What does solder contain?

Variety of solders for soldering

Soldering is one of the effective ways to connect various metal parts and device components. The advantages of soldering are that it creates a permanent connection, almost homogeneous in structure, moreover, it is electrically conductive and resistant to corrosion.

To join metals, a special substance is used - soldering solder. This is an alloy that is used to create a joint between parts.

Refractory and low-melting

Solders for soldering are divided into refractory and low-melting. They are also called hard and soft. All types of solders are widely used in mechanical engineering, electrical engineering, and electronics.

Hard solders are used when it is necessary to achieve high joint strength. Probably, such connections could be called constructive. Their melting point reaches 500 ℃ and above.

This temperature is dangerous for most components of electronic circuits, especially for semiconductor devices and limits their use, so other alloys are used for soldering - low-melting alloys.

They are obtained by adding more lead to tin. All low-melting solders have a melting point of about 200 - 240 ℃.

With a melting point less than 200 degrees

There are also solders with very low melting points. This is, for example, POSK-50-18. From the marking it follows that this solder contains 50% tin, 18% cadmium, and 32% lead.

This solder melts at a temperature of 142 – 145 ℃. It is very plastic, but due to its cadmium content, it is toxic.

Another example of such low-melting solders is POSV-50 (it has the name Rose). Here the number 50 indicates a bismuth content of 50%, and tin and lead are present in the composition in equal proportions - 25% each.

Solder melting temperature is 90 – 94 ℃. These two soldering products most often come in tablet-like shape and size. Wood's third alloy contains 10% tin, 40% lead, 40% bismuth, 10% cadmium.

Its melting point does not exceed 72°C. Due to the presence of cadmium in its composition, it is toxic. Rose and Wood alloys are quite expensive.

Indium solders are often used for soldering semiconductors, since their melting point is about 117 ℃. In this alloy, indium replaces tin, and lead is also added to soften it and make it more fluid.

Some indium solders can be used to solder glass. In this case, the edges of the latter are simply rubbed with paste before soldering.

Tin-lead

Depending on the composition of the alloys, more precisely, on the percentage of components, the names of solder brands are formed.

For example, POS-30. The letters abbreviate the chemical composition - tin-lead solder, and the number indicates the percentage of tin in the composition - 30%.

Alloys containing tin and lead are generally classified as low-melting solders for soldering.

The most common brands are:

• POS-90. Used when the presence of lead is undesirable. These can be various machines and mechanisms intended for the food industry and agricultural sectors. Lead, when combined with certain chemical elements and in the air, emits toxic fumes that are harmful to the health of living organisms.
• POS-60. Universal solder. It is widely used for soldering due to the combination of its good strength characteristics and the temperature to which radioelements are tolerant.
• POS-40. It is used for soldering galvanized iron products. Used in the repair of heating appliances and pipes.
• POS-30. This brand is used for tinning, that is, for applying a layer of tin to the surface in order to give it anti-corrosion properties.

Lead makes the alloy soft and fluid, making soldering easier. A rod with a high lead content (more than 30%) can be easily bent, whereas a pure tin rod can only be bent with great difficulty.

Containing antimony

To reduce the degree of oxidation of the alloy in the liquid state and give the soldering a better appearance, antimony is introduced into its composition. According to GOST 21930-76, all tin-lead solders for soldering, depending on the chemical composition, are classified into:

• antimony-free;
• low antimony, with antimony content up to 0.5%;
• antimonous, containing more than 0.5% antimony.

The same GOST also determines the areas of primary use of each brand.

Table 1. Chemical composition of solders

Chemical composition, % Brand of solder OKPO code Main components Tin Antimony Cadmium Copper Lead Antimony-free Low antimony Antimony

POS 90	17 2311 1100 04	89-91	—	—	—	The rest is the same
POS 63	17 2312 0100	62,5-63,5	—	—	—	«
POS 61	17 2312 1100 10	59-61	—	—	—	«
POS 40	17 2314 1100 00	39-41	—	—	—	«
POS30	17 2321 1100 09	29-31	—	—	—	«
POS 10	17 2326 1100 06	9-10	—	—	—	«
POS 61M	17 2312 1200 07	59-61	—	—	1,2-2,0	«
POSK 50-18	17 2313 1200 02	49-51	—	17-19	—	«
POSK 2-18	17 2343 1100 09	1,8-2,3	—	17,5-18,5	—	«
POSSu 61-0.5	17 2312 1400 01	59-61	—	—	—	The rest is the same
POSSu 50-0.5	17 2313 1100 05	49-51	—	—	—	«
POSSu 40-0.5	17 2314 1200 08	39-41	—	—	—	«
POSSu 35-0.5	17 2315 1200 03	34-36	0,05-0,5	—	—	«
POSSU 30-0.5	17 2321 1200 06	29-31	—	—	—	«
POSSu 25-0.5	17 2322 1200 01	24-26	—	—	—	«
POSSu 18-0.5	17 2323 1100 10	17-18	—	—	—	«
POS 95-5	17 2311 1200 01	Ost.	4,0-5,0	—	—	—
POSSu 40-2	17 2314 1300 05	39-41	1,5-2,0	—	—	The rest is the same
POSSu 35-2	17 2315 1300 00	34-36	1,5-2,0	—	—	«
OSSu 30-2	17 2321 1300 03	29-31	1,5-2,0	—	—	«
POSSu 25-2	17 2322 1300 09	24-26	1,5-2,0	—	—	«
POSSu 18-2	17 2323 1200 07	17-18	1,5-2,0	—	—	«
POSSu 15-2	17 2324 1100 05	14-15	1,5-2,0	—	—	«
POSSu 10-2	17 2326 1200 03	9-10	1,5-2,0	—	—	«
POSSu 8-3	17 2326 1300 00	7-8	2,0-3,0	—	—	«
POSSu 5-1	17 2327 1100 01	4-5	0,5-0,1	—	—	«
POSSU 4-6	17 2327 1200 09	3-4	5,0-6,0	—	—	«
POSSU 4-4	17 2327 1300 06	3-4	3,0-4,0	—	—	«

Foreign stamps

There are also foreign-made compounds. They are marked differently, but the mark can determine the composition of the alloy. An example is the Sb62Pb36Ag2 alloy produced by the American company Indium Corporation.

