Solder POS 40 - technical characteristics, composition and how it differs from POS 61

Greetings to dear readers! In this material I tried to collect all the data about PIC solder. This Tin-Lead Solder is the most popular solder for mounting radio components and is used more often than others in radio engineering. I will try to explain why this is so and tell you about the types and technical characteristics of POS series solders. I’ll also tell you a terrible secret about POS-60 and POS-62 solders. Go!

Types of POS solders

First, let's remember what types of solders are made from alloys of the tin-lead group. The most popular are antimony-free solders POS-10, POS-40, POS-61 and POS-90. POS solder containing antimony is called POSSU. Antimony in the solder adds several percent to its strength.

When we talk about melting a mixture of tin and lead, we need to remember the definitions of solidus and liquidus . When any mixture of two or more metals is heated, the melting (transformation from solid to liquid phase) of the lightest particles occurs first. This temperature mark is called the solidus of the alloy.

With a further increase in temperature, more refractory components begin to melt. As soon as they melt, the liquidus . The PIC solder is now completely melted. This process is explained in more detail by a picture taken from a presentation on the topic of alloys.

Between these two points is a state of increased ductility of the solder . In this state, the solder can be pulled and deformed without losing integrity.

There are eutectic alloys - solders, in which the solidus and liquidus points coincide. This is very convenient when soldering and indicates the high quality of the solder.

Use of tin-lead group alloys

The soldering process is the joining of several metallized parts together. In this case, the exposure temperature does not exceed the critical threshold at which destruction of parts or circuit boards occurs. The main objectives of using soldering products are to ensure the most even temperature viscosity, at which uniform spreading occurs over the surface.

Tin is used for soldering quite often; the material serves as a component of the largest number of solders. In its pure form, the metal is very expensive and is used for soldering important products and elements. Divided into categories with and without lead.

Lead solders

Various soldering materials are used using lead. The material is fusible, soft and easy to process. Easily dissolves in an alkaline environment and acidic impurities.

Lead solder

Products labeled PIC are considered the most popular in use. The percentage of elements allows you to work with different environments and materials. They differ in temperature and other parameters that are important for a reliable connection. Zinc, bismuth or antimony are added to lead compounds to provide protection against oxidation and other destructive factors.

About the composition of solder

The name of the solder of the tin-lead group indicates the tin content in it. For example, POS-40 contains 40% tin, and POS-61 contains almost 61% tin. The rest consists of lead and additional impurities. By appearance, you can estimate the composition . If the PIC solder is more matte and dark, then it contains more lead. If it is lighter and shiny, then there is more tin. This is best understood by comparison. Look at the photo to see what a sheet of tin and a sheet of lead look like.

The strength of solder depends not only on the alloy alloy, but also on the metal being soldered. For example, to solder copper or zinc, several percent of copper or zinc are added to the POS solder, respectively. This reduces chemical erosion of the metal and increases the surface strength of the joint.

Solder alloying

To improve performance characteristics, alloying of solder with the following substances is used:

• adhesion is improved by the addition of copper, cadmium, antimony, aluminum, silver and zinc;
• ductility and resistance to thermal cycling are improved by the addition of indium, silver, manganese, bismuth, and lithium;
• Nickel, cobalt, zinc, silicon, boron, iron add strength
• The corrosion resistance of solder is increased by nickel and copper;
• Heat resistance is increased by silicon, zirconium, tungsten, vanadium, cobalt, niobium, hafnium.

Good solder from China - reality: blue KAINA

Somehow I was once disappointed with solder from China and abandoned research in this area. And so, having repeatedly seen mention of the very decent quality of KAINA blue solder, I decided to study this issue. In short: the solder turned out to be really good. More details on the reel... I ordered a reel weighing 500 grams, rod diameter 0.7mm. Everything came in a bag wrapped in bubble wrap:

Taking out the subject of review:

The same... solder only on the side:

The weight was an honest 500 grams, though together with the reel:

But the seller did not promise the net weight of the solder. To understand the sizes:

Removing the paper wrapper, as expected, we see a coil of thin solder wire:

The wire diameter is close to the declared one (0.75 mm):

At the same time, let's measure the coil:

A little about the declared properties: The declared content is 60% tin and 40% lead; Flux content 2%; The flux used is CF10 (rosin activated - does not require rinsing under normal operating conditions).

The following solders are available: Kaisi (from China):

I really can’t recommend this solder; it doesn’t stick well to the soldering iron, and when it hardens, it forms a rough matte surface.

