JM12—6预应力锚头(图1A)为标准件,按设计要求,夹片(图1B)材料为45钢材,热处理后硬度HRC43—48,锚头由天津市建筑四公司综合厂生产。建机所在试验台施工安装时,锚头夹片承受60吨静拉应力,2—3天后夹片开始断裂,松扣后钢丝射出十多米。事后,我们对夹片断裂件进行化学成分分析,硬度测量,金相组织分析和宏、微观断口分析,以揭示破坏原因。一、对断裂夹片的试验结果: 3.断口金相分析: 1·夹片断裂大都沿梅花筋纵向断裂成碎块,其余为与轴线成45°角横向断裂(图2),断口呈亮灰色,宏观为无塑性变形开裂(图 JM12-6 prestressed anchor head (Figure 1A) as a standard parts, according to design requirements, clip (Figure 1B) material is 45 steel, HRC43-48 hardness after heat treatment, anchor head by the Fourth Construction Company of Tianjin plant production. Construction machine test bench construction and installation, the anchor head clip to withstand 60 tons of static tensile stress, 2-3 days after the clip began to break, loose wire shot more than 10 meters. Afterwards, we conducted chemical composition analysis, hardness measurement, microstructure analysis and macroscopic and microscopic fracture analysis of the fracture pieces to reveal the cause of the fracture. First, the fracture of the clip results: 3. Fracture Metallographic Analysis: 1. Clip fracture along the plum tendon longitudinal rupture into pieces, and the rest of the horizontal axis at a 45 ° angle fracture (Figure 2), the fracture was bright Gray, macroscopic plastic deformation cracking (Figure