AISI4140 is equivalent to China’s 42CrMo steel.
42CrMo steel belongs to ultra high strength steel, with high strength and toughness, high hardenability, no obvious temper brittleness, high fatigue limit after quenching and tempering, multiple impact resistance, good low temperature impact toughness, it has high creep strength and durability in high temperature. This steel is suitable for manufacturing large and medium-sized plastic molds that require a certain strength and toughness. It is used to make forgings that require higher strength and greater tempering section than 35CrMo steel, such as large gears for locomotive towing, supercharger transmission gears, rear axles, highly-loaded connecting rods and spring clips. Deep oil drill pipe joints and salvage tools below 2000m.