Property Classes and Grades

12 property classes, each with tensile strength, yield strength, hardness and the matching nut class defined by the relevant ISO standard.

Carbon Steel

5 classes

Class	Standard	Tensile Rm	Yield Rp0.2	Hardness	Nut class
Property Class 4.8	ISO 898-1	420 MPa	340 MPa	HRB 67–95	4
Property Class 5.8	ISO 898-1	520 MPa	420 MPa	HRB 82–95	5
Property Class 8.8	ISO 898-1	800 MPa	640 MPa	HRC 22–32	8
SAE J429 Grade 2	SAE J429	414 MPa	393 MPa	HRB 70–100	—
SAE J429 Grade 5	SAE J429	828 MPa	634 MPa	HRC 25–34	—

Alloy Steel

3 classes

Class	Standard	Tensile Rm	Yield Rp0.2	Hardness	Nut class
Property Class 10.9	ISO 898-1	1040 MPa	940 MPa	HRC 32–39	10
Property Class 12.9	ISO 898-1	1220 MPa	1100 MPa	HRC 39–44	12
SAE J429 Grade 8	SAE J429	1034 MPa	896 MPa	HRC 33–40	—

Stainless Steel A2 (304)

2 classes

Class	Standard	Tensile Rm	Yield Rp0.2	Hardness	Nut class
A2-70 Stainless	ISO 3506	700 MPa	450 MPa	—	A2-70
A2-80 Stainless	ISO 3506	800 MPa	600 MPa	—	A2-80

Stainless Steel A4 (316)

2 classes

Class	Standard	Tensile Rm	Yield Rp0.2	Hardness	Nut class
A4-70 Stainless (316)	ISO 3506	700 MPa	450 MPa	—	A4-70
A4-80 Stainless (316)	ISO 3506	800 MPa	600 MPa	—	A4-80