... Black steel hex screw Process:Mahined and turned Surface:BO SGS audited More than 20 years experience in special fastener 1,Name:Black steel ... hex screw;black hex screw;steel hex screw 2,For the similar ... ,12.9,etcCarbon steelGr.B,Gr.C,Gr.D,Gr.36,Gr.58,1010,1015,1016,1020, ... hardware fastener ,especially the cutting/turning parts. Black steel hex screw