熔渗法制备结晶器铜板表面改性层的基础研究

发布时间：2019-07-01 11:20

【摘要】：近来,连铸结晶器铜板表面改性层的制备技术成为钢铁冶炼行业的研究热点。连铸结晶器铜板表面改性层的要求主要是具有高的耐磨性,及改性层与基体间有较好的传热性能和结合力。目前,国内外有关连铸结晶器铜板表面改性层的制备技术主要有电镀、化学镀、热喷涂和高温自蔓延等,其中应用最为广泛的是电镀技术。这些表面改性技术,虽然在一定程度上提高了结晶器铜板表面的耐磨性,但是改性层的导热率较低,并且改性层与铜基板的结合力不高。而W-Cu/WC-Cu复合材料,具有高硬度、耐磨性以及良好的导热导电性能,并且可以调整铜含量达到与基体铜板之间形成较好的冶金结合。因此,我们将粉末冶金方法引进到结晶器铜板表面改性技术中,通过熔渗法制备W-Cu/WC-Cu改性层,为W-Cu/WC-Cu改性层在结晶器铜板上的实际应用,做好基础研究。本论文主要是从钨骨架烧结温度、钨粉末粒度、熔渗方式三个方面来优化W-Cu改性层的制备工艺,从骨架烧结温度、熔渗温度以及碳化钨粉末粒度三个方面来优化WC-Cu改性层的制备工艺。结果得出： (1)最佳的W-Cu40改性层制备工艺为：采用-300目W粉,1300℃保温烧结钨骨架,并在1350℃测渗,制备的改性层组织最均匀,且致密度高； (2)最佳的WC-Cu50改性层制备工艺：采用粒径1μm的WC颗粒,1120℃烧结碳化钨骨架,并在1350℃熔渗,制备的改性层组织均匀、致密度高。实验还通过测量密度、摩擦磨损实验、剪切实验、热疲劳实验,检测材料的致密度、耐磨性能、界面结合强度以及界面抗热疲劳性能。摩擦实验结果表明：(1)W-Cu合金改性层的耐磨性远远高于Ni；随着W-Cu40改性层中W颗粒粒径的增大,耐磨性降低；随钨含量增加,W-Cu合金改性层的耐磨性能提高； (2)制备的WC-Cu50改性层具优异的耐磨性能,且随着WC颗粒粒径的减小,制备的改性层的耐磨性能提高。剪切实验结果表明：W-Cu40改性层与铜基板之间的结合较好,界面剪切时从基体铜端断裂。热疲劳实验结果表明：(1)W-Cu40改性层具有良好的抗热疲劳性能。随着W-Cu合金改性层中钨含量的增加,经冷热循环后产生的疲劳裂纹越宽；随W-Cu合金改性层中W颗粒粒径的增大,经冷热循环后产生的疲劳裂纹可能性降低,产生裂纹的宽度也较窄；随实验温度的提高,W-Cu合金改性层界面处裂纹普遍变宽；(2)不同粒径的WC颗粒制备的WC-Cu50改性层经600℃水冷循环200次界面未发现裂纹,改性层具有较好的抗热疲劳性能。
[Abstract]:Recently, the preparation technology of the surface modified layer of the copper plate of the continuous casting crystallizer has become the hot spot in the iron and steel smelting industry. The requirement of the surface modification layer of the copper plate of the continuous casting crystallizer is mainly to have high wear resistance and good heat transfer performance and binding force between the modified layer and the substrate. At present, the preparation technology of the surface modification layer of the copper plate of the continuous casting crystallizer at home and abroad is mainly electroplating, chemical plating, thermal spraying and high-temperature self-propagation. The surface modification technology improves the wear resistance of the surface of the crystallizer copper plate to a certain extent, but the thermal conductivity of the modified layer is low, and the bonding force between the modified layer and the copper substrate is not high. And the W-Cu/ WC-Cu composite material has high hardness, wear resistance and good thermal conductivity, and can adjust the copper content to form a good metallurgical bond with the base copper plate. Therefore, we introduced the powder metallurgy method to the surface modification technology of the crystallizer copper plate, and the W-Cu/ WC-Cu modified layer was prepared by the infiltration method, and the W-Cu/ WC-Cu modified layer was applied to the crystallizer copper plate, and the basic research was made. The preparation technology of W-Cu modified layer was optimized from three aspects of the sintering temperature of the tungsten skeleton, the particle size of the tungsten powder and the infiltration mode, and the preparation of the WC-Cu modified layer was optimized from three aspects of the sintering temperature, the infiltration temperature and the particle size of the tungsten carbide powder. Process. Results The preparation method of (1) the optimal W-Cu40 modified layer comprises the following steps of: (1) preparing the W-Cu40 modified layer by using -300-mesh W powder and 1300 DEG C for sintering the tungsten skeleton, and measuring the permeability at the temperature of 1350 DEG C, so that the prepared modified layer structure is the most uniform; and (2) the best WC-Cu5 The preparation process of the 0 modified layer comprises the following steps of: adopting WC particles with a particle size of 1 & mu; m, sintering the tungsten carbide framework at 1120 & deg; C, and fusing at 1350 & deg; C to prepare the modified layer group; In that experiment, the density, the friction and wear experiment, the shear test, the thermal fatigue experiment, the density of the test material, the wear resistance, the bond strength of the interface and the strength of the interface are also measured by the experiment. The results of the friction experiments show that (1) the wear resistance of the W-Cu alloy modified layer is much higher than that of Ni; with the increase of the particle size of W particles in the W-Cu40 modified layer, the wear resistance is decreased; and the W-Cu alloy is modified with the increase of the tungsten content. The wear resistance of the layer is improved; (2) the prepared WC-Cu50 The modified layer has excellent wear resistance and is prepared with the reduction of the particle size of the WC particles. The results of the shear test show that the bonding between W-Cu40 modified layer and copper substrate is higher. The results of thermal fatigue test show that: (1) W-C The modified layer of the W-Cu alloy has good thermal fatigue resistance. With the increase of the tungsten content in the W-Cu alloy modified layer, the wider the fatigue crack generated after the cold and hot cycle, the possibility of the fatigue crack generated after the cold and hot circulation is reduced with the increase of the particle size of the W particles in the W-Cu alloy modified layer, The width of the crack is also narrow; with the increase of the experimental temperature, the crack in the interface of the W-Cu alloy modified layer is generally widened; (2) the WC-Cu50 modified layer prepared by the WC particles with different grain diameters is not found through the 200-time interface of the water-cooling cycle of 600 DEG C
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TF341.6

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