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31CrMoV9 nitriding steel

31CrMoV9 is a nitriding steel which has at least 2.3%Cr, 0.15%Mo, 0.1%V as strengthening alloy elements.
Due to its high wear resistance,it is mainly used in the automotive industry and general components mechanical engineering.

31CrMoV9 equivalent steel grades:

31CrMoV9 mechanical properties:

25Cr2MoV Alloy steel

25Cr2MoV steel has good intergranular corrosion resistance, excellent corrosion resistance and cold working stamping performance. It has strong corrosion resistance to oxidizing acid (such as nitric acid), alkali solution and most organic and inorganic acids.

Due to its proper hardenability, the microstructure of the alloy is homogeneous sorbite, bainite or very fine pearlite after proper metal heat treatment. Therefore, 25Cr2MoV has higher tensile strength and yield ratio, higher toughness and fatigue strength, and lower toughness and brittle transition temperature.
Generally, the steel material can be used in the state of quenching and tempering, and can also be used after normalizing and high temperature tempering.

25Cr2MoV  steel mechanical properties:

Tensile strength σ B (MPA): 1090
Yield strength σ s (MPA): 1042
Elongation δ 5 (%): 18
Reduction of area ψ (%): 63
Impact toughness value α Ku (J / cm2): 213
Hardness: 308HB

100CrMn6 bearing steel

100CrMn6 is a kind of bearing steel, Chromium ball bearing steel.

100CrMn6 steel equivalent grade:

100CrMn6 mechanical properties:

Tensile strength:115-234MPa

Yield Strength:154MPa

Elongation:56δ5≥(%)

36CrNiMo4 alloy structural steel

36CrNiMo4 is an alloy structural steel. As a property of 36CrNiMo4 steel, density is closely related to the composition of 36CrNiMo4 steel.

36CrNiMo4 steel equivalent grade:

36CrNiMo4 mechanical properties:

Tensile strength σ B (MPA): ≥ 980 (100)
Yield strength σ s (MPA): ≥ 835 (85)
Elongation δ 5 (%): ≥ 12
Impact energy Akv (J): ≥ 78
Impact toughness value α kV (J / cm2): ≥ 98 (10)
Hardness: ≤ 269HB

34CrMo4 alloy structural steel

34CrMo4 steel is a kind of alloy structural steel. It has high rupture strength and creep strength at high temperature, good impact toughness at low temperature, good hardenability, no tendency to overheat, small quenching deformation, fair plasticity and medium machinability when cold forming. Poor weldability, preheating before welding, post welding heat treatment and stress relief are generally used after quenching and tempering treatment, and can also be used after high and medium frequency surface quenching or quenching and low and medium temperature tempering.

34CrMo4 steel equivalent grade:

34CrMo4 mechanical properties:

Tensile strength σ B (MPA): ≥ 985 (100)
Yield strength σ s (MPA): ≥ 835 (85)
Elongation δ 5 (%): ≥ 12
Reduction of area ψ (%): ≥ 45
Impact energy Akv (J): ≥ 63
Impact toughness value α kV (J / cm2): ≥ 78 (8)
Hardness: ≤ 229HB

Classification of steel

Ferrous, steel and nonferrous metals
Before introducing the classification of steel, the basic concepts of ferrous metals, steel and non-ferrous metals are briefly introduced.
1. Ferrous metals are iron and its alloys. Such as steel, pig iron, ferroalloy, cast iron, etc. Steel and pig iron are based on iron, carbon as the main added element of alloy, collectively known as iron carbon alloy.
Pig iron refers to the product made by smelting iron ore in blast furnace, which is mainly used for steelmaking and casting.
Cast pig iron is melted in an iron melting furnace to obtain cast iron (liquid state), which is called cast iron casting.
Ferroalloy is an alloy composed of iron and silicon, manganese, chromium, titanium and other elements. Ferroalloy is one of the raw materials for steel-making. It is used as deoxidizer and alloy element additive in steel-making.
2. The pig iron for steelmaking is put into the steelmaking furnace and smelted according to a certain process to obtain steel. Steel products include ingots, continuous casting billets and direct casting of various steel castings. Generally speaking, steel refers to the steel rolled into various steels. Steel belongs to ferrous metal, but steel is not equal to ferrous metal.
3. Nonferrous 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 and titanium are also used in industry. These metals are mainly used as alloy additives to improve the properties of metals. Tungsten, titanium and molybdenum are mostly used to produce cemented carbide for cutting tools. These nonferrous metals are called industrial metals. In addition, there are precious metals: platinum, gold, silver, and rare metals, including radioactive uranium and radium.

Classification of steel
Steel is an iron carbon alloy with carbon content between 0.04% and 2.3%. In order to ensure its toughness and plasticity, the carbon content generally does not exceed 1.7%. Besides iron and carbon, the main elements of steel are silicon, manganese, sulfur and phosphorus. The classification methods of steel are various, 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 ≤ 0.035%)

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 alloy element content ≤ 5%); B. medium alloy steel (total alloy element content > 5 ~ 10%); C. high alloy steel (total alloy element content > 10%).

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

4. Classification by metallographic structure
(1) Annealed: A. hypoeutectoid steel (ferrite + pearlite); B. eutectoid steel (pearlite); C. hypereutectoid steel (pearlite + cementite); D. ledeburite steel (pearlite + cementite).
(2) Normalized: A. pearlitic steel; B. bainitic steel; C. martensitic steel; D. austenitic steel.
(3) Having no or partial transformation

5. Classification by use
(1) Construction and engineering steel: a. ordinary carbon structural steel; b. low alloy structural steel; c. reinforced steel.
(2) Structural steel
a. Mechanical manufacturing steel: (a) quenching and tempering structural steel; (b) surface hardening structural steel: including carburizing steel, ammoniating steel and surface quenching steel; (c) easy 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 and acid resistant steel; b. heat resistant steel: including anti-oxidation steel, hot strength steel and air valve steel;c. electric heating alloy steel; d. wear resistant steel; e. low temperature steel; f. electrical steel.
(5) Professional steel, such as bridge steel, ship steel, boiler steel, pressure vessel steel, agricultural machinery steel, 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 structural steels for specific applications
(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 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) electrothermal alloy steel; (d) electrical steel; (E) high manganese wear-resistant steel.

7. Classification by smelting method
(1) According to the type of furnace
a. Open hearth steel: (a) acid open hearth steel; (b) basic open hearth steel.
b. Converter steel: (a) basic converter steel. Or (a) bottom blown converter steel; (b) side blown converter steel; (c) top blown converter steel.
c. EAF steel: (a) EAF steel; (b) electroslag furnace steel; (c) induction furnace steel; (d) vacuum consumable furnace steel; (E) electron beam furnace steel.
(2) According to deoxidation degree and pouring system
a. The results show that there are three kinds of steels: rimmed steel; B. semi killed steel; C. killed steel; D. special killed steel.