TRIP steels: the features of chemical composition and structure, prospects of application (overview)

Abstract

This article provides a brief overview of steels prone to transformation induced plasticity (TRIP), which belong to the class of advanced high-strength steels (AHSS). The necessary set of properties in these steels is formed due to the partial preservation of supercooled austenite in the structure. The article considers the mechanism of TRIP transformation, which depends on the value of the temperature of the beginning of the martensitic transformation. It is shown that the amount and stability of supercooled austenite can be influenced by varying the temperature and time parameters of heat treatment. In addition to heat treatment, the qualitative and quantitative parameters of metastable austenite are significantly influenced by the alloying of TRIP steels, and the alloying elements themselves can be divided into several main groups (ferrite-stabilizing, increasing the stability of supercooled austenite and micro-alloying). In the final part of the article, the prospect of using TRIP steels in the aerospace industry is considered, where reducing the metal consumption of parts is a priority. It is also worth considering that the production of parts using additive technologies is widespread in the aerospace industry. Therefore, the use of TRIP steels as a material in additive manufacturing leads to the formation of a new concept for creating parts with a unique set of properties, primarily with high structural strength, light weight and the possibility of self-adaptation to extreme external exposures.

Development of the heat treatment mode for TRIP steel additionally alloyed with aluminium

“…The properties of these steels depend on the chemical composition and the mode of heat treatment, which directly affect the amount of metastable austenite preserved in the structure, its morphology, and the carbon content in it [3]. Heat treatment of these steels consists of two-stage isothermal annealing: at first in the intercritical interval, then in the interval of bainitic transformation.…”