Repair method for turbine blade sawtooth crown abrasion failure

Abstract

The invention discloses a repair method for a turbine blade sawtooth crown abrasion failure and aims at providing a method which can effectively improve the abrasion resistance of turbine blade sawtooth crowns, is good in alloy powder matching property and can repair a turbine blade sawtooth crown abrasion failure in a near-net forming mode. According to the following technical scheme, the repair method can be achieved by comprising the steps that size repairing is conducted on sawtooth crown working surfaces through laser stereo-forming fusion-covering anti-abrasion alloy powder, the laser powder is 500 W, the spot size is phi 1.2-phi 1.3 mm, the scanning speed is 5-6 mm / s, the powder feeding rate is 11-12 g / min, and three anti-abrasion alloy layers are subjected to fusion covering in an accumulative mode; and after near-net forming repairing is achieved, heat preservation is conducted for 30 min at the temperature of 950 DEG C+ / -10 DEG C, and vacuum destressing heat treatment is conducted. A sawtooth crown anti-abrasion layer repaired through the repair method is very excellent in anti-shearing strength, hardness and fretting resistance, good in matching property with a base body material and high in cold-heat fatigue resistance, is subjected to repeated cold and heat cycles and is free of cracks, block falling and other failures, and the requirement for an overhaul period of an engine is met.

Description

technical field [0001] The invention relates to the field of maintenance of aero-engine parts, in particular to a repair method for laser cladding wear-resistant alloy powder on the wear surface of the serrated crown of the second-stage turbine working blade whose material is ЖС6У. Background technique [0002] The rotor blades of the second-stage turbines of aero-engines are porous air-cooled crowned blades made of high-temperature alloy precision casting. The tail is made with a sawtooth crown structure, which absorbs vibrations and prolongs the working life of the turbine blades. Due to the aerodynamic bending moment acting on the turbine working blades during operation, the fretting wear of the sawtooth crown structure in long-term service gradually reduces the vibration damping effect and increases the risk of blade fatigue fracture. When the engine is returned to the factory for overhaul, in order to reduce the cost of replacing the new turbine blades, it is necessary...

AI Technical Summary

Problems solved by technology

Practice has found that the disadvantage of this method is that the full cathode arc can only heat the surface of the "sandwich", and the melting of the solder sheet in the center of the "sandwich" completely depends on heat conduction, the controllability is poor, and surface overburning often occurs. However, the phenomenon that the thin sheet of brazing material in the center part is still not melted causes the surface of the blade crown to partially collapse and the brazing material in the center part is not melted and not fully brazed, and the brazing quality is unstable and the qualified rate is low.

[0004] In the prior art, in order to improve the wear resistance of the blade crown of the turbine blade, a method of overlaying CoCrW / CoCrMo alloy by argon arc welding is disclosed for K403 and K417 alloy blades, and a method of laser cladding CoCrW alloy powder is disclosed for DZ125 alloy blades. The above methods exist The disadvantage is that the CoCrW / CoCrMo wear-resistant layer of surfacing (or cladding) has a large difference in thermal expansion coefficient from the blade base material, and the cold and heat fatigue resistance is poor. Cracks and blocks are prone to appear in the cycle