Tin and lead are ductile, low-melting metals, with increased corrosion resistance in atmospheric and some acidic conditions.

Lead is a metal with a face-centered cubic lattice; it does not undergo allotropic transformations in the solid state. The melting point of lead is 327 ºС.

Tin can be in two crystalline modifications: a-Sn (gray tin) with a diamond lattice - below +13 ºС and b-Sn (white tin) with a body-centered tetragonal lattice. In the cold, plastic b-tin crumbles into a gray a-Sn powder. This phenomenon is called tin plague ... The melting point of tin is 232 ºС.

Calculation of the temperature threshold of recrystallization in accordance with the rule of A.A. Bochvara (T p = 0.4 T m) gives the numbers –123 and –147 ºС, i.e. the temperature threshold for recrystallization lies well below 0 ºС. Thus, plastic deformation of lead and tin at room temperature is hot deformation. No work hardening is observed in these metals with such deformation.

The main area of ​​application of pure tin is tinning tin. Pure lead is used for the lining of devices for sulfuric acid production and containers for hydrochloric acid. Lead is also used for cable sheaths to protect them from soil corrosion.

An important field of application for lead and tin are solders, as well as alloys for typographic fonts, anatomical impressions, and fuses. In addition to lead and tin, these alloys also contain bismuth and cadmium. In pairs, all these elements form among themselves systems with low-melting eutectics without intermediate phases and chemical compounds, i.e. form simple eutectic systems (Figure 8.8). In ternary systems, ternary eutectics are formed between these elements, which are even more fusible than double ones. The melting temperature of these eutectics is 90-100 ºС. In the quaternary system of these components, a quaternary eutectic with a melting point of 70 ºС is formed. Practically used Wood's alloy in its composition is close to eutectic (50% Bi, 25% Pb, 12.5% ​​Sn and 12.5% ​​Cd).

To obtain even more low-melting alloys, mercury is introduced into them, for example, an alloy with a Bi-36% content; Pb-28%; Cd-6% and Hg-30% has a melting point of 48 ºС.

Both pure tin and lead-tin alloys containing tin from 3 to 90% and a small amount of antimony (up to 2% Sb) are used as solders for brazing copper, steel and many other products.

The melting point of solders depends on the tin content and can be roughly determined from the Pb-Sn double diagram. The most fusible solder is an alloy with 61% Sn, marked with POS 61. There are alloys POS 18, POS-40, POS-61, POS 90, etc. Alloys of lead with antimony and arsenic (10-16% Sb and 1-4% As) are used for typographic fonts.

And alloys from this material have certain properties that are due to their initial state.

General description of tin

It is important to note here that there are two types of these raw materials. The first type is called white tin, and it is the β-modification of this substance. The second type is the α-modification, which is better known as gray tin. During the transition from one modification to another, namely from white to gray, a strong change in the volume of the substance occurs, since a process such as crumbling metal into powder occurs. This property is usually called. It is also important to note here that one of the most negative properties of tin is its tendency to frost. In other words, at temperatures from -20 to +30 degrees Celsius, a spontaneous transition from one state to another can begin. In addition, the transition will continue, even if the temperature is raised, but after the process has begun. Because of this, raw materials have to be stored in places with a rather high temperature.

Properties of tin and lead

It should be said that tin, lead and alloys made from these materials have very few properties in common. For example, the purer the tin, the higher the chance that it will be affected by the plague. Lead, in turn, does not undergo allotropic transformations at all.

However, it should also be noted that additional substances are used to slow down this kind of transformation in tin. Materials such as bismuth and antimony proved to be the best. The addition of these substances in the amount of 0.5% will reduce the rate of allotropic transformation to almost 0, which means that white tin can be considered completely stable. Here it can be noted that to a lesser extent, but still an alloy of tin and lead is used for the same purpose.

If we talk about the properties of lead, then it has a higher melting temperature - 327 degrees Celsius, than tin - 232 degrees. The density of lead at room temperature is 11.34 g / cm 3.

Characteristics of tin and lead

To begin with, the recrystallization of work-hardened lead tin and alloys occurs at a temperature that is considered below room temperature. For this reason, the process of their processing is of the hot type.

