某卡盘T型块在设备调试期间发生断裂。为查明卡盘T型块的断裂原因，对其进行了化学成分分析、显微组织分析、硬度测试、断口分析及受力分析。结果表明：卡盘T型块断裂的主要原因是材料强度低及卡爪设计不合理导致卡盘T型块受力增大。最后，根据卡盘T型块的断裂原因，提出了相应的改进措施。

One T block of a chuck fractured during the commissioning period of a machine tool. To find out the fracture reasons, the T block of the chuck was tested and analyzed from the aspects of chemical composition, microstructure, hardness, fracture surface and force. The results show that the main fracture reasons of the T block of the chuck were its low strength of the material and the increased stress of the T block due to the unreasonable design of the claw. Eventually, the appropriate improvement measures were put forward according to the fracture reasons of the T block of the chuck.