화학공학소재연구정보센터
Journal of Materials Science, Vol.36, No.17, 4279-4284, 2001
Metadynamic recrystallization of austenitic stainless steel
Interrupted torsion tests were performed in the temperature range of 900-1100 degreesC, strain rate range of 5.0 x 10(-2)-5.0 x 10(0)/sec and interpass time range of 0.5-100 seconds to study the characteristics of metadynamic recrystallization (MDRX) for austenitic stainless steel. To compare the MDRX with static recrystallization (SRX), the pass strain was applied above the critical strain (epsilon (c)) (epsilon (c) = 2.2 x 10(-3) D-o(1/2) Z(0.089), where Z is Zener-Hollomon parameter, Z = (epsilon) over dot exp((380000 J/mol)/RT) and D-0 is as-received grain size) to obtain the MDRX during interpass time. It was found that the kinetics of MDRX were dependent of the strain rate and deformation temperature but were nearly independent of the change in pass strain after the peak strain. The time for 50% metadynamic softening, t(50), was determined as follows: t(5)0 = 1.33 x 10(-11) (epsilon) over dot (-0.41) D-0 exp((230000 J/mol)/RT) and this calculated value was consistent with the measured value. The Zener-Hollomon parameter was impossible to evaluate the MDRX fraction, because the fractional softening values were different at the same Z values. The new parameter (MDRX parameter) considering deformation temperature, strain rate and interpass time was proposed to evaluate the MDRX fraction. The MDRX-parameter was determined as 3.25 x 10(-19) (epsilon) over dot(0.3) t(i)(0.6) T-12.