Mechanical Properties of CR3 Steel: The mechanical properties of CR3 Steels are analogous to SPCE steels, but unlike the JIS G3141 standard, the ISO 3574 standard does not classify the least tensile strength but it ascertains the maximum range. The maximum yield strength is 220 MPa, the tensile strength is 350 MPa and minimum elongation is 35 percent. The hardness is 50 HRB maximum.