FORMATION OF A STRUCTURE OF SINGLE-PHASE ALPHA-SOLID SOLUTION IN KH30K15M3 ALLOYS UNDER THE CONDITIONS OF PHASE HARDENING

An alpha --> (alpha + sigma) transformation commonly accompanies the p roduction of castings of highly coercive alloys based on Fe-Cr-Co-Mo. The presence of a sigma-phase in the structure of the alloys decreases markedly their technological properties and makes the heat treatment for a highly coercive stare inefficient. For this reason the alloys ar e transformed to the state of a single-phase alpha-solid solution befo re plastic deformation, mechanical, or thermomagnetic treatment. Howev er, the effect of the alpha reversible arrow (alpha + sigma) transform ation on the structure of the alpha-solid solution formed in the rever se transformation has not been studied yet. The present work is devote d to the problem. The study concerns the structure of the alpha-solid solution obtained in firing Kh30K15M3 alloys with different contents a nd morphologies of the sigma-phase in the single-phase region.