What is the difference between 42CrMo steel and 40Cr 45# steel

42CrMo steel is alloy structural steel with carbon content of 0.38-0.45%, chromium content of 0.9-1.2%, molybdenum content of 0.15-0.25%, tensile strength of 1100MPa and yield point of 950MPa. 42CrMo steel is used to make parts with high load and reliability.

45# steel is high-quality carbon structural steel, carbon content is 0.42-0.50%, tensile strength is 610MPa, yield point is 360MPa; 45# steel is used for general shaft parts.

40Cr steel is alloy structural steel with carbon content of 0.37-0.45%, chromium content of 0.8-1.1%, tensile strength of 1000MPa and yield point of 800MPa. 40Cr steel is used for load-bearing parts.