It was found that the broach was locally overheated due to bandsegregation of carbide, and under-tempered. These factors caused fracture of broach as a result of high internal stress.
严重的碳化物带状偏析，使拉刀产生局部淬火过热和回火不足，造成内应力急剧增高，最终导致拉刀断裂。
2
It is found that the 'delamination always takes place along the centerline segregationband in pipe-line steel produced by continuous casting and then controlled rolling.
初步研究发现，对由连铸然后经控制轧制生产的管线钢层状撕裂几乎总是沿中心线偏析带发生。
3
Results show that the primary cause to the laminar defect of the umbrella bone steel in the process of cold bending to U-shape is the severe carbon segregation in the steel band.