Reasons Analysis and Countermeasures of Internal Cracks of 100 mm GCr15SiMn Bearing Steel Bars

In order to solve the problem of internal crack defect of 100 mm GCr15SiMn bearing steel bars, the production conditions, environmental conditions and physical and chemical properties of the products were analyzed. The results show that comprehensive influence of the factors such as air moisture, raw material moisture, high temperature heat transfer of continuous casting slab, low temperature of rolled wire and so on, caused the internal stress of the GCr15SiMn bearing steel bars was too large in the production process. The concentration release of the thermal stress and microstructure stress in the slow cooling pit led to the generation of internal cracks. Finally, the improvement measures were put forward for the causes of the internal cracks, and the internal cracks in the bearing steel bars were reduced greatly.