Effect of the Initial Structural State of Cr–Mo High-Temperature Steel on Mechanical Properties after Equal-Channel Angular Pressing

Resumo

The regular patterns of the formation of an ultrafine-grained structure in heat-treated relaxation-resistant high-temperature chrome–molibdenum steel during equal-channel angular pressing (ECAP) have been shown. The importance of this work is in a deeper understanding of the theoretical concepts and practical aspects of structure formation upon ECAP and in the possibility of expanding the field of application of this steel by creating advanced technological processes for producing ultrafine-grained semifinished and finished products showing a qualitatively new level of physical and mechanical properties. ECAP and heat treatment have been used for the first time to form an ultrafine-grained structure in the investigated steel. Submicrocrystalline structures formed in materials have been shown to substantially enhance the complex of mechanical properties, bringing the material closer to those of the high-strength class. The proposed technologies allow the manufacture of defect-free volume workpieces with a uniform ultrafine-grained structure and various combinations of strength and plasticity.