摘要
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 mold, by simulating the actual work conditions of lead ingot casting, comparison tests between the quartz particulate reinforced gray cast iron matrix surface composites obtained by infiltration casting technology and gray cast iron were carried out. After the tests, by microstructure and elements in the samples were analyzed by means of SEM, EDS, and especially the failure mechanisms of the sample surface layers were discussed. The results show that： the failure of the composites is due to its own casting defects, and the interface thermal stress of composite layer/substrate, quartz sand/matrix initiates cracks, furthermore, and the infiltration of liquid lead, cooling water, and the air promotes the cracks＇ initiation and propagation. The failure of the gray cast iron is due to the synergistic effects of stress and oxidation at the graphite＇s boundary in the surface layer, which leads to crack initiation at the tip of graphite firstly, gradual propagation, and final delamination of the surface. Therefore, as lead ingot mold materials, the failure factors of the surface composites are more than those of gray cast iron. The estimated service life of the quartz sand particulate reinforced gray cast iron matrix surface composites is less than gray cast iron. This indicates a new research direction to lead ingot mold materials.
出处
《热加工工艺》
CSCD
北大核心
2013年第7期7-10,共4页
Hot Working Technology
基金
国家自然科学基金项目(51265019)
关键词
石英
灰铸铁
表面复合材料
失效机理
铅锭
quartz sand
gray cast iron
surface composites
failure mechanism
lead ingot mold
