Product instruction:Used in general engineering,non safety critical application.Such as building making,aviation,shipbuilding, ... and screw, it is divided into steel bolt and stainless steel bolt according material. The steel bolt divided into grade 4.8 bolt ... , grade 8.8 bolt. Stainless steel bolt divided into stainless steel SUS201 bolt,SUS304 olt,SUS316 bolt according material ...