低い加工力と高い生産性を持つ孔型圧延を用いた結晶粒超微細化を目的とした実用的強加工法の開発

摘要

各種産業分野において，機器や装置の高性能化に伴い軽量で強風　靭性，耐食性に優れた材料の開発が求められている．また，資源制約のある合金元素の依存度を極力低減し，希少資源の代替化?節約を図ることも求められている．%The ultra-refinement of grain size is one of the most promising methods for improving mechanical properties of structural materials. The ultra-refinement of grain size by severe plastic deformation has attracted attention for improving the mechanical properties of metallic materials; however, practical processes for severe plastic deformation have not been developed yet. For industrial application to develop a new process that solving problems of the existing processes for severe plastic deformation is required. We develop four new processes to produce severe plastic deformation with grooved rolling. The first one is to roll Ti bar sequentially through grooved rolls changing the shape of grooves with keeping the area of the grooves. The second one is to repeat rolling by rotating Ti bar by 90 degrees with rolls with rectangular groove. The third one is to twist squared Ti bar by putting it through two grooved rolls that have the same squared shapes of grooves as the bar and grooved rolls set in the twisted state around a rolling axe. The fourth one is to repeat bending Ti bar by rolling with grooved rolls in different diameter. As a result we succeed in the deformation of Ti bars in all four processes.