汽车压铸及铸造铝合金

介绍了汽车铝合金中压铸、铸造合金的比例,变化趋势,在某些国家地区的产量。详细介绍了日本和美国近些年来各类汽车铝材的发货量,中国和日本压铸、铸造铝合金的化学成分、性能、特点及应用,各种铸造铝合金的热处理规范,汽车用高强度铸造铝合金的特点,典型汽车铸造铝产品的选材、生产与性能。介绍了压力铸造、金属型低压铸造、科斯沃斯法、气化模铸造工艺,列出了低压铸造工艺生产的各类铸件特征、材料和工艺。预测了汽车用铝的前景。     

高强Al-Ni系铸造铝合金的挤压铸造及强化机制

为了开发新的高强铸造铝合金材料,分别采用3种铸造工艺,砂型铸造、金属型铸造和挤压铸造,制备了一种以Al-Ni共晶体系为基础的AlZn6Ni4Mg2Cu铸造铝合金材料。研究了Ni元素、热处理和铸造工艺对其微观组织、力学性能的影响规律,揭示了其强化机制。结果表明:4%(质量分数)的Ni在该铝合金中形成了大量的共晶组织(α-Al+Al_3Ni),同时改善其力学性能和铸造性能,起到了共晶强化的作用;固溶和时效热处理导致Al_3Ni相的球化和MgZn_2相的时效析出,提高了该铝合金的强度;相比砂型铸造和金属型铸造,挤压铸造时该铝合金的晶粒和Al3Ni相最细小,力学性能最佳,抗拉强度为586 MPa,断后伸长率为3.5%。由此得出:AlZn6Ni4Mg2Cu铸造铝合金的强化机制为η(MgZn_2)相的时效强化和Al_3Ni相的弥散强化,挤压铸造加T6热处理后,该铝合金的力学性能达到最佳值。     

Strengthening technology and mechanism for semi-solid die casting of aluminum alloy

Combined with theoretical evaluation,an optimized strengthening process for the semi-solid die castings of A356 aluminum alloy was obtained by studying the mechanical properties of castings solution treated and aged under different conditions in detail,then,the semi-solid die castings and liquid die castings were heat treated with the optimized process.The results show that the mechanical properties of semi-solid die castings of aluminum alloy are superior to those of the liquid die castings,especially the strengthening degree of heat treated semi-solid die castingsis much greater than that of liquid die castings with the tensile strength more than 330 MPa and the elongation more than 10％,and this is mainly contributed to the non-dendritic and more compact microstructure of semi-solid die castings.The strengthening mechanism of heat treatment for the semi-solid die castings of A356 aluminum alloy is due to the dispersive precipitation of the second phase(Mg2 Si) and formation of GP Zone.     

铝板带连铸连轧工艺装备及工程建设综述

比较了铝板带三种主要热轧生产方式的优点及各自的局限性,说明了连铸连轧工艺在铝板带生产中的独特优点,以及连铸连轧工艺的发展情况,分析了连铸连轧工艺在我国铝板带加工行业的应用前景.结合正在建设的国内首条Hazelett铝板带连铸连轧生产线,对铝板带连铸连轧生产线的技术参数、设备组成及工程建设情况等进行了介绍和讨论.     

Microstructures of electromagnetic casting and direct chill casting LY12 aluminum alloys

1　INTRODUCTIONElectromagneticcasting (EMC)isatechnologydevelopedbythecombinationofmagnetohy drodynamics (MHD )andcastingengineering[13] .TheEMCtechnologydependsontheelectromagneticforcetopreventthemetalfromtouchingthemold .Dependingontheinteractionofeddycurrentsinducedinthemetalandthemagneticfieldoftheinductor ,theliquidmetalcolumniskeptstable[4 6 ] .Thecon tactlesscastingofEMCmayeliminatetheliquidationbuild upsandfeathercrystals ,relievethescalpingop erationbeforethehotrollprocess …     

