Effect of temperature on flow and work hardening behavior of high bainite dual phase (HBDP) steels

Abstract High bainite dual phase steel has been subjected to tension test at different temperatures from 25 to 500 °C with strain rate of 4.6 × 10−4 s−1 to investigate the effect of temperature on its mechanical properties. Stress–strain curves of steels showed serration flow at temperature range of 200–350 °C and smooth flow at the other temperatures. In agreement with previous studies on some steels, peaks in the variations of yield strength (YS) and ultimate tensile strength (UTS) and minima in ductility were observed at temperature range of 200–350 °C which are various manifestations of dynamic strain aging (DSA). It has been also found that ferrite volume fraction has no effect on the temperature range of serrated flow but work hardening decreased slightly with increasing ferrite volume fraction. The tensile test data were also analyzed in term of Hollomon equation and it was found that this steel has two work hardening stages. In this study the effects of temperature on Hollomon equation parameters and onset strain of stage II hardening were investigated. The observed peaks/plateaus in the variation of Hollomon equation parameters with temperature at the intermediate temperature range have been identified as the other manifestation of dynamic strain aging. The work hardening analysis of flow stress data revealed that, in the DSA region, the onset strain of stage II work hardening is athermal.

[1]  G. Schoeck.  The portevin-le chatelier effect. A kinetic theory , 1984 .

[2]  U. F. Kocks,et al.  New observations on the mechanisms of dynamic strain aging and of jerky flow , 1979 .

[3]  Y. Estrin,et al.  Dynamic strain ageing and the mechanical response of alloys , 1991 .

[4]  J. Lian,et al.  The relationship between ductility and material parameters for dual-phase steel , 1993, Journal of Materials Science.

[5]  B. K. Choudhary,et al.  Influence of temperature and strain rate on tensile work hardening behaviour of type 316 LN austenitic stainless steel , 2002 .

[6]  J. Jonas,et al.  Effect of cooling rate after hot rolling and of multistage strain aging on the drawability of low-carbon-steel wire rod , 1995 .

[7]  Wenzhe Chen,et al.  Effect of dynamic strain aging on high temperature properties of austenitic stainless steel , 2004 .

[8]  K. G. Samuel,et al.  The influence of temperature and prior cold work on the strain-hardening parameters of a type 316 LN stainless steel , 1992 .

[9]  P Rodriguez,et al.  Serrated plastic flow , 1984 .

[10]  J. Jonas,et al.  Dynamic Strain Aging and the Wire Drawing of Low Carbon Steel Rods , 1995 .

[11]  T. Mcnelley,et al.  Inverse strain-rate sensitivity and the portevin-le chatelier effect , 1978 .

[12]  S. H. M. Anijdan,et al.  Room-temperature mechanical properties of dual-phase steels deformed at high temperatures , 2005 .

[13]  A. Ekrami,et al.  High temperature mechanical properties of dual phase steels , 2005 .

[14]  S. Wadekar,et al.  Effect of serrated flow on deformation behaviour of AISI 403 stainless steel , 2000 .

[15]  Yuri Estrin,et al.  The portevin-Le Chatelier effect in deformation with constant stress rate , 1985 .

[16]  George Krauss,et al.  Steels: Heat Treatment and Processing Principles , 1990 .

[17]  Y. Estrin,et al.  The rate dependence of the portevin-Le chatelier effect , 1988 .

[18]  K. A. Padmanabhan,et al.  Deformation behaviour of sheets of three aerospace Al-alloys , 2001 .

[19]  Zhonghao Jiang,et al.  Theoretical model for the tensile work hardening behaviour of dual-phase steel , 1991 .

[20]  S. Endo,et al.  Effect of Volume Fraction of Constituent Phases on the Stress-Strain Relationship of Dual Phase Steels , 1999 .