As a key hot-end component, high-pressure turbine blades are a decisive factor limiting the minimum life cycle of modern high-performance engines. During use, they are scrapped due to tip fretting wear and fatigue cracks. Burning damage often occurs on the intake edge of high-vortex blades. Conventional arc welding methods have large heat-affected zones and uncontrollable deformation, making it impossible to repair the blade tip. Blade tip wear and fatigue cracks can be accurately repaired using laser cladding additive manufacturing technology.

Artifact introduction

High-pressure turbine blades, as key hot-end components, are the decisive constraints on the minimum life cycle of modern high-performance engines. During use, the blade tip is scrapped due to fretting wear and fatigue cracks, and the intake edge of the high-vortex blade often also suffers from burning. Conventional arc welding methods have large heat-affected zones and uncontrollable deformation, making it impossible to repair the blade tip. Blade tip wear and fatigue cracks can be accurately repaired using laser additive manufacturing technology. At present, in China, there is still a lack of systematic basic research on the repairability assessment of damaged hot-end components of aero-engines, the selection and research of repair process methods, and the assessment of the use reliability of components after repair. There is no complete, reliable, and operable system. According to the repair technical standards, the key hot-end components that were damaged in the large civil aviation passenger aircraft engine were completely sent abroad for repair.

Skills requirement

1. Repair of high-pressure turbine blades

High-pressure turbine blades are prone to cracks due to the easy formation of low-melting-point eutectic phases during repair. The thickness of the blade is uneven, the heat accumulation state and temperature gradient of different parts are greatly different, and the process window is narrow, requiring precise energy density control to achieve good molding effects. A certain brand of high-pressure turbine working blades can achieve the following technical effects:

• The thinnest part of the leaf tip reaches 0.3mm;
• “Zero” deformation;
• The structure is dense, without defects such as microcracks and pores;
• The depth of the heat-affected zone is not greater than 200μm
• The performance of additive materials is better than that of the blade matrix, and its performance reaches or even exceeds that of the original parts;

2. Burning damage of cast alloy high vortex blades

Nickel-based superalloys are widely used in the manufacture of turbine blades and guide vanes for aero-engines due to their good high-temperature strength and corrosion resistance and their long-term use in engine operating environments below 1000°C. During the long-term use of aero-engines, turbine blades are subject to wear, impact, high-temperature gas, and thermal and cold fatigue, which may cause damage such as cracks, wear, and corrosion, leading to the scrapping of a large number of blades.

The air inlet edge and blade tip have a full appearance after laser cladding additive manufacturing. There are no macro cracks, no micro cracks and other defects, and the blade deformation is controllable.