Effect of partitioning time in intercritical region on microstructure and mechanical properties of IQ&P steel

doi:10.13251/j.issn.0254-6051.2020.11.022

Abstract

Abstract: Taking a Cu-bearing low carbon steel as the research object, the effects of partitioning time in intercritical region on the microstructure evolution, elements partition and the mechanical properties after IQ&P treatment were studied by means of SEM, EPMA and tensile experiment. The kinetics calculation for elements partitioning was carried out by Dictra software. The results show that the block-shaped martensite in the tested steel forms in the initial ferrite region after IQ treatment, and the amount of granular martensite and the distance between lath martensite decrease with the increase of partitioning time in intercritical region. The measuring results show that the relative partition rate of C, Mn and Cu is consistent with the calculated results, but the actual partition rate for these elements is lower than the calculated results. With the increase of partitioning time in intercritical region, the tensile strength of the tested steel after IQ&P treatment first increases and then decreases, while the elongation continues to decrease. When the partitioning time is 600 s, a good comprehensive mechanical property is obtained, and the product of strength and elongation reaches 16 963.24 MPa·%.

Key words: partitioning time in intercritical region, kinetics calculation, microstructure evolution, mechanical properties

CLC Number:

TG142.4

Chang Xue, Zheng Xiaoping, Su Xue, Tian Yaqiang, Chen Liansheng. Effect of partitioning time in intercritical region on microstructure and mechanical properties of IQ&P steel[J]. Heat Treatment of Metals, 2020, 45(11): 121-125.

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