... according to clients' specifications and drawings under guaranteed by quality control system of third part Approval of Manufacturer Certificate. ... Hastelloy, etc.), stainless steel ( duplex stainless, UNS31803, SAF2205, SAF2507, etc. ), high stainless ( UNS31254, 317L, 904L, etc. ), common stainless ( 304, 304L, ... drawings of the clients. Pressured Vessel, Boiler Pressure Component & Heat Exchanger