... competitive price, high and stable quality. Product Name Seamless Steel Tubes for Boiler, Pressure Vessel & Heat Exchanger American Standard ASTM ... 5310,GB 6479,GB 9948,GB 18248,GB/T 18984 Grade 10,20,20G,16Mn,37Mn,12CrMo,12Cr1MoV, ... British standard BS 3059-1,BS 3059-2, Grade 320,360,440,243 Japan Standard JIS G3454, ... JIS G3461,JIS G3462 Grade STP G370,STP G410,STB 340,STB 410 ...