중탄소강의 경화능에 미치는 응력의 영향 = The Effect of Stress on Hardenability in Medium Carbon Steel

국문 초록 (Abstract)

중 탄소 강에서 경화능 및 입자성장에 미치는 static stress와 dynamic stress의 영향을 조사하였다.
탄소강 봉은 용질 원자의 편석 및 잔류 응력을 제거하기 위해 925℃에서 1hr. 소준되었다. 그 후 0∼3.3% 범위내로 pre-strain을 주었다.
Jominy end-quenching test는 일정한 냉각속도에서 하였으며 경화능은 static stress가 증가함에 따라 증가되었다. 입자 성장지수, ｎ이 static stress와 dynamic stress에서 서로 비교되었다. 거기서 ｎ값은 dynamic stress에서가 static stress에서 보다 훨씬 더 컸다.

다국어 초록 (Multilingual Abstract)

The effects of static stress and dynamic stress on hardenabilty and grain growth in medium carbon steel were investigated.
Carbon steel bars were normalized at 925℃-1hr in order to eliminate the segregation of solute atoms and to relieve the residual stress, and then pre-strained in the range of 0 to 3.3%.
Jominy bars were prepared for ø l"×L4". In order to observe pre-structure before quenching, grain growth with time was investigated at 800℃, 850℃, 900℃.
Jominy end-quenching test was undertaken at constant cooling velocity. Hardenability was enhanced with increasing static stress.
Activation energy for grain growth with static stress and dynamic stress was investigated.
Austenite grain growth was much more accelerated with increasing static stress and dynamic stress.
Grain growth exponent, ｎ was compared with static stress and dynamic stress.
That value under dynamic stress was much more bigger than that under static stress.