... U.S.A. materials are 301, 302, 304, 304L.Main executive standards are as follows: Stainless steel seamless pipes GB5310 ... -95 for high-pressure boiler, stainless steel seamless pipes GB64792000 for high-pressure fertilizer ... and heat exchanger, stainless steel seamless pipes GB/Tl4976-02 for liquids, stainless steel seamless pipes GB/T14975-02, ASTM, A269 ...