Influence of core sand properties on flow dynamics of core shooting process based on experiment and multiphase simulation

The influence of core sand properties on flow dynamics was investigated synchronously with various core sands, transparent core-box and high-speed camera. To confirm whether the core shooting process has significant turbulence, the flow pattern of sand particles in the shooting head and core box was reproduced with colored core sands. By incorporating the kinetic theory of granular flow(KTGF), kinetic-frictional constitutive correlation and turbulence model, a two-fluid model(TFM) was established to study the flow dynamics of the core shooting process. Two-fluid model(TFM) simulations were then performed and a areasonable agreement was achieved between the simulation and experimental results. Based on the experimental and simulation results, the effects of turbulence, sand density, sand diameter and binder ratio were analyzed in terms of filling process, sand volume fraction(αs) and sand velocity(Vs).     

铝锭铸造机铝液流量控制器的研究与设计

针对铝锭铸造过程为非线性、时变过程,不容易建立精确的数学模型,基于模糊控制算法设计铝液流量控制器,给出模糊控制器结构、搭建方法及其控制流程图。实践验证,与普通PID控制比较,能快速进入恒液位稳定区,过程超调量很小,控制系统大大改善了响应速度、时滞等性能,为流量是采用浮标直接控制或浮标-杠杆控制铝锭铸造设备改造提供参考。     

铝合金壳盖压铸工艺优化研究

通过对铝合金壳盖压铸件进行实体造型,采用铸造数值模拟软件Z-Cast对铝合金壳盖压铸过程的压力场、速度场和温度场进行数值模拟,根据模拟结果分析浇注系统和溢流槽尺寸的合理性,重新设计、优化浇注系统的形状和布置位置,得到合理的压铸方案。对于铝合金压铸件结构和压铸工艺设计有着重要的指导意义。     

电磁振荡下半连铸Al合金凝固组织的细化机制

在半连铸7075铝合金过程中, 通过同时施加稳恒磁场和交变磁场的方法, 使凝固熔体产生受迫振荡, 研究了电磁振荡的强度和频率对晶粒细化的影响规律. 对电磁振荡作用下, 合金凝固组织的细化机理进行了探讨. 结果表明 电磁振荡法获得的晶粒尺寸要较CREM法所获得的小, 且随着电磁振荡强度增加及频率降低, 铸锭整体组织变得更加细小和均匀.     

Effect of sand dilation on distortions and pattern allowances during steel sand casting

Mechanical interactions between the sand mold and casting have a great impact on pattern allowances. In this study, the effect of core expansion on distortions during steel casting is investigated. A hollow steel cylinder is cast using silica and zircon sand cores. The evolution of the cylinder’s inner diameter is measured in situ using LVDTs. During solidification, core expansion is found to distort the inner diameter into a barrel-shaped profile, generating the largest expansion at the mid-height. The experiments are simulated using a sequential thermo-mechanical coupling. In the stress analysis, the steel and sand are modeled using an elasto-visco-plastic constitutive law and the Drucker–Prager Cap model, respectively. The simulations reveal that sand dilation due to shear stresses, as opposed to thermal expansion, accounts for the majority of the increase in the inner diameter. The measured and predicted pattern allowances are found to be in excellent agreement.     

原铝铸造优化配铝算法分析与软件开发

对铝电解铸造配料进行了详细分析，研究了配料算法，提出了优化配铝方案．并对此方案的软件实现作了简要介绍。     

Preparation of big size open-cell aluminum foam board using infiltration casting

This paper presents an infiltration casting technique for manufacturing big size open-cell aluminum foam boards. The principle and key technologies of infiltration casting are also analyzed. Based on the previous practice of the small size aluminum foam production, the die for preparing big size aluminum foam boards is designed and manufactured. The experiments on aluminum boards of 300 mm × 300 mm × （20-75） mm, with the pore size ranging from 1.0 to 3.2 mm and average porosity of 60%, have been performed. The experimental results show that a reliable infiltration process depends critically on the pouring temperature of the molten AI-alloy, the preheated temperature of the mould and salt particles and vacuum. Current research explores the possibility of large-scale manufacturing and application of the aluminum foams.     

