Abstract
The impact toughness and microstructure of a dual phase 12 wt-% Cr steel (3CR12) have been investigated. In particular, the occurrence of non-metallic inclusions has been studied in relationship to the detailed chemistry of the steel. The effect of these inclusions on the modes and morphology of fracture has also been determined. It is shown that splits form parallel to the rolling plane when Charpy specimens are subjected to impact testing. Non-metallic inclusions, particularly manganese sulphides, facilitate low energy modes of fracture associated with the splitting phenomenon. Stringered and pancake-shaped inclusions also prevent the formation of equiaxed ferrite on annealing, thus retaining the directional microstructure. Careful control of the chemistry of the steel permits the most deleterious inclusions to be restricted to levels at which acceptable impact properties are maintained.
MST/637
Get full access to this article
View all access options for this article.