普通炭素鋼の焼入組織に関する研究(第5報) : 低炭素マルテンサイトの生成条件について

概要

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It was generally believed that the mechanical properties of carbon steel were remarkably changed by heat treatment. But, generally speaking, in the case that the carbon content was below 0.2% it was difficult to expect the effect of heat treatment. In this paper, the present investigators, therefore, made a study of the effect of the quenching temperature and coolant on formatitive condition of low carbon martensite in the mild steel with carbon 0.07% preceded by normalizing at appropriate temperature through means of hardness, impact and metallography test. A summary of the results is shown below : (1) Except for spindle oil, in order to produce the maximum quench hardening effect it is necessary to quench after keeping 10 minutes about 900℃, and it is unconcerned in coolant. (2) 10% NaCl solution is best for coolant. (3) Factors affected on Charpy's impact value on the quenched mild steel are not hardness but its structure and austenite grain size.
山口大学の論文