Tightly metal sealed valve - has nickel-phosphorus coating on one sealing element, which does not tend to cold welding

摘要

The hermetically sealed valve has sealing elements of relatively hard material. At least one of the sealing elements has a coating of an alloy, which does not tend to cold welding pref. a nickel-phosphorous alloy. The alloy is applied or formed without use of electric current. Preferably the coating is applied to the valve seat (5), which has a stellite ring (7), welded into a high-grade steel ring (6). The welding seams may be also covered by the coating, which has a thickness of approx. 20 microns and is subsequently heat hardened.