40Cr alloy belongs to gb3077 "alloy structural steel". The carbon content of 40Cr steel is 0.37% ~ 0.44%, which is slightly lower than that of 45 steel. The content of Si and Mn is equivalent, and the content of Cr is 0.80% ~ 1.10%. In the case of hot rolling supply, the 1% Cr basically does not work, and their mechanical properties are roughly the same. Because the price of SA633 high-strength structural steel grade D is about half of that of 45 steel, 40Cr is not needed for the purpose of economy.
Chemical elements of 35CrMnSi steel: C: 0.32-0.39, Si: 1.10-1.40, Mn: 0.80-1.10, Cr: 1.10-1.40. The mechanical properties of 35CrMnSi steel: tensile strength 1620 MPa; yield strength 1280 MPa; elongation after fracture: 9%; reduction of area: 40; impact energy: 31J. SA633 high-strength structural steel grade D, 35CrMnSi steel is used to manufacture medium speed, heavy load, high strength parts and high strength components, such as aircraft landing gear and high pressure blower blades. 35CrMnSi can partly replace the corresponding CrNi alloy steel in manufacturing small and medium section parts.
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