缝隙浇道宽度对A357铝合金铸件质量的影响  

Effects of Slit Runner Width on Quality of the A357 Aluminum Alloy Castings

作　　者：樊振中[1] 王胜强[1] 王建国[1] 王海龙[1] 刘建军[1] 

机构地区：[1]中国航发北京航空材料研究院北京市先进铝合金材料及应用工程技术研究中心

出　　处：《特种铸造及有色合金》2017年第5期473-477,共5页Special Casting & Nonferrous Alloys

摘　　要：通过设计不同宽度尺寸的缝隙浇道,借助FEM仿真计算分析与力学性能测试,研究了缝隙浇道宽度对A357铝合金铸件凝固组织与力学性能的影响。结果表明,受铸件/铸型界面传热影响,凝固固相从界面尖端换热区域析出分布,并逐渐转移至心部区域;缝隙浇道宽度与铸件壁厚比例系数设置偏低时,受缝隙浇道补缩影响,易产生集中性缩松缺陷;反之,受缝隙浇道截面临界压力与凝固末期反抽影响,易产生氧化夹渣与缩松缺陷。缝隙浇道宽度与铸件壁厚的最佳比例系数为1.2,此时A357合金的抗拉强度、屈服强度与伸长率分别为342 MPa、310 MPa与9.4%,断口形貌为韧窝断裂。Effects of slit runner width on microstructure and mechanical properties of the A357 aluminums alloy castings were investigated by designing different width of the runner,FEM simulation analysis and tensile testing.The results indicate that the solid phase is solidified nearby the heat exchange interface,and gradually transferred to the core area due to effect of interface heat transfer.Segregated shrinkage metallurgical defects can be observed as a result of the feeding distance of slit runner when the ratio of slit runner width with casting wall-thickness is low,however,in turn,lots of oxide inclusions and shrinkage porosities can be generated under influence of critical pressure of the cross section and extraction at the end of the solidification process.The peak value of tensile strength,yield strength and elongation can be presented when the proportionality coefficient between slit runner width and thickness size of casting is set to 1.2,where their reach 342 MPa,310MPa and 9.4%,respectively,and the fracture morphology is characterized by dimple fracture mechanism.

关 键 词：A357铝合金 凝固组织 缝隙浇道 温度梯度 

分 类 号：TG292[金属学及工艺—铸造]