鹽浴燒入に關する研究
スポンサーリンク
概要
- 論文の詳細を見る
The heat treatment, which consists of quenching steel from a temperature well over the critical into a salt bath at a temperature between 180 and 400℃ and holding it there until it is completely transformed, has aroused considerable interest, because the steel subjected to such heat treatment has a better toughness at a high hardness than that found in the same steel quenched into oil and tempered to the same hardness. The data so far published by E. C. Bain and E. S Davenport have referred only to p'ain carbon steel. The author investigated the effects of various alloy elements, bath temperature and holding time in a salt bath on the effectiveness of this heat treatment. Steels selected for this investigation are carbon steels and alloy steels with contents as shown in the following table. C steel C 0.5∿1.3% Cr steel C 0.7%, Cr 1.0∿3.0% Ni steel C 0.7%, Ni 1.0∿3.0% Ni-Cr steel C 0.3∿0.7%, Ni 3.0%, Cr 0.5% Ni-Cr-Mo steel C 0.3∿0.7%, Ni 3.0%, Cr 0.5%, Mo 0.5% The results of the investigation are outlined bellow : - (1) This treatment is very effective for C steels of about 0.7∿0.9% C, Cr steels of about 0.7%C, Ni-Cr steels and Ni-Cr-Mo steels of 0.3% C. It is not however, effective for Ni steels of about 0.7%C, Ni-Cr steels and Ni-Cr-Mo steels of about 0.7%C. (2) The holding time in the salt both and it's temperature are carrelative, and it is desirable to hold them in salt bath until the austenite is completely transformed. (3) In their discussion of the superior toughness of salt-bath-quenched plain carbon steel when compared with oil-quenched samples tempered to the same hardness, Davenport and Bain refer to the presence of micro-cracks in the oil quenched pieces as the probable cause of their inferior toughness. According to the author's experiments, however, no crack is found in the oil quenched pieces of these alloy steels. The author believes that the superior toughness of the salt-bath-quenched samples is due to the micro-structure which is different from that of steel quenched into oil, and also to the lower stress of transformation.
- 社団法人日本鉄鋼協会の論文
- 1939-12-25