壓鑄過(guò)程壓室及鑄型界面?zhèn)鳠岬难芯?/H1>
發(fā)布時(shí)間：2019-06-15 01:03
【摘要】：壓鑄作為一種先進(jìn)的金屬成形方法,具有生產(chǎn)效率高、鑄件尺寸精度好、力學(xué)性能優(yōu)良、易于成形薄壁復(fù)雜零件等優(yōu)點(diǎn),廣泛地應(yīng)用于汽車、航空航天、通信電子等領(lǐng)域。壓鑄過(guò)程中液態(tài)金屬與壓室及鑄型的界面換熱決定了鑄件凝固的初始狀態(tài)和凝固方式,是影響鑄件質(zhì)量的重要因素之一。因此,研究整個(gè)壓鑄過(guò)程中的傳熱條件,確定液態(tài)金屬與壓室及鑄型之間的界面換熱系數(shù),建立精確有效的界面?zhèn)鳠釛l件,對(duì)于優(yōu)化壓鑄工藝、預(yù)測(cè)和控制鑄件質(zhì)量、避免鑄造缺陷的產(chǎn)生以及模擬仿真技術(shù)在壓鑄行業(yè)的發(fā)展具有非常重要的意義。論文采用實(shí)驗(yàn)和數(shù)值模擬相結(jié)合的方法,對(duì)壓鑄過(guò)程液態(tài)金屬與壓室及鑄型之間的界面?zhèn)鳠釂?wèn)題進(jìn)行了系統(tǒng)的研究。研究了采用熱傳導(dǎo)反算法確定界面換熱系數(shù)這類反問(wèn)題的測(cè)溫難點(diǎn),設(shè)計(jì)了用于研究壓鑄界面換熱的測(cè)溫方案,包括通用測(cè)溫單元、專用測(cè)溫壓室以及實(shí)際壓鑄模具,系統(tǒng)進(jìn)行了壓鑄測(cè)溫實(shí)驗(yàn),精確地獲得了不同工藝條件下壓室及鑄型內(nèi)部的溫度數(shù)據(jù)。深入研究了熱傳導(dǎo)反問(wèn)題的求解技術(shù)和凝固過(guò)程的界面換熱機(jī)制,耦合液態(tài)金屬在壓室及鑄型中的溫度場(chǎng)求解,建立了考慮液態(tài)金屬在壓室流動(dòng)的界面?zhèn)鳠岫S反算模型,優(yōu)化了未來(lái)時(shí)間步長(zhǎng),分析了反算模型的穩(wěn)定性條件,確定了壓鑄過(guò)程反算參數(shù)選擇的可接受域,開(kāi)發(fā)了壓鑄全過(guò)程界面?zhèn)鳠岱辞蟪绦�。基于界面�(zhèn)鳠岱此隳Ｐ图俺绦?系統(tǒng)求解了液態(tài)金屬在壓室中的溫度場(chǎng)及其不同位置的界面換熱系數(shù),結(jié)果表明靜態(tài)無(wú)壓射條件與常規(guī)壓鑄條件下液態(tài)金屬與壓室界面換熱情況存在較大差異。同時(shí),壓室中部界面換熱系數(shù)均隨液態(tài)金屬流動(dòng)方向依次降低,壓室壁溫度也存在兩端高中間低的分布。在常規(guī)壓鑄條件下,由于沖頭運(yùn)動(dòng)的影響,壓室末端換熱系數(shù)存在雙峰現(xiàn)象。分析了填充率、合金、低速、高速和增壓等工藝參數(shù)的影響,預(yù)測(cè)了壓室預(yù)結(jié)晶組織(ESCs)的形核及在鑄件中分布。研究了液態(tài)金屬與鑄型界面換熱系數(shù)的變化規(guī)律分析了充型過(guò)程及工藝參數(shù)的影響,建立了金屬與鑄型界面換熱邊界模型,并用于實(shí)際壓鑄件溫度場(chǎng)的求解和熱平衡分析,驗(yàn)證了反算模型的合理性。
[Abstract]:Die casting, as an advanced metal forming method, has many advantages, such as high production efficiency, good dimensional accuracy, excellent mechanical properties, easy to form thin-wall complex parts and so on. It is widely used in automobile, aerospace, communication electronics and other fields. The interface heat transfer between liquid metal and die chamber and mold determines the initial state and solidification mode of casting solidification, which is one of the important factors affecting the quality of castings. Therefore, it is of great significance to study the heat transfer conditions in the whole die casting process, to determine the interfacial heat transfer coefficient between liquid metal and die chamber and mold, and to establish accurate and effective interface heat transfer conditions for optimizing die casting process, predicting and controlling casting quality, avoiding casting defects and the development of simulation technology in die casting industry. In this paper, the interfacial heat transfer between liquid metal and die chamber and mold in die casting process is studied systematically by means of experiment and numerical simulation. The temperature measurement difficulty of determining interface heat transfer coefficient by heat conduction inverse algorithm is studied. The temperature measurement scheme used to study interface heat transfer in die casting is designed, including general temperature measurement unit, special temperature measuring pressure chamber and actual die casting die. The temperature measurement experiment of die casting is carried out, and the temperature data of die chamber and mold under different technological conditions are obtained accurately. The solving technology of inverse heat conduction problem and the interface heat transfer mechanism of solidification process are deeply studied, and the temperature field of liquid metal in pressure chamber and mold is solved. A two-dimensional inverse calculation model of interface heat transfer considering liquid metal flow in pressure chamber is established, the future time step is optimized, the stability condition of reverse