Under cold box resin sand production condition,the main defects influencing internal cavity cleaness of engine cylinder block and head,as well as their formation mechanisms were described.Combining with the common technical schemes to improve internal cavity cleaness of cylinder block and head in Chinese foundries and existing problems at present,some examples of using cold box core modificator to improve internal cavity cleaness of cylinder block and head were introduced in detail.The production practice showed:(1)Eliminating internal cavity veining defect was the top important target,rationally using the veining-solving process measures was the key to prevent internal cavity sintering fomation (derivation),burning-on worsening,and internal cavity surface coating skin as well as the casting dimensions beyongd tolerance.(2)The cold box core modificator had the practical effects such as eliminating internal cavity veining of castings,inhibiting sand core sintering,reducing internal cavity burning-on,as well as preventing shrinkage deformation,and in addition,had advantages in respect of comprehensive cost.%介绍了冷芯树脂砂生产条件下,影响发动机缸体、缸盖内腔清洁度的主要因素及其形成机理,结合当前国内铸造企业解决发动机缸体、缸盖内腔清洁度的常见技术方案及存在问题,详细阐述了冷芯改性剂对缸体、缸盖内腔清洁度的改善案例.生产实践表明:(1)解决内腔脉纹缺陷是提高内腔清洁度的首要目标,合理采用解决脉纹的工艺措施是防止铸件产生(衍生)内腔烧结、粘砂恶化、内腔表面涂料皮及铸件尺寸超差的关键所在;(2)冷芯改性剂具有消除铸件内腔脉纹、抑制砂芯烧结、缓解内腔表面粘砂及防止铸件收缩变形等实践效果,在综合成本上具有优势.
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