Steel - seven types of steel
1, according to the quality classification
(1) ordinary steel (P≤0.045%, S≤0.050%)
(2) Stainless steel (P, S were ≤0.035%)
(3) High quality steel (P≤0.035%, S≤0.030%)

2, according to the chemical composition of classification
(1) carbon steel: a low carbon steel (C≤0.25%); b carbon steel (C≤0.25 ~ 0.60%); c high-carbon steel (C≥0.60%)...
(2) alloy steel:. A low-alloy steel (total content of alloying elements ≤5%) b alloy steel (total content of alloying elements> 5 ~ 10%) c of high-alloy steel (alloying elements the total content of> 10%). .
(3) the burning of carbon steel can evaporate into carbon dioxide, ignited will reduce the quality of steel samples. But the burning mass will increase, reason: steel iron combined with oxygen to generate iron oxide, and carbon containing less than iron
 
3, press molding method Category:
(1) forged steel; (2) steel; (3) hot rolled steel; (4) cold-drawn steel.

4, classified according to the microstructure
(1) annealed state a. Sub-eutectoid steel (ferrite + pearlite) b. Eutectoid steel (pearlite) c. Eutectoid steel (pearlite + cementite) d. Ledeburite ( pearlite + cementite).
(2) normalizing the state:.. A pearlitic steel; b bainitic steel; c martensitic steels; d austenitic steels...
(3) no phase change or phase change part

5. By Application
(1) Architectural and engineering steel: a common carbon structural steel; b low alloy steel; c reinforced steel....
(2) a structural steel machinery manufacturing steel: (a) quenched and tempered structural steel; (b) surface hardening steel: including hardened steel, ammonia, steel, surface hardening of steel; (c) easy to cut structural steel; ( d) cold plastic forming of steel: including cold stamping steel, cold heading steel. b. spring steel c. Bearing Steel
(3) tool steel:... A carbon tool steel; b alloy tool steel; c high-speed tool steel.
... (4) the special properties of steel: a steel heat-resistant stainless steel b includes antioxidant steel, heat resistant steel, alloy steel valves electric c; d resistant steel; e cryogenic steel; f... Electrical steel
(5) specialty steel - such as bridges of steel, ship steel, boiler steel, pressure vessel steel, steel and other farm machinery.

6, comprehensive classification
(1) ordinary carbon steel a structural steel: (a) Q195; (b) Q215 (A, B); (c) Q235 (A, B, C); (d) Q255 (A, B); ( e) Q275. b. Low alloy structural steel c. ordinary structural steel for a particular purpose
(2) Stainless steel (including high quality steel)
 . A structural steel: (a) high-quality carbon structural steel; (b) alloy structural steels; (c) spring steel; (d) free cutting steel; (e) bearing steel; (f) the specific use of high-quality structural steel.
 . B tool steel: (a) carbon tool steel; (b) alloy tool steel; (c) high-speed tool steel.
 . C steel special properties: (a) acid-resistant stainless steel; (b) heat-resistant steel; (c) electric steel; (d) Electrical steel; (e) high wear-resistant manganese steel.
 
7. The method of smelting classification
(1) Press the furnace Seed
 . A open-hearth steel: (a) an acid open-hearth steel; (b) basic open-hearth steel.
 . B converter steel: (a) Bessemer steel; (b) a basic converter steel. Or (a) bottom blowing converter steel; (b) side-blown converter steel; (c) BOF steel.