... : 6~12m. 5. Certificate:ISO90001:2000,API. MaterialCarbon steel ,alloy steel ,stainless steel SizeSeamless steel DN15~DN600 , OD:21.3~609.6MMButt-welding DN15 ... ~DN1200 ,OD:21.3~1219.2MMGalvanized or Erw steel OD:114~1440mm.W.T1-60mm /SCH10~SCH160, STD, XS ... , drill,hydraulic, oil structure , boiler, heat exchanger, super heater TechnicsCold rolled Cold DrawnEFW Hot rolled ExtrudedERW