| 摘要 |
PURPOSE:To increase the rate of hydride depositing in the circumferential direction of a pipe, and to obtain a high quality zirconium alloy coated pipe free from defects in its internal surface, by defining and introducing processing parameters, and performing a pilger rolling under the conditions satisfying the equation of rolling conditions. CONSTITUTION:A pipe 5 is rolled out by feedig a base pipe 3 into a gap between roll dies 1, 2 rotating a fixed amount while rotating the pipe 3 by a fixed angle. At that time, a processing parameter QTepsilon is defined and introduced, which is capable of being quantitatively related to both of the direction of hydride of the pipe 5 and the amounts of elastic recovery of both of the pipe 5 and a mandrel 4. Then a zirconium alloy pipe is rolled under the condition which satisfies the equation (t; the wall thickness of the rolled pipe, D1; the outer diam. of the pipe 3, d; the mean diam. of the rolled pipe, t1; the wall thickness of a pipe, T'; the wall thickness of the pipe 3 at the position where the processing of wall thickness is commenced on the way of rolling, D', the mean diam. of the pipe 3 at the position where the processing of wall thickness is commenced on the way of rolling). |
