@article{oai:uec.repo.nii.ac.jp:00008937, author = {Oba, Wataru and Imaizumi, Yusuke and Kajikawa, Shohei and Kuboki, Takashi}, journal = {Journal of Materials Processing Technology}, month = {Dec}, note = {This paper presents application of two-step forming for improving the forming limit in rotary nosing with a relieved die. Nosing is one method which is used for reducing the diameter of a tube tip. “Two-step nosing” is composed of two stages and different dies are applied for the two stages. The die shapes are determined based on the occurrence tendency of defects in “one-step nosing”, where only one die is used through the whole process. In this research, a series of experiments and numerical analyses of one-step nosing was carried out for investigating the mechanism of the occurrence of defects. As a result, it is revealed that the occurrence of defects was highly relevant with the contact area between the die and tube. Based on the result of one-step nosing, the optimum die shapes were determined for the two stages, and then “two-step nosing” improved the forming limit 9% higher than one-step nosing under the optimum condition. Furthermore, “two-step nosing” was experimentally applied for forming eccentric nosed tubes, and its superiority was verified.}, pages = {350--358}, title = {Two-step forming for improvement of forming limit in rotary nosing with relieved die for fabrication of axisymmetric and eccentric nosed tubes}, volume = {262}, year = {2018} }