大型立式车床立柱裂纹缺陷的原因分析与对策

Cause Analysis and Countermeasures of Cracks on Large Vertical Lathe Column

介绍了大型立式车床立柱铸件的结构及技术要求,详细阐述了原生产工艺及铸件出现裂纹的位置和特征,针对大型立式车床立柱存在的裂纹问题进行了分析,认为铸件壁厚不均,当壁厚的凝固处于弹性阶段时期铸造应力超过机械强度后引起了冷裂纹的产生。采取了优化端面芯头结构、形状大小及层次,优化铸件部分圆,调整化学成分,保证铸件上表面壁厚均匀,调整开箱起坑工序等措施。生产结果显示:生产验证的16件同型号、同类型的立柱铸件均没有产生裂纹缺陷,此种裂纹缺陷得到有效解决。

The structure and technical requirements of large vertical lathe column casting are introduced,the original production process,the location and characteristics of cracks in the casting are described in detail,the cracks in the large vertical lathe column are analyzed.It is considered that the wall thickness of the casting is uneven,and the solidification of the wall thickness is in the elastic stage.When the casting stress exceeds the mechanical strength,the cold cracks will occur.Measures such as optimizing the structure,shape,size and level of the end face core;optimizing the part circle of the casting;adjusting chemical composition;ensuring uniform wall thickness on the upper surface of the casting;adjusting the unpacking and pit lifting process are taken.The production results show that there are no cracks in the 16 column castings of the same model and type,and this kind of cracks have been effectively solved.