Wanhetong Steel (shandong) Co., Ltd. is one of the steel companies with a long history and profound cultural heritage in China. This article will introduce the classification of steel. Before introducing the classification of steel, let's briefly introduce the basic concepts of ferrous metals, steel and non-ferrous metals.
1. Ferrous metals refer to iron and iron alloys. Such as steel, pig iron, iron alloys, cast iron, etc. Steel and pig iron are alloys based on iron and carbon as the main added element, collectively referred to as iron-carbon alloys.
Pig iron refers to the product made by smelting iron ore in a blast furnace, which is mainly used for steelmaking and casting.
Put the cast pig iron in a molten iron furnace to smelt it, that is, cast iron (liquid), and cast the liquid cast iron into castings. This kind of cast iron is called cast iron.
Ferroalloy is an alloy composed of iron and elements such as silicon, manganese, chromium, and titanium. Ferroalloy is one of the raw materials for steelmaking. It is used as a deoxidizer and alloy element additive for steel during steelmaking.
2. Put the pig iron for steelmaking into the steelmaking furnace and melt it according to a certain process to get steel. Steel products include ingots, continuous casting billets and various steel castings directly cast. The steel usually refers to steel rolled into various steel materials. Steel belongs to ferrous metals, but steel is not completely equal to ferrous metals.
3. Non-ferrous metals, also known as non-ferrous metals, refer to metals and alloys other than ferrous metals, such as copper, tin, lead, zinc, aluminum, brass, bronze, aluminum alloys and bearing alloys. In addition, chromium, nickel, manganese, molybdenum, cobalt, vanadium, tungsten, titanium, etc. are also used in industry. These metals are mainly used as alloy additives to improve the performance of metals. Among them, tungsten, titanium, molybdenum, etc. are mostly used to produce hard alloys for cutting tools. The above non-ferrous metals are all called industrial metals. In addition, there are precious metals: platinum, gold, silver, etc. and rare metals, including radioactive uranium, radium, etc.
Steel is an iron-carbon alloy with a carbon content between 0.04% and 2.3%. In order to ensure its toughness and plasticity, the carbon content is generally not more than 1.7%. In addition to iron and carbon, the main elements of steel include silicon, manganese, sulfur, phosphorus, etc. There are many ways to classify steel, and the main methods are as follows:
1. Classification by quality
(1) Ordinary steel (P≤0.045%, S≤0.050%)
(2) High-quality steel (P, S are both ≤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 (C≤0.25~0.60%); c. High carbon steel (C≤0.60%).
(2) Alloy steel: a. Low alloy steel (total alloying element content ≤ 5%); b. Medium alloy steel (total alloying element content > 5~10%); c. High alloy steel (total alloying element content > 10%).
3. Classification by forming method: (1) Forged steel; (2) Cast steel; (3) Hot rolled steel; (4) Cold drawn steel.
4. Classification by metallographic structure
(1) Annealed state: a. Hypoeutectoid steel (ferrite + pearlite); b. Eutectoid steel (pearlite); c. Hypereutectoid steel (pearlite + cementite); d. Ledeburite steel (pearlite + cementite).
(2) Normalized state: a. Pearlite steel; b. Bainite steel; c. Martensitic steel; d. Austenitic steel.
(3) No phase change or partial phase change
5. Classification by use
(1) Steel for construction and engineering: a. Ordinary carbon structural steel; b. Low alloy structural steel; c. Reinforced steel.
(2) Structural steel
a. Steel for machinery manufacturing: (a) Quenched and tempered structural steel; (b) Surface hardening structural steel: including carburizing steel, ammonia impregnated steel, and surface hardening steel; (c) Free-cutting structural steel; (d) Cold plastic forming steel: including cold stamping steel and cold heading 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 acid-resistant steel; b. Heat-resistant steel: including oxidation-resistant steel, heat-resistant steel, and valve steel; c. Electric heating alloy steel; d. Wear-resistant steel; e. Low-temperature steel; f. Electrical steel.
(5) Specialized steels - such as steel for bridges, ships, boilers, pressure vessels, and agricultural machinery.
6. Comprehensive classification
(1) Ordinary steel
a. Carbon structural steel: (a) Q195; (b) Q215 (A, B); (c) Q235 (A, B, C); (d) Q255 (A, B); (e) Q275.
b. Low alloy structural steel
c. Ordinary structural steel for specific purposes
(2) High-quality steel (including ** high-quality steel)
a. Structural steel: (a) High-quality carbon structural steel; (b) Alloy structural steel; (c) Spring steel; (d) Free-cutting 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) Stainless acid-resistant steel; (b) Heat-resistant steel; (c) Electric heating alloy steel; (d) Electrical steel; (e) High manganese wear-resistant steel.
7. Classification by smelting method
(1) Classification by furnace type
a. Open-hearth steel: (a) Acid open-hearth steel; (b) Basic open-hearth steel.
b. Converter steel: (a) Acid converter steel; (b) Basic converter steel. Or (a) Bottom-blown converter steel; (b) Side-blown converter steel; (c) Top-blown converter steel.
c. Electric furnace steel: (a) Electric arc furnace steel; (b) Electric slag furnace steel; (c) Induction furnace steel; (d) Vacuum consumable furnace steel; (e) Electron beam furnace steel.
(2) Classification by deoxidation degree and casting system
a. Boiling steel; b. Semi-killed steel; c. Killed steel; d. Special killed steel.
