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1、內(nèi)蒙古科技大學(xué)碩士學(xué)位論文摘要連鑄技術(shù)是現(xiàn)代煉鋼生產(chǎn)過(guò)程中重要的成型技術(shù),而結(jié)晶器是連鑄機(jī)的心臟,在連鑄過(guò)程中,提高連鑄機(jī)的產(chǎn)量,改善鑄坯的質(zhì)量,延長(zhǎng)結(jié)晶器的壽命,結(jié)晶器錐度都起著決定性的作用。多年來(lái)人們一直在開(kāi)發(fā)許多數(shù)學(xué)模型來(lái)研究結(jié)晶器,但是很少有把結(jié)晶器的錐度曲線(xiàn)計(jì)算出來(lái),所以開(kāi)發(fā)能夠正確反映結(jié)晶器錐度的數(shù)學(xué)模型很有意義。本文對(duì)圓坯①180,①230,①350在結(jié)晶器的凝固過(guò)程中進(jìn)行數(shù)值模擬研究;在準(zhǔn)確計(jì)算鑄坯溫度場(chǎng)分布情況的基礎(chǔ)上,充分的考慮了鑄坯材料物性參數(shù)與溫度相關(guān)的情況,建立了鑄坯熱應(yīng)力的模型。模擬了圓坯①180,①230,m350在凝固過(guò)程中鑄坯不同拉速、不同鋼種的溫度
2、場(chǎng),鑄坯坯殼生長(zhǎng)、收縮規(guī)律。模擬結(jié)果表明,拉速越大,鑄坯在結(jié)晶器里面坯殼厚度越薄,鑄坯的收縮越小,鑄坯在結(jié)晶器出口的表面溫度越大;拉速越小,結(jié)果則相反。模擬結(jié)果還表明,相同規(guī)格的低碳鋼鑄坯在結(jié)晶器的出口溫度,坯殼厚度,收縮量比中碳鋼的要大。本文對(duì)圓坯①180,①230,①350的結(jié)晶器銅管在工作狀態(tài)中進(jìn)行數(shù)值模擬研究;在準(zhǔn)確計(jì)算結(jié)晶器溫度場(chǎng)分布情況的基礎(chǔ)上,充分的考慮了結(jié)晶器的受力狀況及材料物性參數(shù)與溫度相關(guān)的情況,建立了結(jié)晶器熱應(yīng)力的模型。模擬結(jié)果表明拉速越大,結(jié)晶器冷面、熱面的溫度場(chǎng)越高,結(jié)晶器的位移量越大;拉速越小,結(jié)果則相反。相同拉速、相同坯型的低碳鋼銅管的位移量、溫度比中碳
3、鋼的要低。最后本文結(jié)合鑄坯和結(jié)晶器的模擬計(jì)算得出結(jié)晶器理想的錐度曲線(xiàn),并得出不同拉速和鋼種對(duì)結(jié)晶器錐度的影響規(guī)律。結(jié)果表明,結(jié)晶器的最優(yōu)錐度為多錐度的拋物線(xiàn)曲線(xiàn),鑄坯的拉速越大,結(jié)晶器的總錐度越小。中碳鋼結(jié)晶器的總錐度要比低碳鋼的要大。關(guān)鍵詞:圓坯;連鑄;結(jié)晶器;錐度;數(shù)值模擬內(nèi)蒙古科技大學(xué)碩士學(xué)位論文AbstractContinuouscastinghasbeenoneoftheimportantmoldingtechnologiesduringthecourseofsteelmakinginmodemtimes.Andthemouldisthecoreofcontinuousca
4、stingmachine.Thetaperofmouldplaysimportantroleinraisingoutput,improvingthebilltqualityandprolongingthemouldlifespaninthecourseofcontinuouscasting.Themathematicalmodelofmouldhadbeenstudiedformanyyears,butthemouldtapercouldhardlybecalculatedbymathematicalmodel.Hence,thedevelopmentofmathematicalmo
5、delwhichcouldresponsemouldtapercorrectlyissignificant.Thenumericalsimulationofroundbilletinsolidificationprocessisstudiedinthispaper.Thenthemodelofthermo—stressforroundbilletWasdevelopedwithconsideringthematerialthermo—propertiesrelatingtotemperature.Temperaturedistribution,shellgrowthandshrink
6、ageofroundbilletunderdifferentkindsofsteelandspeedaresimulated.Thesimulationresultsshowedthat,thethicknessofbilletbecomesthinner,theshrinkageofshellislowerandthetemperatureofbillethightenswitlltheincreasingofcastingspeed.Atthesamebilletandcastingspeed,thebillettemperature,thickness,shrinkageoft
7、helowcarbonsteelwillhigherthanthemediumcarbonsteel.Thenumericalsimulationofmouldincontinuouscastingofroundbilletisstudiedinthispaper.Thenthemodelofthermo-stressformouldWasdevelopedwithconsideringstressconditionofmouldandthemateria