S45c
* chemical composition:
Carbon C: 0.42~0.50
Silicon Si:0.17~0.37
Manganese Mn:0.50~0.80
Sulfur S: ≤0.035
Phosphorus P: ≤0.035
Chromium Cr:≤0.25
Nickel Ni:≤0.25
Copper Cu:≤0.25

* mechanical properties:
Tensile strength σb (MPa):≥600(61)
Yield strength σs (MPa):≥355(36)
Elongation ratio δ5 (%): ≥16
Reduction of area Psi (%): ≥40
Impact merit Akv (J):≥39
Resilient value αkv (J/cm2):≥49(5)
Degree of hardness: Not heat treatment‚ ≤229HB; Annealed steel‚ ≤197HB
Test specimen size: The test specimen size is 25mm

* heat treatment regime and Microstructure:
Heat treatment regime: Hot‚ 850℃; Quenching‚ 840℃; Tempering‚ 600℃.

S50c
* chemical composition:
Carbon C: 0.47~0.55
Silicon Si:0.17~0.37
Manganese Mn:0.50~0.80
Sulfur S: ≤0.035
Phosphorus P: ≤0.035
Chromium Cr:≤0.25
Nickel Ni:≤0.25
Copper Cu:≤0.25

* mechanical properties:
Tensile strength σb (MPa):≥630(64)
Yield strength σs (MPa):≥375(38)
Elongation ratio δ5 (%): ≥14
Reduction of area Psi (%): ≥40
Impact merit Akv (J):≥31(4)
Resilient value αkv (J/cm2):≥39(4)
Degree of hardness: Not heat treatment‚ ≤241HB; Annealed steel‚ ≤207HB
Test specimen size: The test specimen size is 25mm

* heat treatment regime and Microstructure:
Heat treatment regime: Hot‚ 830℃; Quenching‚ 830℃; Tempering‚ 600℃.

Scr420
* chemical composition:
Carbon C: 0.18~0.23
Silicon Si:0.15~0.35
Manganese Mn:0.60~0.90
Sulfur S: Permits the remaining content ≤0.030
Phosphorus P: Permits the remaining content ≤0.030
Chromium Cr:0.90~1.20
Nickel Ni: Permits the remaining content ≤0.25
Copper Cu: Permits the remaining content ≤0.030

* mechanical properties:
Tensile strength σb (MPa):≥835(85)
Yield strength σs (MPa):≥540(55)
Elongation ratio δ5 (%): ≥10
Reduction of area Psi (%): ≥40
Impact merit Akv (J):≥47
Resilient value αkv (J/cm2):≥59(6)
Degree of hardness: ≤179HB
Test specimen size: The test specimen blank dimension is 15mm

Scm415
* chemical composition:
Carbon C: 0.13~0.18
Silicon Si:0.15~0.35
Manganese Mn:0.60~0.90
Sulfur S: Permits the remaining content ≤0.030
Phosphorus P: Permits the remaining content ≤0.030
Chromium Cr:0.90~1.20
Nickel Ni: Permits remaining content ≤0.25 copper Cu: Permits the remaining content ≤0.030
Molybdenum Mo:0.15~0.25

* mechanical properties:
Tensile strength σb (MPa):≥440(45)
Yield strength σs (MPa):≥295(30)
Elongation ratio δ5 (%): ≥22
Reduction of area Psi (%): ≥60
Impact merit Akv (J):≥94
Resilient value αkv (J/cm2):≥118(12)
Degree of hardness: ≤179HB

Test specimen size: The test specimen blank dimension is 30mm

* heat treatment regime and Microstructure:
Heat treatment regime: Quenching 900℃‚ air cooled; Tempering 650℃‚ air cooled.
Microstructure: Ferrite + pearlyte + few bainites

Scm420
* chemical composition:
Carbon C: 0.18~0.23
Silicon Si:0.15~0.35
Manganese Mn:0.60~0.90
Sulfur S: Permits the remaining content ≤0.030
Phosphorus P: Permits the remaining content ≤0.030
Chromium Cr:0.90~1.20
Nickel Ni: Permits the remaining content ≤0.25
Copper Cu: Permits the remaining content ≤0.030
Molybdenum Mo:0.15~0.25

* mechanical properties:
Tensile strength σb (MPa):≥885(90)
Yield strength σs (MPa):≥685(70)
Elongation ratio δ5 (%): ≥12
Reduction of area Psi (%): ≥50
Impact merit Akv (J):≥78
Resilient value αkv (J/cm2):≥98(10)
Degree of hardness: ≤197HB

Test specimen size: The test specimen blank dimension is 15mm

* heat treatment regime and Microstructure:
Heat treatment regime: Quenching 880℃‚ the water cooling‚ the oil are cold; The tempering 500℃‚ the water cooling‚ the oil are cold.

Scm440
* chemical composition:
Carbon C: 0.38~0.43
Silicon Si:0.15~0.35
Manganese Mn:0.60~0.90
Sulfur S: Permits the remaining content ≤0.030
Phosphorus P: Permits the remaining content ≤0.030
Chromium Cr:0.90~1.20
Nickel Ni: Permits the remaining content ≤0.030
Copper Cu: Permits the remaining content ≤0.030
Molybdenum Mo:0.15~0.30

* mechanical properties:
Tensile strength σb (MPa):≥1080(110)
Yield strength σs (MPa):≥930(95)
Elongation ratio δ5 (%): ≥12
Reduction of area Psi (%): ≥45
Impact merit Akv (J):≥63
Resilient value αkv (J/cm2):≥78(8)
Degree of hardness: ≤217HB

Test specimen size: The test specimen blank dimension is 25mm

* heat treatment regime and Microstructure:
Heat treatment regime: Quenching 850℃‚ the oil is cold; The tempering 560℃‚ the water cooling‚ the oil are cold. Microstructure: Tempering sorbite.