在锻造12L柴油机曲轴(42CrMoA 钢)时,个别曲轴平衡块的分模面处经常出现线状缝隙。为了提高曲轴的锻造质量和成品率,本文对其类型与成因进行了分析。通过对成分、缝隙部位宏观和微观形貌分析,确认主缝隙属于锻造折叠,而副缝隙属于淬火裂纹;对12L柴油机曲轴裂纹成因分析后,提出了工艺改进措施;方案实施后,基本杜绝了这两种缺陷的产生。 When forging a 12L diesel crankshaft (42CrMoA steel), linear crankshafts often appear at the parting plane of individual crankshaft balancers. In order to improve crankshaft forging quality and yield, this paper analyzes the type and causes. Through the analysis of macroscopic and microscopic features of the components and cracks, it is confirmed that the main slit belongs to the forging and folding, while the secondary slit belongs to the quenching crack. After the crankshaft crack of 12L diesel engine is analyzed, the improvement measures are put forward. After the implementation of the scheme, it is basically eliminated Two kinds of defects.