| 摘要 |
PCT No. PCT/GB91/01311 Sec. 371 Date Feb. 5, 1993 Sec. 102(e) Date Feb. 5, 1993 PCT Filed Aug. 1, 1991 PCT Pub. No. WO92/05908 PCT Pub. Date Apr. 16, 1992.A method of welding comprises forming an alternating current electric arc between an electrode (32) of a tungsten inert gas welding torch (30) and a metallic substrate (10). The alternating current has a square wave form which is self supporting and does not require intercycle high frequency support. The square wave alternating current has a wave bias ratio equal to or greater than 90% forward current to 10% reverse current. A metal welding rod (38) is supplied into the electric arc for depositing a weld deposit (40) on the metallic substrate (10). The welding method is used to apply a metallic wear resistant coating (40) to an edge surface (20 or 22) on a shroud (18) of a turbine blade (10) and is used to seal a cooling passage of a turbine blade or turbine vane.
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