TiAl合金铸造工艺数值模拟及分析

利用数值模拟方法对比研究了重力铸造、离心铸造和真空吸铸等工艺铸造TiAl合金涡轮铸件的工艺过程,分析了TiAl合金熔体在型腔中的充填规律及凝固特性.结果表明,传统的重力铸造及离心铸造容易产生浇不足、缩松、缩孔等缺陷,真空吸铸技术能大幅提高钛合全熔体的充填能力,且充填过程十分平稳,凝固过程中易于补缩,是小型TiAl合金铸件理想的成型方法.     

基于Magma的桥壳浇注系统分析与优化

针对某型号桥壳在浇注过程中出现缩松、缩孔缺陷,采用MAGMA软件对铸件的浇注工艺进行了数值模拟,通过分析其在充型和凝固过程中的温度场、流场及缩松、缩孔分布图,提出了浇注系统的优化工艺,并对优化后的工艺能否有效消除铸件的缩松、缩孔缺陷进行了再分析。实验结果表明:使用底注式浇注工艺替换原先的中注式浇注工艺能有效地消除桥壳的缩松、缩孔缺陷,提高桥壳的合格率。     

基于AnyCasting大型薄壁鞍座铸造工艺优化

针对大型薄壁铸件鞍座铸造过程中易产生缩松、缩孔缺陷等问题,基于AnyCasting模拟软件对鞍座的充型和凝固过程进行了模拟。根据模拟结果分析缩松、缩孔缺陷的位置分布,发现铸件内部有缩松、缩孔现象产生,并通过实际浇注试验对比缺陷位置以验证模拟结果的可信性。采用在热节位置添加内冷铁的改进方案,结果表明,原缺陷产生位置在凝固过程中优先凝固,消除了缩松、缩孔缺陷,为类似薄壁铸件实际生产提供相应指导。     

TiAl基合金叶片吸铸成形缺陷的数值模拟

采用有限元软件ProCAST模拟TiAl基合金液在金属型真空吸铸成形铸造工艺中的充型凝固过程,分析在充型凝固过程中产生缺陷的原因,并进行了相关的实验验证。在模拟过程中发现铸件中确实存在模拟预测的缺陷,且缺陷主要集中在叶片隼部,在叶身部位出现少量的缩松缺陷,模拟和实际相吻合。     

TiAl基合金叶片吸铸成形缺陷的数值模拟

采用有限元软件ProCAST模拟TiAl基合金液在金属型真空吸铸成形铸造工艺中的充型凝固过程,分析在充型凝固过程中产生缺陷的原因,并进行了相关的实验验证。在模拟过程中发现铸件中确实存在模拟预测的缺陷,且缺陷主要集中在叶片隼部,在叶身部位出现少量的缩松缺陷,模拟和实际相吻合。     

球铁长叉件消失模铸造工艺研究及数值模拟

采用底注和顶注式消失模工艺铸造了球铁长叉件,并用ProCAST软件对两种工艺方案进行了充型和凝固过程的模拟。针对两种工艺产生严重缩孔、缩松的问题,改进后采用阶梯式浇注工艺,并对改进工艺过程进行了模拟,结果表明,阶梯式浇注工艺消除了铸件内部的缩孔、缩松缺陷。实际生产结果和模拟结果的对比证实了改进方案的可行性。     

薄壁铝合金铸件低压铸造工艺优化及设计

利用viewcast软件模拟铸件的充型和凝固过程,从凝固过程模拟结果发现铸件局部厚大部位容易产生缩孔、缩松缺陷。根据模拟结果和理论分析,设计了合适的冷铁和工艺补贴,同时,将浇注温度从700℃降低至680℃;对改进后的方案再次进行凝固模拟,铸件缩孔和缩松缺陷消失。     

薄壁铝合金铸件低压铸造工艺优化及设计

利用viewcast软件模拟铸件的充型和凝固过程,从凝固过程模拟结果发现铸件局部厚大部位容易产生缩孔、缩松缺陷。根据模拟结果和理论分析,设计了合适的冷铁和工艺补贴,同时,将浇注温度从700℃降低至680℃;对改进后的方案再次进行凝固模拟,铸件缩孔和缩松缺陷消失。     

复杂薄壁框类铝合金铸件工艺设计及数值模拟

介绍了一种复杂薄壁框类铝合金铸件的铸造工艺:采用三箱造型,设计了所需砂芯结构,并对中箱造型工艺进行了简化。设计了圆形底注式浇注系统,借助ProCAST软件研究铸件充型和凝固过程。根据初始方案模拟得到缩孔、缩松位置分布和大小,通过在预测的缺陷处合理放置冒口、保温套和冷铁等对铸件进行有效补缩,基本消除了缩孔、缩松等铸造缺陷。     

基于ProCAST软件的发动机连杆铸造仿真及优化

借助ProCAST软件,对发动机连杆用钛铝合金真空吸铸过程进行仿真分析。探究了浇注温度与速度对铸件充型过程与凝固特性的影响;并获得了钛铝合金连杆吸铸工艺参数的优化图。结果表明,合理提升浇注温度与钛铝合金液的浇注速度,均有利于铸件充型。     

