees the substance a dull gray color and a matte surface.
3. With an increased lead content, the product becomes plastic; for example, a wire with a cross-section of 6 mm is bent by hand without visible effort.

Sometimes, for high-quality soldering, a ready-made mixture is used - this is solder in the form of a wire, and the flux is sealed inside. Manufacturers produce similar substances with flux tolerance within 1-3% of the total weight, which has a beneficial effect on the soldering process and increases labor productivity, since there is no need to constantly dip the soldering iron tip into a jar of flux.

Based on consistency, they are available in two types: soft or hard solder, and based on the melting point, ordinary and refractory types are distinguished.

Solder wettability

This term means the adhesion of molecules of a liquid melt to a solid surface, the degree of which determines the fluidity of soldering . For good soldering, liquid solder qualitatively wets the surface where soldering occurs, and its boundary forms an acute angle.

Dried flux can only be removed by mechanical cleaning, because additional alloy has appeared. If a drop of molten substance forms an obtuse angle with the surface, then this indicates unsatisfactory wetting quality, which is counteracted by dirt, grease stains or a metal oxide film.

Options for wettability of soldering surfaces with molten flux.

Melting temperature

The main criterion for choosing high-quality alloys is that they must come into a liquid state earlier than the structures being joined , and the melting point of the solder differs significantly from that of another type, for example, those containing lead impurities.

The presence of different impurities affects the ability to melt at the same temperature, for example, POS-40 melts when it reaches 238 0C, but there are refractory solders and special devices are used for their melting.

Low temperature options

In first place is the VUDA alloy with the composition: 10% Sn and Cd each, 40% Pb and Bi, the beginning of the melt is 65-72 0C. The second position is occupied by a solder called ROSE, which begins to melt at 90-94 0C. Consists of: 25% tin and lead each, and the remaining 50% is bismuth. The above alloys are expensive solders.

The third place among low-temperature products is occupied by POSK-50-18, with a temperature of 142-145 0C. This solder contains 50% tin, 32% lead and 18% cadmium, which enhances corrosion resistance but adds toxicity.

The second nominee (called ROSE) is very popular among radio amateurs, but in domestic radio electronics its marking is POSV-50, where the numbers are the percentage of bismuth. Used for installation/dismantling and tinning of overheat-sensitive copper tracks on printed circuit boards.

Soft look stamps

Solder for soldering in this category is used with a ready-made flux located inside the wire, so melting occurs simultaneously . A product called Tretnik has become widespread because it contains a third of the lead of the total composition. Tin, which is part of the alloy for soldering, is environmentally friendly, so it is allowed to use this type in the food industry.

Soft types of solders are used for soldering parts that are afraid of overheating, for example: transistors or fuses. Due to its toxicity, WOOD alloy is used in limited areas of human activity.

Domestic alloys are marked with the abbreviation POS, but if there are other substances, a letter corresponding to the name is added at the end, for example, POSV-33 - this solder contains equal parts of tin, lead and bismuth.

Main technical parameters

Soldering materials are divided according to the following parameters:

1. Conductivity , for example, solders containing aluminum have better similar values ​​than those marked PIC.
2. Tensile strength , unit kg/mm. This parameter directly depends on the percentage of tin.
3. Melting point , which depends on the chemical composition.

Table of temperature and application depending on the chemical composition of the solder.

Flux

Solder with rosin in the form of a hollow wire twisted into rings is common on sale . A flux of similar composition is made from coniferous trees; such a substance becomes soft when heated to 50 ° C, and at 250 ° C it begins to boil with partial evaporation. Rosin must be removed after finishing work, otherwise oxidation will occur, and the substance, absorbing moisture from the air, will begin to interfere with the proper operation of the devices.