It contains 62% tin, 36% lead and 2% silver. Silver is often added to the composition to increase fluidity after the solder has melted.

Another example is the product produced by the Canadian company UNIVERSALPRIBOR. Its marking is SN62/36/2 NC. This material is in the form of a paste and from the marking it follows that its composition is: 62% tin, 36% lead, 2% silver. NC (No Clean) means that the solder balls are contained within a flux gel.

Release form

Solder comes in various forms. Initially, at the factory, these are pigs. The letter Ch is then added to the brand designation. For example, Ch POS-40. GOST 21930-76 determines the shape and size of pigs for each material and type.

Solder for retail sale comes in rods with a diameter of 8 mm, in the form of solder wire wound on a spool or rolled into a spiral and placed in a plastic tube.

Very often, soldering wire is a tube made of tin-lead alloy, inside of which there is flux - a substance that helps improve the quality of soldering.

Flux destroys the oxide film on the parts being soldered and prevents further oxidation of the soldered joint during its cooling.

Rosin, a product of the distillation of pine resin, is often used as a flux. It melts at a temperature of 68 ℃, under normal conditions it is hard, brittle, and yellow in color.

Pastes for microcircuits

Solder is also available in the form of solder paste. It is a plastic mass consisting of flux and a binder, which contains many tiny balls of tin-lead solder with flux.

Such pastes are used for stencil soldering, that is, when the use of conventional soldering methods is impossible due to the small size of the components.

These can be microcircuits or components in BGA packages. The pastes are applied to the terminals with a spatula and melted with a hairdryer or infrared soldering iron.

Due to the fact that solder pastes dry out quickly, they should be stored in special, hermetically sealed tubes.

To restore BGA packages, that is, to update the solder balls on their terminals, also called reballing, solder balls are produced. It can be either tin-lead or lead-free.

This is a high quality pure product with a very precise chemical composition.

The balls are stored in tightly closed jars at a temperature of +20 - +30 ℃ and a humidity of no more than 60-70%. The shelf life of such solder is usually no more than 12 months. Used for soldering critical components.

DIY making

If you have enough tin and lead, you can make your own solder. To maintain the proportions, you can weigh the required amounts of lead and tin on ordinary kitchen scales, be sure to use some kind of support.

Lead is poisonous, so there should be no traces of it on the scales. For the same reason, when working, it is necessary to organize good ventilation of the room, use safety glasses and gloves, and, if necessary, a respirator.

To weigh the required amount of materials, it is enough to know their density. For tin it is 7.30 g/cm³, for lead it is 11.35 g/cm³. By making a simple proportion, you can determine the amount for different compositions of alloys.

You can use a small steel container directly to prepare the alloy. In it you need to bring lead and tin to the melting temperature.

After they take on a liquid state, you need to remove the top layer with a steel spoon. This is slag formed when it combines with oxygen in the air.

Then you need to carefully but thoroughly mix the two metals and pour them into a mold made of some refractory material. Forms made of plaster or tin may be suitable for this.

This composition can be successfully used when installing electronic circuits, soldering wires and cables, and connecting copper or brass pipes.

All solders for soldering, despite their diversity, have different properties and characteristics. The correct selection of one or another composition for each specific case will ensure a high-quality and reliable connection using soldering.

Source: https://svaring.com/soldering/pripoj/klassifikacija

Melting temperature of tin for soldering, POS-40 and POS-60 solder, technical characteristics

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.

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.

Used in protective fuses in radio equipment.

An even lower temperature WOOD alloy (Sn 10%, Cd 10%, Pb 40%, Bi 40%). Melting point - 65−72 °C. Since the alloy contains 10% cadmium, it is toxic, unlike ROSE.

Both ROSE and WOOD are quite expensive solders.

Solder paste

Source: https://tokar.guru/metally/temperatura-plavleniya/temperatura-plavleniya-pripoya-i-tehnicheskie-harakteristiki.html

Physical and mechanical properties and chemical composition of POS 40 solders

Solder POS 40 is a universal consumable material for soldering parts made of various metals and alloys. It is made on the basis of a mixture of tin, lead and additional materials that improve the quality characteristics of the connection.

Description

Antimony-free tin-lead solders POS 40 are classified as low-melting materials . As the name suggests, the composition does not contain antimony, which sets it apart from the line of related filler elements.

The unique combination of main components allows the use of solder not only in industry, but also in everyday life. It can be used to solder cable and wire materials, various electronic circuits, and even galvanized steel.

Solder has many advantages, including:

• low melting point;
• high fluidity of the molten material;
• excellent wettability, which ensures the strength of the connection;
• absence of compounds hazardous to health;
• after crystallization, the connection has good corrosion resistance;
• simple rules of application;
• the ability to use low-power household soldering irons;
• wide choice of release forms.

Material characteristics

Let's consider the main physical and mechanical properties of solder 40:

• Material density – 9.3 g/cm2;
• Electrical resistivity – 0.159 Ohm*m;
• Temporary mechanical tensile strength – 32 MPa;
• Elongation at break – 60%;
• Impact strength – 4.0 kgf/cm2;
• Brinnell hardness – 12.5 HB.

Chemical composition

The main difference between the material under consideration is the almost complete absence of antimony in the composition . According to the requirements of interstate standards, its mass fraction does not exceed 1.0%. This gives the composition high ductility, due to the absence of tin and antimony compounds. In addition, antimony-free solder can be used to join parts made of zinc and alloys based on it.

The main elements of solder are:

1. Lead . The mass fraction in the composition is 59-61%.
2. Tin . The mass fraction in the composition is 39-41%.

The temperature at which tin melts for soldering depends on the ratio of the base materials. The temperature characteristics of this material will be discussed below.

