The effect of Si on the toughness of high strength Mn-Si-Cr series bainitic steels

The relationship between the toughness and silicon content of high strength Mn-Si-Cr series bainitic steels has been investigated. The results show that with increasing in silicon content, the onset temperature of the steel's tempered martensite embrittlement (TME) rises; moreover, the minimum value of tested toughness decreases and the tempering temperature corresponding to the minimum value of toughness increases. This phenomenon results from the effect of silicon on the stability of filmy carbon-enriched retained austenite in carbide-free-bainite/martensite (CFB/M) microstructure.