K417G轮盘喷丸表面残余应力激光超声检测

Laser Ultrasonic Measurement of Residual Stress on K417G Disc Peening Surface

激光超声能够实现对部件内部缺陷及其残余应力状态的无损检测功能。设定传感器中心频率为2.5 MHz,利用软件完成数据采集过程并对其实施滤波处理。先对K417G轮盘进行热模锻处理,之后再对其表面实施喷丸,沿长度方向在K417G镍基合金上共设置5个点,控制临近点的距离为1.96 mm,表面波声速为2950 m/s。测试结果表明:x与y方向上都到达了2949 m/s以上的表面波声速,K417G轮盘表面形成了压应力作用。X射线衍射(XRD)与超声检测都显示形成了压应力,具有相同变化趋势。采用XRD方法测试得到的最大径向残余应力为-906 MPa。采用更大测试深度的激光超声方法进行处理时,获得了比XRD测量结果更小的测试参数。研究对了解金属试样喷丸后的表面残余应力分布具有很好的实际价值,有助于后续机加工工艺的精选。

Laser ultrasound can realize the function of nondestructive testing of internal defects and residual stress state of components.The center frequency of the sensor was set as 2.5 MHz,and the software was used to complete the data acquisition process and implement filtering processing.The K417 G disc was first treated by hot die forging,and then shot peening was carried out on its surface.A total of 5 points were set on the K417 G nickel-based alloy along the length direction.The distance of the adjacent points was controlled as 1.96 mm,and the surface wave velocity was 2950 m/s.Test results show that the surface wave velocity above 2949 m/s is reached in both x and y directions,and the compression stress is formed on the surface of K417 G disc.Both XRD and ultrasonic examination showed that compressive stress was formed,with the same variation trend.The maximum radial residual stress measured by XRD method is-906 MPa.The laser ultrasonic method with larger test depth can obtain smaller test parameters than the XRD measurement results.This study is of great practical value to understand the surface residual stress distribution of metal samples after shot peening,which is helpful for the subsequent machining process selection.