... production procedure: raw elements(C,Fe,Ni,Mn,Cr,Cu etc.,)--smelted ingots by AOD finery--hot rolled into black surface ... pieces--checking quality--package4.surface:black,pickling,polish,milling,peeled, etc.,5.common sizes we have large stocks,diameter from 1mm ... used in chemical, shipping,architecture,machine-made ,household products industry etc.7.samples are available,pls feel free to contact with ...