Investigation of residual stress within linear friction welded steel sheets by alternating pressure via X-ray diffraction and contour method approaches

Abstract

This paper presents a thorough investigation of the influence of the applied pressure on the behavior and distribution of residual stress (RS) within linear friction welded medium carbon steel sheets. The RS in the longitudinal and transverse directions was determined using the X-ray diffraction (XRD) technique. The contour method (CM) was also used to provide 2D maps of RS normal to the cut surface. The RS results determined by the CM were verified with those obtained by the XRD. Both measurement techniques were able to discern the influence of the applied pressure on the behavior of the induced RS. It was noticed that a large change in the applied pressures led to a pronounced variation in RS behavior. With the increase of the applied pressure, the tensile RS gradient near the weld line was decreased. Further, the compressive RS induced in the vicinity of the weld line was decreased, and its behavior was flattened with the increase of the applied pressure. The influence of the applied pressure on the trend of the full-width at half-maximum (FWHM) of the XRD peak and the microhardness distribution was also examined. A remarkable increase was noticed in the FWHM and microhardness at the weld line with the increase of the applied pressure. The behavior of the microhardness at the weld line demonstrated the role of the FWHM as an index of the material hardening.