... M3-M22 Standard NO.: DIN933,DIN931,DIN934 Material:: Carbon steel,stainless steel Grade: 4.8-12.9 Finish: zinc,black,chrome,nickel ... of bolts, it has the outer thread's main function is to cooperate with the nuts. Using this thread ... parts fucked. • Applications:main service in the petrochemical industry, food machinery, construction decoration, solar energy industry, water treatment equipment ...