The exact amount of the above chemical elements depends on the manufacturer and the availability of auxiliary components designed to improve the quality of the seam and facilitate soldering of complex metals and alloys. Percentage of additional elements:

• iron – up to 0.02%;
• nickel – up to 0.02%;
• sulfur – up to 0.02%;
• aluminum – up to 0.002%;
• copper – up to 0.05%;
• arsenic – up to 0.02%;
• zinc – up to 0.002%;
• bismuth – up to 0.2%.

Melting temperature

Let's consider the temperature indicators of the material:

• Solder begins to melt at a temperature of 183 Cº;
• The transition to a liquid state of aggregation occurs at 238 Cº;
• The complete crystallization interval is 69 Cº.

Please note that the melting temperatures of POS 40 and POS 60 solders are practically the same . At the same temperature threshold for the onset of melting, POS 60, due to the higher tin content in the composition, becomes liquid faster - at 193Cº. POS 40 has a longer crystallization interval, which negatively affects work productivity.

An important parameter is the percentage of solubility of tin in lead. At normal temperature, this figure will be 2%, while upon reaching the eutectic level, approximately a fifth of all tin will dissolve in lead.

Decoding

The abbreviation of the material contains information about the composition:

• “P” indicates the purpose of the material – solder.
• “O” - the composition contains tin;
• “C” contains lead;
• “40”—the mass fraction of tin is 40%.

Varieties

The production of tin-lead solder without antimony grade POS 40 is subject to the requirements of interstate standards. According to the instructions of the regulatory documentation, the following release forms are provided for the composition:

• wire;
• rod;
• ribbon;
• tubes;
• ingots;
• paste;
• liquid flux;

The most common form of release for home use is wire. The minimum cross-sectional value is 0.5 mm, with an error of 0.05 mm. This solder is used for soldering the smallest parts. The maximum wire diameter is 7 mm, with a dimensional error of 0.2 mm.

For work on an industrial scale, it is more convenient to use solder in the form of rods or ingots . The maximum diameter of the rod is 8 mm - this is the largest among all produced forms. The heaviest type of solder is a cast billet, the weight of which can reach 20 kg.

Use in everyday life and at work

Antimony-free solders with low tin content have found their application in the field of low-temperature soldering. This technology is characterized by a more economical cost of the production process, with high quality characteristics.

POS 40 is used for the following work:

• Creation of permanent connections of metal parts.
• Repair of radio electronics and other products that do not withstand high temperatures.
• Elimination of defects in vessels and containers that are operated without pressure and are not exposed to high temperatures.

At mass production enterprises, the material in question is used in the assembly of electronic circuits, printed circuit boards and other control devices.

After crystallization, the solder demonstrates high electrical conductivity, which is the main selection criterion, since these elements are not subject to shock, vibration and other mechanical influences during operation.

Thus, POS 40 has proven itself as a means of connecting various semiconductors.

Another area of ​​application of solder is sealing various metal vessels and containers. The low temperature of change in the state of aggregation allows the composition to be used as a means for tinning metal.

The features of working with solder are no different from the use of other compounds of the lead-tin group. The surface to be treated must undergo preparatory treatment - this is the key to a high-quality connection.

The main soldering conditions are that the melting temperature of the base surface must be lower than the solder temperature . For POS 40 solder, the temperature of complete melting of the material is 238 Cº.

This is enough to obtain a high-quality connection due to high performance parameters.

In addition to the high quality of the connection, the undoubted advantage of solder is its ease of use. Any soldering machine is suitable for the job, including household appliances.

Technical characteristics imply the use of all types of flux . Active compounds such as hydrochloric acid, zinc chloride or ammonium chloride effectively clean the workpieces from traces of corrosion.

Their use requires caution - excessive impact on the workpiece leads to the removal of the surface layer of the material. Neutral fluxes prevent negative processes, so their use does not risk damaging the metal surface.

Regulatory nomenclature

Like its main competitor - POS 61 solder, POS 40 is manufactured in compliance with the requirements and instructions, including production conditions and testing methods, of the interstate standard for solders GOST 21930-76.

Popular manufacturing companies

The material in question is a domestic product. The following companies are engaged in its production:

• Plant of metals and alloys;
• SKAT;
• Ukrnichrome;
• Solder plant;
• Reggaeton;
• Technological lines.

Conclusion

The material in question has high quality characteristics, similar to POS 61 solder. There is no clear answer to the question: “Which solder is better than POS 40 or POS 61?” It all depends on the conditions of the work and the properties of the surface being treated.

Source: https://svarka.guru/payka/oborudovaniya/pripoy-pos-40.html

Types of Tin-Lead Solders (POS)

The most famous of the solders are POS 10, POS 40, POS 61 and POS 90 (antimony-free solders). And POS containing antimony is called POSSU . antimony increases the strength of the solder by several percent.

If we are talking about melting a compound of tin and lead, you need to know the definitions of solidus and liquidus . If you heat any mixture of two or more metals, the melting (transformation from solid to liquid state) of the lightest particles will occur first. This is the temperature point called the solidus of the alloy.

With further heating, the more refractory metals in the alloy begin to melt. After they melt, the liquidus . After which the PIC solder is considered completely melted.

Between the solidus and liquidus points there is a state of increased ductility of the solder . At this temperature, the solder can be deformed and pulled without losing integrity.

There are solders in which the solidus and liquidus points coincide , they are called eutectic alloys . This indicator indicates that the solder is of high quality; such solder is very convenient for soldering.

About the composition of the PIC

POS-40 contains 40% tin, and POS-61 contains about 61% tin. Everything else is lead and additional impurities. By appearance you can determine what kind of solder you have in front of you. Matte and dark solder contains more lead. Light and shiny - more tin. This can best be seen in comparison.

The strength of the solder depends, along with the alloying of the alloy, on the metal being soldered. To solder zinc or copper, a little zinc or copper is added to the POS, respectively. This reduces chemical erosion of the metal and increases the surface strength of the joint.

