MODERN STRUCTURAL STEELS WITH TRIP-EFFECT

Abstract

Purpose. The aim of this work is to analyze the latest literature data on current state of the issue in the development of the chemical composition and heat treatment modes of steels that implement the TRIP effect under loading. Due to the deformation martensitic transformation of retained austenite, these steels have increased mechanical and operational properties with cost-saving alloying. Methodology. The information published over a long period of time in scientific literature, including domestic sources and high-rating foreign publications are used in this work. The information is systematized by the main TRIP-steels’ types and relates to their chemical composition and heat treatment technology. Findings. The article presents a retrospective of the research progress on the development of structural TRIP effect added steels namely: high-alloy single-phase metastable austenitic steels, as well as low-alloy multiphase TRIP-assisted steels, in which the TRIP effect plays an supporting role, as an additional strengthening and providing increased plasticity mechanism. The latter group of steels includes low alloy TRIP-assisted steels, δ-TRIP steels and maraging TRIP steels. The typical alloying schemes and applied heat treatment modes that make it possible to achieve the optimal phase-structural components ratio, the volume fraction and stability of retained austenite to deformation martensitic transformation in steels and, as a result, to provide an increased mechanical and operational properties were described. The key role of the carbide-free structure formation is noted, which is achieved by alloying with silicon and/or aluminum in providing high properties of steel. The prospects of using modern structural TRIP steels in the automotive and in the machine-building industry are shown. Recommendations for further research directions in this area are made. Originality. The article provides an analysis and systematization of relevant literature data on the development of technologies for the production of multiphase structural steels with retained metastable austenite, realizing the TRIP effect. Practical value. The results of the research can be used as reference materials in solving material design problems, as well as for educational purposes in the preparation of specialized professionals in engineering specialties.