塔式起重机转台10.9级螺栓断裂分析  

Fracture Analysis of 10.9 Stage Bolt for Tower Crane Turntable

作　　者：文军[1,2] 李毅 张东亚[1,2] 冯坤 WEN Jun;LI Yi;ZHANG Dongya;FENG Kun(Jiangsu Xuzhou Construction Machinery Research Institute, Xuzhou Construction Machinery Group, Xuzhou 221004, China;State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery, Xuzhou Construction Machinery Group, Xuzhou 221004, China)

机构地区：[1]徐工集团江苏徐州工程机械研究院,江苏徐州221004 [2]徐工集团高端工程机械智能制造国家重点实验室,江苏徐州221004

出　　处：《热加工工艺》2018年第8期249-252,共4页Hot Working Technology

摘　　要：某工程机械塔式起重机转台连接用10.9级40Cr螺栓在使用1.5年后发生断裂,对断裂螺栓的宏观断口、化学成分、硬度、金相组织、微观形貌等方面进行分析。结果表明：该螺栓在较低公称应力下发生疲劳断裂,断裂原因主要是由于热处理工艺不合理导致的螺栓表面脱碳、整体硬度不符合使用要求。建议严格控制螺栓的热处理工艺,减少脱碳,提高螺栓硬度和强度。The 10.9 stage 40Cr bolt for connection of the turntable of a mechanical tower cranewas broken after 1.5 years. The fracture bolt was analyzed through macroscopic fracture, chemical composition, hardness, metallographic structure and scanning electron microscope. The results show that, the fatigue fracture of the bolt occurs under low nominal stress condition. The cause of the fracture is mainly due to the deearburization of the bolt surface and the overall hardness lower than the standard requirement caused by the unreasonable heat treatment process. It is suggested that the heat treatment process of the bolts should be strictly controlled to reduce decarburization, improve the hardness and strength of the bolts.

关 键 词：塔式起重机 螺栓 疲劳断裂 脱碳 硬度 

分 类 号：TG157[金属学及工艺—热处理]