42 cr mo4

42 Cr Mo4 is a popular alloy steel with excellent versatility and toughness. It is used extensively in the manufacturing industry, especially in the automotive and machinery sectors. The steel is known for its high tensile strength, durability, and resistance to wear and tear. Here’s everything you need to know about 42 Cr Mo4:

Chemical Composition

The chemical composition of 42 Cr Mo4 steel includes 0.38% – 0.45% carbon, 0.60% – 0.90% manganese, 0.15% – 0.30% silicon, 0.90% – 1.20% chromium, 0.15% – 0.25% molybdenum, and 0.030% maximum phosphorus and sulfur.


42 Cr Mo4 steel is highly versatile and has several applications. The most common use is in the automotive industry where it is used in the production of gearboxes, suspension systems, and crankshafts. It is used in the manufacture of machinery parts and components for industries such as construction, mining, and earthmoving. The steel is also used in the energy sector for drilling, oil and gas exploration, and pipeline transport.

Mechanical Properties

42 Cr Mo4 has excellent mechanical properties such as high tensile strength, good toughness, and hardness. It has a yield strength of 900 MPa and a tensile strength of 1100 MPa. The steel has a rockwell hardness of 22 HRC to 56 HRC.

Heat Treatment

Heat treatment is essential for enhancing the properties of 42 Cr Mo4. The steel can be heated to 840°C – 870°C and quenched in water or oil. This process improves the toughness and hardness of the steel.


Welding 42 Cr Mo4 steel requires special precautions to avoid cracking and brittleness in the heat-affected zone. Preheating is necessary to avoid excessive heat in the welding zone.


42 Cr Mo4 steel is an excellent choice for manufacturing machinery and automotive parts. With its high hardness, toughness, and wear resistance, it is suitable for demanding applications that require reliability and stability. The alloy can also be used in the energy sector, making it a versatile material for various industries. Heat treatment is crucial for enhancing the properties of the steel, while welding requires proper precautions to avoid cracking and brittleness.

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