... Steel Tubes for Boiler, Pressure Vessel & Heat ExchangerAmerican Standard ASTM A53,ASTM A106,ASTM A333,ASTM A334,ASTM ... Gr.A,B GRA,B, C; GR1,GR6; GR.A-1,GR.CChinese Standard GB 3087,GB 5310,GB 6479 ... ,37Mn,12CrMo,12Cr1MoV,15CrMo,35CrMo,10MoWVNb, etc.German Standard DIN 1629,DIN 17175Grade St 37.0,St 44 ... ,STB 340,STB 410,STB510,STB A12,STB A22European Standard EN 10216-1, EN 10216-2Grade P235TR1, P235GH, ...