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Chemical Composition of 20CrMnH Alloy Steel
Through an innovative chromium-manganese alloy design and a precision heat treatment process, 20CrMnH alloy steel has set a new standard in the fields of automotive transmission and engineering machinery.
20CrMnH steel utilizes a "chromium-manganese composite strengthening" mechanism. The 0.90%–1.20% chromium content facilitates the formation of M23C6-type carbides (sized 50–200 nm), while the 0.90%–1.20% manganese content expands the austenite phase field, thereby enhancing hardenability.
Key Thermomechanical Processing Steps for 20CrMnH Alloy Steel:
Controlled Rolling and Controlled Cooling (Final rolling temperature: 860 ± 10°C; Cooling rate: 10°C/s)
Gas Carburizing (930 ± 5°C for 15 hours; Carbon potential: 1.05%)
Direct Quenching (Quenching oil temperature: 80 ± 5°C)
Low-Temperature Tempering (180°C for 2 hours)
This process ensures that the carbide banding structure in Φ120 mm bars remains at Grade ≤ 2 (per GB/T 13299), and that ultrasonic flaw detection results comply with the GB/T 4162 Class B standard.
Characteristics of Carburized 20CrMnH Alloy Steel:
Effective Hardened Layer Depth (550 HV): 0.8–1.2 mm
Hardness Gradient (Surface to Core): HV 680 → HV 280 (at a depth of 2 mm)
Residual Austenite Content: ≤ 20% (determined via X-ray diffraction)
Key Performance Data for 20CrMnH Alloy Steel:
Contact Fatigue Life (L10): ≥ 1.5 × 10⁷ cycles (at a contact stress of 1600 MPa)
Scuffing Resistance (FZG Test): ≥ Grade 10
Machinability: Improved by 15% compared to 20CrMnTi steel
20CrMnH steel utilizes a "chromium-manganese composite strengthening" mechanism. The 0.90%–1.20% chromium content facilitates the formation of M23C6-type carbides (sized 50–200 nm), while the 0.90%–1.20% manganese content expands the austenite phase field, thereby enhancing hardenability.
Key Thermomechanical Processing Steps for 20CrMnH Alloy Steel:
Controlled Rolling and Controlled Cooling (Final rolling temperature: 860 ± 10°C; Cooling rate: 10°C/s)
Gas Carburizing (930 ± 5°C for 15 hours; Carbon potential: 1.05%)
Direct Quenching (Quenching oil temperature: 80 ± 5°C)
Low-Temperature Tempering (180°C for 2 hours)
This process ensures that the carbide banding structure in Φ120 mm bars remains at Grade ≤ 2 (per GB/T 13299), and that ultrasonic flaw detection results comply with the GB/T 4162 Class B standard.
Characteristics of Carburized 20CrMnH Alloy Steel:
Effective Hardened Layer Depth (550 HV): 0.8–1.2 mm
Hardness Gradient (Surface to Core): HV 680 → HV 280 (at a depth of 2 mm)
Residual Austenite Content: ≤ 20% (determined via X-ray diffraction)
Key Performance Data for 20CrMnH Alloy Steel:
Contact Fatigue Life (L10): ≥ 1.5 × 10⁷ cycles (at a contact stress of 1600 MPa)
Scuffing Resistance (FZG Test): ≥ Grade 10
Machinability: Improved by 15% compared to 20CrMnTi steel
