... .fine finish 4.ideal percentage elongation 5.good mechanical property black steel pipe 1)Application: conveyance of gas, petroleum, liquid, and ... .5-10mmB: Surface finish: black, blank, bright and galvanizedC: Length of each pipe: 500mm-13,000mmD: Steel grade: st35,st35.8,st37 ... 587 etc.DIN2391,DIN2394, DIN17175, EN10210, EN10305 etcAPI,GB black steel pipe for normal and mechanical sturcture