Hex Socket bolt also called hex socket cap screw. Its a bolt with a column-shape head (socket head) and internal hex drive. The most widely used are DIN 912 / ISO 4762 hex socket cap screw and ANSI B 18.3 socket head cap screws. There are more types of hex socket drive bolts and screws, for example pan head, button head, flat head and countersunk head. Metric series carbon steel hex socket drive bolts and screws generally supplied in class 8.8, class 10.9 and class 12.9 as per DIN and ISO standard, while inch series always in Grade 5 and Grade 8 as per SAE standard. Stainless steel socket drive screws normally in A2-70 and A4-80 (AISI 304 and AISI 316). The regular surface treatment for steel hex socket bolts are black oxide, zinc coating, and dacromate or wax coating.
