Effect of initial microstructure on austenite transformation and grain growth behavior of 20CrMnTi steel during pseudo-carburizing process

doi:10.13251/j.issn.0254-6051.2020.06.033

Abstract

Abstract: The cementite precipitation behavior of 20CrMnTi steel during spheroidizing annealing and its interaction with ferrite recovery and recrystallization were studied, and the effects of initial microstructure as-in hot-rolled state, quenched state and spheroidizing annealed state on austenite transformation and grain growth behavior during pseudo-carburizing were emphatically analyzed. The results show that coarse ferrite + pearlite microstructure and uniform fine lath martensite microstructure can be found in the hot-rolled and quenched specimens, respectively. However, the matrix and the carbide microstructures in the spheroidized specimens are nonuniform in micro-scale due to the interaction of carbide precipitating with recovery, recrystallization of martensite matrix. During pseudo-carburizing, the average grain size of austenite decreases in the order of hot rolled state, quenched state and spheroidizing annealed state, but the non-uniformity factor increases in the same order. The nucleation density and homogeneity of austenite related to the initial microstructure are one of the key factors controlling the austenite grain growth behavior during carburizing.

Key words: 20CrMnTi steel, carburizing, initial microstructure, austenite transformation, grain growth

CLC Number:

TG156.8⁺1

Li Jun, Huang Jian, Jia Tao. Effect of initial microstructure on austenite transformation and grain growth behavior of 20CrMnTi steel during pseudo-carburizing process[J]. Heat Treatment of Metals, 2020, 45(6): 157-162.

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