Effect of Intercritical Annealing Temperature on Microstructure and Mechanical Property of High Al-Low Si TRIP Steel

doi:10.12068/j.issn.1005-3026.2019.12.006

Abstract

Abstract: The high Al-low Si TRIP steels were annealed at different intercritical temperatures. The microstructures and mechanical properties were examined to establish the relationship between work hardening exponent and phase components， and the effect of retained austenite stability on mechanical properties of tested steels were analyzed. The results show that， with the increase in intercritical annealing temperature， the content of bainite gradually decreased， while the volume fraction of retained austenite increased first and then decreased. The volume fraction of retained austenite reached largest when annealing temperature was 930℃. The tensile strength of experimental steel decreased with the increase of intercritical annealing temperature， and the elongation increased first and then decreased. When the annealing temperature was 930℃， the tensile strength was 665MPa， and the elongation reached its maximum of about 30%， and the resulting product of strength and elongation was approximately 20GPa·%. By combining EBSD analyses and tensile tests， it can be concluded that the retained austenite possessed moderate stability when the tested steel was annealing at 930℃， so that work hardening ability is continuously provided during tensile testing period. As a result， the plasticity of annealed TRIP steels had been improved.

Key words: TRIP steel, microstructure, retained austenite, twin martensite, mechanical property

CLC Number:

TG156.1

HUANG Hui-qiang， DI Hong-shuang， ZHANG Tian-yu， YAN Ning. Effect of Intercritical Annealing Temperature on Microstructure and Mechanical Property of High Al-Low Si TRIP Steel[J]. Journal of Northeastern University Natural Science, 2019, 40(12): 1700-1706.

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