Multi-objective optimization of process parameters during low-pressure die casting of AZ91D magnesium alloy wheel castings

Multi-objective optimization has been increasingly applied in engineering where optimal decisions need to be made in the presence of trade-offs between two or more objectives. Minimizing the volume of shrinkage porosity, while reducing the secondary dendritic arm spacing of a wheel casting during low-pressure die casting(LPDC) process, was taken as an example of such problem. A commercial simulation software Pro CASTTM was applied to simulate the filling and solidification processes. Additionally, a program for integrating the optimization algorithm with numerical simulation was developed based on SiPESC. By setting pouring temperature and filling pressure as design variables, shrinkage porosity and secondary dendritic arm spacing as objective variables, the multi-objective optimization of minimum volume of shrinkage porosity and secondary dendritic arm spacing was achieved. The optimal combination of AZ91 D wheel casting was: pouring temperature 689 °C and filling pressure 6.5 kPa. The predicted values decreased from 4.1% to 2.1% for shrinkage porosity, and 88.5 μm to 81.2 μm for the secondary dendritic arm spacing. The optimal results proved the feasibility of the developed program in multi-objective optimization.     

New filling system design for bolster casting and computer simulation

The new filling system is smooth filling without gas gap.It works well in avoiding the generation of defects such as porosity and inclusion.The pouring basin,sprue,runner and the gate of the bolster casting were designed according to the principle of the new filling system.The filling and solidification process of the bolster casting were also simulated.It was found that the filling process was smooth,and air entrapment and shrinkage were avoided.Finally,a further validation of the new filling system of bolster casting was carried out in a foundry.     

镁合金副车架压铸过程计算机仿真与工艺优化

基于AnyCasting软件,采用正交试验研究了压铸过程中冲头速率、模具温度、浇注温度对镁合金副车架铸件气孔含量、氧化倾向、冷隔和缩松等缺陷的影响,并得到了优化的压铸工艺参数:冲头速率为7m/s、模具温度为250℃、浇注温度为700℃。在该工艺参数条件下,获得了表面和内部品质良好的镁合金副车架压铸件,同时验证了通过模拟仿真优化压铸工艺参数方法的有效性。     

设计合理的浇注方案以保证充填和补缩--熔模铸件铸造方案设计系列讲座之一

合理的浇注速度和静压头、型壳透气性、浇注时的金属液温度和型壳温度、避免浇注时型壳憋气、避免浇注中途停顿以及保证充填平稳等是保证充填的重要影响因素。避免铸件出现缩孔(松)的措施有缩孔转移和缩孔分散两种措施，应根据不同铸件结构合理应用。     

真空吸铸叶轮铸件水力模拟试验研究

根据相似原理设计制作了真空吸铸叶轮铸件的水力模拟模型，研究了水充填模型型腔过程中型内压力和充型速度变化规律，通过实验确定了合理的充型工艺参数，并将其应用于实际叶轮吸铸试验中，消除了铸件内的大面积气孔缺陷。     

铝镁合金消失模铸造技术研究及应用新进展

阐述了铝镁合金消失模铸造技术的现状,重点介绍了铝镁合金消失模铸造在浇注充型、振动凝固、压力凝固、壳型铸造等技术研究方面的新进展。作者认为,消失模铸造铝镁合金,必须重点解决针孔、缩松等缺陷,提高液态合金的充型能力和铸件的力学性能。     

镁合金发动机缸体压铸充型和凝固过程的数值模拟

在对镁合金发动机缸体压铸件进行工艺分析的基础上,通过应用正交试验方法,并使用模拟软件对金属液的充型和凝固过程进行数值模拟。结合各组试验所得的不同数据,确定了压铸件生产的优化工艺参数:模具预热温度为220℃,浇注温度为670℃,压射速度为8.5m/s,并确定了工艺参数对铸件缺陷的影响顺序。且在该组优化的工艺参数下,通过对金属液的充型和凝固过程的动态观察,预测充型时间、凝固时间和可能存在的缩松、缩孔及气孔缺陷的分布与体积分数。实现了发动机缸体压铸工艺参数的优化。     

Numerical simulation and optimization of shell mould casting process for leaf spring bracket

Although the shell mould casting process has a wide range of application in many fields,the prediction of casting defects is still a problem.In the present work,a typical leaf spring bracket casting of ZG310-570 was fabricated by shell mold casting.The finite element model and ProCAST software were utilized for simulating the filling and solidification processes of the casting;and the formation mechanism of the gas pore,and shrinkage porosity defects were analyzed.The results indicate that the gas pore and shrinkage porosity defects are formed due to air entrapment,insufficient feeding and non-sequential solidification.Subsequently,through changing the position of risers,adding a connecting channel between the risers,and setting blind risers at the U-shaped brackets,an optimized gating and feeding system was established to improve the quality of the casting.After optimization,the gas pore and shrinkage porosity defects of the leaf spring bracket casting are effectively eliminated.The experiment results with the optimized casting process are in good agreement with the numerical simulation,which verifies the validity of the finite element model in the shell mould casting.