一种30CrMnSi钢大型筒形件在旋压过程中发生开裂，通过宏观观察、化学成分分析、断口分析、显微组织观察、扫描电镜和能谱分析等方法，并结合对生产过程的排查，分析了筒形件开裂的原因。结果表明：筒形件旋压前热处理工艺不当，导致硬度、组织均不均匀，这是筒形件发生旋压开裂的主要原因；通过改进热处理工艺，选用适用于大型工件的双向交替冷却方式，并对旋压工艺进行改进、完善，此后的旋压件均未发生开裂，产品性能满足技术要求。

A large cylindrical part of 30CrMnSi steel cracked during spinning process. Through macroscopic observation, chemical composition analysis, fracture analysis, microstructure observation, scanning electron microscope and energy spectrum analysis, and conbined with inspection of production process. The reasons for cracking of cylindrical part were analyzed. The results showed that improper heat treatment process of cylindrical part before spinning led to uneven hardness and structure. This was the main reason for spinning cracking of cylindrical part. By improving heat treatment process, the two-way alternating cooling method suitable for large workpieces was selected. In addition, the spinning process was improved and perfected. After that, no cracks occurred in spinning products, and product performance met technical requirements.