What are the commonly used materials for chains, and how are their chemical composition and heat treatment

ChainCommonly usedMaterial : 40Cr,40Mn,45Mn,65Mn

40Cr

40CrBeChainThe most commonly used material. "Cr" means metallic chromium (gè)chemical symbol.40Cr is often referred to as "Four Fragments".Chemical composition (mass fraction,%):

C0.37~0.44

Si0.17~0.37

Mn0.50~0.80

Cr0.80~1.10

Ni≤0.30. Mechanical properties 

【Mechanical properties】 

Sample blank size (mm): 25 

Heat treatment: 

The first quenching heating temperature (℃): 850; Coolant: Oil 

The second quenching heating temperature (℃):- 

Tempering heating temperature (℃): 520; Coolant: water, oil 

tensile strength(σb/MPa): ≧980 

Yield point(σs/MPa): ≧785 

断后Elongation(δ5/%): ≧9 

rate of reduction in area(ψ/%): ≧45 

Impact absorption work (Aku2/J): ≧47 

Brinell hardness(HBS100/3000) (annealed or high temperature tempered state): ≦207

40Mn

Chemical composition (mass fraction,%):

silicon Si: 0.37～0.44

manganese Mn: 0.70～1.00

sulfur S: ≤0.035 (group: high-quality steel)

磷 P: ≤0.035 (group: high-quality steel)

铬 Cr: ≤0.25

nickel Ni: ≤0.30

copper Cu: ≤0.25

【Mechanical properties】

tensile strength σb(MPa): ≥590(60)

Yield Strength σs(MPa): ≥355(36)

Elongation δ5(%): ≥17

rate of reduction in area ψ(%): ≥45

Impact energy Akv(J): ≥47

Impact toughness value αkv(J/cm2): ≥59(6)

Hardness: not heat-treated≤229HB; Annealed steel ≤207HB

Sample size: The sample size is25 mm

40Mn carbon structural steel can obtain better comprehensive mechanical properties after quenching and tempering. The cutting performance is good, but the welding performance is poor, the cold deformation plasticity is low, and there is a tendency to temper brittleness. It is generally used in the quenched and tempered state, and can also be used in the quenched and tempered state. Used in quenched and tempered or normalized state.

45Mn

45Mn is a substitution40CrThe more successful new steel grade, it has higher strength, hardness, Abrasion resistanceAnd good toughness, itsHardenabilityCompare40Cr is slightly higher, and the critical hardening diameter in oil is 18～33mm; after normalizing, the machinability is good, and the performance of cold drawing, thread rolling, tapping, forging, and heat treatment is also good. The grains grow at high temperatures. The tendency of oxidation, decarburization and quenching deformation are small; but it has temper brittleness, and its tempering stability is slightly worse than that of 40Cr steel.

The main ingredients are Fe(Iron element), and contains the following few elements (mass fraction,%):

carbon C: 0.42～0.50%

silicon Si: 0.17～0.37%

manganese Mn: 0.70～1.00%

sulfur S: ≤0.035%

磷 P: ≤0.035%

铬Cr: ≤0.25%

nickel Ni: ≤0.25%

copper Cu: ≤0.25%

【Mechanical properties】

tensile strength σb(MPa): ≥620(63)

Yield Strength σs(MPa): ≥375(38)

Elongation δ5(%): ≥15

rate of reduction in area ψ(%): ≥40

Impact energy Akv(J): ≥39

Impact toughness value αkv(J/cm2)：≥49(5)硬度：未热处理≤241HB;退火钢≤217HB

Heat treatment process:Normalizing at 850°C, quenching at 840°C, and tempering at 600°C.

65Mn

Commonly known"Spring Steel"

After heat treatment and cold drawing hardening, the strength is higher, and it has a certain degree of toughness and plasticity; under the same surface condition and complete hardening, the fatigue limit is equivalent to that of the alloy spring.

Chemical composition (mass fraction,%):

carbon C: 0.62～0.70

silicon Si: 0.17～0.37

Manganese Mn: 0.90～1.20

Sulfur S: ≤0.035

Phosphorus P: ≤0.035

Chromium Cr: ≤0.25

Nickel Ni: ≤0.25

Copper Cu: ≤0.25 [mechanical properties]

tensile strength Rb(MPa): ≥980

Yield Strength Rs(MPa): ≥785

Elongation δ10(%): 14~21.5

rate of reduction in area ψ(%): not less than 10

in factChainManufacturing materialsSelectiveVery wide, mainly depending on the operating conditions.Generally, the low-alloy structural steel as described above can also be stainless steel, carbon structural steel, high-alloy structural steel, etc.