Journal of the Southern African Institute of Mining and Metallurgy
On-line version ISSN 2411-9717
LEACH, L.J.; SIYASIYA, C.W. and STUMPF, W.E.. Effect of dual phase microstructure on the toughness of a Cr-Mo low-alloy plate steel. J. S. Afr. Inst. Min. Metall. [online]. 2013, vol.113, n.2, pp. 109-113. ISSN 2411-9717.
Quench and tempered Cr-Mo plate steel was found not to contain a fully martensitic structure as a result of either slow slack quenching or insufficient hardenability at the cooling rates used. The resulting microstructure contains bainite in combination with martensite. It is necessary to examine the implications of bainite for the toughness of the final product. Loss of toughness arises primarily from the inter-lath carbides that typically form in upper bainite. An investigation into the effect of upper bainite in a martensitic matrix of a steel grade containing 0.17% C, 0.1% Cr, 0.54% Mo, and 20 ppm B indicated lower toughness than in a fully martensitic structure.
Keywords : upper bainite; toughness; instrumented impact.