... thread bolt Dia:Min 5mm Surface :BO SGS audited More than 20 years experience in special fastener field 1,Name: Black thread ... bolt;Thread bolt;Black bolt 2,For the similar bolt,what ... 9,etcCarbon steelGr.B,Gr.C,Gr.D,Gr.36,Gr.58,1010,1015,1016,1020,1045,etcAlloy steel4130 ... hardware fastener ,especially the cutting/turning parts. Black thread bolt