Quench Temperature-Dependent Phase Transformations During Nonisothermal Partitioning

Quench Temperature-Dependent Mechanical Properties During Nonisothermal Partitioning

“…All these are somewhat dependent on the quench temperature. This is further substantiated by another recent finding of the present authors, [11] where they showed a slight variation in the amount of retained austenite and its carbon content with quench temperature. However, an increase in the retained austenite film thickness and enhanced self-tempering of martensite was reported with increasing quench temperature.…”

“…[7] The model proposed by Speer et al [15] was used here for the selection of different quench temperatures, namely 190°C, 230°C, 270°C and 310°C, the details of which can be found elsewhere. [11] As the deformed austenite shows modified phase transformation kinetics, further experiments were carried out to adequately deform the austenite prior to Q&P. The forged steel plate with initial dimensions of 80 9 150 9 45 mm 3 was austenitized at 1200°C for 2 hour and subsequently hot-rolled to 80 9 350 9 15 mm 3 in 3 passes. The finish rolling temperature was maintained at~930°C (see Figure 1(b)).…”

“…THE steels treated by an energy-efficient quenching and nonisothermal partitioning (Q&P) process [1][2][3][4][5][6][7][8][9][10][11][12] show stabilization of the austenite between the martensitic laths. In this process, the steel is austenitized, hot-rolled, quenched to a temperature between M s and M f and coiled.…”

“…[1,[4][5][6][7][8][9][10][11][12] Depending upon the extent of carbon enrichment of the remaining austenite, it may fully be retained at the room temperature or may partially transform to secondary martensite and/or bainite. [6][7][8][9]11,12] In some of the studies, [1][2][3][4] the effect of nonisothermal partitioning on the microstructure evolution and/or tensile properties of steel has been found to be comparable to that obtained by conventional isothermal partitioning process. Moreover, in a recent investigation, [7] the quenched and nonisothermally partitioned steel has been reported to have improved impact toughness, better work-hardening capacity and comparable wear resistance to that of a fully martensitic microstructure.…”

“…These changes might alter the mechanical properties of the same steel for different quench temperatures, which were not a part of that report. [11] The available literature on quenching and nonisothermal partitioning process shows a drop in the tensile strength and increase in the ductility with increasing quench temperature. [2,3,9] However, to the best of the authors' knowledge, the effect of quench temperature on impact toughness and wear resistance, for nonisothermally partitioned steels, in particular, has not been studied.…”