Asachi (purchased offline):

Good solder, bought at a big discount during a sale of leftovers, but I have it 2mm in diameter, which is not always convenient. When used on a soldering iron, perhaps due to the large diameter, it leaves dark traces of flux that are not easy to wipe off (hardened rosin):

The droplets shine after hardening.

Domestic product from Ryazan (purchased offline):

Not a bad solder, a droplet is closer to glossy, but not as beautiful as ASACHI's.

Above kaisi below Ryazan:

The solder from the review begins to melt at 190 degrees. I usually solder at 290 degrees. It fits perfectly, I used it to solder several welding machine boards from this review:

It sticks to the soldering iron perfectly, the droplets shine, there are no traces of flux left, but I still recommend washing it off, for example, with isopropyl alcohol or acetone.

I have modified the welder boards, and many who ordered will soon receive black modified versions.

The layout of the elements has been changed, slots have been added (separating the 220-volt and low-voltage parts of the board), an SMD indicator LED has been added, which simplifies debugging.

Currently, for me, this is the most acceptable solder available and available on the market. Of course, it is more expensive than cheap Chinese competitors - but it is impossible to solder with them (I use lead-free solder to dilute it when soldering). I can confidently recommend it, despite point 18 - I tried to find shortcomings in it - and did not see anything like that.

I hope someone finds the information useful! Thanks to those who read.

The product was provided for writing a review by the store. The review was published in accordance with clause 18 of the Site Rules.

Technical characteristics of POS and POSSu solders

In order not to describe all the technical characteristics of solders of the tin-lead group, I will simply provide a table of parameters. It can be used to determine the melting point, density, electrical resistivity, thermal conductivity, tensile strength, elongation, impact strength and Brinell hardness of solders.

An analysis of the table shows that the most fusible among the list is cadmium with a melting point characteristic of 145 degrees Celsius. The strongest solder is POSSu 4-6 solder with a tensile strength of 6.5 kgf/sq.m. mm.

Technical characteristics of POS-10 solder

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

The POS-10 soldering temperature is 299 degrees Celsius. The solidus point is 268 degrees.

Advantages of POS-10 solder:

• high melting point is useful when soldering equipment cases.

Disadvantages of POS-10 solder:

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

Solder Diameter

Choosing a solder wire diameter that is suitable for the task at hand can make a big difference when soldering. Small diameter solder makes it much easier to apply small amounts of solder. This is very convenient for soldering surface mount components. For larger components, using small diameter solder requires a significant length of solder to be fed to the joint, increasing soldering time and the risk of overheating the components.

For surface mount applications, I prefer 0.5mm solder. For most electronics work, solder with a diameter of 0.4 to 1.0 mm will work well. If you do a lot of work on surface mount devices, aim for the lower end of this range.

Best before date

Yes. Indeed! Solder has an expiration date. For the alloys mentioned above, it is recommended to use solder wire within three years from the date of manufacture. However, I'm just now finishing a roll of 0.7mm 60/40 RMA flux-cored solder that I started in the late 1980s, and the solder joints I make today work as well as ever.

However, observe the expiration date of the soldering paste. Solder paste consists of small balls of solder in a flux. Over time, the flux will oxidize, making it ineffective. As a result, the solder will not flow correctly and it becomes very difficult to get a good solder joint. The shelf life of solder paste is about six months. By cooling the solder paste, the shelf life can be extended to up to a year. It goes without saying, but please do not store solder in the refrigerator that you use for food!

Technical characteristics of POS-30 solder

Solder for soldering of the POS 30 brand is an intermediate link between POS 10 and POS 40. The composition of POS 30 solder is as follows: 30% tin and 69.5% lead. The rest is impurities and doping. Solder POS 30 can be easily replaced with POS 40, which is described below. The melting point (liquidus) is 238 degrees, and the plasticity temperature (solidus) is 183 degrees Celsius. According to the technical characteristics, POS 30 solder is most often used for soldering and tinning of zinc sheets and radiators.

Advantages of POS-30 solder:

• good adhesion;
• high strength.

Disadvantages of POS 30 brand solder:

• high lead content;
• often produced in rods.

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.

Technical characteristics of POS-40 solder

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

The soldering temperature of the solder is 238 degrees Celsius, and the solidus is 183 degrees.

Advantages of POS-40 solder:

• good ratio of ductility and melting point;
• because of this, it tolerates thermal cycling better than POS-61.

