| 摘要 |
<p>PURPOSE:To easily improve the residual stress of a cylindrical body by heating the cylindrical body from the outside surface side for a short period to generate the distribution of the temp. difference between the inside and outside surfaces of the cylindrical body in the longitudinal direction thereof and the distribution of the average temp. in the thickness of the cylindrical body in the longitudinal direction thereof. CONSTITUTION:The cylindrical body having the residual tensile stress on the inside surface by welding, etc., is heated for the short period from the outside surface side. The distribution of the temp. difference between the inside and outside surfaces of the cylindrical body in the longitudinal direction thereof and the distribution of the average temp. in the thickness of the cylindrical body in the longitudinal direction thereof are thereby generated. The tensile stress on the inside surface of the cylindrical body occurring in the above-mentioned former distribution and the tensile stress on the inside surface of the cylindrical body occurring in the latter distribution are superposed and the above-mentioned heating is so executed that the tensile stress on the inside surface of the cylindrical body, i.e., the sum thereof exceeds the yield point in the range of the above-mentioned residual stress to be improved. The heating is thereafter stopped and the above-mentioned residual tensile stress is modified to the extremely small residual tensile stress or residual compressive stress, by which the residual stress of the cylindrical body is improved.</p> |
