Heat treatment optimization and carbon partitioning behavior of Cr-alloyed Q&P steel

doi:10.13251/j.issn.0254-6051.2024.09.018

Abstract

Abstract: A new type of Cr-alloyed (>2%) Q&P steel was designed, and the effects of quenching and partitioning processes on the microstructure and properties of the tested steel were studied. The effect of Cr on the volume fraction of retained austenite and carbon partitioning of the Q&P steel was evaluated through thermodynamic calculations. The results show that when the quenching temperature is 230 ℃ and the partitioning temperature is 400 ℃, the Cr-alloyed Q&P steel obtains the best strength-plasticity matching (tensile strength of 1180 MPa, percentage total extension at fracture of 18.6%), and the strength-elongation product reaches 21 GPa·%. At the same time, in a wide quenching temperature range (210-270 ℃), the strength-elongation product exceeds 19.5 GPa·%. Thermodynamic calculation results show that compared with conventional composition Q&P steel, Cr-alloying increases the carbon content in austenite during the partitioning process, thereby increasing the volume fraction and stability of retained austenite.

Key words: Q&P steel, microstructure, mechanical properties, retained austenite, carbon partitioning

CLC Number:

TG142.1

Zhang Yu, Li Shengyang, Wei Xiaolu, Chai Zhisong, Li Yong. Heat treatment optimization and carbon partitioning behavior of Cr-alloyed Q&P steel[J]. Heat Treatment of Metals, 2024, 49(9): 110-116.

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