Alloying POS

Solder performance can be improved by doping with the following substances:

• Plasticity and resistance to thermal cycling are improved due to the addition of silver, indium, lithium, manganese, and bismuth.
• corrosion resistance is improved by nickel and copper.
• Cobalt, silicon, zirconium, hafnium, vanadium, tungsten, and niobium contribute to increasing heat resistance
• Solder becomes stronger if you add boron, iron, nickel, cobalt, zinc, and silicon.
• The addition of silver, copper, zinc, cadmium, antimony and aluminum improves adhesion .

Characteristics of POS and POSS

The characteristics of solders of the tin-lead group are shown in the parameters table. Here you can see such characteristics as electrical resistivity, melting point, tensile strength, density, impact strength and Brinell hardness, thermal conductivity, relative elongation of existing varieties of POS and POSSU.

The table shows the lowest melting point solder (cadmium POSK 50-18) with a melting point of 145 °C, and the strongest solder for soldering (POSSu 4-6) with a tensile strength of 6.5 kgf/mm2.

Characteristics of POS 10

POS 10 has the following chemical composition: 9-10% tin, about 89% lead, 0.2% bismuth, 0.1% antimony and other impurities in small quantities. POS-10 is used for tinning and soldering contact surfaces of electronics. For example, it is used to fill control plugs in radio electronics housings and solder relays.

Soldering temperature POS 10 - 299 °C. The solidus point is 268 °C.

Pros of POS 10

• high melting point is useful when soldering equipment cases.

Cons of POS 10

• high resistivity - 0.2 Ohm•mm2/m;
• high content of lead, which is hazardous to health;
• low strength and tensile strength of about 3.2 kgf/mm2.

Characteristics of POS 30

POS 30 is an intermediate link between POS 10 and POS 40. POS 30 consists of: 30% tin and 69.5% lead. The rest is doping and impurities. POS 30 can be replaced without hesitation by POS 40. The melting point (liquidus) is 238 °C, and the plasticity temperature (solidus) is 183 °C. POS 30 is usually used for soldering and tinning of radiators and zinc sheets.

Pros of POS 30

• good adhesion;
• high strength.

Cons of POS 30

• high lead content;
• often produced in rods.

Characteristics of POS-40

POS 40 consists of 39-41% tin, 59% lead. The remaining impurities are in the same ratio as in POS-10. POS-40 is usually used for soldering and tinning of radio equipment casings made of galvanized iron with galvanized seams.

The soldering temperature of POS-40 solder is 238 °C, and the solidus is 183 °C.

Pros of POS 40

• more resistant to thermal cycling than POS-61;
• good ratio of ductility and melting point.

Cons of POS 40

• elevated liquidus temperature;
• high lead content, which is harmful to health.

Pos. 61 (pos. 60)

There are solders produced according to international standards, for example, Sn60Pb40 solder containing 60% tin and 40% lead. The melting point of 60/40 solder is 191 °C.

Another example is POS-62 . Its melting point c is 184 °C; it can be found in a foreign catalog of solders (for example, Kester ).

Characteristics of POS 61

POS-61 is usually used for soldering and tinning of electronic components and printed circuit boards of precision instruments with highly hermetic seams, for which overheating is not allowed.

Composition of POS-61:

• Tin 59 - 61%;
• Antimony - no more than 0.1%;
• Copper - no more than 0.05%;
• Bismuth - no more than 0.02%;
• Arsenic - no more than 0.02%;
• Iron - no more than 0.02%;
• Nickel - no more than 0.02%;
• Sulfur - no more than 0.02%;
• Zinc - no more than 0.002%;
• Aluminum - no more than 0.002%;
• Lead - the rest - about 38.7 - 40.7%.

The soldering temperature of POS-61 solder is 220 °C. Solidus - 183 °C.

Technical characteristics of POS 61 (according to GOST 21931-76):

• Density determines the weight of POS-61 solder and is equal to 8.5 g/cm3;
• The electrical resistivity is 0.139 Ohm•mm2/m;
• Thermal conductivity is 0.12 kcal/cm•s•deg;
• Tensile strength is 4.3 kgf/mm2;
• The relative elongation is 46%.

Pros of POS 61

• good adhesion to metal surfaces;
• universal solder for soldering and most radio installation work;
• the best ratio of melting temperature and strength;
• accessibility and prevalence;
• often produced in the form of wire (POS 61 T2A);
• low cost.

Cons of POS 61

• versatility reduces performance in special cases, for example when soldering zinc;
• melting temperature is not suitable for all devices;
• solder fumes (lead in it) are harmful to health.

Characteristics of POS-63

POS 63 in accordance with GOST and OCT 4G 0.033.200 is an alloy consisting of 63% tin and 37% lead. This is a kind of modernization of POS-61 solder, adjusted to the international standard J-STD 006B. Many high-quality Chinese solders are similarly labeled Sn63Pb37 . These are eutectic alloys with a melting point of 183 °C.

POS-63 is mainly used for soldering and tinning pins of microcircuits and packaged radio components, printed circuit boards, wires and cables. It is the most common of modern solders . The characteristics of POS 63 solder are very similar to POS-61.

Pros of POS 63

• coincidence of solidus and liquidus points;
• the most common POS series solder;
• relatively low melting point;
• low cost;
• supplied in the form of wire filled with flux.

Cons of POS 63

• often counterfeited, especially in China;
• contains lead, which increases the cost of recycling electronic equipment in accordance with modern safety standards.

Characteristics of POSSu-61-0.5

POSSu-61-0.5 designates a type of antimony solder containing 61% tin, up to 0.5% antimony and about 38% lead.
It is used for soldering and tinning of printed circuit boards and galvanized radio components with increased operating temperature requirements. The melting point is 189 degrees. Pros of POSSu-61-0.5

• increased adhesion to the metal surface due to the antimony content;
• characteristics are identical to POS-61.

Cons POSSu-61-0.5

• difficult to find on sale;
• increased cost.

Characteristics of POS-90

POS-90 consists of 90% tin and 10% lead. It also contains about 0.1% antimony and 0.05% copper. Most often used for soldering and tinning internal seams of medical equipment and food utensils . The melting point of POS 90 is 220 degrees.

