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1、鋁扳坯熱頂一電碰鑄造工藝研充摘要電磁鑄造過(guò)程中金屬液柱在自由表面:狀態(tài)下凝固,是真正的無(wú)模鑄造,極大地改善了鑄錠的表面質(zhì)量。但是,由于電磁鑄造中的電磁攪拌作用以及澆注沖擊使液柱表面氧化膜被破壞并不斷形成新的氧化膜,導(dǎo)致電磁鑄造鑄錠表面和內(nèi)部產(chǎn)生氧化夾雜,并增加了鑄錠的含氣量。本文在鋁板坯電磁鑄造中應(yīng)用熱頂電磁鑄造思想,進(jìn)行了實(shí)驗(yàn)和模擬研究,得到具有~定指導(dǎo)意義的研究結(jié)果:1.設(shè)計(jì)了一整套鋁板坯熱項(xiàng)一電磁鑄造裝置.設(shè)計(jì)了多種屏蔽罩結(jié)構(gòu),測(cè)量了相關(guān)條件下的磁感應(yīng)強(qiáng)度分布,研究了磁場(chǎng)的分布規(guī)律,確定了實(shí)驗(yàn)所需的電源功率
2、以及實(shí)驗(yàn)的凝固界面位置:2.實(shí)驗(yàn)表明,對(duì)開式屏蔽罩與整體式屏蔽罩相比,既有效地抑制了液柱頂部磁場(chǎng),保證液柱的穩(wěn)定,又不明顯削弱液~固界面區(qū)域的磁感應(yīng)強(qiáng)度,有利于實(shí)現(xiàn)半懸浮成型條件:3.進(jìn)行了大量的拉坯實(shí)驗(yàn),確定了澆注溫度、液柱高度和冷卻水量等相關(guān)工藝參數(shù),鑄造出光滑的鑄錠,發(fā)現(xiàn)夾雜均被熱頂滯留在鑄錠的頂面,被阻止進(jìn)入鑄錠內(nèi)部和表面,證明熱頂確實(shí)有效消除了鑄錠的夾雜缺陷;4.對(duì)熱頂一電磁鑄造鑄錠試樣進(jìn)行含氣量分析,發(fā)現(xiàn)試樣的含氣量比普通連續(xù)鑄造、電磁鑄造和電磁連鑄的試樣的含氣量均低,從另一方面證明了熱頂增強(qiáng)了系統(tǒng)的
3、穩(wěn)定性,起到了截留夾雜的效果:5.對(duì)鋁圓錠熱頂~電磁連鑄技術(shù)進(jìn)行了相關(guān)實(shí)驗(yàn)研究,確定了合理的工藝參數(shù),制作出表面優(yōu)于電磁連鑄的鋁圓錠;6.利用有限元軟件,對(duì)鋁扁錠熱項(xiàng)一電磁鑄造系統(tǒng)磁場(chǎng)進(jìn)行了數(shù)值模擬計(jì)算。關(guān)鍵詞:電磁鑄造,熱頂.夾雜,含氣量,磁場(chǎng),數(shù)值模擬鋁扳坯熱頂一電磁鑄造丁藝研究ABSTRAOTMoltenmetaIsolidifiesinfreesurfacestateduringelectromagneticcastingfEMClprocessEMCisrealnon—moldfoundWwhichim
4、provessurfacequalityofingotgreatly.ButthecontinuouslynewbornoxidefilminthesurfaceofliquidcolumnisdamagedbytheelectromagneticstirringinEMCandthepouring—inliquidmetal.whichresultsinthegenerationofinclusionintheinnerandsurfaceofingots.Andaircontentofingotsincrea
5、sestooInthispaper,thethoughtofhot-topEMCisusedinaluminumslabEMC.a(chǎn)ndalotofexperimentalandsimulantresearchesareproceeded,basedonwhich,someresultswithguidingmeaninghavebeenobtained.Awholesetofhot.topEMCdevicesofaluminumslabandsometypesofscreenstructuresweredesig
6、ned.Thedistributionofmagneticfieldundercorrelatedconditionswasmeasured.Andthedistributionruleofitwasresearched.basedonwhich,fheneededpowersupplyandthepositionoffreezinginterfaceweredetermined.Itisindicatedbyexperimentalresultthat,comparedwithintegralscreen,sp
7、litscreencannotonlydepressesmagneticfieldinthetopofliquidcolumn,whichensuresthestabilizationofliquidcolumn.butalsodoesnotweakenmagneticfieldintheregionofliquid.solidboundaryobviously,whichisfavorableformeetingthehalf-suspendingconditionofmolding.Therationalte
8、chniqueparameterssuchasthepositionofthefreezinginterface,pouringtemperature,coolingwaterstrengthandthehe!ightofliquidcolumnwereobtainedbylotsofexperimentsIngotswithsmoothsurfaceweregained