摘要
利用自行设计的反重力铸造凝固装置,考察了未进行去气除渣处理的Sr变质A356合金中孔洞形成情况,发现远离结晶器方向,所取横截面大孔数量由几乎没有增多到7个然后减少到1个,单位面积小孔数量由2个/mm2减少到1个/mm2然后增多到4个/mm2,而纵截面孔隙率则由0.3%增大到中部最大2.5%然后减小到0.9%。这种现象是由于远离结晶器方向冷却速度逐渐变小,温度梯度逐渐变小造成的。
We have developed a counter-gravity withdrawal casting (CWC) to understand porosity formation in Sr modified A356 alloy without degassing. It is found that with distance far from the crystallizer,the number of large pore with the size larger than 0.5 mm in cross section is firstly increased from 0 to 7 then decreased to 1,while the number of small pore with size less than 0.5 mm is firstly decreased from 2 to 1 then increased to 4,however,the porosity rate in transverse section is increased from 0.3% to 2.5% then decreased to 0.9%,which is attributed to the decrease of temperature gradient with decreasing in cooling rate far from the crystallizer.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2008年第5期388-391,共4页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50771031)
关键词
反重力铸造
孔洞
AL-SI合金
孔隙率
Counter-gravity Withdrawal Casting,Pore,Al-Si Alloy,Porosity Rate