Popular formulations

There are three main categories:

1. Light-colored rosin is used when joining copper and other soft non-ferrous metals; an alcohol solution with a concentration of one to five is used in a hard-to-reach area of ​​adhesion; and a mixture of glycerin and rosin is used for hermetic soldering.
2. Fluxes containing alcohol, petroleum jelly or zinc chloride are used to permanently bond non-ferrous and precious metals. The use of paste is justified by the fact that it is more convenient to apply it in the required quantity to the product.
3. Acid-active substances are produced in liquid form, for example, orthophosphoric acid, which has a density of 1.7.

Pasty

Tinol paste has become widespread and is used for soldering various products in hard-to-reach places. It is applied with a spatula, followed by active heating with a soldering iron or other, more powerful electric tool. Often used by inexperienced performers who do not have the skills to work with tin and rosin.

Using PIC

The discoverers of this alloy were pleasantly surprised that it turns into a molten state at a lower temperature, and the eutectic mixture can act as a solvent for the added metal. This is how the very first brands of POS solders were developed.

Lead options

Such mixtures containing lead are characterized by softness, rapid melting and easy processing, which is why they are called lead-containing solders. They are harmful and have been banned for use in soldering electrical components around the world . The percentage of cadmium, mercury, and similar harmful components in equipment is strictly regulated and verified by relevant organizations.

Lead free

Lead-free solder must not contain harmful metals and is considered environmentally friendly, not causing harm to the environment and the solder performers. The simplest example is tin solder, which contains pure tin, has increased wettability and high electrical conductivity. To combat deficiencies, copper, silver and gold are added to them, which helps make the substance harder.

Such a product has an increased melting temperature, but it has not yet been possible to find a complete alternative to standard types of solder, but the main indicator is harmlessness. Tin occupies a major place in the chemical composition, so its inherent properties have a great influence on the solder, because of this, the melting point of lead-free solder is lower, and the material is softer.

Colophon resin

This is the name of the well-known rosin - an amorphous substance with a characteristic fracture and glassy sheen when chipped . In addition to the fact that it has a natural dielectric property, the following features are known:

• dissolves well in gasoline, alcohol, ether and acetone, but remains indifferent to the effects of water;
• the melting point varies between 50-70 degrees, but sometimes rises to 130 0C;
• the chemical composition contains up to 90% resin acids, the basis is abietic acid;
• easily destroyed with minor mechanical impact.

The color varies from light yellow to dark brown shades, which depends on the degree of purification and indicates the amount of foreign impurities. Excellent electrical insulating properties belong to lemon-colored resin.

Secrets of choice

The task of any performer is to create a strong and reliable fastening of radio components to the board, therefore the selection of solder is carried out according to the following parameters:

1. The composition of materials to be soldered - here it is necessary to take into account the characteristics of the material, its ability to overheat and much more.
2. When soldering wires or other large objects, refractory solders are used.
3. Sometimes it is necessary to use solder that has a high ability to conduct electric current; it must be taken into account that the resistance of tin is much lower than that of lead, therefore expensive brands of solder are used for soldering high-frequency circuit boards.

In each specific situation, the performer must clearly know the correspondence of the solder and the product being connected in order to choose the best option for high-quality soldering.

conclusions

Today there is an abundance of different solders on sale, as they say, for all occasions, but you should choose proven samples that will help solder the product with high quality and with high reliability during operation.

Source: https://svarka.guru/payka/oborudovaniya/pripoy.html

Solder for soldering copper

» Soldering » Solder for soldering copper

Metal soldering is often carried out to produce a wide variety of joints. The most difficult metals to process are considered to be brass, aluminum and copper. The reliability and quality of the resulting connection largely depend on the type of consumables used. Solder for soldering copper must be selected taking into account the conditions under which the product will be used.

