Black steel hinge pin Surface:BO Process:Machined and turned SGS ... field 1,Name: Black steel hinge pin;Steel hinge pin;Black hinge pin 2,For the similar hinge pin,what can we do ... ?(1), Ability for the material of this kind of hinge pin: Grade3.6,4.6,4.8,5.6,6 ... .8,10.9,12.9,etcCarbon steelGr.B,Gr.C,Gr.D,Gr.36,Gr.58,1010,1015,1016, ... fastener ,especially the cutting/turning parts. Black steel hinge pin