| 摘要 |
PURPOSE:To arrange so that a remaining stress distribution is a plate thickness direction may be measured simply by boring a hole in the plate thickness direction of a metal material where a stress remains and exposing the hole to an environment which causes cracks due to stress corrosion. CONSTITUTION:A hole 2 is bored in the plate thickness direction of a position distant by X1 from a weld line and then is exposed to an environment where stress corrosion occurs (e.g. in the case of 18-8 stainless steel, 42% magnesium chloride solution in boiling condition). In addition, cracks are caused to develop starting at the hole surface. Next, the plate is cut in the plate thickness direction including the axial center of the hole at the surfaces of X direction, Y direction, 45 deg. direction, etc. Following this procedure, after polishing the cut section, it is etched and then the length of a crack 5 is measured by means of a low-magnification microscope. Further the intensity of a remaining stress in the cut direction of the surface is measured by a X-ray method, a gauge method, etc. so that the relationship of this stress value and the afore-mentioned crack 5 length is computed. As a result, it is possible to obtain a stress distribution of a plate in the X direction, Y direction and 45 deg. direction of the hole on stress unit basis. |