Solder classification

There are a variety of consumables that can be used for soldering copper products. The most common ones are:

1. 1S is considered soft solder. The composition of this alloy includes silver, which ensures high ductility. Pipes subjected to soldering when using 1S are used to create cold and warm water supply systems. In this case, additional fluxes for copper are purchased, since they are not included in the composition of the metal.
2. Rosol 3 also belongs to the group of soft solders. Low temperature alloy suitable for working with thin products. Its melting point is 240°C. The resulting compound serves well at high and low temperatures.
3. Rolot 94 is considered a hard metal. Brazing of copper pipes is carried out when the system will be operated at high pressure. The operating temperature is 730°C. A value that is too high means that the solder cannot be used for thin products. Heating the soldering iron tip to a high temperature can damage the workpiece itself.
4. Rolot 2 is a soft solder containing a small amount of silver. It is suitable for standard soldering procedures and is inexpensive.

Materials with impurities of zinc and lead should be included in a separate category. They are included in most formulations to impart special qualities.

Which solder should I choose?

A large number of varieties of different solders makes it difficult to choose the most suitable one. All alloys are divided into two categories:

1. Soft ones melt at a temperature of 425°C.
2. The operating temperature of the hard alloy is +460+560°C.

Some options include silver. They are quite expensive; with increasing concentration, the melting point decreases.

When choosing solder, the following points are taken into account:

1. Thickness of connected products.
2. Purpose of the equipment. Food-grade copper requires special alloys.

The soldering procedure is suitable for joining copper products of various sizes. During operation, the solder used fills small gaps. There are two types of connection:

1. High-temperature is characterized by the fact that melting is carried out at a temperature of 450°C. An alloy is selected that includes copper and silver, as they make it possible to obtain a reliable seam. The resulting weld is called hard; it is annealed to increase ductility. Cooling is recommended to be done naturally. The solid connection is suitable for pipes with a diameter of 12-159 mm. Most often, the high-temperature method is used to obtain a gas pipeline or heating system.
2. Low temperature is carried out at temperatures less than 450°C. Solder may contain tin or lead. The width of the resulting seam should be in the range of 7-50 mm. A connection of this type is not inferior in strength to the first one, but it does not have to be annealed. The use of low temperature to melt the metal determines the safety of the procedure. The seam can be obtained by connecting a pipe with a diameter of 6-108 mm.

What will be needed in the process?

To carry out the work in question, materials and tools are required. Among the features we note the following points:

1. The surface to be joined is cleaned using flux. It removes oxidative film and reduces surface tension.
2. The main material can be called solder. For high temperatures, a version that does not contain lead is suitable. This point is indicated on the packaging. Solder is made in the form of wire of various lengths, the cross-sectional diameter is 3 mm.
3. Work with pipes can be carried out using a pipe cutter. It is used for cutting the workpiece into separate parts.
4. Deburring is carried out using a special chamfer remover. Severe defects in the end surface will cause the two parts to fail to be joined end-to-end.
5. The inner surface of the pipe is cleaned with a brush or brush. This is done in order to provide the required system throughput.
6. In some cases, soldering can only be carried out when the workpiece is preheated. For this, a gas burner is used, which has a narrowly directed flame. The version with a cylinder containing a mixture of propane and butane can last for a long period.

The most commonly used are electric soldering irons, which are made for processing copper workpieces. The device can work with soft and hard solder. Working with an electric soldering iron is quite simple; just turn it on and select the required temperature setting. To mark the soldering area, use a tape measure, marker, or building level.

Technological tips and notes

Only with experience can high-quality soldering be carried out. Common problems include the following:

1. Defects on the surface of parts cause deterioration in the quality of the connection. They appear when cutting a workpiece. Soldering over defects results in reduced strength.
2. Minor contamination also reduces the strength of the connection. Therefore, degreasing is carried out using special compounds.
3. Insufficient width of the installation gap. The required strength when connecting products with a cross section of 6-108 mm is achieved if the gap is 7-50 mm.
4. If you heat the workpiece before using it to an insufficient temperature, then even with a slight load the seam will collapse.
5. Flux covers the entire surface unevenly. Oxides can cause defects.
6. Overheating of the contact area causes flux and solder to lose their qualities.
7. Ignoring safety rules when carrying out work. Too high a temperature may cause the chemicals to react. Therefore, it is recommended to work with protective gloves and a mask.

