... F436 4.Material:Carbon steel Specification of our washer: 1.NameNon-standard flat washer with small holes 2.StandardDIN, IFI, ISO, ... Zinc plated,Passivated, Nickle plated, H.D.G., Black Oxided, Dacromet,Geomet,etc7.Production TechniqueStamping, Machining,etc8.Production ... Zinc plated,Passivated, Nickle plated, H.D.G., Black Oxided, Dacromet,Geomet,etc6.Production TechniqueStamping, Machining,etc7. ...