| 摘要 |
PURPOSE:To prevent breakage from a tensile force applied part or the vicinity thereof in a tension test, by providing temp. difference such that the temp. of the tensile force applied part of a metal material becomes lower than that of the part to be pulled thereof. CONSTITUTION:Both end parts of a pipe 1 are grasped by chucks 2a while the central part thereof is heated in a heating furnace 3 using a heater 3a and the chuck parts 2a are pulled to apply plastic deformation to the pipe 1. At this time, the end parts of the pipe 1 are lower than the central part thereof in temp. and strength becomes high toward the end parts corresponding to a temp. gradient. Therefore, no breakage is generated at the chuck parts 2 and the vicinities thereof and uniform pulling can be performed and dimensional correction such as the removal of bending, the adjustment of a wall thickness and the reduction in residual stress are enabled. |
