著者

長島 伸夫 早川 正夫 長井 寿 升田 博之 中西 栄三郎 中西 宣文 岩崎 勝

出版者

公益社団法人 自動車技術会

雑誌

自動車技術会論文集 (ISSN:02878321)

巻号頁・発行日

vol.53, no.4, pp.815-820, 2022 (Released:2022-07-25)

参考文献数

13

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老廃スクラップから創製した1180MPa級リサイクル鋼板について引張試験ならびに穴広げ試験を実施し,さらに部品要求性能として重要な疲労強度特性を把握するため荷重方式の異なる疲労試験を実施した.これらの結果から,スクラップから創製したリサイクル鋼板の自動車用鋼板としての適応性について検討する.

著者

長島 伸夫 早川 正夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集A編 (ISSN:18848338)

巻号頁・発行日

vol.79, no.797, pp.23-33, 2013 (Released:2013-01-25)

参考文献数

24

被引用文献数

3 2

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Micro-hardness distribution was measured by using an ultra-micro hardness test at a crack tip under a plane strain condition for a crack propagation test specimen made of a low-carbon austenite stainless steel JIS-SUS316L. Moreover, crystal orientations were analyzed by EBSD for individual crystal grains in the plastic strained area at the crack tip. The conclusions can be summarized as follows. (1) The mean strain in a 500-μm region around the crack tip was supposed with 3% from the hardness distribution in an ultra-micro hardness test. Therefore, the plasticity strain distribution of the crack tip under a plane strain condition can be visualized based on the ultra-micro hardness and an experience equation of the true strain by measuring the hardness distribution. (2) When the analysis by EBSD increased the step size of the KAM map, the local misorientation increased. On the other hand, the color map of some grain boundary neighborhoods reversed when the step size changed in a GROD map. Therefore, an analysis of KAM is suitable for the local transformation of the crack tip neighborhood. (3) From the results of an EBSD analysis, it became clear that a local heterogeneous transformation occurred in random grain boundaries at the crack tip, and the transformation hardly occurred at the CSL grain boundary of the crack tip.