Differences between 20Cr and 40Cr alloy

20Cr steel: 20Cr alloy steel is mostly used to make carburized parts (oil quenching) with high core strength requirements, surface wear, cross section below 30mm, or messy shape and light load, such as: machine tool gearbox gears, gears Shaft, cam, worm, piston pin, claw clutch.
 
For parts with small heat treatment deformation and high wear resistance, high-frequency surface quenching should be carried out after carburizing, such as gears, shafts, spline shafts with a modulus of less than 3. This steel can also be used in the quenched and tempered state for the production of parts with high operating speeds and moderate impact loads. This steel can also be used as a low-carbon martensitic quenching steel, further adding the steel's yield strength and Tensile strength (approximately 1.5 to 1.7 times added).
 
40Cr steel: This steel is used to make mechanical parts that accept medium load and medium speed after being tempered, such as the steering knuckle of the car, the rear half shaft, and the gears, shafts, worms, spline shafts, center sleeves on the machine tool.