Steel sheet and rolled

Steel (from it. Stahl) – an alloy of iron with carbon (and other elements), containing not less than 45% iron, and in which the carbon content is in the range from 0.02 to 2.14%, and the content from 0.6% up to 2.14% corresponds to high carbon steel. If the carbon content in the alloy exceeds 2.14%, then this alloy is called cast iron. Carbon gives alloys strength and hardness, reducing ductility and toughness.

Steel with high elastic properties are widely used in machine building and instrument making. In mechanical engineering, they are used for the manufacture of springs, shock absorbers, power springs for various purposes, in instrument engineering – for numerous elastic elements: membranes, springs, relay plates, bellows, extensions, suspensions.

The earliest known steel samples were discovered during excavations in Anatolia (Turkey). They are about 3800 years old, they date back to 1800 BC. Indian steel enjoyed a high reputation in ancient times. Medieval bulat, widely known in Central Asia and Eastern Europe, originated from Indian steel. Steel learned to produce at the end of the era of Antiquity and in Western Europe. In the Middle Ages, steel was widely used for making knives (Romanesque sword, Ulfbert’s Swords). Damascus steel from which Shamshir was forged was known in the Middle East. In medieval Japan, famous katanas, wakizashis, and tantos were made from steel — Tamahagane. There is a version that Japanese swords of the XI-XIII centuries were made of alloy steel with an admixture of molybdenum. In Europe, steel allowed to lengthen swords, which later evolved into a sword (in the XV century) and a rapier.

The technology of cast steel is invented by the English engineer Gentsman, but it penetrates into continental Europe only at the beginning of the 19th century (thanks to Krupp). Since 1854 rifled artillery was made of steel (Armstrong Cannon). In the XX century steel began to make tank armor.

Types of steel:

There are many ways to classify steel, by purpose, by chemical composition, by quality, by structure.

By designation, steels are divided into many categories, such as structural steels, corrosion-resistant (stainless) steels, tool steels, heat-resistant steels, and cryogenic steels.

Chemical composition of steel is divided into carbon and alloyed; including carbon content – low carbon (up to 0.25% C), medium carbon (0.25–0.6% C) and high carbon (0.6–2% C); According to the content of alloying elements, alloyed steel is divided into low-alloyed – up to 4% of alloying elements, medium-alloyed – up to 11% of alloying elements and high-alloyed – over 11% of alloying elements.

By quality they began to be divided into: ordinary quality, high-quality, high-quality and especially high-quality, since they became, depending on the method of their preparation, contain a different number of non-metallic inclusions. The essence of the process of iron processing for steel is to reduce to the desired concentration of carbon and harmful impurities – phosphorus and sulfur, which make the steel brittle and brittle. Depending on the method of carbon oxidation, there are various ways of processing iron to steel: converter, open-hearth and electrothermal.

The structure of the steel is divided into austenitic, ferritic, martensitic, bainitic and pearlitic. If the structure is dominated by two or more phases, the steel is divided into two-phase and multi-phase.

Steel is subject to mandatory labeling. To clarify information on a specific steel grade, so-called marochnik can be used.

Alloyed steels, in contrast to unalloyed, have a slightly different designation, since they contain elements that are specially introduced in certain quantities to provide the required physical or mechanical properties.

For example:

  • Chromium (Cr) increases hardness and strength.
  • Nickel (Ni) provides corrosion resistance and increases hardenability.
  • Cobalt (Co) increases heat resistance and increases impact resistance.
  • Niobium (Nb) helps to improve acid resistance and reduces corrosion in welded structures.

Deciphering steel grades requires knowing what letters are used to designate certain chemical elements that make up the grade or alloy.

If at the very end of the mark is the letter A, this is how high-grade steel is indicated, the content of phosphorus and sulfur in which is minimized (S <0.03% and P <0.03%) and all conditions of high-quality metallurgical production are met.

Two letters A at the very end (AA) indicate that this steel grade is extremely pure, that is, there is practically no sulfur and phosphorus in it.

The letter symbols “kp”, “ps”, “cn” are used to indicate the degree of deoxidation of steel:

  • “kp” – boiling
  • “ps” – semi-calm
  • “cn” – calm

Characteristics of steel

  • Density: 7700–7900 kg / m³ (7.7 to 7.9 g / cm³).
  • Specific weight: 75500-77500 N / m³ (7700-7900 kgf / m³ in the MKGSS system).
  • Specific heat capacity at 20 ° C: 462 J / (kg • ° C) (110 cal / (kg • ° C)).
  • Melting point: 1450–1520 ° C.
  • Specific heat of fusion: 84 kJ / kg (20 kcal / kg, 23 Wh / kg).
  • coefficient of thermal conductivity at a temperature of 100 ° C

Steel sheet and rolled steel are produced according to:

GOST 380-05 Carbon steel of ordinary quality. Stamps.

GOST 16523-97 Rolled thin-sheet carbon steel of high quality and ordinary quality for general use. Technical conditions.

GOST 19903-74 Hot rolled sheet metal. Range.

The steel product range includes various steel grades:

Hot rolledcoils

The inner diameter of the coil is 850 ± 50 mm, dimensions 1.2–12.0 x 800–1524 mm, in rolls of a mass of 10-23 tons.
The inner diameter of the lightweight roll is 600 ± 50 mm, dimensions are 1.2-4 x 100-1300 mm, in rolls with a mass of 5-8 tons, the hem is cut.
Specific dimensions are agreed upon checkout.

Hot-rolled sheets

Sizes 1,2-12,0 x 800-1524 x 2000-6000 mm
Specific dimensions are agreed upon checkout.

Cold-rolled coils

The inner diameter of the roll for thicknesses of 0.47 mm and more is 600 ± 10 mm, weight is 4-8 tons. The internal diameter of the roll for thicknesses of 0.6 mm and less is 508 ± 10 mm, weight 2-4 tons. Specific dimensions are agreed upon checkout.

Cold rolled sheet

Dimensions 1.2-12.0 x 800-1524 x 2000-6000 mm.
Specific dimensions are agreed upon checkout.