Microstructure and mechanical properties of 0.2C-5Mn-1.5Al medium manganese TRIP steel

doi:10.13251/j.issn.0254-6051.2020.04.013

Abstract

Abstract: The equilibrium phase diagram, microstructure and mechanical properties of 0.2C-5Mn-1.5Al medium manganese TRIP steel under different annealing processes was studied by means of calculation of phase diagram (CALPHAD) method, scanning electron microscopy (SEM), X-ray diffractometry (XRD), and tensile test. The influence of Al on equilibrium phase diagram, intercritcal annealing process, and mechanical properties are also studied. The results show that Al addition expands the intercritical region and shift the region to higher temperatures. The intercritical annealing temperature is increased, the austenite reverse transformation process is accelerated, the annealing time is shortened, the aggregation of C and Mn elements is promoted. The retained austenite content is effectively improved, and the deformation process TRIP effect is enhanced. With the increase of annealing temperature, the austenite content and elongation of 0.2C-5Mn-1.5Al steel show a trend of increasing first and then decreasing, while the yield strength decrease slightly, tensile strength continue to increase. And annealing at 760 ℃ for 3 min, the best mechanical properties are obtained, the elongation is 32%, and the strong plastic product is 35 GPa·%, which show that the addition of Al element effectively increases the comprehensive mechanical properties of manganese TRIP in 0.2C-5Mn.

Key words: medium manganese TRIP steel, annealing process, phase transformation law, microstructure and mechanical properties, austenite content

CLC Number:

TG142.1

Wang Runxun, Wang Baofeng, Li Yan, Ding Wei, Pan Hongbo. Microstructure and mechanical properties of 0.2C-5Mn-1.5Al medium manganese TRIP steel[J]. Heat Treatment of Metals, 2020, 45(4): 63-68.

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