机车内燃机涡轮增压器涡轮盘的激光修复

Laser Repair of Turbine Disc of a Locomotive Internal Combustion Engine Turbocharger

某机车内燃机涡轮增压器运行时发生故障,其涡轮盘(材质为GH2036合金)明显磨损,提出采用激光熔覆技术进行修复。为验证激光修复的可行性,采用横流连续波CO2激光器在GH2036合金基材表面熔覆厚约1mm的Ni基合金,并对原始合金及激光熔覆后合金在室温及模拟涡轮盘服役温度(650℃)条件下的力学性能进行对比测试。激光熔覆后合金的室温冲击韧性从31.5J/cm2提高到48.1J/cm2。冲击韧性的提高使得熔覆后合金在260MPa时的室温疲劳寿命由3.28×105周次增加到4.91×105周次。650℃条件下,激光熔覆对合金的拉伸性能影响不大。激光熔覆后合金的持久寿命略有降低,如320 MPa条件下由68.6h降低到60.5h,350MPa条件下由21.2h降低到20.5h。总之,激光熔覆技术对GH2036合金的综合力学性能影响较小,可用于涡轮盘的修复。

A turbine disc （made of GH2036 alloy） was worn during service. A laser cladding method has been presented to repair the turbine disc. To verify the feasibility of the laser repair technique, laser cladding on GH2036 alloy using Nibased alloy powders by CO2 laser and the test of mechanical properties for the alloy with and without cladding coating at room temperature and 650 ℃ were carried out. The thickness of the cladding coating was about 1 mm. For the cladded alloy, the impact toughness was enhanced from 31.5 to 48.1 J/cm2 and thereby the fatigue life for 260 MPa at room temperature increased from 3.28×105 to 4.91×105. At the temperature of 650 ℃, the laser cladding has slight influence on the tensile property of the alloy. The endurance life of the cladded alloy decreased from 68.6 to 60.5 h at 320 MPa and from 21.2 to 20.5 h at 350 MPa. It was found that the laser cladding method slightly influences the comprehensive mechanical property and can be used to repair the turbine disc.