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Heat Treatment Process and Properties of SAE4118H Steel
SAE4118H is an American-standard, high-strength alloy structural steel characterized by excellent hardenability and machinability. It is widely utilized in the manufacturing of automotive gears, transmission shafts, and heavy machinery components.
SAE4118H Steel Chemical Composition (%):
Carbon (C): 0.17–0.24
Chromium (Cr): 0.80–1.10
Molybdenum (Mo): 0.15–0.25
Manganese (Mn): 0.40–0.70
Sulfur (S) / Phosphorus (P): ≤ 0.035 (for both)
SAE4118H Steel Properties:
High Strength: Tensile Strength ≥ 885 MPa; Yield Strength ≥ 685 MPa
High Toughness: Impact Energy ≥ 98 J/cm²; Reduction of Area ≥ 50%
SAE 4118H Steel Heat Treatment Process:
Normalizing: 900–925°C, Air Cooling (for grain refinement)
Quenching: 850–880°C, Oil/Water Cooling
Tempering: Select temperature according to requirements
SAE 4118H Steel: Processing and Treatment Recommendations
Machining: Exhibits good machinability when in the annealed state with a hardness of ≤170 HB.
Carburizing Control: Direct quenching should be performed immediately after gas carburizing at 930°C to prevent grain coarsening.
Failure Prevention: Avoid tempering within the 250–400°C range (the first-type temper embrittlement zone).
SAE4118H Steel Chemical Composition (%):
Carbon (C): 0.17–0.24
Chromium (Cr): 0.80–1.10
Molybdenum (Mo): 0.15–0.25
Manganese (Mn): 0.40–0.70
Sulfur (S) / Phosphorus (P): ≤ 0.035 (for both)
SAE4118H Steel Properties:
High Strength: Tensile Strength ≥ 885 MPa; Yield Strength ≥ 685 MPa
High Toughness: Impact Energy ≥ 98 J/cm²; Reduction of Area ≥ 50%
SAE 4118H Steel Heat Treatment Process:
Normalizing: 900–925°C, Air Cooling (for grain refinement)
Quenching: 850–880°C, Oil/Water Cooling
Tempering: Select temperature according to requirements
SAE 4118H Steel: Processing and Treatment Recommendations
Machining: Exhibits good machinability when in the annealed state with a hardness of ≤170 HB.
Carburizing Control: Direct quenching should be performed immediately after gas carburizing at 930°C to prevent grain coarsening.
Failure Prevention: Avoid tempering within the 250–400°C range (the first-type temper embrittlement zone).