A common measure was corrosion resistance under atmospheric conditions. However, a small difference lies in the resistance to corrosion under the influence of minor substances. For example, lead manifests itself best of all when interacting with concentrated compositions of certain acids - sulfuric, phosphoric, etc. Tin, in turn, is best resistant to solutions from food acids. The scope of application of these substances individually also differs. Tin is widely used for tinning tin, while lead has found its use for the lining of sulfuric acid production equipment.

Alloy systems

It is important to start here with the fact that tin-lead alloy is an even more fusible material than alone. Such mixtures are most widely used as solders, for making typographic fonts, for casting fuses, etc. Such a system as "tin - lead" belongs to the group of the eutectic type. An important property of all materials belonging to this category is that their melting temperature is in the region from 120 to 190 degrees Celsius. In addition, there are groups of ternary eutectics. An example is the tin-lead-zinc alloy system. The melting temperature of such materials drops even lower, and its limit is 92-96 degrees Celsius. If you add a fourth component to the alloy, then the melting temperature will drop to 70 degrees. If we talk about the use of a tin-lead alloy as a solder, then most often up to 2% of such a substance as antimony is introduced into their composition. This is done in order to improve the flowability of the solder. It is worth noting here that the melting temperature can be controlled by the tin / lead ratio. The most low-melting raw materials melt at 190 degrees.

Babbits

We have already figured out the name of the alloy of tin and lead - this is a eutectic. This group of substances with such a composition is most widespread in the production of bearing alloys, which are called "babbits". This material is used as a filling for bearing shells. The most important thing here is to choose the right material so that it can easily run in to the shaft. At first glance, it seems that a mass of tin and lead alloys with various solders is an excellent yield. However, in reality this is not entirely true. Such materials turned out to be too soft, and the coefficient of friction between the shaft and such an insert was high. In other words, during operation they got too hot, because of this, low-melting metals began to "stick" to the shaft. To avoid this disadvantage, a small amount of harder substances were added. In this way, a material was obtained that is both soft and hard.

Composition of the substance

In order to achieve a substance that has exactly the opposite characteristics, the following substances were used. The most important thing is that they lie immediately in the two-phase region α + β. The β-phase crystals are enriched with a solder such as antimony. They act as solid, brittle substances. Crystals of the α-phase, in turn, are a soft and plastic base. In order to avoid such disadvantages as the melting of solid crystals and their floatation, another component is added to the mixture - copper. Thus, from a piece of lead and tin alloy with the addition of some other substances, it is possible to create a bearing material babbitt, which combines two opposite qualities - hardness and softness. The classic and most widespread product of this brand is the B83 babbit. The composition of this alloy is as follows: 83% Sn; 11% Sb; 6% Cu.

Alternative

It is worth saying that from the point of view of economy, tin-based babbits are very unprofitable, since this material costs quite a lot. In addition, tin itself is considered a scarce substance. For these two reasons, alternative bearings have been developed based on lead, antimony and copper. In this composition, antimony crystals act as a solid base. The soft base is a direct alloy of lead and antimony. Copper is used here in the same way as lead in the previous composition, that is, to prevent the crystals of the solid base from floating up.

However, here it is worth mentioning the shortcomings. The lead and antimony eutectic is not as plastic as the tin phase. Therefore, parts manufactured in this way suffer from rapid wear. To level this disadvantage, however, some tin has to be added. The use of ternary eutectics is not very common.

pewter

Alternative descriptions

Rocky shallow

Small rocky island devoid of vegetation

Water stone

Long rocky shallows

G. shiny pillowcase, a thin layer on what, shell, semi, irrigation, enamel; dullness on the eye, whitish darkening of the transparent membrane of the eye. Old. headband, probably light, shiny. Old. outerwear, cloak, mantle. Luda was cut with gold. Perm. silty, cold, gray soil, blue clay; hard soil. Vologodsk. perm. oat milk, esp. use during field work. Ryaz. brew, salamata. Keremet, Votyak goddess. Lud m. Old. crazy, stupid, crazy. Ludi, ludi. arch. dazzling shine, whiteness. Luda sat down. mara or hassle, diversion of the eyes. Let Luda, fool, let fog. Luda arch. limestone river bottom, natural flooring; arch. underwater or water flat stones, shoals; granite bald patches. Herring and nuts are caught on ludas. Psk. * an obsessive, boring person. Ludoga petersburg. whitefish fish, from Ptin's nose, on Lake Ladoga. Ludik m. Ludyak vyat. perm. gray, silty soil hardening in the sun, luda. Ludik eats the ground. Ludan m. Old. damask fabric, or a kind of damask. Psk. a silk thing, like a scarf, an apron. Tinned, ludanium penz. silk. Ludushka or ludka, ludushka f. arch. olon. luda, meaning shallow, stone, and old. dry, often diarrhea islet. Tinkering what, cover with half a day, molten tin; tinned copper dishes, iron sheets, turning them into tin or white iron. Cheat, cheat. -sya, to be ludim. Fish out the pan, puff them all, again. Tinning Wed ludka about. action by value verb Tinkering, tinkering someone, jokingly. beat, pound, ask a scuffle. Tinned, related to tinning. Tinkering master. Tinning m. Workshop where tinkering. Tinker m. Who tins the dishes. Ludila, a brawler, a bully. -shchikov belonging to him .; -shichich, generally referring to him. Tinker, dazzle with brilliance, whiteness, shine, mirror. The snow pours in the sun. Silver pours into the forge