Pros of POS 90

• low lead content;
• rarely counterfeited;
• low resistance;
• high strength.

Cons of POS 90

• high cost (higher than POS-61);
• low plasticity.

Solder for connoisseurs of high-quality sound

This type of solder is well known to fans of Hi-End electronics . This is solder for soldering audio equipment, produced in the 30s - 50s of the last century. These solders have high purity components, which has a positive effect on the highest quality sound. To hear the effect of such solder, you need both a high-quality sound source, a sound emitter, and excellent hearing.

Experts “listen” the solder and formulate their own alloys for better sound transmission.
The most famous for music lovers is solder from Kester . It sells for $10 per meter. Every year it becomes less and less. Its composition is close to POS-90.

Kester solder is composed of 85.9% tin, 8.5% lead, 3.28% silver, 0.34% copper, 0.79% sodium, 0.55% magnesium and 0.27% mercury.

There is also a solder containing 50% tin and 50% lead Sn50Pb50 .

Buy products based on the article:

Source: https://ampero.ru/news/410480-raznovidnosti-pripoev-olovyanno-svintsovyh-pos.html

Solder for soldering. Types of solders and fluxes

   One of the main elements of electrical and radio installation work is soldering. The quality of soldering is largely determined by the ability to choose flux and solder for soldering. To facilitate this choice, the article provides brief information about hard and light solders and fluxes, their use and their manufacture.

   Soldering is the joining of hard metals using molten solder, which has a melting point lower than the melting point of the base metal. The solder should dissolve the base metal well, spread easily over its surface, and well wet the entire soldering surface, which is ensured only if the wetted surface of the base metal is completely clean.

   To remove oxides and contaminants from the surface of the metal being soldered, to protect it from oxidation and to provide better wetting with solder, chemicals called fluxes are used.

   Solder for soldering is a low-melting alloy of metals intended for connecting wires, leads, parts and assemblies by soldering.

Previously, solders were designated by three letters - POS (tin-lead solder), followed by a two-digit number showing the tin content as a percentage, for example POS-40, POS-60. The best solder is pure tin. However, it is expensive and is used in exceptional cases.

During radio installation, tin-lead solders are often used. In terms of soldering strength, they are not inferior to pure tin. Such solders melt at a temperature of 180 - 200 ° C.

Selecting solder for soldering

   The choice of solder is made depending on the following factors:

• metals or alloys to be joined
• soldering method
• temperature restrictions
• part size
• required mechanical strength
• corrosion resistance, etc.

   To solder thick wires, use solder with a higher melting point than for soldering thin wires. In some cases, the conductivity of the solder must also be taken into account (reminder: the resistivity of tin is 0.115 ohm x mm2/m, and that of lead is 0.21 ohm x mm2/m).

Solder for soldering is divided into three groups: refractory, low-melting and ultra-low-melting.

Refractory solders (radio amateurs practically do not use them). Refractory solders include solders with a melting point above 500 °C, which create very high mechanical strength of the joint (tensile resistance up to 50 kg/mm2).

Their disadvantage is precisely that they require high heating temperatures and, although the strength of such soldering is very high, intense heating can lead to undesirable consequences: you can, for example, “release” a steel part.

 The disadvantage of hard solders is that they require high heating temperatures, and although the strength of such soldering is very high, intense heating can lead to very undesirable consequences: you can overheat an expensive part and damage it (for example, a transistor or microcircuit), you can “let go” ", for example, a steel part (spring).

Low-melting (ham radio) solders. This category includes solders with a melting point of up to 400 °C, which have relatively low mechanical strength (tensile strength up to 7 kg/mm2). In radio engineering installation work, low-melting solders are mainly used. They contain tin and lead in various proportions, for example, POS-61 solder, which contains 61% lead, 38% tin and 1% various additives.

Ultra-low-melting (ham) solders. There are also alloys that contain, in addition to tin and lead, bismuth and cadmium. These alloys are the most fusible: some of them have a melting point of less than 100 °C. The mechanical strength of the connection of such alloys is very low.

Previously, they were used for soldering crystals in crystal detectors. Currently, low-melting cadmium-bismuth alloys are used in the repair of printed circuit boards.

They are also used for soldering transistors, since according to technical specifications it is recommended to solder them with solder with a melting point not exceeding 150 °C.

   For soldering transistors, you can use the so-called Wood's alloy with a melting point of 75 ° C, which contains: tin - 13%, lead - 27%, bismuth - 50%, cadmium - 10%. Wood's alloy can be prepared according to the specified recipe yourself or purchased at a pharmacy. Soldering is carried out with a weakly heated soldering iron. Rosin is used as a flux.

Amateur radio solder for soldering

   Nowadays, solder wire with a cross-section of 1 to 5 mm is used for soldering. The most common are 1.5-2 mm multi-channel solders.

Multi-channel means that inside the tin wire there are several channels of flux, which ensures the formation of an even, shiny and reliable solder.

 Such solder is sold in coils - at radio markets, in flasks - in which it is rolled into a spiral, and in reels (the amount of solder in them is such that it will last for more than one year). It is recommended to purchase it in the form of a wire, the thickness of a match - it is more convenient to solder.

   When soldering installation wires of radio equipment, it is convenient to use tin-lead solders, cast in the form of thin rods with a diameter of 2 - 2.5 mm. You can make such rods yourself by pouring molten solder into a vessel with a hole pre-made in the bottom. The vessel should be held above a sheet of tin or a metal plate. After cooling, the rods should be cut into pieces of the required length.

   Modern solders used in soldering electronic circuits are produced in the form of thin tubes filled with a special resin (colophonium), which acts as a flux. The heated solder creates an internal bond with metals such as copper, brass, silver, etc.

, if the following conditions are met: the surfaces of the parts to be soldered must be cleaned, that is, the oxide films formed over time must be removed from them, the part at the soldering site must be heated to a temperature exceeding the melting point of the solder.

