Bolt with washer
Washer head screws are manufactured from low-carbon steel Grade 4.6 to alloy steel Grade 10.9. Standard thread diameters range from M4 to M24 with coarse pitch per ISO 4017. Their tensile strength varies between 400 and 1040 MPa. The integrated flat washer is typically made from hardened steel with a hardness of 300 to 400 Vickers. The washers outer diameter is designed to be 1.7 to 2.5 times the screws nominal diameter. Washer thickness is approximately 0.15 to 0.3 times the screw diameter. Common coatings include hot-dip galvanizing with a thickness of 45 to 80 microns. This coating provides corrosion resistance for up to 1000 hours in salt spray tests. The final tightening torque for Grade 8.8 ranges from 10 to 600 Newton-meters.
The screw structure consists of a hexagonal head, a fixed washer, and a threaded shank. The head height is typically 0.6 to 0.8 times its nominal diameter. The integrated washer reduces surface pressure by up to 40% by creating a larger contact area. This design prevents head sinking into soft materials. The standard operating temperature range is -50 to +150°C. Production tolerance for thread diameter follows accuracy grade 6g. The washer often features a diamond knurl texture with a depth of 0.05 mm to increase friction. These screws can withsta
