Classification of steel

Finished material

Building materials - rebar, wire rod, coil screw, round steel

Pipes - seamless pipes, welded pipes

Sheet - cold, hot rolled sheet/coil, medium and heavy plate, color coated sheet (galvanized sheet, color coated sheet, tin-plated sheet, galvanized steel sheet), silicon steel, strip steel

Profiles - angle grooves, H-section steel, square steel, flat steel, bulb flat steel

special steel

: Structural steel, tool steel, die steel, spring steel, bearing steel, cold heading steel, hard wire

Steel is an iron-carbon alloy with a carbon content between 0.0218% and 2.11%. In order to ensure its toughness and plasticity, the carbon content generally does not exceed 1.7%. In addition to iron and carbon, the main elements of steel include silicon, manganese, sulfur, and phosphorus. There are various classification methods of steel, and the main methods are as follows:

1. Classification by quality

Carbon steel: a. Low carbon steel (C≤0.25 percentage points); b. Medium carbon steel (0.25≤C≤0.60 percentage points);

c. High carbon steel (C≥0.60 percentage points).

Low alloy steel (total content of alloying elements <5%); b. Medium alloy steel (5%≤total content of alloying elements ≤10%); c. High alloy steel (total content of alloying elements>10%).

2. Classification by forming method: (1) forged steel; (2) cast steel; (3) hot rolled steel; (4) cold drawn steel.

4. Classification by metallographic organization

Annealed state: a. Hypo-eutectoid steel (ferrite + pearlite); b. eutectoid steel (pearlite); c. hypereutectoid steel (pearlite + cementite); d. ledeburite steel (Pearlite + Cementite).

Normalized state: a. pearlitic steel; b. bainitic steel; c. martensitic steel; d. austenitic steel. (3) No phase change or partial phase change

5. Classification by use

Engineering steel: a. ordinary carbon structural steel; b. low-alloy structural steel; c. reinforced steel.

Carburizing steel: a. Nitriding steel; b. Steel for surface quenching; c. Free-cutting structural steel; d. Steel for cold plastic forming: including steel for cold stamping and cold heading.

Carbon tool steel; a. alloy tool steel; b. high-speed tool steel.

Special performance steel: a. stainless acid-resistant steel; b. heat-resistant steel: including chemical steel, heat-strength steel, gas valve steel; c. electrothermal alloy steel; d. wear-resistant steel; e. low-temperature steel; f. electrician Use steel.

Steel for bridges, steel for ships, steel for boilers, steel for pressure vessels, steel for agricultural machinery, etc.

6. Comprehensive classification

good steel

(including good steel)

Structural steel: (a) good carbon structural steel; (b) alloy structural steel; (c) spring steel; (d) free-cutting steel; (e) bearing steel; (f) good structural steel for special purposes.

Tool steel: (a) carbon tool steel; (b) alloy tool steel; (c) high-speed tool steel.

Special performance steel: (a) stainless acid-resistant steel; (b) heat-resistant steel; (c) electrothermal alloy steel; (d) electrical steel; (e) high manganese wear-resistant steel.

7. Classification by smelting method

Electric furnace steel: (a) electric arc furnace steel; (b) electroslag furnace steel; (c) induction furnace steel; (d) vacuum consumable furnace steel; (e) electron beam furnace steel.