Stoneist. Island

Stoneist. shallow

Rocky island

Stone out of water

Stone protruding from the water; coastal rocky shoal

Small rocky and bare island

Small rocky island

Alloy for the tinker

Tinning alloy

Rocky shallow

Rosin

Long stony shallow

Coastal stony shallow

Purchase of tin-lead solders

Solder PIC is an alloy of metals used to join metal parts by melting the solder.

Tin Lead Solders- the most common group of solders. In labeling tin lead solders the letters indicate the composition of the solders; the numbers are the percentage of tin.

Main components tin lead solders are tin and lead.

Tin Lead Solders can be very effective if you know the basic principles of work and their scope.

Solder seams are divided into several groups:

1. dense and durable seams - withstand the pressure of gases, liquids;
2. strong seams - able to withstand mechanical stress;
3. tight seams - do not allow gases, liquids under low pressure to pass through.

The soldering quality depends on the diffusion rate. Clean solder surfaces help increase diffusion. But if the surface of the metal is oxidized, diffusion is sharply reduced or stopped altogether.

Tin Lead Solders must have both maximum viscosity and high resistance, the soldering method directly depends on the melting temperature of the solder.

Tin-lead solder POS60 widely used for soldering electrical equipment and radio components, printed circuits. The tin content of 60% ensures a low melting point, which averages 183-188 degrees Celsius.

Solder POS61 used when soldering thin parts, when overheating the parts is contraindicated.

Solder POS62 has the lowest melting point, contains 62% tin in its composition. This lead-tin solder is used to connect thin wires.

Solder POS40 avoids overheating during soldering. The section of tin-lead solder is thin, 1 or 2 mm in diameter. The time of action of high temperature on lead-tin solder POS40, due to the small diameter of the wire, is minimal. Solder POS40 similar to POSS4-6 solder in terms of strength. Tin solder is used for soldering copper, lead, iron, tinplate.

Tin-lead solder POS30 used for brazing copper, brass, iron, galvanized, galvanized sheets, radio equipment, flexible hoses.

Solder POS18 when soldering end-to-end, it has a high soldering strength. Tin solder is used in cases where the melting point is not critical.

Solder POS90 It is widely used for soldering the internal seams of food items.

Popular soft solders for soldering radio components - low-temperature alloys:

• Tin-lead solders with antimony;
• POSK tin-lead solders with cadmium;
• Tin-lead solders POS30 for tinning and soldering of sheet zinc, radiators;
• Tin-lead solders POS40 for tinning and soldering galvanized iron parts, radiators;
• POS60 tin-lead solders for soldering radio components;
• Tin-lead solders POS61 for soldering radio components;
• Tin-lead solders POS63 for soldering radio components;
• Tin-lead solders POS90.

Through tin lead solders soldering work is carried out, two main operations are performed:

• tinning and
• soldering.

Tinning - the coating of metal surfaces with pure tin or an alloy of tin and lead with a small percentage of impurities - provides a strong connection and is a preparatory process for soldering parts.

Soldering is the connection of wires, radio components using solders in a molten state. After the tin-lead solder solidifies, a strong bond is formed.

The more tin is in the solder, the softer the solder. Solders with pure tin content are used for soldering the inside seams of food utensils.

Buying tin lead solders:

You can buy tin-lead solders POS and POSS in any quantities from the manufacturer - LLC TINKOM.

At TINCOM LLC you can buy tin-lead solders:

Antimony free solders

Low antimony solders

Antimony solders

Tin-lead solders price

Tin Lead Solder Prices different markings depend on the size of the ordered batch.

