【摘要】：工藝?yán)鋮s和潤滑是冷軋技術(shù)的核心之一,在傳統(tǒng)的冷軋工藝中,一般采用乳化液進(jìn)行潤滑和冷卻,針對傳統(tǒng)乳化液和純油軋制存在的問題和不足,本文提出一種利用液氮來代替乳化液進(jìn)行冷卻和潤滑的新型技術(shù)方案,有望解決傳統(tǒng)冷軋過程中存在的乳化液污染,循環(huán)系統(tǒng)維護(hù)困難以及帶材表面質(zhì)量難以控制的問題。本研究就是針對液氮冷卻和潤滑給冷軋潤滑理論和冷卻系統(tǒng)設(shè)計(jì)等帶來的一系列新問題而提出的,通過該研究,不但可以弄清液氮在冷軋過程中的冷卻和潤滑機(jī)制,為液氮的控制與合理利用提供科學(xué)依據(jù),而且有望建立新的冷軋冷卻潤滑系統(tǒng),為新一代軋制冷卻和潤滑技術(shù)的開發(fā)提供了新思路。論文主要工作和研究結(jié)果如下： (1)通過對液氮噴射過程的理論分析和計(jì)算,以液氮穩(wěn)定膜態(tài)沸騰理論為基礎(chǔ),提出了理論換熱系數(shù)計(jì)算模型,分析了單一變量對液氮噴射換熱系數(shù)的影響,在此基礎(chǔ)上進(jìn)行了液氮噴射冷卻軋輥實(shí)驗(yàn)研究,通過理論分析,給出了各個實(shí)驗(yàn)參數(shù)對換熱系數(shù)的影響,最后通過數(shù)學(xué)方法回歸出了各參數(shù)與換熱系數(shù)的模型公式,為液氮應(yīng)用冷軋軋輥溫度場的計(jì)算奠定了基礎(chǔ)。 (2)液氮應(yīng)用冷軋條件下,其強(qiáng)冷性會對軋材和軋輥的性能產(chǎn)生影響,因此對軋輥材質(zhì)和帶材的低溫特性進(jìn)行了實(shí)驗(yàn)研究,分別對其進(jìn)行了低溫壓痕硬度測試、拉伸和沖擊試驗(yàn),帶材在-20℃時沖擊功明顯下降,隨著冷卻溫度的下降,軋材和軋輥的硬度、強(qiáng)度都有所提高。 (3)液氮冷卻潤滑可明顯降低帶鋼表面殘油和殘鐵含量,提高冷軋后帶鋼表面清潔性；液氮冷卻潤滑下冷軋帶鋼獲得了比傳統(tǒng)方式更低的帶鋼溫度和軋輥溫度；利用Hill軋制力反算了軋制過程中的摩擦系數(shù),得出液氮冷軋過程的摩擦系數(shù),確定液氮冷卻潤滑下潤滑狀態(tài)為邊界潤滑。 (4)對液氮在平整軋制過程中的應(yīng)用可行性進(jìn)行了實(shí)驗(yàn)研究,結(jié)果表明,液氮在大延伸率和小延伸率平整過程中都表現(xiàn)出了很好的延伸率和軋制力控制穩(wěn)定性,液氮的應(yīng)用還提高了軋輥對帶鋼的遺傳復(fù)制率,獲得了更好的軋后帶鋼表面粗糙度,延長軋輥的使用周期。
[Abstract]:Process cooling and lubrication are the core of cold rolling technology. In the traditional cold rolling process, emulsion is generally used to lubricate and cool, aiming at the problems and shortcomings of traditional emulsion and pure oil rolling. In this paper, a new technical scheme of cooling and lubricating with liquid nitrogen instead of emulsion is proposed, which is expected to solve the problems of emulsion contamination in traditional cold rolling process, difficult maintenance of circulating system and difficult control of strip surface quality. This study is aimed at a series of new problems brought by liquid nitrogen cooling and lubrication to cold rolling lubrication theory and cooling system design. Through this study, not only the cooling and lubrication mechanism of liquid nitrogen in cold rolling process can be clarified. It provides a scientific basis for the control and rational utilization of liquid nitrogen, and it is expected to establish a new cold rolling cooling lubrication system, which provides a new idea for the development of a new generation of rolling cooling and lubrication technology. The main work and results are as follows: (1) based on the theoretical analysis and calculation of liquid nitrogen injection process, a theoretical model of heat transfer coefficient is proposed based on the theory of liquid nitrogen stable film boiling. The influence of a single variable on the heat transfer coefficient of liquid nitrogen injection is analyzed. Based on this, the experimental study of liquid nitrogen spray cooling roller is carried out. The influence of each experimental parameter on the heat transfer coefficient is given through theoretical analysis. Finally, the model formulas of each parameter and heat transfer coefficient are regressed by mathematical method, which lays a foundation for the calculation of temperature field of cold rolling roll with liquid nitrogen. (2) under the condition of cold rolling with liquid nitrogen, its strong chilling property will affect the properties of rolling material and roll. Therefore, the low temperature properties of roll material and strip are studied experimentally, and the hardness of indentation at low temperature, tensile test and impact test are carried out respectively. The impact energy of strip decreased obviously at -20 鈩，

本文編號：2256025