高品质镀锡基板夹杂物行为基础研究

发布时间：2018-02-02 20:47

本文关键词： 镀锡基板夹杂物上浮润湿性能卷渣　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：高品质镀锡板在材料强度、硬度、伸长率、塑性应变比等力学性能和洁净度方面要求十分严格,而基板中夹杂物控制成为制约高品质镀锡基板生产的重要环节。围绕镀锡基板夹杂物演变行为,本文开展一系列基础研究工作,并将研究成果应用于某公司镀锡基板生产线,为进一步提高镀锡基板品质提供理论依据。本文主要内容如下:(1)从热力学角度,对精炼及轧制过程的夹杂物演变规律进行系统研究。在此基础上提出了精炼、连铸过程夹杂物演变机制;分析了轧制过程中夹杂物的成分及形貌,提出了镀锡板轧制过程夹杂物的变形机制。(2)基于LF精炼过程中钢液、钢渣及耐火材料的相互作用,建立了钢液/钢渣/夹杂物传质动力学模型,计算结果与工业取样结果吻合。静吹4min时,夹杂物平均成分不能进入低熔点区域,静吹时间提高到8min,平均成分进入低熔点区域。通过计算及工业取样验证表明,钢液中来自于耐材侵蚀的Mg量占钢液中总Mg量的82.9%,耐材侵蚀为钢液中Mg的主要来源。(3)采用液态石蜡模拟钢中液态夹杂物上浮,并对液态夹杂物在上浮过程中的碰撞及在渣钢界面处的行为进行了研究。在体系润湿性一定的前提下,低黏度渣有利于夹杂物的穿过界面。采用物理模拟的方法研究了润湿性能对夹杂物上浮速度的影响。Re1时,润湿性能对粒子上浮匀速速度有显著影响,粒子与水非润湿条件下,阻力系数降低;Re500时,润湿性能对粒子上浮匀速速度无明显影响。非润湿性夹杂物较润湿性夹杂物在中间包内有更高的去除率。液态钙铝酸盐夹杂物在钢液中碰撞后发生完全熔合,形貌为球状;CaS与高熔点钙铝酸盐夹杂物之间未发生熔合,呈串状粘附,这也阻碍了钙铝酸盐的进一步变性。(4)研究了结晶器内钢液卷渣机制,分析了影响卷渣的因素,基于量纲分析原理,对P]V测得的卷渣速度数据进行拟合,得到了临界卷渣速度公式。研究了非牛顿流体保护渣抑制卷渣与润滑性协调机理,设计了高拉速新型水口,提出了水口结构评价指数。
[Abstract]:The mechanical properties and cleanliness of high quality tinplate are very strict in terms of material strength, hardness, elongation, plastic strain ratio, etc. However, the control of inclusions in the substrate becomes an important link to restrict the production of high quality tin plated substrates. A series of basic research work has been carried out around the evolution behavior of the inclusions in the tin plated substrates, and the research results have been applied to the tin plating substrate production line of a company. In order to provide theoretical basis for further improving the quality of tin plated substrate, the main contents of this paper are as follows: 1) from the point of view of thermodynamics, the evolution of inclusions in refining and rolling process is systematically studied. The evolution mechanism of inclusions during continuous casting, the composition and morphology of inclusions in rolling process are analyzed, and the deformation mechanism of inclusions in tinplate rolling process is put forward, which is based on the interaction of molten steel, slag and refractories during LF refining. A mass transfer kinetic model of molten steel / slag / inclusions was established. The calculated results were in agreement with the results of industrial sampling. The average composition of inclusions could not enter the low melting point region after static blowing for 4 min. When the static blowing time is increased to 8 min, the average composition enters the low melting point region. The results of calculation and industrial sampling show that, In molten steel, the amount of mg from corrosion of refractory material accounts for 82.9% of the total amount of mg in molten steel, and corrosion of refractory material is the main source of mg in liquid steel.) liquid paraffin wax is used to simulate the floating of liquid inclusions in steel. The collision of liquid inclusions in the floating process and the behavior at the interface of slag and steel were studied. The effect of wettability on the floating velocity of inclusions was studied by physical simulation. When the resistance coefficient is reduced by Re500, The wettability has no obvious effect on the uniform velocity of particle floating. The non-wettable inclusions have a higher removal rate than the wettable inclusions in the tundish. The morphology shows that there is no fusion between spherical cas and high melting point Calcium-aluminate inclusions, which also hinders the further denaturation of calcium aluminate. (4) the mechanism of molten steel coiled slag in the mold is studied, and the factors influencing the slag winding are analyzed. Based on the dimensionality analysis principle, the critical slag velocity formula was obtained by fitting the data of slag volume velocity measured by P] V. the coordination mechanism between the inhibition of slag volume and lubricity of non-Newtonian fluid mold flux was studied, and a new type of nozzle with high drawing speed was designed. The evaluation index of nozzle structure is put forward.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TF76;TG335.5

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