本文關(guān)鍵詞： 納米碳酸鈣 鎂鈣耐火材料 性能 鋼水　出處：《武漢科技大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：在冶煉高純凈度鋼時(shí),人們往往希望中間包工作襯材料中含有游離的CaO,因?yàn)橛坞xCaO具有凈化鋼水的能力。就中間包工作襯用鎂鈣耐火材料而言,目前較廣泛采用的是通過添加石灰石來提供CaO,其粒度一般在0.5mm以下,但實(shí)踐證明由于中間包包襯結(jié)構(gòu)、厚度等對(duì)傳熱的影響以及包襯中石灰石分解動(dòng)力學(xué)和烘烤時(shí)間等方面的原因,石灰石在中間包烘烤期間并沒有完全分解,連鑄過程中繼續(xù)分解產(chǎn)生的CO_2會(huì)進(jìn)入鋼水中對(duì)鋼水質(zhì)量產(chǎn)生影響,同時(shí)石灰石分解后留下的氣孔孔徑較大,使材料的強(qiáng)度降低。本文以納米碳酸鈣取代石灰石作為氧化鈣源,采用電熔鎂砂和納米碳酸鈣為主要原料,制備了鎂鈣質(zhì)干式料和鎂鈣質(zhì)澆注料,研究納米碳酸鈣添加量對(duì)材料性能的影響。同時(shí)用澆注成型法制備含納米碳酸鈣的MgO-CaO耐火坩堝,在真空感應(yīng)爐中研究其與鋼水反應(yīng)過程中對(duì)鋼中Mn、C元素含量和鋼水總氧含量的影響。研究得到如下結(jié)論:1)將納米碳酸鈣引入到干式料中起到了填充氣孔的作用。經(jīng)1500℃熱處理后的試樣孔徑分布由雙峰分布轉(zhuǎn)變?yōu)閱畏宸植?平均孔徑降低。納米碳酸鈣添加量為2.5wt%時(shí),干式料表觀密度以及強(qiáng)度等性能相對(duì)較好。另外,中間包干式料烘后強(qiáng)度隨著酚醛樹脂加入量的增加有一定提高,考慮到酚醛樹脂分解殘留氣孔對(duì)燒結(jié)的影響,適宜添加量為1.5bwt%。2)將納米碳酸鈣引入到澆注料中,經(jīng)1500℃處理后的試樣孔徑分布由雙峰分布轉(zhuǎn)變?yōu)閱畏宸植?孔徑分布變窄,材料的平均孔徑略有升高。納米碳酸鈣的加入使得材料的強(qiáng)度有不同程度的降低,體積密度下降,顯氣孔率增加。綜合考慮加入量為5wt%較適宜。3)在冶煉過程中納米碳酸鈣分解放出的CO_2氣體會(huì)與鋼水中元素發(fā)生反應(yīng),使得錳鋼鋼水中的Mn、C含量降低,鋼水總氧含量隨冶煉時(shí)間增加先快速升高,后趨于穩(wěn)定。
[Abstract]:When smelting high purity steel, people often expect free Cao in tundish lining because free CaO has the ability of purifying molten steel. In terms of magnesia-calcium refractory for tundish lining. At present, it is widely used to provide Cao by adding limestone, the grain size of which is generally less than 0.5 mm, but it has been proved by practice because of the tundish lining structure. The influence of thickness on heat transfer, the decomposition kinetics and baking time of limestone in the lining, etc., the limestone did not completely decompose during the baking of the tundish. During the continuous casting process, CO_2 produced by continuous decomposition will influence the quality of molten steel, and the pore diameter left by limestone decomposition will be larger. In this paper, magnesia-calcium dry material and magnesia-calcium castable were prepared by using nano-calcium carbonate instead of limestone as calcium oxide source and fused magnesia and nano-calcium carbonate as main raw materials. The effect of nano-CaCO3 addition on the properties of the materials was studied. Meanwhile, the MgO-CaO refractory crucible containing nano-CaCO3 was prepared by pouring molding method. Mn in steel was studied in vacuum induction furnace during reaction with molten steel. Effects of C element content and total oxygen content in molten steel. The pore size distribution was changed from double peak distribution to single peak distribution after heat treatment at 1500 鈩，

本文編號(hào)：1456977