对36U型钢弯曲断裂及性能异常原因进行分析，发现断裂的主要原因是碳、硅含量超标、锰含量严重超标，使组织中出现较多贝氏体，且铁素体含量降低，同时断裂试样硬度比正常试样硬度高近一倍，最终导致U型钢性能异常、弯曲断裂。

By analyzing of the brittleness cracking and the property abnormity for the 36U profiled steel, it is found that the cracking is originated in the excess content of C, Si and Mn introducing the large amounts of bainite and less ferrite. The hardness of bend brittleness crack sample is a times more than the normal sample.