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为了提高铅锭模的服役寿命,采用模拟铅锭铸造实际工况的方法,对铸渗法制备的石英/灰铸铁基表面复合材料和灰铸铁基材进行了模拟试验。通过SEM、EDS等手段对试验后的试样微观形貌、元素组成进行了分析,重点讨论了试样表面层的失效机理。结果表明:复合材料的失效是由于其自身存在铸造缺陷,在复合层/基材、石英/基体的界面热应力作用下,裂纹萌生,同时,铅液、冷却水、空气的渗入促进裂纹的萌生与扩展;灰铸铁的失效是由于在应力和氧化的协同作用下,表面层内石墨尖端萌生裂纹,并逐渐扩展,造成表层剥落。因此,在铅锭模工况下,造成复合材料失效的因素更多,估计其使用寿命不及灰铸铁基材。这为铅锭模具材料的发展指明了新的方向。
In order to improve the service life of lead ingot molds, a simulation test was carried out on the quartz / gray cast iron-based surface composites and gray cast iron substrates prepared by infiltration infiltration method by simulating the actual working conditions of lead ingot casting. The microstructure and elemental composition of the sample after the test were analyzed by means of SEM and EDS, and the failure mechanism of the sample surface layer was discussed. The results show that the failure of the composites is due to the existence of casting defects. The crack initiation occurs under the thermal stress of the composite layer / substrate and the quartz / matrix interface. Meanwhile, the penetration of lead liquid, cooling water and air promotes the initiation of cracks And expansion; gray cast iron failure is due to the synergistic effect of stress and oxidation, the surface layer of graphite tip crack initiation, and gradually expanded, resulting in surface spalling. Therefore, in the lead ingot mold conditions, resulting in more failure of composite materials, it is estimated that the service life of gray cast iron substrate. This indicates a new direction for the development of lead ingot mold material.