充型形态对低压铸造薄板铸件凝固过程的影响

Influence of Filling Patterns on Solidification Process of Thin Wall Plate Castings Produced by Low Pressure Casting

用低压铸造方法浇铸了壁厚为 5mm和 2mm的Al 4 5 %Cu薄板铸件 ,测试了温度场 ,并考察了反重力铸造的两种基本充型形态———反向充填和顺序充填对铸件温度分布和铸件质量的影响。研究表明 ,反向充填产生的温度分布不利于铸件补缩 ,易产生缩松缺陷 ;顺序充填产生的温度分布使铸件倾向于顺序凝固 ,有利于得到组织致密的铸件 ,但易在最后凝固部位产生应力和裂纹。实际生产中可根据两种充型形态下铸件的凝固特点采用合适的浇注系统和充型工艺参数 。

Thin wall plate castings with thickness 2mm and 5mm were produced by low pressure casting.The temperature fields were measured.The influence of the two basic filling patterns of counter gravity casting on the initial temperature distribution and quality of the castings was studied.The results indicated that the temperature distribution caused by the reverse filling was not good for feeding the contraction of castings,easy to cause porosity.On the contrary,the temperature distribution caused by sequential fil ling made castings solidify sequentially and was good for producing dense castings,but it was easy to cause stress and cracks in the last solidifying locate of the casting.Proper runner system could be used to eliminate casting defects according to the solidification characteristics under the two filling patterns.