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Basic knowledge of steel

time��2017/9/26 9:51:26��source����visits��

Ferrous metals, steels and nonferrous metals
Before introducing the classification of steel, a brief introduction to the basic concepts of ferrous metals, steels and nonferrous metals is given.
1. Ferrous metals are alloys of iron and iron. Such as steel, pig iron, iron alloy, cast iron and so on. Stainless steel tube and pig iron are based on iron, carbon as the main additive elements of the alloy, collectively referred to as iron carbon alloy.
Pig iron is the product of smelting iron ore into a blast furnace. It is mainly used for making steel and casting.
Put the casting pig iron smelting in cupola, to obtain iron (liquid), the liquid cast iron cast into casting, the cast iron is cast iron.
Ferroalloy is made of iron and silicon, manganese, chromium, titanium and other elements. Ferroalloy is one of the raw materials for steelmaking. It is used as deoxidizer and alloying element additive in steel making.
2, the steel pig iron into the steel-making furnace, according to a certain process smelting, that is, steel. Steel products are steel ingot, continuous casting billet and direct casting of various steel castings. Generally speaking, steel is generally used to make steel made of various kinds of steel. Steel belongs to ferrous metals, but steel is not exactly black metal.
3. Nonferrous metals, also called non-ferrous metals, refer to metals and alloys other than ferrous metals, such as copper, tin, lead, zinc, aluminum, and brass, bronze, aluminium and bearing alloys. Also in the industry also uses chromium, nickel, manganese, molybdenum, cobalt, vanadium, tungsten, titanium, the metal alloy is mainly used as additives, to improve the performance of the metal, tungsten, titanium, molybdenum and other hard alloy tool used in the production of. All these non-ferrous metals are called industrial metals. In addition, there are precious metals: platinum, gold, silver and other rare metals, including radioactive uranium, radium and so on.
Two. Classification of steel
Steel is an iron carbon alloy with carbon content between 0.04%-2.3%. In order to ensure its toughness and plasticity, carbon content is generally not more than 1.7%. The main elements of iron are iron, carbon, silicon, manganese, sulfur and phosphorus. There are many kinds of steel classification methods, and the main methods are as follows: seven kinds:
1, according to quality classification
(1) ordinary steel (P = 0.045%, S = 0.050%)
(2) high quality steel (P, S = 0.035%)
(3) high quality steel (P = 0.035%, S = 0.030%)
2., according to chemical classification
(1): A. carbon steel low carbon steel (C = 0.25%); B. (C = 0.25~0.60%) in carbon steel high carbon steel; C. (C = 0.60%).
(2): A. alloy steel, low alloy steel (alloy element content is less than or equal to 5%); B. alloy (5~10% alloy element content >); C. alloy steel (alloy element content > 10%).
3, according to the forming method classification: (1) forging steel; (2) cast steel; (3) hot rolled steel; (4) cold drawn steel.
4. Classification according to metallographic structure
(1) annealed state: A. eutectoid steel (ferrite + Zhu Guangti); B. eutectoid steel (Zhu Guangti); C. eutectoid steel (Zhu Guangti + cementite); D.; austenitic steel (Zhu Guangti + cementite).
(2) normalizing condition: A. pearlitic steel; B. bainitic steel; C. martensitic steel; D. austenitic steel.
(3) without phase change or part of phase change
5. Classification by purpose
(1) building and engineering steel: A. ordinary carbon structural steel; B. low-alloy structural steel; C. reinforced steel.
(2) structural steel
Steel manufacturing machinery: A. (a) quenched and tempered steel; surface hardening (b) steel structure: including carburizing steel, surface hardened steel, with infiltration of ammonia (c) free cutting steel; steel structure; (d) cold forming steel: cold stamping steel, 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, hot strong steel, air valve steel; C. electric alloy steel; D. wear-resistant steel; e. low temperature steel; F. steel for electrical purposes.
(5) professional steel - such as bridge steel, shipbuilding steel, boiler steel, steel for pressure vessel, steel for agricultural machinery, etc..
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. general purpose 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) easy to cut steel; (E) bearing steel; (f) high quality structural steel for certain purposes.
B. tool steels: (a) carbon tool steels; (b) alloy tool steels; (c) high speed tool steels.
C. special performance steel: (a) stainless acid resistant steel; (b) heat-resisting steel; (c) electric alloy steel; (d) electrical steel; (E) high manganese wear resistant steel.
7, according to smelting method classification
(1) according to the kind of furnace
A.: open hearth steel (a) acid open hearth steel; (b) basic open hearth steel.
B. converter steel: (a) Bessemer steel; (b) basic Bessemer steel. Or (a) bottom blown converter steel; (b) side blown converter steel; BOF steel (C).
C. electric arc furnace (a) steel: steel; steel electroslag furnace (b); (c) induction furnace (d) steel; vacuum consumable steel; (E) electron beam furnace steel.
(2) according to the degree of deoxidization and pouring system
A. boiling steel; B. semi killed steel; C. killed steel; D. special killed steel.

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