Carbon Steel Pipe with High Quality 1.WT:4-70mm OD:25-370mm 2.Certification:API ... X52,X60 API-for petroleum,natural gas, industrial dilivery(gas,water,oil)60-630×1.53-40 Rectangular TubeQ195,Q235,Q345 ... /2003- Public works, mining, textile, electric power, boilers, drinking water, machinery, military industryDN80-1500-square pipeQ195,Q235,Q345,20#GB ... GR.B/A106 GR.B Carbon Steel Pipe with High Quality