Classification of 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 percent and 2.11 percent. In order to ensure its toughness and plasticity, the carbon content is generally not more than 1.7 percent. In addition to iron and carbon, the main elements of steel include silicon, manganese, sulfur and phosphorus. There are a variety of classification methods for steel, and the main methods are as follows:

1. Classification according to quality

Carbon steel: A. mild steel (C≤0.25 percentage points); B. Medium carbon steel (0.25≤C≤0.60 percentage points);

C. High carbon steel (C≥0.60 percent).

Low alloy steel (total alloying element content <5 percentage points); B. Medium alloy steel (5 percentage points ≤ total alloying element content ≤10 percentage points); C. High alloy steel (total alloying element content >10 percentage points).

2, according to the forming method classification :

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

3, according to the metallographic organization classification

Annealed: A. hypoeutectoid steel (ferrite + pearlite); B. Eutectic steel (pearlite); C. Hypereutectoid steel (pearlite + cementite); D. Leistenitic steel (pearlite + cementite).

Normalizing: A. pearlitic steel; B. Bainitic steel; C. Martensitic steel; D. Austenitic steel. (3) No or partial phase transition occurs

4. Classification by use

Engineering steel: a. Common carbon structural steel; B. Low alloy structural steel; C. Rebar steel.

Carburizing: A. nitriding steel; B. Steel for surface hardening; C. Easy cutting structural steel; D. cold plastic forming steel: including cold stamping steel, cold heading steel.

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, air valve steel; C. Electrothermal alloy steel; D. wear resistant steel; E. Steel for low temperature; F. Steel for electrical purposes.

Bridge steel, ship steel, boiler steel, pressure vessel steel, agricultural machinery steel, etc.

5. Comprehensive classification

Good steel

(including good steel)

Structural steel :(a) good carbon structural steel; (b) alloy structural steel; (c) spring steel; (d) easy cutting steel; (e) bearing steel; (f) Good structural steels for specific purposes.

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

Steels with special properties :(a) stainless acid-resistant steels; (b) heat resistant steel; (c) electrothermal alloy steel; (d) Steel for electrical purposes; (e) high manganese wear resistant steel.

6, according to the smelting method classification

Electric furnace steel :(a) electric arc furnace steel; (b) slag furnace steel; (c) induction furnace steel; (d) vacuum self-consumable furnace steel; (e) Electron beam furnace steel.