Classification and labeling of steel for prefabricated steel structure

Second.the classification of steel for prefabricated steel structure

     Steel is iron and carbon alloy with carbon content between 0.04% and 2.3%. In order to ensure its toughness and plasticity, carbon content is generally not more than 1.7%. The main elements of steel in addition to iron, carbon, there are silicon, manganese, sulfur, phosphorus and so on. Steel classification methods are varied, the main methods are as follows: quality classification

    (1) ordinary steel (P ≤0.045%, S ≤0.050%)

    (2) high-quality steel (P, S are ≤0.035%)

    (3) high quality steel (P <0.035%, S≤0.030%)


2. Classification by chemical composition

    1) carbon steel: a. Low carbon steel (C ≤0.25%); b. Medium carbon steel (0.25 <C ≤0.60%); c. High carbon steel (C> 0.60%).

    2) alloy steel: a. Low alloy steel (alloying element content ≤5%) b. Medium alloy steel (alloying element content of 5 ~ 10%) c. High alloy steel (alloying element content> 10%).


3.     according to the forming method classification:

(1) forged steel; (2) cast steel; (3) hot-rolled steel; (4) cold drawn steel.


4.according to the microstructure (is the study of the internal structure of steel science) classification

    1) Pearlite + cementite) d. Leyer's steel (pearlite) (pearlite) c. Body + infiltration body).

    2) normalizing state: a. Pearlitic steel; b. Bainitic steel; c. Martensitic steel; d austenitic steel.

    3) No phase change or partial phase change

5.according to use classification

1) Construction and engineering steel:

a. Ordinary carbon structural steel;

b. Low alloy structural steel;

c. Reinforced steel.

2) structure steel: 

   A.machinofacture steel :

a)adjust for structural steel;

b)Surface induration structure steel:Including carburized steel, ammonia steel, surface hardened steel;

c) easy to cut structural steel;

d) cold plastic forming steel: including cold stamping steel, cold forging steel.

B.spring steel

C.bearing steel

3) tool steel:

 a. Carbon tool steel; 

b. Alloy tool steel;

c. High-speed tool steel.

4) special performance steel:

a. Stainless steel acid;

b. Heat-resistant steel, including anti-oxidation steel, heat steel, valve steel;

c. Electric alloy steel; d wear steel; e. Electrical steel

    5) professional steel - such as bridge steel, ship steel, boiler steel, pressure vessel steel, agricultural machinery and so on.


6.comprehensive classification

1) Nomal material:

A.carbon construction steel:


(b) Q215 (A, B);

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

(d) Q255 (A, B);

(e) Q275.

(f)electrician use;

B. Low alloy structural steel.

C. general purpose structural steel for specific purposes

2) high quality steel (including high quality steel)

A.Structure steel:

     (a) high quality carbon structural steel;

(b) alloy structural steel;

(c) spring steel;

(d) easy to cut steel;

(e) bearing steel;

(f) high quality structural steel for specific purposes.

     B. tool steel:

(a) carbon tool steel;

(b) alloy tool steel;

(c) high speed tool steel.

  C.special performance steel:

(a)non-acid resistant steel;

(b) heat-resistant steel;

(c) electric alloy steel;

(d) electrical steel;

(e) high manganese wear-resistant steel.

7. according to smelting method classification

     1) by the furnace points

a. Oven steel (with air as oxidant): (a) acid flat furnace steel; (b) alkaline flat steel.

   b. converter steel (with oxygen as oxidant):

(a) acid converter steel;

(b) alkaline converter steel. 

Or (a) bottom-blown converter steel; (b) side-blown converter steel; (c) top-blown converter steel.

       c.electric furnace(Refining high quality steel):

(a)electric arc furnace steel;

(b) electroslag furnace steel;

(c) induction furnace steel;

(d) vacuum consumption furnace steel;

(e) electron beam furnace steel;

     2) according to the degree of deoxidation and pouring system points:

a.boiled steel (incomplete degree of deoxidation);

b. semi-killed steel (deoxidation between the boiling steel and sedimentary steel);

c. sedative steel (more complete degree of deoxidation);

d. special sedative steel (the most complete degree of deoxidation, high quality steel).


8.     according to the shape classification: divided into:

a. Profiles;

b. Plate;

c. Pipe;

d. Metal products four categories.

a. Profile:

Heavy rail: more than 30 kg per meter weight of the rail (including the crane rail);

Light rail: rail of less than or equal to 30 kg per meter.

Large, medium and small sections: ordinary steel round bar, square steel, flat steel, hexagonal steel, I-beam, channel, equilateral and unequal angle steel and rebar.

Wire: 5-10 mm in diameter round bar and wire rod.

Cold-formed steel: steel or steel strip cold-formed steel.

High-quality profiles: high-quality steel round steel, square steel, flat steel, hexagonal steel.

b. Plate:

Thin steel plate: steel plate with thickness equal to or less than 4 mm.

Medium and thick steel plate: thickness greater than 4 mm steel plate.

Medium plate: thickness greater than 4mm less than 20mm);

plank plate: thickness greater than 20mm less than 60mm;

special plate: thickness greater than 60mm.

Strip: also called strip, is actually long and narrow and rolled into thin plate.

Electrical silicon steel sheet: also known as silicon steel sheet or silicon steel sheet.

c. pipe:

Seamless steel pipe: with hot pressing, cold rolling (cold drawing or extrusion) and other methods of production of seamless steel pipe wall.

Welded steel pipe: the steel plate or strip crimping, and then welded steel pipe.

d. metal products: including steel wire, wire rope, steel wire and so on.


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