Formability of quenching-partitioning-tempering martensitic steel. Issue 1 (3rd April 2019)

• Record Type: Journal Article
• Authors: Hao, Qingguo; Qin, Shengwei; Liu, Yu; Zuo, Xunwei; Chen, Nailu; Rong, Yonghua
• Is Part Of: Heat treatment and surface engineering. Volume 1:Issue 1/2(2019)
• Page Start: 32
• Page End: 39
• Publication Date: 2019-04-03
• Subjects: Quenching-partitioning-tempering (Q-P-T) martensitic steel -- forming limit diagram -- strain hardening exponent -- true uniform elongation -- dislocation absorption by retained austenite (DARA) effect; Metals -- Heat treatment -- Periodicals; Materials science -- Periodicals; 671.36
• DOI: 10.1080/25787616.2018.1560141
• Languages: English
• ISSNs: 2578-7616

Abstract

ABSTRACT: A Fe-0.20C-1.49Mn-1.52Si-0.58Cr-0.05Nb (wt%) steel was treated by a novel quenching-partitioning-tempering (Q-P-T) process and traditional quenching and tempering (Q&T) for comparison, respectively. The researches of the mechanical properties and forming limit diagrams reveal that Q-P-T martensitic steel has more retained austenite (10.8%) than the Q&T martensitic steel (less than 3%), which makes Q-P-T martensitc steel possess higher strain hardening exponent and true uniform elongation than the Q&T martensitic steel. The high value of hardening exponent ( n ) and true uniform elongation ( εu ) stem from the low initial dislocation density in martensitic matrix in Q-P-T martensitic steel before deformation and the high strain hardening rate and dislocation absorption by retained austenite (DARA) effect of retained austenite during deformation. Moreover, the n, or the εu, is a most important parameter in all the apparent parameters affecting the formability of metal sheets, and this conclusion is of practical importance in the comparison of several steels' formability.