... 310S,430,430F 3) ISO9001. stainless steel square bar,hot rolled ,polished,various sizes,strict tolerance,high quality ... black surface--pickling into acid liquid--polished by automatically machine--cutting into pieces--checking quality--package4.surface:black, ... *200mm6. application:stainless steel square bar is widely used in chemical, shipping,architecture,machine-made, household products industry ,etc ...