| 摘要 |
<p>PURPOSE:To improve remarkably the residual stress of a stainless steel pipe, etc., by heating locally the outside surface positioned on the outside of the inside surface while cooling water is held interposed on the inside surface of the stainless steel pipe, etc., within the range of the quantity of heat input expressed by the specific equation determined from the thickness of the pipe wall and the average radius of the pipe wall and cooling the same. CONSTITUTION:A heating point.B is set on the outside surface positioned on the outside in the radial direction of the point A to be treated on the inside surface of, for example, the stainless steel pipe P while the cooling water W is interposed on the inside surface thereof always at about 0.3mm/sec. A tungsten electrode S of, for example, a TIG welding machine is thereupon operated and the heating point B is locally heated in the range where the quantity Q of heat input Joule/mm is expressed by the equation in a gaseous Ar atmosphere by the arc heat thereof. The stress of the yield point or above is generated to the pipe wall between the heating point B and the inside surface and thereafter the stainless steel pipe P is cooled. In the equation, T; the thickness of the pipe wall (mm), R; the average radius of the pipe wall (mm).</p> |
