摘要
以获得高内在质量的镁合金消失模铸件为目标,试验研究了镁合金低压真空消失模铸造工艺中真空度对铸件质量的影响。试验结果表明:负压真空度过低不利于模样热解产物的排除,过高会引起液态金属前沿产生"附壁效应",充型时真空度大小可以根据铸件的复杂程度和壁厚来选择,壁厚较大铸件可以用较低的真空度,壁厚较薄的铸件应使用较高真空度。镁合金真空低压消失模铸造最佳的真空度参数范围为0.02～0.03 MPa。
In this paper,the researches were focused on the effect of vacuum level on the internal casting quality of magnesium alloy parts.The results indicate that vacuum could increase the filling pressure differential,the foam pyrolysis product escaped rate and molten metal filling velocity.The application of higher vacuum likely established a pressure gradient at the metal-mold interface,which caused the liquid metal front to change its profile from convex to concave.And the liquid metal advanced preferentially along the mold walls and the liquid-EPS products possibly agglomerated in the center regions,thus likely remains entrapped in the solidified casting.The vacuum level can be selected according to the structures and wall thickness of castings.The optimum vacuum level for low-pressure EPC magnesium alloy is 0.02-0.03 MPa.
出处
《铸造》
CAS
CSCD
北大核心
2010年第12期1276-1279,共4页
Foundry
基金
国家高技术研究发展计划(863计划)资助项目(2007AA03Z113)
