我厂2001年承接了φ2.2m×6.5 m磨机检修任务,在检修过程中发现进料端中空轴有一“丁”字形裂纹,长度分别为110mm和30mm(图1)。观察发现裂纹附近有数处栽钉修复痕迹。据此,初步判断裂纹处原有较多气孔或夹砂,出厂前已用栽钉法修补,因对铸造缺陷处理不彻底而产生裂纹。 I plant in 2001 to undertake the φ2.2m × 6.5 m mill maintenance tasks found in the process of feeding the hollow shaft has a “D” shaped crack, the length of 110mm and 30mm (Figure 1). Observed that there are several cracks near the nailing repair traces. Accordingly, the initial judgment of the cracks at the original stomata or more sand, the factory has been planted with nailing method repair, casting defects due to incomplete processing and cracks.