Using X-Ray Diffraction in Studying on the Influence of Pulse Frequency onto Surface Layer Residual Stress of Cold-Forging Mold Steel SKD11 after CNC Wire Cutting Machining ☆

X-ray diffraction is a nondestructive measurement method, that can accurately determine the residual stress on the surface layer of crystalline material. Residual stress is a significant cause for various damage in the surface layer of cold forging mould steel SKD11, thus have large influence to the mould performance and long life. In the case of finishing fabrication of CNC wire cutting machine, the pulse frequency strongly affects to the residual stress. This research investigate the relation between pulse frequency and the residual stress using X-ray diffraction. The experimental result showed that the optimum pulse frequency should be 180-200 pulses/ms; for the frequency higher than 200 pulses/ms, the residual stress tends to remain constant