Executive Standard: JIS G4053-2003
● Features and application:
With moderate-intensity, cold plastic deformation of high and low temperature performance, and the corresponding carbon content of steel compared to the high hardenability. Generally used as a small cross-section parts, and 20Cr steel rather, can be used for carburized pinion, small axes, steel sleeve, piston pin, engine bushing, steering wheel shaft, valve push rod, etc.; also can be used for quenching steels, cold heading, such as bolts or large sections of the quenched parts. .
● Chemical Composition:
Carbon C: 0.17 ~ 0.23
Si Si: 0.15 ~ 0.35
Manganese Mn: 1.20 ~ 1.50
Sulfur S: to allow the residual content ≤ 0.030
Phosphorus P: ≤ 0.030 to allow the residual content of chromium Cr: allow the residual content of ≤ 0.35
Ni: to allow the residual content of ≤ 0.25
Copper Cu: to allow the residual content of ≤ 0.30
● Mechanical Properties:
Tensile strength σb (MPa): ≥ 785 (80)
Yield strength σs (MPa): ≥ 590 (60)
Elongation δ5 (%): ≥ 10
Reduction of area ψ (%): ≥ 40
Impact energy Akv (J): ≥ 47
Impact toughness αkv (J/cm2): ≥ 59 (6)
Hardness: ≤ 187HB
Sample size: Sample size is 15mm rough
● Heat treatment and microstructure specifications:
Heat treatment specifications: 1) quenching 850 ℃, water, oil cooling; tempering, 200 ℃, water, air-cooled. 2) quenching 880 ℃, water, oil cooling, tempering, 200 ℃, water, air-cooled.
● Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract.
