Seamless steel tubes in large calibers for high(low and medium) pressure boilers and petrochemical industry Standards：Seamless steel tube GB3087 Chinese national standard GB5310 Chinese national standard ASME SA106 Boiler and pressure vessel code of ASME ASME SA333 Boiler and pressure vessel code of ASME ASME SA335 Boiler and pressure vessel code of ASME DIN17175 Deutsches industrial standard EN10216-2 European standard for pressure pipes Application： For boilers and pressure vessels of medium and low pressures(normally,the cintainer and steam pipelines With the operating pressure not higher than 5.88Mpa，operating temperature below 450℃);for high-pressure boilers(normally，the cintainers，steam pipelines and petrochemical pipelines with the operating pressure not higher than 9.8Mpa．Operating temperature between 450℃~650℃)． Model No.of major steel tubes： 10,20,20G,20MnG,25MnG,15CrMoG,12Cr2MoG,12Cr1MoVG,10Cr9Mo1VNb,SA106B,SA106C,SA333 grade I,SA333 gradeⅥ,SA335 Ps,SA335 P11,SA335 P12,SA335P22,SA335 Pm91,SA335 P92，ST45.8/Ⅲ，15Mo3，13CrMo44,10CrMo910,15NiCuMoNb5-6-4．Etc．