Transactions of Materials and Heat Treatment

Title：Effect of forging and heat treatment process on impact properties of 35CrNi3MoV forgings

Authors： Wang Yingying Liu Haijiang Zhao Wenbin Wang Xing Liu Lin

Unit： Special Steel Business Department Inner Mongolia North Heavy Industry Group Corp.Ltd.

KeyWords： dendritic segregation banded structure forging process quenching and tempering impact toughness

ClassificationCode：TG316

year,vol(issue):pagenumber：2025,50(3):137-143

Abstract：

In order to investigate the cause of unqualified impact performance for 35CrNi3MoV steel precision forgings, the microstructure of ingot and the quenched-and-tempered microstructures of steel billet for the same product produced by free forging and precision forging were observed and analyzed by metallographic microscope and scanning electron microscope. The results show that there is obvious dendritic segregation in the structure of ingot. The forgings formed by free forging have uniform and fine microstructure after quenching and tempering, while the forgings formed by precision forging have obvious banded structure characteristics in the quenched and tempered microstructure, the coarseness is uneven, containing large-sized V-containing carbides along the grain boundaries. Based on this, the forging production process is improved, the forging temperature and holding time of precision forging process are increased, and the original two-pass forming is changed to one-pass forming. At last, the preparatory heat treatment after forging is changed from low temperature annealing to austenitizing heating and holding and then lowering to low-temperature holding annealing. Thus, the impact performance of the forgings is significantly improved after quenching and tempering, resolving the problem of insufficient impact toughness of 35CrNi3MoV steel forgings.

Funds：

国防基础科研计划（JCKY2022208A002）

作者简介：王莹莹（1982-），女，硕士，高级工程师 E-mail：yy1257@qq.com 通信作者：刘海江（1979-），男，硕士，正高工 E-mail：13848522181@163.com

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