电子束焊接K418高温合金裂纹的影响及组织与性能研究

Effect of Cracks in Electron Beam Welding of K418 Superalloy and Its Microstructure and Properties

目的探究工艺参数对K418高温合金焊接裂纹的影响,减少焊接过程中裂纹的产生。方法采用真空电子束对2mm的薄板K418高温合金进行焊接试验,通过改变工艺参数来调控焊接裂纹,使用光学显微镜对焊缝显微组织进行观察,使用显微硬度计对试样进行硬度测量,万能拉伸计对接头进行拉伸试验,使用扫描电镜对断口进行观察。结果在焊接束流为24 mA,焊接速度为600 mm/min时,扫描波形为O形,频率为500 Hz时,焊接接头表面未发现裂纹。通过拉伸试验发现断裂位置为母材,其断口为典型脆性解离断裂。结论采用合适的工艺参数可以减少或消除焊接接头表面裂纹的形成。

The paper aims to study the effect of process parameters on weld crack of K418 superalloy and reduce the formation of cracks during welding.The welding of 2 mm thin plate K418 superalloy was carried out by vacuum electron beam.The welding crack was controlled by changing the process parameters.The microstructure of the weld was observed with optical and scanning electron microscopy.The hardness of the sample was measured with microhardness tester.The tensile test was carried out on the joint with universal tensile tester.The fracture was observed with scanning electron microscope.The results showed that when the welding beam current was 24 mA and the welding speed was 600 mm/min,the scanning waveform was O-shaped.When the frequency was 500 Hz,no crack was found on the surface of the welding joint.Through the tensile test,the fracture position was found to be the base material,and the fracture was a typical brittle dissociation fracture.The formation of surface cracks in the welding joint can be reduced or eliminated under suitable process parameters.