METHOD TO PROTECT SURFACE OF TURBINE BLADE CASTS AT THERMAL TREATMENT Russian patent published in 2015 - IPC B22F3/15 C23C14/00 C23F17/00 

FIELD: machine building.

SUBSTANCE: method involves application of protective coating onto the surface of blade casts and their further hot isostatic pressing (HIP). Prior to protective coating application, the surface of blade casts is covered with at least one layer of ceramics based on refractory oxides 0.1-2.0 mm thick with melting temperature being by at least 50°C higher than the liquidus temperature of blade cast alloy. Heat-resistant metal coating with layer thickness of 15-200 mcm is used as the protective coating. The protective coating can be made from the material chosen from the group including heat-resistant nickel alloy, titanium, chromium. HIP can be carried out before the removal of a ceramic pin forming the inner cavity of the blade casts. Prior to HIP the inner cavity of blade casts can be filled with ceramic powder with melting temperature being by at least 50°C higher than the liquidus temperature of blade cast alloy.

EFFECT: prevention of formation of a changed layer at outer surface of blades which contains precipitations of topologically close-packed phases at heat treatment.

4 cl, 10 dwg, 1 ex