文档介绍：摘 要
冒口设计在铸造中至关重要,它对铸件质量及企业生产成本影响较大。消失模铸钢件缩松缩孔大,所需金属补缩液量多,加上消失模多用暗冒口,暗冒口在冷却时外层易结壳,使暗冒口内金属液只能靠自重下降补缩铸件,极大地降低了冒口的补缩效率。作者调研了数十家消失模铸钢企业,这些企业都是凭经验设计冒口,没有系统的理论指导,所设计冒口大而高,铸件出品率极低,增大了企业的生产成本。
受威廉姆斯芯专利启发,结合发热冒口的特点,作者设计了大中小三种尺寸发热锥,它们和发热冒口一样能够提高消失模暗冒口的补缩效率,因其体积小,所用发热材料少,能够降低成本,而且制造和实践操作简单方便。生产中,将发热锥安装在消失模暗冒口顶部,浇注时,当钢液接触到发热锥后,发生化学反应释放大量热量,延长了暗冒口中金属液的凝固时间,从而使暗冒口上表层不易结壳,进而提高冒口补缩效率。本文通过差热分析 DSC 说明发热锥能够用于消失模暗冒口中;通过浇注试验说明发热锥能够提高暗冒口补缩效率,并制定了不同尺寸发热锥应用的冒口尺寸范围及补缩铸件范围;通过金相分析说明发热材料不会对铸件材质造成影响。
另外,本文总结了冒口的结构种类及冒口尺寸计算方法。另将发热冒口和保温冒口应用于消失模曲轴和消失模耐磨球空心大钢球上,进行浇注实验,对比保温发热冒口和普通冒口对补缩效率的影响。通过铸造模拟对比普通冒口和保温冒口补缩效果。另外,模拟了热侧冒口和冷顶冒口补缩效果。实验及模拟结果说明保温发热冒口和热侧冒口能够提高消失模铸钢件暗冒口补缩效率。
关键词:消失模铸钢件暗冒口补缩效率发热锥保温发热冒口
Abstract
Riser design and layout, which has great effect on casting quality and production cost, is crucial in steel casting production. Lost Foam steel castings will have large shrinkage cavity easily in the process of cooling, so that much metal feeding liquid required. At the same time, blind riser widely used in lost foam casting reduces feeding efficiency because of its characteristic that the outer metal crusts easily when cooling which causes metal liquid can only rely on self-weight to feed the casting. Dozens panies which produce lost foam casting have been researched, the survey found that risers are designed empirically and there is no systematic theoretical guidance in these enterprises, which bring out large and high-riser existence, result in lowing the casting production rate and increasing pany’s production costs.
Inspired by the Williams-core patents, combined with the characteristic of heat riser, the author designed a heat cone in three different sizes, which can increase the blind risers’ feeding efficiency of lost foam casting. Because of their small size, they use less heating material and accordingly low the heat cones’ costs. What’s more, the practical operation of setting the heat cones is simple: just insert the heat cones on the top of the blind riser. When the heat metal li