Evaluation of Internal Stress and Dislocation Velocity in Creep with 25Cr-20Ni Stainless Steels

25Cr-20Ni계 스테인리스강의 크리프 변형중 내부응력과 운동전위밀도의 평가

By the purpose to investigate the change of internal stress and mobile dislocation density in creep, the stress relaxation test is carried out in the condition of each strain. Mobile dislocation density increased until it reached minimum creep rate and after that, it decreased and internal stress didn't have the change approximately until it reached minimum creep rate and after that, it decreased. The stress relaxation rate is fast and approached zero after 1.5 seconds after the beginning of the stress relaxation. And the larger the applied stress is, the larger the internal stress is. By the evaluation of mobility of dislocation, the dislocations glide viscously in STS31OJlTB but it is the dislocations glide viscously which N passes by cutting Cr atom rather than typical viscosity movement after calculating mobility of dislocation.