共查询到19条相似文献,搜索用时 234 毫秒
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综述国内外准沸腾钢连铸技术发展概况,对不同的准沸腾钢连铸技术工艺路线及其技术关键进行探讨,对铸坯皮下气泡的形成机理进行分析研究,在此基础上探讨马钢开发准沸腾钢的必要性和可行性。 相似文献
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通过对有关文献的评述,讨论了连铸板坯皮下气泡的形成原因和分布特点,说明连铸过程中组合式结晶器角缝中上升气流吹入钢水可造成连铸坯皮下气泡。降低钢水过热度、降低拉速以促使结晶器内钢水尽快形成稳定坯壳,从而可以抵抗气流吹入,减轻皮下气泡的形成。由于在组合式结晶器内连铸坯皮下气泡的产生是难以避免的,所以棒材生产线的方坯连铸机不宜采用组合式结晶器,采用管式结晶器是当前的发展趋势。 相似文献
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分析冷轧板表面线状缺陷的形貌特征,将冷轧板表面线状缺陷分为三类,分别为“线状起皮”、“黑线”、“亮线”。通过对各类线状缺陷的分析,得出了线状缺陷的形成原因。结果表明,“线状起皮”和“黑线”是由连铸坯表面皮下夹渣引起的。“亮线”则是由于轧制辊印、钢板表面花纹不同、连铸坯表面微裂纹、连铸坯皮下夹渣、热轧轧破的连铸坯皮下气泡等原因引起的。 相似文献
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连铸中间罐工作衬喷涂料及其应用 总被引:1,自引:0,他引:1
我公司二炼钢连铸中间罐工作衬,采用硅质绝热板时,其铸坯头部皮下气泡严重。引进奥地利奥镁公司连铸中间罐工作衬用喷涂料后,铸坯质量有所改善。本文介绍了喷涂料的性能、施工过程及其使用效果。 相似文献
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本文对转炉低碳、低硅钢小方坯连铸的难点进行了理论分析,认为钢中含氧量是造成小方坯皮下产生气泡的主要原因。通过试验取得与理论计算基本一致的结果。 相似文献
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基于45钢连铸坯生产工艺,实验研究了Ar气泡在铸坯凝固过程中的运动行为,并结合计算机模拟探讨了铸坯捕获气泡的深层机理。结果表明,Ar气泡被铸坯捕获是导致连铸坯气孔缺陷产生、影响铸坯质量的重要原因。 相似文献
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熔模铸钢件气孔的产生与防止 总被引:2,自引:0,他引:2
将熔模铸钢件的气孔分为析出性、侵入性、卷入性3种类型,其中析出性气孔又分为过溶析出性和反应析出性两类,详细论述了熔模铸钢件这几类气孔的形态、产生原因及防止措施。 相似文献
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针对采用水玻璃、树脂等作为粘结剂进行铸件表面合金化时,合金层中容易产生气孔、夹渣缺陷的问题,研究了一种铸件表面合金化新工艺,即加入一种YB成型剂将合金粉末压制成块的方法进行表面合金化,在铸钢ZG65Mn本体表面得到高含Cr、W等元素的合金化层。结果表明,通过消失模铸造工艺,使用YB成型剂较好地消除了水玻璃等粘结剂造成的气孔、夹渣,合金化层和本体之间实现了冶金结合;合金化层具有较好的耐磨性和耐热性能,加入WC后耐磨性可达本体材料的4.82倍,抗氧化性能提高50%左右,且合金化粉末压块放置操作简便、可靠。 相似文献
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叙述灰铸铁件裂隙状氮气孔的主要特征、形成机理。铁液含氮量高引起的氮气孔的防止方法是:铁液中加入钛铁,降低铸铁白口倾向和正确选用增碳剂。防止树脂砂含氮量高引起的氮气孔的方法是:选用低氮树脂、型砂或涂料中加入氧化铁粉和避免树脂受潮。 相似文献
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Dr. C. R. Chakravorty Dr. M. Chakraborty 《International Journal of Cast Metals Research》2013,26(1):37-42
AbstractMetal-mould reactions in casting Al-Li alloys in sodium-silicate-bonded sand moulds have been studied by the modified Gertsman technique. Molten Al-2.7% Li alloy was poured into a bottom-gated vertical cylindrical mould cavity (150 mm x 50 mm dia) made from no-bake organic-binder-based sands. At the bottom of the mould cavity, a standard AFS three-ram sodium-silicate-bonded sand sample (the test sample) was placed vertically to provide the necessary interface for investigation. After cooling, the reaction products formed at the interface and samples from the bottom portion of the castings were collected for investigation. These were analysed to find Li loss from the casting as a result of metal-mould reactions. The casting was vertically sectioned and visually observed for appearance of blow holes, if any, while the sub-surface was studied for microhardness variation. The as-cast surface and the reaction products were also studied by SEM and X-ray diffraction analysis.The study reveals that the Li in the molten alloy enters into vigorous chemical reaction with the sodium silicate resulting in the release of metallic sodium and formation of reaction products containing αLithium aluminium meta silicate. Li is thus lost from near the surface of the casting. Probably, the sodium released causes the gas blow holes in the sub-surface of castings due to its high vapour pressure at the working temperature. 相似文献
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A laser lap welding process for zinc-coated steel has a well-known unsolved problem-porosity formation. The boiling temperature of coated zinc is lower than the melting temperature of the base metal, which is steel. In the autogenous laser welding, the zinc vapor generates from the lapped surfaces expels the molten pool and the expulsion causes numerous weld defects, such as spatters and blow holes on the weld surface and porosity inside the welds. The laser-arc hybrid welding was suggested as an alternative method for the laser lap welding because the arc can preheat or post-heat the weldment according to the arrangement of the laser beam and the arc. CO2 laser-micro plasma hybrid welding was applied to the lap welding of zinc-coated steel with zero-gap. The relationships among the weld quality and process parameters of the laser-arc arrangement, and the laser-arc interspacing distance and arc current were investigated using a full-factorial experimental design. The effect of laser-arc arrangement is dominant because the leading plasma arc partially melts the upper steel sheets and vaporizes or oxidizes the coated zinc on the lapped surfaces. Compared with the result from the laser-TIG hybrid welding, the heat input from arc can be reduced by 40%. 相似文献