1.Specification Of Seamless Carbon Steel NBK Tube Seamless Carbon Steel PipeStandardANSI,ASTM A192/A179/A106/A53/A500,ASME SA192/SA179/SA106/SA53/SA500 ,API.DIN,GB.JISMaterialA106 Gr A,B,A53 Gr B,ASTM A179,A315B,A335 P11,A335 P22,A335 P5OD1/4"-40",13mm-1000mmWTSCH5,SCH10,SCH20,SCH40,SCH60,SCH80,SCH100,SCH120,SCH160,XXSUsageStructure..