Abstract: The precipitation hardening ferrous alloy (14Crl8Nil2Si4Mo4WVNb) for hard facing the sealing surfaces of high temperature and high pressure valves is described.This alloy is a kind of Cr-Ni type stainless steel strengthened properly with a selection of chemical elements.It has proved to have excellent properties, particularly in ageing strengthening, crack resistance and machinability.This alloy is in many respects superior to cobalt base alloy and has been used for surfacing valves for power stations working at 540℃,100kg/cm².After many years in operation the surfaced layers have been found to be satisfactory,so this newly developed surfacing electrode 547Mo has widly been used to produce the valves for power stations.