Acta Metallurgica Sinica (English Letters) ›› 2015, Vol. 28 ›› Issue (3): 386-393.DOI: 10.1007/s40195-015-0217-9

• Orginal Article • Previous Articles     Next Articles

Stability of Retained Austenite Through a Combined Intercritical Annealing and Quenching and Partitioning (IAQP) Treatment

Ri-Ming Wu1,2, Wei Li1, Cheng-Lin Wang1, Yi Xiao1, Li Wang3, Xue-Jun Jin1()   

  1. 1 School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd, Shanghai, 200240, China
    2 School of Materials Science and Engineering, Shanghai University, 149 Yanchang Rd, Shanghai, China
    3 State Key Lab of Development and Application Technology of Automotive Steels, Baosteel Research Institute, Shanghai, 201900, China
  • Received:2014-07-30 Revised:2014-09-08 Online:2015-01-21 Published:2015-07-23


Intercritical annealing (IA) at various temperatures followed by quenching and partitioning (IAQP) treatments was conducted on a cold-rolled Fe-0.2C-1.42Si-1.87Mn (wt%) sheet steel. Optimized microstructure and enhanced mechanical properties were achieved through appropriate adjustment of IA temperatures. The steel which was annealed at 1,033 K for 600 s, then quenched to 573 K and partitioned at 693 K for 20 min, designated as 1033QP steel, exhibits maximum 16.3 vol% retained austenite (RA) with good mechanical properties (ultimate tensile strength 886 MPa and total elongation 27%). It was found that the thermal and mechanical stabilities of RA are mainly influenced by the combined effect of its average carbon content and amount of adjacent martensite. Furthermore, the transformation-induced plasticity effect increased the peak n-values observed at the second stage of the work hardening of IAQP steels.

Key words: Intercritical annealing and quenching and partitioning treatment (IAQP), Retained austenite (RA), Average carbon content (ACC), Amount of adjacent martensite (AAM), Transformation-induced plasticity (TRIP)