結晶粒微細化に及ぼす繰り返し曲げ加工の影響（繰り返し曲げ加工による結晶粒微細化技術の開発）

摘要

As a technology to manufacture fine-grained steel, accumulative bending process after hot rolling was proposed, and multi-bending equipment of laboratory scale were established. The effects of accumulative bending on microstructure and ferrite grain size by changing the thermo-mechanical conditions were investigated. As the results, a microstructure with the grain size of 2.2μm was obtained at specimen surface by accumulative bending after hot rolling in the optimized thermal condition. By the results of FE analysis, it was cleared that equivalent strain was accumulated on not only surface but also center of thickness.%近年，自動車用部材などの軽量化を目標に，鋼板の高強度化に関する研究が盛んである。鋼板を高強度化する手法には，固溶強化，析出強化などもあるが，合金元素削減，リサイクル性などの観点から，結晶粒微細化による高強度化が注目されている。