... finish 4.ideal percentage elongation 5.good mechanical property schedule 20 steel pipe1)Suitable for conveyance of gas, petroleum, liquid, and ... ,st37,st37.4,st45,st52,SAE,grade A,B etc.E: Conforms to international standards, like:Astm A106,179,192,199 ... .For all details, please never hesitate to contact us. schedule 20 steel pipe