Certain difficulties arise in the case of large surfaces with good thermal conductivity, since the power of the soldering iron may not be enough to heat it.

Making your own solder for soldering

   To independently prepare solder, the components of the composition (tin and lead) are weighed on a scale, the mixture is melted in a metal crucible over a gas burner and, after mixing the melt with a steel rod, the slag film is removed from the surface of the melt with a steel plate. Then the melt is carefully poured into molds - troughs made of tin, duralumin or gypsum. Melting must be performed in a well-ventilated area, wearing safety glasses, gloves and an apron made of coarse fabric.

Why do you need flux when soldering?

   During soldering, the temperature of the parts being connected increases significantly. At the same time, the rate of oxidation of metal surfaces increases. As a result, the solder wets the parts being joined worse. Therefore, it is necessary to use auxiliary substances and fluxes.

What is flux?

Flux is an auxiliary material that is designed to remove the oxide film from parts being soldered during soldering and ensure good wetting of the surface of the part with liquid solder. Without flux, solder may not adhere to the metal surface.

Purpose of fluxes: reliably protect the surface of the metal and solder from oxidation, improve the conditions for wetting the metal surface with molten solder.

 The effect of a flux depends on its composition; available fluxes either dissolve oxide films on the surface of the metal (and sometimes the metal itself), or protect the metal from oxidation when heated. Thus, the flux forms a protective film over the soldering area.

   Soldering fluxes

   Flux is already contained in modern solder in the form of a thin core. When solder melts, it is distributed over the surface of the liquid metal. The surfaces of already tinned metals are also coated with flux before joining them (actually soldering). In this case, flux is a surfactant, that is, a Surface Active Substance. After the parts come into contact, excess flux between them comes out and evaporates all the time because its evaporation temperature is lower than that of solder.

   Fluxes are different. For example, to repair metal utensils, they use “soldering acid” - a solution of zinc in hydrochloric acid. You cannot solder radio structures with this flux - over time it destroys the soldering. For radio installation, it is necessary to use fluxes that do not contain acid, for example, rosin.

Requirements for amateur radio fluxes

   The choice of flux is an important issue. Previously, only rosin was used, there was no other flux. Why rosin is bad - rosin, alcohol rosin flux belong to the category of active fluxes. The first disadvantage is that at high temperatures, not only the metal oxide is removed, but also the metal itself.

The second drawback is that cleaning the board after soldering with rosin is a big problem. You can only wash off the residue with alcohol or solvents (and even then, sometimes it’s easier to pick it out with something sharp). Flux residues on the board are not only unsightly from an aesthetic point of view, but also harmful.

On boards with small gaps between conductors, the growth of dendrites (in other words, short circuits) caused by galvanic processes on a contaminated surface is possible.

What is the solution - on the modern materials market you can find a wide range of fluxes that are washed off with ordinary water, do not destroy the soldering iron tip and provide high quality soldering. Such fluxes are usually sold in syringes, which is very convenient for use.

How to replace flux

   Regardless of what flux is used, the finished soldering must be wiped with a cloth soaked in rectified alcohol or acetone, and also cleaned with a stiff brush or brush moistened with a solvent to remove flux residues and dirt. In some exceptional cases, instead of rosin, you can use its substitutes:

• rosin varnish, available in hardware stores. It can be used as a liquid flux instead of a solution of rosin in alcohol. The same varnish can also be used for anti-corrosion coating of metals.
• resin - pine or spruce resin - is an accessible material, especially for amateurs living in rural areas. You can prepare this flux yourself. Resin collected from trees in the forest must be melted in a tin over low heat (the resin may ignite over high heat). Pour the melted mass into matchboxes.
• an aspirin tablet available in any home medicine cabinet. The disadvantage of this flux is the unpleasant smell of smoke released when aspirin melts.

   Nowadays a large number of different so-called “no-clean” fluxes are produced, both liquid and in the form of a semi-liquid gel. Their peculiarity is that they do not contain components that cause oxidation and corrosion of the parts being connected, do not conduct electric current and do not require washing the board after soldering. Although it is still better to remove all flux residues from the soldered parts after completing soldering.

   To apply liquid flux, you can use a brush, a cotton swab or just a match, but it is more convenient to use the so-called “flux applicator”. You can try to buy a branded flux applicator that costs about $20-30. It is also convenient to use flux in the form of a gel or paste. To apply it, you can use a disposable syringe, but because of its thickness, you will have to use a thicker syringe needle.

We will be glad if you subscribe to our Blog!

[wysija_form id=”1″]

Source: https://powercoup.by/stati-po-elektromontazhu/pripoy-dlya-payki

Solder classification

Solder is a material that is used to join metals by soldering. It always has a melting point lower than the parts being joined. Most solders are themselves metals that conduct electricity, but there are exceptions.

Over time, a huge number of solders have been created, which differ in composition, ratio of materials, and the presence of additives. For ease of use, it was necessary to classify them. First of all, all existing compounds were divided into soft and hard.

Soft solders

Soft solders have a low melting point, which does not exceed 300 °C. Moreover, their tensile strength varies in the range of 16–100 MPa.

Most of them are an alloy of two metals: tin and lead. The percentage of materials varies greatly. Today alloys are used that can contain from 10% to 90% tin. They have their own POS marking, to which is added the amount of tin as a percentage (from POS-10 to POS-90). The melting point also varies in the range of 220-280 °C, depending on the ratio of the material.

In addition, there are other types of soft solders that are used for specific applications.

• POSS. Standard tin-lead solder, but additional antimony is added to the alloy. Thanks to this, it can be used when working with galvanized surfaces while maintaining high strength; in addition, the addition of antimony gives the solder ductility.
• POSK . The abbreviation stands for tin-lead-cadium. Its main feature is its reduced melting point. Thanks to this, POSK is excellent for soldering elements whose overheating is unacceptable.
• POTs or "A". Tin-zinc solder, which, due to its chemical properties, is suitable for soldering aluminum and joining copper products to aluminum.

