The Classification Of Steel

    The main elements in addition to iron, carbon steel, silicon, manganese, sulfur, phosphorus, etc.

    Steel classification method is varied, the main method has the following seven:

1.According to the quality of classification

(1) ordinary steel (Ps0.045%, Ss0.050%)

(2)  the high quality steel (P, S < 0.035%),

(3)  high quality steel (Ss0.030 Ps0.035%, %)

The classified by chemical composition

(1) carbon steel: 

a. Low carbon steel  (C < 0.25%).

b. medium carbon steel (C < ~ 0.250.60%).
c. high carbon steel (C < 0.60%)

(2) alloy steel:

a. low alloy steel (alloy element total content < 5%).

b. in alloy steel (alloy element total content > 5 ~ 10%);

c. high alloy steel (alloy element total content >10%)

2.According to the forming method of classification

(1) forging steel;

(2) cast steel;

(3) hot rolled steel,

(4) cold-drawn steel.

3.According to the microstructure classification

(1) annealing state: 

A. hypoeutectoid steel (ferrite + pearlite);

B. eutectoid steel (pearlite);

C. hypereutectoid steel (pearlite and cementite);

D. ledeburite steel (pearlite and cementite)

(2) the state of the fire: 

A. pearlitic steel;

B. bainite steel;

C.  martensitic steel;

D.  austenitic steel.

(3) without phase change or part of a phase change

4.Microstructure classification

(1) annealing state: 

A. hypoeutectoid steel (ferrite + pearlite);

B. eutectoid steel (pearlite);

C. hypereutectoid steel (pearlite and cementite);

D. ledeburite steel (pearlite and cementite).

(2)  the state of the fire:   A. pearlitic steel;

B. bainite steel;

C. martensitic steel;

D. austenitic steel.

(3) without phase change or part of a phase change

5. According to the classification purpose

(1) construction and engineering steel: 

A. ordinary carbon structural steel; B. low alloy structural steel; C. reinforced steel.

(2) structural steel:

A. machinery manufacturing steel quenched and tempered steels:

(a) quenched and tempered steel;

   (b) surface hardening steel: including carburizing steel, permeability of ammonia steel, surface quenching steel;

(c) free cutting steel;

(d) cold plastic forming steel: including cold-formed steel, LengHui steel.

B. spring steel

C. bearing steel

(3) tool steel: A. carbon tool steel;

B. alloy tool steel;

C. high speed tool steels

(4) the special performance of steel: A. acid-proof stainless steel; B. heat resistant steel, including oxidation heat intensity steel, steel, steel valve;

C. electrothermal alloy steel;

D. wear resistant steel;

E. cryogenic steel;

F.electrical steel.

(5) professional steel: such as Bridges with steel, ship steel, boiler steel, pressure vessel steel, agricultural machinery, steel, etc.

6. Comprehensive classification

(1) ordinary steel

A. arbon structural steel: 

(a) Q195.

(b) Q215(A, B);

(c) Q235 (A, B,C);

(d) Q255 (A, B);

(e) Q275o

B.  low alloy structural steel

C. specific use of common structural steel

(2) the high quality steel (including advanced high-quality steel)

7. According to the smelting method classification

(1) according to the furnace

A. converter steel: 

(a) Bessemer steel;

(b) basic Bessemer steel.

Or (a) converter steel;

(b) side blown converter steel;

(c) ld converter steel.

B. electric steel: 

(a) electric arc furnace steel;

(b) electroslag furnace steel;

(c) induction furnace steel.

(d) vacuum self-consuming furnace steel;

(e) electron beam furnace steel.

(2) According to the degree of deoxidation and pouring system,

A. boiling steel;

B. semi-calm steel;

C. calm steel;

               D. special calming steel.