Effect of quenching holding time on microstructure and properties of FB2 heat-resistant steel

doi:10.13251/j.issn.0254-6051.2023.08.033

Abstract

Abstract: Microstructure of FB2 martensitic heat-resistant steel after quenching and tempering under different quenching holding time were observed by means of optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The tensile properties, impact absorbed energy and hardness of the heat treated FB2 steel were tested at room temperature. The results show that when quenching at 1100 ℃, the strength, plasticity and hardness of the FB2 steel after quenching and tempering have no apparently change with the quenching holding time increasing from 1 h to 8 h, while the impact absorbed energy decreases. When the quenching holding time is increasing from 8 h to 16 h, the strength and plasticity change little, the hardness decreases and the impact absorbed energy increases. With the increase of quenching holding time in the range of 1-8 h, the prior austenite grain size of the FB2 steel is increased, and the number of undissolved carbides is decreased, meanwhile, the alloying elements diffuse unevenly and the grain boundary carbide coarsening increases after tempering. However, there are still carbides undissolved when the quenching holding time is extended to 16 h, and no significant difference in the carbide sizes at grain boundaries and the intragranular boundaries.

Key words: FB2 steel, quenching, microstructure, holding time, mechanical properties

CLC Number:

TG156

Zhao Jiqing, Yang Gang, Yin Huifang. Effect of quenching holding time on microstructure and properties of FB2 heat-resistant steel[J]. Heat Treatment of Metals, 2023, 48(8): 199-204.

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