... elongation 5.good mechanical property black steel pipe 1)Application: conveyance of gas, petroleum, liquid, and electricity;2)We ... 5-10mmB: Surface finish: black, blank, bright and galvanizedC: Length of each pipe: 500mm-13,000mmD: Steel grade: st35 ... B etc.E: Conforms to international standards, like:Astm A106,179,192,199,200,210,213,333, ... etcAPI,GB black steel pipe for normal and mechanical sturcture