We recently deliveried some pcs Duplex stainless steel ASTM A890 4A swing check valves to a client, they are 8" 1500LB, high pressure, use bolted bonnet design.  the Duplex stainless steel valve have very good anti corrosion performance,  it is used for heat exchanger, cold shower and device of seawater resistant and high temperature resistant concentrated nitric acid in oil refining, chemical fertilizer, paper making, petroleum and chemical industry.   Duplex stainless steel valve have 2205 valve, 2507 valve, ASTM A890 4A valve, ASTM A890 5A valve, ASTM A182 F51 valve, ASTM A182 F53 valve.