Influence of tempering temperature on microstructure and mechanical properties of forged 35CrMo steel with large-scale

doi:10.13251/j.issn.0254-6051.2022.08.039

Abstract

Abstract: Influence of tempering temperature on microstructural characteristics and mechanical properties of forged 35CrMo steel with large-scale was investigated after quenching and tempering, especially focusing on the dynamics of cementite precipitation during tempering process and the inhomogeneity of microstructure and mechanical properties. The results show that the banded microstructure of ferrite and pearlite in the forged steel can be completely eliminated after quenching and tempering, the microstructure is mainly composed of tempered martensite with abundant cementite, and some tempered bainite along prior austenite grain boundary is also observed. The kinetics of cementite precipitation can be divided into two stages comprising rapid growth stage controlled by C diffusion and steady size stage controlled by Cr diffusion. The anisotropy of mechanical properties still exists in the forged 35CrMo steel after quenching and tempering. With the increase of tempering temperature, the transverse and longitudinal strengths decrease, while the ductility and toughness are improved concurrently. It is concluded that the optimal combination of strength, ductility and toughness can be obtained when tempered at 570 ℃。

Key words: 35CrMo steel, quenching and tempering, cementite, mechanical properties, anisotropy

CLC Number:

TG142.1

Liao Jia, Fu Tao, Wang Xiaowei, Yu Shengfeng, Wang Ruiqi, Peng Fei. Influence of tempering temperature on microstructure and mechanical properties of forged 35CrMo steel with large-scale[J]. Heat Treatment of Metals, 2022, 47(8): 232-236.

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