carbon-steelSAE J429
SAE J429 Grade 5
Medium carbon steel, quenched and tempered. Head marked with 3 radial lines.
Tensile Rm828 MPa
Yield Rp0.2634 MPa
HardnessHRC 25–34
Nut class—
Mechanical properties
- Property class
- SAE J429 Grade 5
- Defined in
- SAE J429
- Tensile strength Rm (min)
- 828 MPa
- Yield strength Rp0.2 (min)
- 634 MPa
- Hardness
- HRC 25–34
- Matching nut class
- —
- Material
- Carbon Steel
Where this grade is used
Property classes are stamped on the head of bolts and screws above 5 mm diameter. A SAE J429 Grade 5 fastener is specified where the joint needs a proof load of roughly 571 MPa or less. Always match the bolt class with a nut of class — or higher so the bolt fails before the thread strips.