对铸铁件气孔和气缩孔防止措施的认识

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1、万方数据对铸铁件气孔和气缩孑L防止措施的认识周亘l，王峰1；张全2(1．无锡一汽铸造有限公司，江苏无锡214026；2．无锡汇泉铸品有限公司，江苏无锡214024)摘要：气孔是由铁液内部的气体形成的。降低型砂、芯砂发气量、增加和增大排气眼、平稳浇注等常用气孔防止措施只能排除和减少铁液外围的气体和有限地减少进入铁液内部的气体，但未必能排除已进入铁液内部的气体，因此这些措施防止气孔的作用往往是有限的，并不能彻底消除气孔。排除铁液内部气体是防止气孔的关键，因而要尽量提高液面温度，使液面推迟形成氧化膜，使铁液内

2、部气体在液面被氧化膜封闭之前有充分时间排出。对防止气孔应当注意的其它问题也进行了介绍，指出气缩孔的根源不是气孔而是缩孔，囚此不町能采用防止气孔的方法，只能采用防止缩孔的方法消除气缩孔。还例举了防止气孔和气缩孔的实例。关键词：铸铁；气孔；气缩孔；排气眼；氧化膜中图分类号：TG250．6文献标识码：A文章编号：1003—8345(2011)Z1—0059—12DOI：10．39696．issn．1003-8345．2011．z1．010UnderstandingofMeasurestoPreventBlow

3、holeandShr．nkage—BIOwh0IeDefectsofIronCastingsZHOUGenl，WANGFen91，ZHANGQuan2(1．WuxiFirstAutomotiveFoundryCo．Ltd．，Wuxi214026，China；2．WuxiHuiquanCastingProductsCo．Ltd．，Wuxi214024，China)Abstract：Theblowholeisformedfromthegasinsidetheironmelt．Thecommon—usedme

4、asurestopreventblowholesuchasreducinggasevolutionofthemoldingsandandcoresand，increasingnumberofventingholes，enlargingventingholes，pouringwithoutturbulence，etc．couldonlyremoveorreducethegasoutsidetheironmeltandinalimiteddegreereducethevolumeofthegasenteri

5、ngtheironmelt，buteouldn’tremovethegashavingenteredtheironmelt，thereforetheblowholepreventioneffectofthesemeasureswasoftenlimitedandcouldnotthoroughlyeliminateblowholes．Toremoveoutthegasinsidetheironmeltisthemostimportantkeymeasuretopreventtheblowholeform

6、ation．Andthekeymeasuretoremoveoutthegasinsidetheironmeltistoelevateaftpossiblethetopsurfacetemperatureoftheironmeltinsidethemoldcavityinordertopostponetheoxidefilmformationonthemeltsurfacesothatthereissufficienttimeforthegasinsidetheironmelttoescapethrou

7、ghthetopsurfaceofthemeltbeforethetopSurfacebeingclosedbytheoxidefilm．Someotherproblemswhichshouldbepayattentionstopreventblowholeswereintroduced．Itwaspointedoutthattheshrinkage-blowholeisformednotfromablowhole，butfromashrinkagecavity，andtherefore，itcanbe

8、eliminatednotbyadoptingblowhole—preventingmeasures，butonlybyadoptingshrinkage—preventingmeasures．Somepracticalexamplesofblowholepreventionandshrinkage-blowholepreventionweregiven．Keywords：castiron；blowhole；shrinkage-blowho