低炭素鋼の焼鈍脆性に關する研究
1951 年 37 巻 11 号 p. 570-578
詳細
1951 年 37 巻 11 号 p. 570-578
In case of annealing low carbon steel, sometimes an "anneal-brittleness", (named by the author) occurs accompanied by its softening and a remarkable decrease in impact value. This report treats of the results of inspection on the cause of developing "anneal-brittleness" and its prevention. Some of chief conclusions are as follows:
1. Anneal-brittleness occurs remarkably in low carbon rimmed steel, while it seldom occurs in killed steel.
2. Anneal-brittleness occurs, because ferrite grains become coarse and cementite separates out around the boundaries of ferrite grains when low carbon steel is cooled slowly from high temperature.
3. Anneal brittleness increases remarkably with decrease of the C content and with increase of the N, O or P content.,
4. From the viewpoint of quality, killed steel should be used instead of rimmed steel if anneal brittleness is undesirable. In case of rimmed steel anneal-brittleness can be avoided by such normalizing in which aircooling rate is high.