Disadvantages of POS-40 solder:

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

Soldering process

Combining 2 or more parts using soldering is carried out for:

— obtaining electrical contact with low resistance;

- obtaining a strong seam (sometimes thermal, absolutely sealed).

The soldering process is based on the difference in melting temperatures between the solder and the metals being joined. While the soft alloy melts and becomes liquid and fluid, the metals being joined remain solid. Molten metal flows over the parts being joined, filling the voids between them. During the soldering process, an intermediate layer is formed, which includes the combined parts of the solder and the material of the elements being combined. With its help, a single structure is formed from two or more parts. Rosin or an alcohol solution of rosin act as a flux when soldering PICs.

Before starting work, you need to choose the right solder based on:

— properties of the materials being combined;

— requirements for connection strength;

— corrosion resistance of the junction;

- its cost.

And when soldering parts that conduct current, the conductivity coefficient is also taken into account.

For soldering copper wires, use POS-40 based on rosin. Stainless steel can be joined with conventional POS, but for flux they use a special material that is more active than rosin.

The terrible secret of POS-60 solder

Now the time has come for the terrible secret of POS 60 solder . According to GOST 21930-76 entitled “Tin-lead solders in ingots. Technical specifications" and GOST 21930-76 "Tin-lead solders in products. Technical specifications", solder such as POS-60 simply does not exist. GOST 21930-76 itself can. Here is the complete table from this GOST.

So “ POS-60 ” is jargon or a popular designation for “the solder that everyone solders with.” It seems to me that this is due to confusion in the designation of POS-61. Because when the tin content in the solder according to GOST is from 59 to 61%, it is more logical to call it POS-60 rather than POS-61.

Among the solders produced according to international standards there is Sn60Pb40 solder . This is a solder solder containing 60% tin and 40% lead. It could be called POS-60, if at least specifications for it were developed. According to international data describing the characteristics, the melting point of 60/40 solder is 191 degrees Celsius.

The same story with POS-62 type solder . Such lead solder according to GOST has not yet been invented. So, if they ask me “what is the melting temperature of POS-62 solder,” I know that the answer with the figure 184 degrees Celsius must be looked for in the imported solder catalog. For example, you can use the Kester solder catalog.

3.3. Classification of fluxes and their designation system

Soldering fluxes

- substances and compounds used to prevent the formation of an oxide film on the surface of the solder and soldered material, as well as to remove oxidation products from the soldering zone. The melting point of fluxes is lower than the melting point of solder. Fluxes are used in solid, paste and powder form, as well as in the form of aqueous, alcohol or glycerin solutions.

Fluxes

used for soldering are classified according to: temperature range of activity;
nature of the solvent; the nature of the activator of the determining action; mechanism of action; state of aggregation. Depending on the temperature range of activity,
soldering fluxes are divided into: low-temperature (≤ 450 ° C); high temperature (> 450 °C).

By the nature of the solvent

soldering fluxes are divided into: water-based; non-aquatic

By the nature of activators

Low-temperature soldering fluxes
that determine their action are divided into: rosin; acidic; halide; hydrazine; fluoroborate; aniline; stearic.

By the nature of the activators of the determining action, high-temperature soldering fluxes

divided into: halide; fluoroborate; boride-carbon dioxide.

If the flux contains several activators, all activators must be named. For example, rosin-halide, fluoroborate-halide flux.

By mechanism of action

soldering fluxes are divided into: protective;
chemical action; electrochemical action; reactive. According to their state of aggregation,
soldering fluxes are divided into: solid; liquid; pasty.

Technical characteristics of POS-61 solder

The designation of solder, as we found out, is quite controversial, but you can’t argue against GOST. POS-61 is 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 solder

The chemical composition of POS-61 solder is as follows:

• 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 - everything else - about 38.7 - 40.7%.

The soldering temperature of POS-61 solder is 220 degrees Celsius. Solidus is 183 degrees. I even shot a slow motion video of this solder melting on my Olympus Tough TG-860 at 240fps.

Solder POS 61 GOST 21931-76 has the following technical characteristics:

• Density determines weight and is equal to 8.5 g/cu. cm.;
• The electrical resistivity is 0.139 Ohm x mm2/m;
• Thermal conductivity is 0.12 kcal/cm x s x deg;
• Temporary tensile strength is 4.3 kgf/sq.mm.;
• The relative elongation is 46%.

Advantages of POS-61 brand solder:

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

Disadvantages of POS-61 type solder:

• 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.

