Formation of Ferrite-Cementite Ultrafine Grained Microstructure by Warm Compression for SM490 Martensite Steel

Abstract:

The low carbon steel, SM490 was austenized at different temperatures followed by quenching into water to obtain martensite microstructures with different grain sizes. Then specimens were heated up to 600°C followed by warm-compression at έ=1.7x10-3 s-1 (strain rate) to investigate the dynamic recrystallization behavior. The influence of pre-tempering before compression was also investigated. The microstructure observations were performed with FE-SEM and orientation imaging analysis with EBSD. It is confirmed that the dynamic recrystallization occurred in the tempered martensite as well as the as-quenched marteniste, resulting in fine grained ferrite microstructure with about 2μm. The dynamic recrystallization grain size is hardly dependent on the block size of initial martensite.

• Periodical: Materials Science Forum (Volumes 558-559)
• Pages: 539-544
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.558-559.539
• Online since: October 2007
• Authors: J.H. Li, Ping Guang Xu, Yo Tomota, Yoshitaka Adachi
• Keywords: Dynamic Precipitation, Dynamic Recrystallization (DRX), Martensite, Ultra-Fine Microstructure, Warm Compression

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