Splitting phenomena occurring in the martensitic transformation of Cr13 and CrMoV14 stainless steels in the absence of carbide precipitation

Previously unknown splitting phenomena were detected in the martensitic transformation of XCr13 and XCrMoV14 stainless steels using high resolution dilatometric analysis. These splittings, which are denominated M(so) in this article, indicate the martensitic subtransformation of areas of austenite rich in carbon and carbide-forming elements. In contrast to other types of splitting known until now, the M(so) occur in the absence of carbide precipitation during cooling. From the experimental results obtained in this study, it can be concluded that the splittings resulted from concentration gradients produced in the austenite as a consequence of the partial or total dissolution of M(23)C(6) carbides during heating.