Transformation Behavior During Isothermal Partitioning Process in Micro-alloyed Q&P Steel
A low-carbon steel micro-alloyed with Nb, V and Ti was subjected to partial austenitized followed by two-step quenching and partitioning (Q&P) process. Combined use of static dilatometer, SEM and EPMA techniques revealed the microstructure evolution and elements variation during partitioning process. The result shows that the retained austenite normally located inside or around M/A the island with blocky morphology as well as obvious carbon enrichment. With increasing partitioning time, the carbon enrichment region expanded and the carbides precipitated inside the tempered martensite. The rate of Bainite transformation dilatation during partitioning process accelerated with increasing partitioning time, whereas carbide precipitation during martensite temper lead to a compression at the same time.
KeywordsQuenching and partitioning Isothermal partitioning Bainite Temper martensite
The authors acknowledge support by the National Natural Science Foundation of China (Nos. 51674080, 51404155 and U1260204), the Program for New Century Excellent Talents in University (NCET-13-0111) and the Program for Liaoning Excellent Talents in University (LR2014007).
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