高镍奥氏体球墨铸铁涡壳的铸造工艺优化  

Casting Technology Optimization of High-Ni Austenite Nodular Iron Volute Housing

作　　者：程凤军 CHENG Feng-jun(Changzhou Vocational Institute of Industry Technology,Changzhou 213164,China)

机构地区：[1]常州工业职业技术学院,江苏常州213164

出　　处：《现代铸铁》2024年第1期5-9,53,共6页Modern Cast Iron

摘　　要：介绍了高镍奥氏体球墨铸铁涡壳铸件的结构及铸造工艺,针对试制过程中出现的表面缩孔、缩松、显微缩松以及组织中的碎块状石墨、表面恶化层、碳化物等问题进行了工艺优化,最后指出:(1)高镍奥氏体球墨铸铁液态收缩量大、石墨化膨胀弱,冒口设计遵循顺序凝固原则是防止涡壳产生缩孔、缩松缺陷的有效措施;(2)涡壳厚处和舌尖易形成碎块状石墨,强化孕育可防止缺陷的产生;(3)表面恶化层超标,可通过较高的残余镁量和砂芯刷涂料进行防止;(4)由于冷却速度较慢,舌尖部位碳化物析出数量较多,良好的孕育可减少碳化物析出量,热处理也可改变碳化物体积分数及其形态。The structure and production technology of a high-Ni nodular iron volute housing casting were introduced.In order to eliminate the defects including surface shrinkage cavities,shrinkage porosities,micro-shrinkage porosities and chunky graphite,surface worsening layer,carbide,the casting technology optimization was conducted.Finally,pointed out:(1)Since the liquid contraction rate of the high-Ni austenite nodular iron was high,its graphite expansion volume was less,to design the riser according the directional solidification principle was the effective measure to prevent shrinkage cavities and porosities of volute housing.(2)Since chunky graphite was easy to occur in the thick place and the tongue tip of the volute housing,intensifying inoculation could prevent such type defect.(3)Surface worsening layer exceeding standard could be avoided by relatively higher residual Mg content and brushing the sand cores with coating.(4)Since cooling rate being slower,more amount carbide precipitated in the tongue tip place,good inoculation could reduce carbide precipitating amount,and heat treatment could also change the volume fraction and morphology of the carbide.

关 键 词：球墨铸铁 碎块状石墨 碳化物 显微缩松 

分 类 号：TG255[金属学及工艺—铸造]