Turbine blade crack welding repair method capable of refining structure

Abstract

The invention discloses a turbine blade crack welding repair method capable of refining a structure, and belongs to the technical field of turbine blade welding repair. The method comprises the following steps of: performing welding processing by adopting a laser-arc hybrid welding method, performing induction heating in the turbine blade welding repair process, controlling an area near a weldingseam to form a temperature gradient, changing the welding solidification process, the temperature field, the thermal stress and the residual stress field distribution, reducing the local high-level residual stress generated after welding, improving the structure and crystallization conditions of the welding seam and a heat affected zone, promoting grain refinement, and controlling structure transformation.

Description

technical field [0001] The invention belongs to the technical field of welding and repairing turbine blades, in particular to a welding repair method for cracks in turbine blades capable of refining the structure. Background technique [0002] The turbine blade is a key component of a heavy-duty gas turbine. The end structure of the blade is an air-cooled cavity structure. The turbine blade is located at the hot end of the gas turbine. The high-temperature gas discharged from the combustion chamber directly acts on the turbine blade, and the blade is subjected to high temperature. The corrosion and oxidation of gas; and due to the frequent start and stop of gas turbine peaking operation and sudden load changes, the blades will also generate high thermal stress. Therefore, the failures of turbine blades are mainly defects such as wear, corrosion, cracks, and missing materials. With the prolongation of service time, the wear becomes more prominent, and the higher the operating...

AI Technical Summary

Problems solved by technology

However, since the gas turbine blade is a nickel-based superalloy with high Al and Ti content, it is highly sensitive to thermal cracks during welding and post-weld heat treatment, and laser repair is a rapid and uneven thermal cycle. During the welding process, highly concentrated instantaneous heat input and rapid cooling after welding, there is a large temperature gradient between the weld seam and the heat-affected zone and the area far away from the weld seam, resulting in a local high level of residual stress after welding, and the weld seam and heat-affected zone microstructure coarsening, even microstructure transformation, and reduced mechanical properties, so effective technical measures must be taken to reduce residual stress and refine the microstructure of welds and heat-affected zones

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