Abstract: There have been times when the thrust rod have been failed, there are different types of failure modes, but failure caused by surface defects is not easily detected. This paper analyzes the modes and causes of fracture failure of the rod head during fatigue testing using analytical methods such as chemical composition testing, hardness testing, microstructure observation, macroscopic and microscopic observation of the fracture. The results indicate that the combined effects of surface decarburization and corrosion defects on the rod head creates stress concentration points. Under the effects of alternating stress, cracks start to sprout from the stress concentration points and propagate from the outside to the inside until fracture failure occurs.

Key words: thrust rub head; decarbonization; corrosion products; fracture failure

摘要： 推力杆失效时有发生，失效种类也多种多样，但由表面缺陷导致的失效不易被察觉。 文章借助化学成分检测、硬度检测、显微组织观察、断口宏观和微观观察等分析方法，对疲 劳试验过程中杆头断裂失效的模式和原因进行了分析。结果表明，由于杆头表面脱碳及腐蚀 缺陷的共同作用，形成应力集中点，并在交变应力作用下，裂纹由应力集中点开始萌芽并由 外向内扩展，直至断裂失效。

关键词: 推力杆杆头；脱碳；腐蚀产物；断裂失效