Grade 8 bolts are made of alloy steel and have a tensile strength of at least 150,000 PSI.

Grade 5: Identified by three radial lines, these bolts have a tensile strength of up to 120,000 PSI. Grade 8: These are high-strength bolts marked with six radial lines and have a tensile strength of up to 150,000 PSI.

Shear strength is typically 60% of tensile strength, and the minimum tensile strength of a grade 8 bolt is 150,000 psi.