What is the difference between 45Mn steel plate and 40Cr steel plate

What is the difference between 45Mn steel plate and 40Cr steel plate?

1. Comparison of chemical composition between 45Mn steel plate and 40Cr steel plate:
Chemical composition of 45Mn steel plate: C 0.42-0.50, Si 0.17-0.37, Mn 0.70-1.00, Cr ≤0.25, Ni≤0.30, Cu≤0.25.

Chemical composition of 40Cr steel plate: C 0.37-0.44, Si 0.17-0.37, Mn 0.50-0.80, Cr 0.80-1.10.

2. Comparison of mechanical properties between 45Mn steel plate and 40Cr steel plate:
Mechanical properties of 45Mn steel plate: Tensile strength: 620 MPa, Yield strength: 375 MPa, Elongation after fracture: 15%, Reduction of area: 40%, Impact absorption energy: 39J.

40Cr steel plate mechanical properties: tensile strength: 980 MPa, yield strength: 785 MPa, elongation after fracture: 9%, reduction of area: 45%, impact absorption energy: 47J.