Working with copper is different from soldering metal. All the features can only be known by a master who has extensive experience in carrying out such work.

Sergey Odintsov

Source: https://electrod.biz/payka/pripoy-dlyai-medi.html

Melting temperature of solder

The main consumable material during soldering is solder. This is the metal alloy that is fused onto the surface of the base material. But it does this in such a way as not to melt the place where the soldering occurs.

This is achieved due to the fact that the melting temperature of the solder is lower. This parameter is one of the fundamental ones when determining characteristics, when choosing a brand for surfacing and other nuances of use.

After all, according to this parameter, the main classification occurs, which distinguishes soft and hard solders.

Solder for soldering

Soft ones include all those that melt at a value below 300 degrees Celsius. As a rule, these are all those things that are used at home, since they can be dealt with with ordinary tools.

The quality of their connection is not always as good as that of representatives of the other group, but ease of use and improved adhesion often compensate for this. Solids include those in which melting occurs at levels above 300 degrees Celsius. These are more difficult to work with, since they require not only a special flux, but also special tools.

Some of these materials melt at temperatures above 700 degrees, so an ordinary soldering iron is not enough and a more powerful burner is needed.

Soft solder with a melting point below 300 degrees Celsius

It is worth noting that there are several values ​​in this parameter. There is an initial melting temperature, at which the material just begins to transform into a liquid state, and there is a final melting point, at which the alloy completely becomes liquid. For soldering, the first option is taken, as it helps to maintain the viscosity of the material, which makes the work easier and more convenient.

Properties

It is worth noting that many of its properties depend on the temperature at which solder melts. This is due to the composition, because if it contains refractory metals, which in their pure form have high strength, then when added to the alloy they retain these qualities, albeit not fully.

Thus, the direct dependence of the strength of the connection on the melting point is almost always correct. A simple example is Wood's alloy, which is one of the lowest melting options.

In practice, it turns out to be very fragile and can crack or fly off from small temperature influences.

Here there is a dependence on what temperature the resulting compound will withstand. The melting point of the solder must be lower than that of the base metal, otherwise it would already be a welding process.

Soldering with high-temperature solders itself occurs at high temperatures, and accordingly, the connection will better resist such effects.

The thermal conductivity of the solder is also an important factor, because if it is at a low level, it helps to better withstand high temperatures and protects the part from overheating.

Melting temperature of solders

Differences in temperature can be very large, as can be seen in the table example. Moreover, this applies even to neighboring brands in the same series, since much is determined by the additives in the composition and other nuances. Here is the basic data for the most common brands:

Solder name	Melting point, degrees Celsius
Wood's alloy	70
Alloy Rose	90
PSRZI	141
POSI 30	170
AKP	235
PSR 1.5	280
PSR 2	248
POS 50	245
POS 61	192
POS 10	299
POS 40	238
POS 61	190
O2	232
POSSU 95-5	240

Temperature Recommendations

The melting point of soft solders, although it does not exceed 300 degrees, while in hard grades the spread is much greater, still, even in this case the difference is more than three times. Thus, it is worth selecting heat treatment tools that have the power required to achieve the desired parameters.

A higher or lower temperature may not be suitable, so this may be one of the reasons why the solder does not stick to the soldering iron. Deviation when choosing a temperature regime is allowed within small limits, about 10-20 degrees Celsius, preferably in a higher direction.

After all, it is not always possible to accurately set operating parameters, especially on simple soldering irons.

The possibility of a harmless increase in the temperature of the tool is due to the fact that the solder has an initial melting point when it flows from solid to liquid. At this time, the liquid becomes relatively viscous and plastic enough for use. This is followed by the second melting point, when the material already becomes as liquid as possible. It’s already more difficult to work here, so the choice of mode should be just between these two indicators.

Source: https://svarkaipayka.ru/material/pripoj-dlya-payki/temperatura-plavleniya-pripoya.html