Development of Local Diameter-Enlarged Processing Method by High-Frequency Induction-Heating Method
In the present work, a new local hot working method is proposed to achieve a higher diameter- enlargement ratio and higher processing efficiency than those that can be obtained by cold working. Further, a high-frequency induction-heating device is built; this device is installed in a diameter-enlargement processing machine developed originally. A local diameter- enlargement part was formed by processing after being heated locally by the heating device, and its diameter- enlargement deformation behavior and its surface temperature were investigated experimentally. The diameter-enlargement ratio achieved with the proposed method was twice the diameter-enlargement ratio that can be achieved by cold working, with local heating for 120 s. This hot working method was effective for the diameter-enlargement forming process. The diameter- enlargement deformation behavior can be predicted approximately by a cycle parameter considering the effect of blue shortness.
