灰铸铁缸体表面异常锈斑产生原因分析

发布时间：2018-02-12 10:46

  本文关键词： 缸体 异常锈斑 夹渣　出处：《热加工工艺》2016年15期 　论文类型：期刊论文

【摘要】：基于发动机缸体在铸造成形后放置过程中出现异常锈斑且人工打磨后反复出现的问题,对缸体表面产生异常锈斑的原因进行了分析研究。通过对锈斑表面和截面两个方向研磨及显微观察发现,在每一异常锈斑的浅表面均存在着大小不等的夹渣。进一步的扫描电镜观察及能谱分析发现,这些夹渣是Ba、Ca、Al、S等外来元素的富集区。分析认为,二次孕育残存在铸件表面并与外界空气相连的夹渣起到了吸潮的作用,使冷芯砂中水分以及空气中的水分子聚集在夹渣附近,并与基体中的铁碳元素发生电化学反应导致了表面异常锈斑的产生。
[Abstract]:Based on the problem of abnormal rust and repeated occurrence after manual grinding, the engine cylinder block is placed in the process of casting and forming. The causes of abnormal rust spot on cylinder surface are analyzed and studied. The grinding and microscopic observation of rust spot surface and section are carried out. There are slag inclusions of different sizes on the shallow surface of each abnormal rust spot. Further scanning electron microscope observation and energy dispersive analysis show that these slag inclusions are rich areas for foreign elements such as Bahcai Alnn S, etc. The residual residue of the second inoculation on the surface of the casting and connected to the outside air plays the role of moisture absorption, which makes the moisture in the cold core sand and the water molecules in the air gather in the vicinity of the slag. The electrochemical reaction with iron and carbon in the matrix leads to the formation of abnormal rust spots on the surface.
【作者单位】： 重庆机电控股集团铸造有限公司;四川大学制造科学与工程学院;
【分类号】：U464.13;TG251
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本文编号：1505450