In addition to PSC (Solder “A”), there are other lead-free solders that are used less frequently. To provide the necessary additional properties, their alloy includes copper, silver, and bismuth.

Brazing alloys

This class includes alloys whose melting point starts at 300 °C and sometimes crosses the 1000 °C mark. Due to this, their strength also increases significantly. The MPa value here ranges from 100 to 500.

In most cases, the base alloy is copper or silver. There are many variations in their combination with other metals. As a result, the melting point, mechanical strength, as well as physical and chemical properties change.

Among copper solders, PMC solders with the addition of zinc are the most widely used. The percentage of copper is indicated in the alloy marking. The most actively used solders are PMC-36, PMC-46, PMC-51 with a melting point of 825–870 °C.

Solders that are considered silver are actually alloys. A significant part of the composition is occupied by silver itself, and the rest consists of copper and zinc. Moreover, the abbreviation indicates only the amount of Ag. There are many varieties of such alloys, from PSr-10 to PSr-70.

Silver solders opened up new possibilities. Today, they are used to solder many metals together. They allow you to work with titanium, brass, bronze, nickel and other materials that cannot be soldered with more common solders.

Other classification criteria

In addition to dividing solders into two main types, they are classified according to a number of other characteristics.

• Melt type . Some of the solders used melt completely, and some only partially. At the same time, there are compositional options that combine both alloys.
• By main chemical element . Solder is usually called the metal that is present in its composition in the greatest quantity.
• According to the method of obtaining solder . Some solders are sold ready-made, while others are formed directly during the soldering process. The latter are a combination of layers of alloys, flux, rosin, and foil.
• By the presence of flux . Some solders must be fluxed separately during the soldering process, while some immediately have the necessary coating.
• According to the shape of the products . The most common are wire, rod, and tubular solders. For specialized applications, sheet, powder and even paste options can be used.

02.07.2018

Source: https://www.skala.ru/articles/klassifikatsiya-pripoev/

Solder for soldering copper, aluminum, brass, steel, stainless steel. Composition of solder for soldering. Types of solders for soldering

When it is necessary to reliably fasten various solid connections together, soldering is most often chosen for this. This process is widespread in many industries. Home craftsmen also have to solder.

This operation helps not only when the TV or computer has failed, and to restore it it is necessary to replace the burnt microcircuit or chip. Using this process, refrigeration equipment and industrial systems are restored. Soldering helps if you need to get a tight connection.

In addition, some materials simply cannot be combined in any other way. Aluminum, copper, and brass cannot be joined by welding.

In order to obtain a high-quality and reliable, as well as hermetically sealed connection, you need to have not only good equipment and special skills, but also suitable consumables - solders and fluxes for soldering.

Solder alloys and types of flux are selected depending on the materials with which you will have to work. For example, when working with aluminum products, a different flux is needed than what is suitable for copper or silver. Below we will look at the main characteristics of each of them and choose the best option for the job.

Various metal alloys are used as it. There are also compositions based on pure metal. In order to create high-quality connections using one or another solder, these materials must differ in certain qualities.

Wettability

First of all, any type of solder must have excellent wettability. Without this characteristic, the parts being soldered simply will not be able to reliably contact each other. What is wettability? This is such an interesting phenomenon when the strength of the bonds between the particles of a solid and a liquid is higher than that of the molecules of the liquid.

If there is wettability, then the liquid will spread over the surface and enter all cavities. So, if solder solder does not wet copper, for example, then it cannot be used on that metal. Pure lead is not used for soldering.

Its wetting characteristics are very poor and high quality joints cannot be counted on.

Important properties of solders

Whatever the type and type of alloy, whatever material it is used with, it should not contain heavy metals or any other toxic substances above the established norm. The composition of the solder matches the material of the parts as closely as possible. Otherwise, you will not be able to get a reliable connection. There will be excessive fragility.

Any solder, regardless of type and purpose, must be heat-stable. Also, solder for soldering must be electrically stable. The coefficients of thermal expansion and thermal conductivity should be taken into account. They should not differ significantly from those values ​​that apply to soldered products.

Types of solders for soldering

All existing alloys for this operation are divided into soft, or fusible, where the melting point is up to 450 degrees Celsius, and hard. Here it significantly exceeds the above value.

Purpose of soft solders

POS-90 is designed to work with parts that will then be processed using galvanic technology. POS-61 can be used to repair high-precision equipment. The alloy is also ideal for joining high-demand parts made from a wide variety of materials. POS-61 has proven itself as a solder for soldering copper and brass. Solder is suitable when it is necessary to achieve strong connections with a high degree of electrical conductivity.

POS-40 is widely used for operations with non-critical and imprecise parts. In this case, the working area can heat up to high temperatures. POS-30 is suitable for soldering copper or brass, steel alloys and iron.

Solid

Among refractory alloys, only two groups are distinguished and widely used. These are mainly copper or silver alloys.

The first group includes solders made of copper and zinc. They are well suited for those connections that will only be subject to static loads. The fragility of these alloys does not allow their use in components that will experience shock or any vibration.

Copper solders or zinc-based compounds include PMC-36 and PMC-54. The first is an ideal solder for soldering brass and any other copper joints. The second is suitable for working on copper, bronze or steel parts.

If you need to connect two steel parts together, then you can use pure copper, brass grades L-62, L-62, L-68. These brass-based solders create stronger, more ductile joints. Copper alloys do not have these characteristics.

Silver alloys are considered the highest quality. The composition may also contain zinc and copper. PSR-70 – solder for soldering copper, for working with brass or silver parts. This element is suitable if the connection point must conduct electricity. PSR-65 is used in the production of jewelry, fittings, and water pipes. PSR-45 is necessary for connecting those parts that operate under vibration and shock loads.

Other types

There are also other, less popular solders. They are often used for rare metals or special conditions. For example, nickel-based compositions are intended for products that operate at elevated temperatures. They also solder stainless alloys. Gold-based solders are used to work with vacuum tubes. There are corresponding solders for magnesium.

