High strength screw rod for oil drilling platform black 35CrMo 1.standard:DIN975 2.grade:12.9 3.material:35CrMo 4.black High strength screw rod for oil drilling platform black 35CrMo1.Standards:DIN ,ANSI/ASME,BS,GB,JIS,Non-standard2.Metail:Carbon steel,stainless steel,alloy steel3.class:4.8,8.8,10.9,12.9.etc...4.Surface:plain,zinc plated,black oxide,hot dip galv.etc.5.Size:M2-M686.Packing:in bulk ...