Lead is a bluish metal, has a large specific gravity and almost minimal hardness (can be cut with a knife). Lead melting point such that it can be melted at the stake or at home. In its pure form, lead quickly becomes coated with an oxide film and dims. At normal temperatures, lead is inert to most acids.
The melting point of lead without impurities is about 328 degrees. In molten form, the metal has good casting qualities. When pouring lead into a sand form, it is necessary for the metal to have good fluidity; for this purpose, the melt is brought to a temperature exceeding the melting point by approximately 100-120 degrees. Easily machined, forged, high ductility of the metal allows you to easily roll it to a minimum sheet thickness.
The boiling point of lead is in the range of 1749 degrees.
In molten form, it has a noticeable volatility, which increases with increasing temperature. Lead dust, fumes of oxides and lead itself are poison to the human body. The presence of 0.3 g of lead or its components in the body leads to severe poisoning. During crystallization, lead is subject to great shrinkage, usually it is about 3.5%. In the earth's crust, lead is most often found in the form of compounds; in its pure form, it is quite rare.
It has been established that mainly it occurs in the form of sulfides in various rocks.
As impurities, it can contain elements such as antimony, copper, iron, tin, bismuth, arsenic, sodium, etc. Most of the impurities are undesirable, especially in the manufacture of critical parts, because they lead to a modification of the chemical and mechanical properties of the metal. Zinc and bismuth reduce lead resistance to acids. The presence of magnesium or calcium leads to an increase in strength, and the antimony-doped metal is characterized by a multiple increase in hardness.
Copper increases the resistance of the product from lead to sulfuric acid, barium and lithium increase the hardness. The melting point of lead in the presence of impurities does not undergo significant changes. The range of applications of lead products is wide enough. The main consumers of this material are cable and battery production, where it is used as a cable sheath and in the manufacture of battery plates.
Fraction and bullets are made from lead. The low melting point of lead allowed in the past, the hunters themselves make bullets and shots.
The anticorrosive capabilities of lead allow it to be used to apply a protective layer to objects made of iron. In addition, this property of lead is widely used in the manufacture of paints and varnishes. The main component of the ship's meerk, which paint the underwater part of the ship, is the pigment, which is based on lead.
The lead sheath of the cable is able to protect against corrosion the electric and telephone cables laid underground and water in an aggressive environment. At what temperature does lead, tin, bismuth and cadmium melt, take into account in the manufacture of electrical fuses. Until today, lead batteries are in demand in the automotive, defense and several other sectors of the economy. True, in recent years, cadmium-nickel batteries have been actively used.
Lead in alloys is widely used in the manufacture of babbit bearings, solder from tin and lead, and printing alloys. Sheets made of lead shield X-rays and radiation. The accident in 1986 at the Chernobyl nuclear power plant was accompanied by intense radioactive radiation, in order to stop the process in the reactor, bags with shot and lead blanks were used.
Lead sheets were used to protect people on helicopters delivering this cargo. The unique properties of lead in this case were indispensable.