Features of aluminum soldering

Connecting aluminum parts by soldering is used in industry and in everyday life. For example, modern bicycle frames are made of aluminum alloys - they often break during extreme riding. The question arises: which solder should I choose?

It is believed that soldering aluminum is a very complex process. But in fact, this is true if the process uses materials for stainless steel or brass, steel, and copper. The reason for this is the oxide film. It is this that does not provide the required level of wettability, and the base metal does not dissolve.

How to solder aluminum and aluminum-based alloys

In order for the work to be carried out at the proper level, the solder for soldering aluminum must contain silicon, aluminum, as well as copper, zinc and silver. Today you can find formulations on sale where all these components are in different proportions.

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

Also for aluminum you can use compounds based on tin and lead. But it is important to properly prepare the work surface, clean it with a stainless steel brush and use active fluxes. But experts do not recommend using such an element.

Any solder for soldering aluminum is high-temperature. The most optimal ones, which allow you to obtain a reliable connection, are aluminum-silicon and aluminum-copper-silicon.

How to solder copper?

As noted above, you can work with most compositions. Both low-temperature fusible and hard solders can be used. Compositions based on tin with lead, tin, silver, copper with silver and zinc are also used.

If you need to repair a computer motherboard or repair a TV in the country, any fusible elements will do. If you need to solder fittings on pipes or repair a plumbing system or refrigerator, then only hard solder for soldering copper will do. This is how you can get high-quality results.

Stainless steel

If you need to connect stainless steel parts, then professionals recommend using rods made of tin and lead. Materials containing cadmium also work well. Low-melting alloys based on zinc can be used. However, they should not be used together with carbon or low-alloy steels. The best solder for soldering stainless steel is a composition based on pure tin. In addition, only tin is allowed if the soldering area will be in contact with food.

If the work will be carried out in a dry or furnace atmosphere, then silver with manganese, chromium-nickel solders or pure copper (or even better, brass) should be used. When soldering has to be done in corrosive conditions, silver tinols with a small part of nickel are used.

Soldering steel

It is not difficult to connect two such parts together. An affordable and effective solder for soldering steel is POS-41. There is also POS-60 and others; even pure tin can be used. But zinc compounds are not suitable. Especially when it comes to carbon or low-alloy materials.

Soldering fluxes

During the operation, flux plays no less a role than solder. It is a chemical solvent and oxide absorber. It also protects metals from oxidation and increases wetting.

To work with elements based on lead and tin, hydrochloric acid and zinc chloride can be used as a flux. Borax and ammonium chloride are also suitable. These are active fluxes. Inactive substances include rosin, petroleum jelly, olive oil and many other substances.

For example, hydrochloric acid solutions can be used with soft solders. Zinc chloride is used with brass, copper, and steel. Ammonia sleeps perfectly dilutes and dissolves fatty substances. For aluminum, a composition of tung oil, rosin, and calcined zinc chloride is used. You can also use concentrated phosphoric acid.

So, we found out what solders exist, and which one is better to use in different cases.

Source: https://FB.ru/article/236397/pripoy-dlya-payki-medi-alyuminiya-latuni-stali-nerjaveyki-sostav-pripoya-dlya-payki-vidyi-pripoev-dlya-payki

Solder POS 61: melting point of tin for soldering, composition and technical characteristics

Most novice radio amateurs who have not encountered soldering before are wondering what solders can be and how they differ from each other.

POS solder is a tin-lead alloy. Depending on the ratio of these elements, there are different markings. The most common is POS 61 solder.

Low temperature solders

Chemical composition of different types of solders.

Low-temperature alloys are used for soldering radio components that are sensitive to high temperatures. These include: POS 40 solder and POS 30 solder. They are widely used in industry, but they are also taken for private use.

POS 30 is excellent for soldering copper and non-copper based alloys. It is used both as a filler material and for tinning parts. A special feature of this brand is the absence of antimony in its composition.

POS 30 makes it possible to obtain reliable sealed connections, which has led to the active use of the material for pipeline systems. In addition, it is characterized by good conductivity and low resistance, which allows it to be used for making small contacts.

The low melting point allows you to avoid overheating of radio components during soldering. At the same time, after hardening, it reliably fixes parts of the product.

From a technical point of view, soldering with this alloy is quite easy. However, it should be borne in mind that if it is used, the parts should not operate at high temperatures.

POS 30 is produced in the form of wire of various diameters from 0.5 to 8 mm. The thickness is chosen based on the problems that need to be solved. To connect small wires and parts, the smallest option is perfect. But repairing cases and soldering large products is easier to do with 8 mm wire.

POS 40 solder has similar technical characteristics to POS 30. It also does not contain antimony. It belongs to the low temperature class. The densities of the noted alloys and the onset of melting temperature are also the same.

They differ from each other, of course, in composition. This is evidenced by the numbers at the end of their markings.

Types of lead-free solders.

POS 40 allows you to obtain high-quality and reliable connections. When working with it, no cracks appear, and there are no unsoldered areas or other defects. Low resistance and good conductivity make it possible to use PIC for soldering electronics.

As noted above, this solder has a low melting point. This also imposes restrictions on the use of products soldered using it.

The most common form of alloy production is wire. Its diameter varies from 0.5 to 7 mm. However, it also exists in the form of rods, foil strips, and small tubes.

Another low-temperature solder is POS 61. However, it contains antimony. The alloy has fairly good ductility. Most widely used for soldering semiconductor equipment. The resistivity of POS 61 solder is 0.139 Ohm*mm2/m.

It is produced in the form of metal ingots weighing about 25 kg, rods with a cross-section from 8 to 15 mm, and wire with a diameter from 0.5 to 6 mm. There are also form factors such as tapes, anodes and tubes.

Bottom line

The melting point of tin makes this material an excellent solder. POS brand solders are particularly widespread. They are used in industry, in private workshops, and by radio amateurs.

Many brands of this solder allow you to choose the necessary alloy, which is ideal for solving almost any problem.

Source: https://tutsvarka.ru/oborudovanie/pripoj-pos