| 摘要 |
PURPOSE:To minimize the working thickness-reduction at the back side of a bending part by lowering the working temperature of the back side of a bending part and elevating the working temperature of the belly side at the time of high frequency bending work. CONSTITUTION:In the bending work of a metallic pipe by high frequency heating, the temperature of the back side of a bending part is regulated to <=1,000 deg.C in case of stainless steel and to <=500 deg.C in case of carbon steel. Further, the temperature of the belly part of the bending part is regulated to >=1,000 deg.C in case of stainless steel and to >=700 deg.C in case of carbon steel. These temperature differences are easily attained by using a high-frequency heating coil having a taper formed by making the coil width at the back side of a bending part wider and the coil width at the belly part narrower. |