Flux for soldering with a soldering iron

An auxiliary substance that promotes the spreading of soldering materials over the surface of the parts being soldered is flux. High-quality connections are created by solders and fluxes ; without one of the components, soldering is impossible. A common type of flux is rosin, made from hard coniferous trees. Softening occurs at 50 °C, and when the temperature reaches 250 °C, the process begins to boil the composition.

Flux for soldering aluminum

Due to the hydrolysis provided for in the manufacture of rosin, the material is not resistant to atmospheric influences. After soldering, it is necessary to remove flux residues, because... the compound may undergo an oxidation process. By absorbing moisture from the atmosphere, rosin can disrupt the operation of radio components.

Popular fluxes for soldering with an electric soldering iron

Soldering of metal joints occurs using various substances. Fluxes are divided into three main categories, differing in their area of ​​application and method of preparation. The process of preparing elements for work may vary; after soldering, it is necessary to remove residues in the manner described in the instructions.

1. Inactive rosin fluxes are used for soldering copper and other types of soft metals. There is a light rosin that is ready for use and does not include additional substances. Alcohol-rosin solution is made from components with a concentration of 1 to 5. It is used for soldering in hard-to-reach places, it is produced in powder form, and must be mixed with alcohol before use. Glycerin - rosin materials are used when a hermetic connection is necessary.
2. Active fluxes suitable for soldering precious and non-ferrous metals include zinc chloride, alcohol or petroleum jelly. The last parameter differs in its composition, when used in a liquid or paste state. It is more convenient to work with flux as a paste; it is possible to apply it directly to the product in the required amount.
3. Acid-active flux is divided into zinc chloride and phosphoric acid. It is performed in the form of liquid solutions or paste, using rosin, zinc chloride, alcohol or petroleum jelly.

Orthophosphoric acid

Orthophosphoric acid consists of water, ethyl alcohol and the acid itself with a density of 1.7. It is used for soldering stainless materials, copper, and silver. Alcohol-based fluxes must be stored in airtight containers. A convenient container for storage is a nail polish jar, the brush does not react to the active medium, and the lid allows you to tightly close the container, avoiding evaporation of the components.

Tinol soldering pastes for soldering

Among the substances offered, there are solder pastes that are produced with a mixed type of flux. It is used when installing open-frame elements in hard-to-reach places. Application occurs with a special spatula, then heating with an electric tool. The result is a reliable, high-quality connection, which is actively used by novice craftsmen in the absence of appropriate experience.

Tinol pasta

It is possible to prepare an alloy for soldering with your own hands; for this you will need the solder required by the element. Using a medium-grain file, tin for soldering in the form of wire is crushed to the state of metal chips. A flux selected from the above in a liquid state is added to the composition, after which the elements are mixed. The composition must be prepared in a small container, the shelf life is limited to 6 months, after which the metal oxidizes in an acidic environment.

Technical characteristics of POS-63 solder

Solder POS 63 is described in GOST and in the industry standard OCT 4G 0.033.200. POS-63 solder is understood as an alloy that consists of 63% tin and 37% lead. This is a kind of modernization of POS-61 solder, adjusted to the international standard J-STD 006B. Most are also labeled Sn63Pb37 . These are eutectic alloys with a melting point of 183 degrees Celsius.

POS-63 is used for soldering and tinning the leads of microcircuits and packaged radio components, printed circuit boards, wires and cables. In general, of modern solders, this is the most common. The technical characteristics of POS 63 solder are approximately the same as those of POS-61. But I haven’t found the exact values ​​yet.

Advantages of POS-63 solder:

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

Disadvantages of POS-63 solder:

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

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.

Technical characteristics of solder POSSu-61-0.5

Solder marking POSSu-61-0.5 indicates a type of antimony solder containing 61% tin, up to 0.5% antimony and about 38% lead. This solder is used for soldering and tinning of printed circuit boards and galvanized radio components under increased operating temperature requirements. But its melting point is 189 degrees.

Advantages of POSSu-61-0.5 solder:

• increased adhesion to the metal surface due to the antimony content;
• technical characteristics are almost the same as POS-61.

Disadvantages of POSSu-61-0.5 solder:

• difficult to find on sale;
• increased cost.

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.

Technical characteristics of POS-90 solder

POS-90 brand solder consists of 90% tin and 10% lead. It also contains about 0.1% antimony and 0.05% copper. It is mainly used for soldering and tinning internal seams of food utensils and medical equipment. Yes, 10% lead can already be put into food products - surprisingly, everything is in accordance with GOST 1976. According to the technical characteristics, the melting temperature of solder type POS 90 is 220 degrees.

