... .WT: customized 4.Certification:ASTM, API 5.Length is customized Steel grades: GB6479 10, 20, 16Mn, 15MnV, 12CrMo, 15CrMo, ... exchangers, condensers and similar heat transfer apparatusnspection/test: chemical composition, mechanical properties (tensile strength, yield strength, elongation, flaring, flattening, hardness, ... hydrostatic testHS Code: 7304900000high quality and service Seamless Steel Tube