calculation model is analyzed, and the receiving region of reverse calculation parameter selection in die casting process is determined. The reverse heat transfer program at the interface of die casting process is developed. Based on the inverse calculation model and program of interface heat transfer, the temperature field of liquid metal in pressure chamber and its interfacial heat transfer coefficient at different positions are solved systematically. the results show that the interface heat transfer between liquid metal and pressure chamber under static non-injection condition is quite different from that under conventional die casting condition. At the same time, the heat transfer coefficient of the middle interface of the pressure chamber decreases with the flow direction of liquid metal, and the temperature of the pressure chamber wall also has the distribution of high and low temperature at both ends. Under the condition of conventional die casting, due to the influence of punch movement, there is a bimodal phenomenon in the heat transfer coefficient at the end of the pressure chamber. The effects of filling rate, alloy, low speed, high speed and supercharging on the process parameters were analyzed, and the nucleation and distribution of (ESCs) in castings were predicted. The variation of heat transfer coefficient between liquid metal and mold was studied. The influence of filling process and process parameters was analyzed. The boundary model of heat transfer between metal and mold was established and applied to the solution of temperature field and thermal balance analysis of actual die castings, and the rationality of the reverse calculation model was verified.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG249.2
【相似文獻(xiàn)】
相關(guān)期刊論文 前10條
1 ;壓鑄監(jiān)測(cè)儀──壓鑄過(guò)程控制的有力工具[J];特種鑄造及有色合金;1995年01期
2 汪誠(chéng);壓鑄過(guò)程利用爆炸法進(jìn)行補(bǔ)縮的初步試驗(yàn)與探討[J];特種鑄造及有色合金;1983年02期
3 吳亮,熊守美,柳百成;應(yīng)用分?jǐn)?shù)步長(zhǎng)法進(jìn)行壓鑄過(guò)程溫度場(chǎng)數(shù)值模擬研究[J];鑄造;1998年11期
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5 周玉輝;吳衛(wèi);周華彬;張光明;;壓鑄模使用壽命與優(yōu)化壓鑄過(guò)程控制[J];鑄造設(shè)備研究;2005年06期
6 呂福寶;壓鑄過(guò)程中加熱—冷卻循環(huán)的監(jiān)控系統(tǒng)[J];柴油機(jī)設(shè)計(jì)與制造;1995年01期
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相關(guān)會(huì)議論文 前5條
1 羅朝\，
本文編號(hào)：2499847
本文鏈接：http://sikaile.net/kejilunwen/jinshugongy/2499847.html
[Abstract]:Die casting, as an advanced metal forming method, has many advantages, such as high production efficiency, good dimensional accuracy, excellent mechanical properties, easy to form thin-wall complex parts and so on. It is widely used in automobile, aerospace, communication electronics and other fields. The interface heat transfer between liquid metal and die chamber and mold determines the initial state and solidification mode of casting solidification, which is one of the important factors affecting the quality of castings. Therefore, it is of great significance to study the heat transfer conditions in the whole die casting process, to determine the interfacial heat transfer coefficient between liquid metal and die chamber and mold, and to establish accurate and effective interface heat transfer conditions for optimizing die casting process, predicting and controlling casting quality, avoiding casting defects and the development of simulation technology in die casting industry. In this paper, the interfacial heat transfer between liquid metal and die chamber and mold in die casting process is studied systematically by means of experiment and numerical simulation. The temperature measurement difficulty of determining