A new empirical formula for the bainite upper temperature limit of steel |
| |
| Authors: | Zhenbo Zhao Cheng Liu Yunxu Liu D O Northwood |
| |
| Affiliation: | (1) Mechanical, Materials and Automotive Engineering, University of Windsor, Windsor, Ontario, Canada, N9B 3P4;(2) Department of Materials Engineering, Jilin Institute of Technology, Changchun, Jilin, 130012, People's Republic of China;(3) Faculty of Engineering & Applied Science, Ryerson Polytechnic University, Toronto, Ontario, Canada, M5B 2K3 |
| |
| Abstract: | The definition of the practical upper temperature limit of the bainite reaction in steels is discussed. Because the theoretical upper temperature limit of bainite reaction, B
0, can neither be obtained directly from experimental measurements, nor from calculations, then, different models related to the practical upper temperature limit of bainite reaction, B
S, are reviewed and analyzed first in order to define the B
0 temperature. A new physical significance of the B
S and B
0 temperatures in steels is proposed and analyzed. It is found that the B
0 temperature of the bainite reaction in steels can be defined by the point of intersection between the thermodynamic equilibrium curve for the austenite ferrite transformation by coherent growth (curve Z
) and the extrapolated thermodynamic equilibrium curve for the austenitecementite transformation (curve ES in the Fe-C phase diagram). The B
S temperature for the bainite reaction is about 50–55 °C lower than the B
0 temperature in steels. Using this method, the B
0 and B
S temperatures for plain carbon steels were found to be 680 °C and 630 °C, respectively. The bainite reaction can only be observed below 500 °C because it is obscured by the pearlite reaction which occurs prior to the bainite reaction in plain carbon steels. A new formula, B
S(°C) =, 630-45Mn-40V-35Si-30Cr-25Mo-20Ni-15W, is proposed to predict the B
S temperature of steel. The effect of steel composition on the B
S temperature is discussed. It is shown that B
S is mainly affected by alloying elements other than carbon, which had been found in previous investigations. The new formula gives a better agreement with experimental results than for 3 other empirical formulae when data from 82 low alloy steels from were examined. For more than 70% of these low alloy steels, the B
S temperatures can be predicted by this new formula within ±25°C. It is believed that the new equation will have more extensive applicability than existing equations since it is based on data for a wide range of steel compositions (7 alloying elements). |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
