Loading...

The effect of pre-straining at intermediate temperatures on the mechanical behavior of high-bainite dual phase (HBDP) steels

Farnoush, H ; Sharif University of Technology

779 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.msea.2012.02.080
  3. Abstract:
  4. High-bainite dual phase (HBDP) steels with 34. vol.% ferrite were subjected to tensile strains of 1%, 3%, and 5% at intermediate temperatures (150-450. °C). Mechanical behavior of pre-deformed steels was then investigated at room temperature. A maximum value for both yield stress and ultimate tensile strength was observed for pre-deformed steels. A minimum elongation was also found in the same pre-deformed specimens at the range of 250-350. °C. It was found that dynamic strain aging (DSA) plays the major role in mechanical properties of pre-strained HBDP steels. The DSA indicator parameter (DSAP) was introduced to evaluate DSA mechanism. Maxima of DSAP were likewise observed at the range of 250-350. °C. At higher pre-deformation temperatures the role of DSA was retarded and as a result, DSAP decreased. In order to shed more light on this matter, response surface methodology (RSM) was employed for the evaluation of important factors (temperature and pre-strain) on DSA. The results showed the statistically significant effects of first order term of both factors as well as second order term of temperature. However, there was no statistically significant interaction between these two factors. The optimization of these two factors for achieving maximum DSAP revealed that the maximum DSAP is 47.5 under the following conditions: temperature of 312. °C; pre-strain of 5%. Moreover, fatigue tests were conducted on pre-deformed specimens at 312. °C. It was demonstrated that higher pre-deformation would lead to higher fatigue limit
  5. Keywords:
  6. Fatigue ; Intermediate temperature deformation ; Dual phase ; Dual-phase steel ; Dynamic strain aging ; Fatigue Limit ; Fatigue tests ; First order ; Indicator parameters ; Intermediate temperatures ; Maximum values ; Mechanical behavior ; Mechanical characterizations ; Pre-deformation ; Pre-strain ; Response surface methodology ; Room temperature ; Second orders ; Ultimate tensile strength ; Bainite ; Deformation ; Fatigue of materials ; Fatigue testing ; Hardening ; Mechanical engineering ; Strain
  7. Source: Materials Science and Engineering A ; Volume 543 , May , 2012 , Pages 224-230 ; 09215093 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0921509312003140