API 674 GB/T 9234-2008 Combined valves,conical valve.plate valve. Low pressure accumulator,high ... treatment is applied to attain strong strength, high hardness, durable and corrosion resistant feature.Plunger (material used: superior ceramic, Colmonoy ... valve, plate valve, ARN valve ,spherical valve and combined valves.They are wear resistant and anti-corrosive after special treatment.All series of ...