Classification of steel
Carbon content in steel is between 0.04%-2.3% of iron-carbon alloys. In order to ensure their toughness and ductility, carbon content of not more than 1.7%. Outside the main elements in addition to iron, carbon steel, Silicon, manganese, sulfur, phosphorus, etc. The classification of a wide variety of steel, its main method has the following seven:
1, classified by quality
(1) steel (p ≤ 0.045%,S ≤ 0.05%)
(2) stainless steel (p and s ≤ 0.035%)
(3) high quality steel (p ≤ 0.035%,S ≤ 0.03%)
2. the classification, according to the chemical composition of
(1) carbon steel: a. mild steel (c ≤ 0.25%); b. carbon (c ≤ 0.25~0.60%); c. high carbon steel (c ≥ 0.6%).
(2) steel: a. low alloy steel (alloy element content ≤ 5%); b. alloy (alloying element content >5~10%); c. high alloy (alloying element content >10%).
3, press forming method: (1) forged steel (2) steel (3) hot-rolled steel, (4) bright steel.
4, classification by microstructure
(1) the annealed State: a. Sub-eutectoid steels (ferritic + pearlitic); b. eutectoid steel (Pearlite); c. hypereutectoid (perlite + cementite); d. ledeburite steel (perlite + cementite).
(2) State of the fire: a. Pearlite steel b. Bainite steel c. Martensitic steels; d. austenitic steel.
(3) no phase change of phase transitions or in part
5, classified by use
(1) steel for construction and engineering: a. ordinary carbon structural steel; b. low-alloy structural steel; c. steel.
(2) structural steel
A. steel used in machinery manufacture: (a) quenched and tempered steels, (b) structure of case-hardened steel: including carburizing steel, seepage of ammonia steels, steels for quenching and (c) structural steel, (d) steels for cold forming: including cold stamping steels, steel for cold heading.
B.-spring steel
C. bearing steel
(3) tool steels: a. carbon tool steel b. alloy tool steel; c. high-speed tool steel.
(4) special steel: a. stainless acidproof steel b. heat-resisting steel: including oxidation resistant steel, heat resistant steel, valve steel; c. electric heating alloy; d. wear-resistant steel e. low temperature steel; f. Electrotechnical steel.
(5) professional steel used for steel, such as bridges, ship steels, steels for boiler and pressure vessel steel for steel, machinery and so on.
6, general classification
(1) steel
A. carbon structural steels: (a) Q195; (b) Q215 (a, b), (c) Q235 (a, b, c), (d) Q255 (a, b), and (e) Q275.
B ... low-alloy structural steel
C. specific use of conventional structural steel
(2) stainless steel (including high quality steel)
A. structural steels: (a) high quality carbon structural steel, (b) alloyed structural steel, (c) spring steel; (d) easily cut steel; (e) bearing steel; (f) structural steel of specific use.
B. tool steel: (a) carbon tool steels, (b) alloy tool steel (c) high-speed tool steel.
C. specific properties of steel: (a) stainless and acid-proof steel; (b) heat-resistant steel, (c) electric heating alloy, (d) electrical steel (e) high manganese wear resistant steel.