Wholesale Purchase of Tin Lead Solders are much cheaper than retail.

There is always a certain amount of tin lead solders that you can buy in our minimal lines at the best price.

Do purchase of tin-lead solders you can by calling work time by contact phones or by placing an order on the website.

Today we can buy tin-lead solders in the form of ingots, bars, wires.

At wholesale purchases of tin-lead solders preferential discounts are provided.

TIN, LEAD AND THEIR ALLOYS

§ I... STRUCTURE AND PROPERTIES OF TIN AND LEAD

Tin and lead stand out among other technical metals with a relatively low melting point, low hardness and high corrosion resistance.

These properties predetermined the main areas of application of these metals. Lead in its pure form is used in chemical apparatus construction, for cable jackets, protection against X-rays and γ-rays, and in other fields. Lead and tin are widely used for the production of antifriction (bearing) alloys, low-melting alloys and solders, anti-corrosion coatings, and also as additives to brass, bronzes and other alloys.

Industry produces tin and lead of various purities (Tables 42 and 43). The physical and chemical properties of these metals are given in Appendix 1.

For tin, depending on the temperature, two crystal structures (modifications) are characteristic. Directly during solidification, tin crystals are formed with a tetragonal lattice, with periods a = 5.82 A, c -3.17 A. This modification of tin is called β = Sn. Tin in the form of a modification is stable up to a temperature of 18 °, and then passes into a new modification ά = Sn with a diamond-type lattice with a period a = 6.46 A.

The transition from one modification to another is accompanied by sharp volumetric changes, which leads to the destruction of tin and its transformation into a black powder. It should be noted that at a temperature of 18 ° and a slightly lower rate of this transformation is very insignificant and can be practically ignored. However, at subzero temperatures (especially minus 30-40 °), the process of polymorphic transformation proceeds very intensively. At first, dark growths appear on the products, and then their complete destruction occurs. The described phenomenon in practice is often called "tin plague". Tin, "sick" with the tin plague, can be restored only by melting.

Some impurities (lead, antimony, etc.) in small amounts sharply reduce the rate of conversion of tin from one modification to another, and three certain concentrations (0.5% and higher) almost completely protect against "tin plague".

Ordinary white tin (β = Sn) crystallizes from the melt in the form of large columnar crystals.

Spontaneous annealing of very pure tin is already quite complete at room temperature.

When crystallized, very pure lead also produces coarse grains.

Lead does not receive work hardening during cold deformation, since its recrystallization temperature is below room temperature.

Technical tin and lead always contain some impurities. All impurities in tin, except for antimony, are practically insoluble at room temperature. The main impurity in tin is lead, which in some grades intended for the manufacture of alloys is allowed in significant quantities (up to 1-2%).

As already noted, pure tin has good chemical resistance. It does not oxidize in humid air, it is stable in organic acids and boiling water. This has long allowed the use of tin for tinning dishes, tin and other anti-corrosion coatings. Impurities significantly reduce the corrosion resistance of tin. In the presence of lead or arsenic in tin, it becomes unsuitable for food utensils and equipment.

Strong acids and alkalis dissolve tin. In this respect, lead is a more resistant material. Lead is especially resistant to sulfuric acid due to the formation of a protective oxide film on its surface. Lead is stable in hot sulfuric acid up to a concentration of 80%, in cold - up to a concentration of 92%. In hydrochloric acid, lead is stable up to a concentration of 10%. Nitric acid acts most strongly on lead.

In dry air, lead does not oxidize, in humid air it is covered with a dull oxide film that has good protective properties. "

§ 2. ALLOYS OF TIN AND LEAD

In industry, five groups of alloys based on tin and lead are widely used:

1) antifriction alloys;

2) low-melting alloys;

3) solders;

4) printing alloys:

5) alloys for cable sheaths.

The structures, properties and applications of these alloys are discussed below.

1. Antifriction alloys

The chemical composition of industrial antifriction alloys based on tin and lead is shown in table. 44. The most important physical and mechanical properties of these alloys are presented in table. 45.

Indicated in table. 44 alloys can be roughly divided into three groups:

1. Tin-based alloys (B93, B90, B83).

2. Lead-based alloys (BS, BK).

3. Tin-lead alloys (B16, BN, BT, B6).

Tin-based alloys