Advantages of POS-90 solder:

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

Disadvantages of POS-90 brand solder:

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

Preferred areas of application for soft and semi-hard solders:

O2

— tinning and soldering of collectors, armature sections and windings of electrical machines with class H insulation, tinning of critical fixed contacts, including those containing zinc;

POS90

— tinning and soldering of internal seams of food utensils and medical equipment;

POS61

- tinning and soldering of electrical and radio equipment, printed circuit boards, precision instruments with highly sealed seams where overheating is not allowed;

POS40

— tinning and soldering of electrical equipment, galvanized iron parts with sealed seams;

POS10

— tinning and soldering of contact surfaces of electrical devices, instruments, relays;

POSK50-18

— soldering of parts made of copper and its alloys that are sensitive to overheating, including soldering of copper-clad aluminum. Soldering of ceramics, glass and plastics metallized with tin, silver, nickel;

POS61M

— soldering of food utensils, medical equipment, electrical and radio equipment, printed circuit boards, parts sensitive to overheating;

POSSu61-0.5

— tinning and soldering of electrical equipment, soldering of printed circuit boards, windings of electrical machines, galvanized radio components under strict temperature requirements;

POSSu50-0.5

— tinning and soldering of aircraft radiators;

POSSu40-0.5

— tinning and soldering of sheet metal, windings of electrical machines, for soldering mounting elements of winding and cable products;

POSSu35-0.5

— tinning and soldering of lead cable sheaths;

POSSu30-0.5

– tinning and soldering of zinc sheets, carbon and stainless steels. Tinning and soldering of wires, cables, bands, radiators, various parts of equipment and devices operating at temperatures up to 160 ° C;

POSSu25-0.5

— tinning and soldering of radiators;

POSSu18-0.5

— tinning and soldering of heat exchanger tubes, electric lamps;

POSSu95-5

;
PSr3Kd
- hot tinning and soldering of collectors, armature sections, bandages and current-carrying connections of heat-resistant electric machines with high rotation speeds. Soldering of pipelines and various parts of electrical equipment.

POSSu40-2

— general-purpose solder;

POSSu30-2

— tinning and soldering in refrigeration equipment manufacturing, electric lamp production;

POSSu18-2, POSSu15-2, POSSu10-2

— soldering in the automotive industry;

POSSu8-3

— tinning and soldering in electric lamp production;

POSSu5-1

— tinning and soldering of parts operating at elevated temperatures;

POSSu4-6

— soldering of tinplate, tinning and soldering of parts with rolled and riveted seams made of brass and copper;

POSSu4

—
4
— tinning and soldering in the automotive industry;

POSK2-18

— tinning and soldering of metallized ceramic parts;

POSI30

;
PSr3I
- soldering of copper and its alloys and other metals, non-metallic materials and glass with metal coatings. Soldering of electronic equipment parts. It has high fluidity and provides good adhesion of soldered surfaces.

The parameters of soft solders with low melting points are given in table. 3.3.

Table 3.3
Soft solders (alloys) with low melting points

Note. They are used in radio circuits with semiconductor devices and in circuits where solder is used as a temperature fuse.

The chemical composition and physical and mechanical properties of solid silver and copper-phosphorus solders are given in Table. 3.4.

Table 3.4
Chemical composition and physical and mechanical properties of solid silver and copper-phosphorus solders

The parameters of copper-zinc and copper-nickel hard solders are given in table. 3.5.

Table 3.5
Copper-zinc and copper-nickel hard solders

The parameters of silver solders with a low melting point are given in table. 3.6.

Table 3.6
Silver solders with lower melting points

The preferred areas of application of hard solders are given in table. 3.7.

Table 3.7
Preferred applications of brazing alloys

The parameters of copper-phosphorus solders are given in table. 3.8.

Table 3.8
Copper-phosphorus solders

Note. For copper-phosphorus and silver solders, borax is used as a flux in powder form or mixed with table salt.

The parameters of solders for soldering aluminum are given in table. 3.9, 3.10.

Table 3.9
Chemical composition and physical properties of solders for aluminum soldering

Table 3.10
Other solders for aluminum soldering

The primary areas of application of solders for soldering aluminum P250A, P300A and P300B are given in table. 3.11.

Table 3.11
Preferred areas of application of solders for aluminum soldering