摘要
研究了挤压铸造工艺条件下,工艺参数(挤压力、浇注温度、模具温度、加压前延迟时间)对Al-Cu合金铸件缺陷的影响。结果表明,挤压铸造有两个临界挤压力,即消除收缩类缺陷的最小挤压力PSC,以及避免宏观偏析的最大挤压力PMS。仅当PSC<P<PMS时,才能获得既无收缩缺陷又无宏观偏析的挤压铸件。随着挤压力的增加,晶间共晶相及共晶团聚等偏析组织的尺寸有所减小,数量也相应减少。浇注温度过高容易造成气孔、夹杂的形成,且明显减小PMS,导致宏观偏析及共晶偏析缺陷的产生。适当的模具温度和较短的加压前延迟时间是获得无铸造缺陷挤压铸件的必要条件。
Effects of processing parameters such as applied pressure, pouring temperature, die temperature and delaying time on the defects in squeeze-casting A1-Cu alloy were investigated. Experimental results show that there exist two critical applied pressures during squeeze casting. One is the critical pressure Psc, above which shrinkage defects can be eliminated, and the other is the critical pressure PMs, under which macro-segregation can be avoided. The sound castings without shrinkage and macro-segregation defects can be obtained when the applied pressure only is in the range of Psc〈P〈PMs. With the increase of the applied pressure, the size and numbers of inter-grain eutectic phase and eutectioids are decreased. High pouring temperature can easily result in the formation of gas hole and inclusions in the castings. Meanwhile, it will bring about the macro-segregation and eutectic segregate defects as a result of decreasing PMS. Moderate die temperature and short delaying time before applying pressure are the essential conditions to prepare sound castings without any defects.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2013年第1期44-48,共5页
Special Casting & Nonferrous Alloys
基金
GD-NSFC联合基金资助项目(U1034001)
国家科技支撑计划资助项目(2011BAE21B00)
省部产学研重点专项资助项目(2009A090100026)
广东省科技攻关资助项目(2008A010300003)
关键词
挤压铸造
AL-CU合金
缺陷
对策
Squeeze Casting
AI-Cu Alloy
Defects
Improving Measures