interface heat transfer coefficient by heat conduction inverse algorithm is studied. The temperature measurement scheme used to study interface heat transfer in die casting is designed, including general temperature measurement unit, special temperature measuring pressure chamber and actual die casting die. The temperature measurement experiment of die casting is carried out, and the temperature data of die chamber and mold under different technological conditions are obtained accurately. The solving technology of inverse heat conduction problem and the interface heat transfer mechanism of solidification process are deeply studied, and the temperature field of liquid metal in pressure chamber and mold is solved. A two-dimensional inverse calculation model of interface heat transfer considering liquid metal flow in pressure chamber is established, the future time step is optimized, the stability condition of reverse calculation model is analyzed, and the receiving region of reverse calculation parameter selection in die casting process is determined. The reverse heat transfer program at the interface of die casting process is developed. Based on the inverse calculation model and program of interface heat transfer, the temperature field of liquid metal in pressure chamber and its interfacial heat transfer coefficient at different positions are solved systematically. the results show that the interface heat transfer between liquid metal and pressure chamber under static non-injection condition is quite different from that under conventional die casting condition. At the same time, the heat transfer coefficient of the middle interface of the pressure chamber decreases with the flow direction of liquid metal, and the temperature of the pressure chamber wall also has the distribution of high and low temperature at both ends. Under the condition of conventional die casting, due to the influence of punch movement, there is a bimodal phenomenon in the heat transfer coefficient at the end of the pressure chamber. The effects of filling rate, alloy, low speed, high speed and supercharging on the process parameters were analyzed, and the nucleation and distribution of (ESCs) in castings were predicted. The variation of heat transfer coefficient between liquid metal and mold was studied. The influence of filling process and process parameters was analyzed. The boundary model of heat transfer between metal and mold was established and applied to the solution of temperature field and thermal balance analysis of actual die castings, and the rationality of the reverse calculation model was verified.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG249.2
【相似文獻(xiàn)】
相關(guān)期刊論文 前10條
1 ;壓鑄監(jiān)測(cè)儀──壓鑄過(guò)程控制的有力工具[J];特種鑄造及有色合金;1995年01期
2 汪誠(chéng);壓鑄過(guò)程利用爆炸法進(jìn)行補(bǔ)縮的初步試驗(yàn)與探討[J];特種鑄造及有色合金;1983年02期
3 吳亮,熊守美,柳百成;應(yīng)用分?jǐn)?shù)步長(zhǎng)法進(jìn)行壓鑄過(guò)程溫度場(chǎng)數(shù)值模擬研究[J];鑄造;1998年11期
4 熊守美;郭志鵬;;壓鑄過(guò)程鑄件-鑄型界面換熱行為的研究進(jìn)展[J];鑄造技術(shù);2008年09期
5 周玉輝;吳衛(wèi);周華彬;張光明;;壓鑄模使用壽命與優(yōu)化壓鑄過(guò)程控制[J];鑄造設(shè)備研究;2005年06期
6 呂福寶;壓鑄過(guò)程中加熱—冷卻循環(huán)的監(jiān)控系統(tǒng)[J];柴油機(jī)設(shè)計(jì)與制造;1995年01期
7 陳照;李曉棠;萬(wàn)旭;;氣塞體鑄件壓鑄過(guò)程的數(shù)值模擬[J];機(jī)械制造與自動(dòng)化;2010年02期
8 江鴻,吳衛(wèi),周桂云;壓鑄過(guò)程中飛邊產(chǎn)生及其防治的研究[J];電加工與模具;2005年01期
9 江鴻,吳衛(wèi),周桂云;關(guān)于壓鑄過(guò)程中飛邊產(chǎn)生及其防治的研究[J];四川工業(yè)學(xué)院學(xué)報(bào);2004年S1期
10 李世釗;吳樹(shù)森;方健儒;周承廣;萬(wàn)里;;汽車變速箱殼體的壓鑄過(guò)程模擬及工藝優(yōu)化[J];特種鑄造及有色合金;2011年04期
相關(guān)會(huì)議論文 前5條
1 羅朝\，
本文編號(hào)：2499847
本文鏈接：http://sikaile.net/kejilunwen/jinshugongy/2499847.html
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