Changes in the state of heat-resistant steel induced by repeated hot deformation

• Published in: Metals and materials international Vol. 24; no. 1; pp. 121 - 129
• Main Authors: Lyubimova, Lyudmila L., Fisenko, Roman N., Tashlykov, Alexander A., Tabakaev, Roman B.
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 2018; Springer Nature B.V; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Continuity (mathematics); Deformation resistance; Dosimeters; Engineering Thermodynamics; Heat and Mass Transfer; Heat resistant steels; Heat treatment; Lattice vibration; Machines; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Metallic Materials; Processes; Regeneration; Residual stress; Restoration; Solid Mechanics; Stress concentration; Stress relaxation; Structural stability; Viscoelasticity; X ray spectra; 재료공학; X-ray diffraction; residual stress; metals; deformation; unit cell parameter
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-017-7031-z

This work deals with the problems of structural regeneration by thermal restoration treatment (TRT). These include the lack of a structural sign showing that TRT is possible, a consensus on TRT modes, the data on the necessary relaxation depth of residual stresses, or criteria of structural restoration. Performing a TRT without solving these problems may deteriorate the properties of steel or even accelerate its destruction. With this in view, the purpose of this work is to determine experimentally how the residual stress state changes under thermal and mechanical loads in order to specify the signs of the restoration of structure and structural stability. The object of this research is unused 12Cr1MoV steel that has been aged naturally for 13 years. Using X-ray dosimetry with X-ray spectral analysis, we study the distribution of internal residual stresses of the first kind during the repeated hot deformation. After repeated thermal deformation, the sample under study transforms from a viscoelastic Maxwell material into a Kelvin-Voigt material, which facilitates structural stabilization. A sign of this is the relaxation limit increase, prevention of continuous decay of an α-solid solution of iron and restoration of the lattice parameter.