GRADE 8 HEX CAP SCREWS BOLTS YELLOW ZINC PLATED
Hex Cap Screws Grade 8 Course Thread yellow zinc yz are sometimes also called hex bolts are considered hardened bolts that are stronger than medium-strength steel screws and they have markings on the top of the head with six 6 radial lines 60 degrees apart. Grade 8 steel hex head cap screws are SAE J429 specifications and have a tensile strength of 150,000 psi and a proof load strength of 120,000 psi and a "Rockwell Hardness" C33 to C39 according to the manufacturer.