1. Key Properties:
High Strength: Both 4140 and 42CrMo4 are low alloy steels known for their high tensile strength, making them ideal for heavy-duty and high-stress applications.
Good Toughness: These steels offer excellent toughness and impact resistance, which makes them suitable for parts exposed to shock loading and cyclic stresses.
Good Hardness: After heat treatment, 4140 and 42CrMo4 achieve excellent hardness, making them resistant to wear and abrasion.
Weldability: Both grades have good weldability, though preheating is recommended for thicker sections to reduce the risk of cracking.
Heat Treatable: These alloys can be quenched and tempered to further improve mechanical properties, offering flexibility for different applications.
2. Applications/Industries:
Automotive: Used extensively for making gears, axles, shafts, and other heavy-duty automotive components that need to withstand high stresses and wear.
Heavy Machinery: Ideal for producing structural components, crankshafts, connecting rods, and other parts for heavy machinery where high strength and fatigue resistance are necessary.
Oil & Gas: Commonly used in oilfield equipment like drill pipes, pressure vessels, and tubing where strength and resistance to harsh conditions are critical.
Aerospace: Employed for aerospace applications like landing gear, structural components, and engine parts, where high strength, toughness, and fatigue resistance are needed.
Tooling & Dies: Both grades are used for manufacturing tooling, dies, and molds that require strength and wear resistance.
3. Certifications/Standards:
SAE J403: Both 4140 and 42CrMo4 conform to the SAE J403 standard for alloy steels, ensuring they meet the necessary chemical composition and mechanical property requirements.
ASTM A519: This standard applies to seamless carbon and alloy steel mechanical tubing, which is relevant for both 4140 and 42CrMo4 seamless pipes.
ISO 9001: Quality management system certification.
4. Chemical Composition:
4140:
Carbon (C): 0.38% – 0.43%
Manganese (Mn): 0.60% – 0.90%
Chromium (Cr): 0.80% – 1.10%
Molybdenum (Mo): 0.15% – 0.25%
Silicon (Si): 0.20% – 0.35%
Phosphorus (P): 0.035% max
Sulfur (S): 0.035% max
Iron (Fe): Balance
42CrMo4:
Carbon (C): 0.38% – 0.45%
Manganese (Mn): 0.60% – 0.90%
Chromium (Cr): 0.90% – 1.20%
Molybdenum (Mo): 0.15% – 0.25%
Silicon (Si): 0.20% max
Phosphorus (P): 0.035% max
Sulfur (S): 0.035% max
Iron (Fe): Balance
5. Technical Specifications:
4140:
Yield Strength:
4140: 415 MPa (minimum)
Tensile Strength:
4140: 690–900 MPa
Hardness:
4140: Approximately 200–285 HB (Brinell hardness)
42CrMo4:
Yield Strength:
42CrMo4: 450 MPa (minimum)
Tensile Strength:
42CrMo4: 700–900 MPa
Hardness:
42CrMo4: Approximately 200–280 HB (Brinell hardness)