The use of steel is widespread around us. The popularization of knowledge about steel is of great significance for us to understand steel products.
Steel is classified according to quality:
(1) ordinary steel: P is less than 0.045%, S is less than 0.05%.
(2) quality steel: P and S are all less than 0.035%.
(3) premium quality steel: P is less than 0.035%, S is less than 0.030%.
Steel is classified according to chemical composition:
(1) carbon steel: low carbon steel (C < 0.25%); medium carbon steel (0.25% < C < 0.60%);
High carbon steel (C > 0.60%)
(2) alloy steel: low alloy steel (alloy less than 5%); medium alloy steel (5% < alloy < 10%);
High alloy steel (alloy > 10%)
According to the forming method:
Forged steel; cast steel; hot rolled steel; cold rolled steel.
Classification by use:
(1) steel for construction and Engineering: common carbon structural steel, low alloy structural steel, and reinforced steel.
(2) structural steel:
A. machinery manufacturing steel: Quenched and tempered structural steel, surface hardened structural steel (including penetration)
Rigid, ammonia infiltrated steel, surface hardening steel, easy cut structural steel and cold plastic forming steel.
Cold stamping steel and cold heading steel)
B. spring steel
C. bearing steel
(3) tool steels: carbon tool steels, alloy tool steels, and high speed tool steels.
(4) special properties steel: stainless acid resistant steel and heat-resistant steel (including oxidation resistant steel, hot strength steel, etc.)
Valve steel), electrothermal alloy steel, wear resistant steel, low temperature steel, electrical steel
(5) professional steel: bridges, ships, boilers, pressure vessels, and agricultural machinery steels.
Classification by metallographic organization:
(1) annealing state:
A. hypoeutectoid steel (ferrite + pearlite)
B. eutectoid steel (Zhu Guangti)
C. hypereutectoid steel (pearlite + osmotic body)
D. laiswell steel (pearlite + penetrant)
A. pearlite steel
B. bainitic steel
C. martensitic steel
D. austenitic steel
(3) no phase transformation or partial phase transition.