Abstract
The residual stress in a large steel casting (1000×1000×400mm) was measured by means of the photographic X-ray method developed in our laboratory. Since the grain size of the steel casting is large, the obtained diffraction lines on the films were spotty and the spots scattered in the radial direction. The peak positions of the diffraction lines was determined by averaging the distance between each diffracted spot and line of the standard substance arithmetically.
The mean value of the residual stress for the specimen annealed at 940°C for 16 hours was 7.6kg/mm2 in tension on the surface of the feeder head side and 10.5kg/mm2 in tension on the surface of the bottom side. The specimen was then cut 15mm in depth from the surface of the feeder head side. The mean residual stress on the newly appeared surface was 3.2kg/mm2 in compression and it was 7.1kg/mm2 in tension on the opposite side. When the specimen was annealed at 650°C for 8 hours, the residual stresses on both surface became almost zero. The distribution of the residual stress in the sample were discussed.