Technical parameters in electromagnetic continuous casting of aluminum alloy

1　INTRODUCTIONElectromagneticcasting (EMC)isanadvancedmaterialprocessingtechniqueinventedbyGetselev[1]andhasbeenwidelyusedintheworldbecauseitsproductshavetheadvantagesofsmoothsurface ,ho mogeneousmicrostructureandgoodworkability[2 ,3] .ElectromagneticcontinuouscastingofsteelisanewtypemethodbroughtforwardbyVives[4 6 ] thatcom binedtheelectromagneticfieldwithcontinuouscast ingtechnique .Itisalsoanewideatoapplythismethodintotheshapingprocessofaluminumalloytoimprovethesurfaceandinnerquality…     

合成粘结剂的技术发展

叙述了铸造工业对合成粘结剂应保证铸件质量和符合环保趋势的两个基本要求的内容;介绍了工业发达国家在芯砂粘结剂和自硬砂粘结剂方面的改进工作情况及其所取得的技术进展;指出了在水溶性粘结剂方面目前的研究工作只是起步,水玻璃的粘结能力远未被充分利用等问题。     

铝-硅合金砂型铸件改为压铸生产的工艺改进

通过一个铝-硅合金端盖压铸件设计实例,探讨了铝-硅合金砂型铸件改为压铸生产时,要在合金化学成分、熔炼工艺和铸件的工艺性能等方面,根据压铸工艺的特点对铸件整个生产工艺进行改进,以满足压铸生产的特殊要求。压铸铝-硅合金中ω（Fe）可以达到1．0％。ω（Fe）〈0．150%时,ω（Mn）要达到0．5％-0．8％,以防止粘模。对于不太重要的铝合金压铸件可以省略熔炼过程中的变质处理过程,通过合理设置加强筋、减少壁厚、减小拔模斜度等措施,改善压铸件的结构工艺性。     

照相机铝合金外壳压铸CAE分析

通过建立温度场计算数学模型,利用有限元软件ProCAST模拟了照相机铝合金外壳的充型过程。通过模拟结果分析,预测了铸件在充型过程中可能出现的相关缺陷以及缩孔疏松形成的位置,并提出了一些修改方案和改进措施。     

电解铝铸造过程金属损耗的预防

对电解铝铸造过程中目前存在的主要问题和影响金属损失的因素进行了分析,认为工艺上可能存在有溜槽过长、垂直导流点多、炉温炉压失控等问题,从而导致铝液的紊流、高温并与复杂炉气的反应,以及精炼扒渣的影响,这些因素均可引起金属氧化损耗增多。为此,提出了相应的改进措施。     

铝带坯双辊铸轧过程瞬态传热数学模型

采用拉格朗日随体坐标建立了铝双辊铸轧过程瞬态传热数学模型。在数学模型中考虑了金属凝固动力学条件和采用试验测定的辊/铝带坯界面接触换热系数边界条件,用有限差分方法对控制方程进行了数值求解,并由现场测试数据验证了传热数学模型的正确性。     

铝合金扁锭热顶电磁铸造技术

根据热顶-电磁铸造的基本思想,设计了一套适合于制取铝合金扁锭的热顶-电磁成型系统,用小线圈法测量了系统内的磁场强度,计算了电磁压力分布,并与普通电磁铸造成型系统的结果进行对比分析;依据热顶电磁铸造的成型条件,确定了相关的控制参数;通过大量的拉坯实验,探讨了热顶对防止电磁铸造坯易产生表面夹杂缺陷的作用.结果表明:采用热顶-电磁铸造法不仅可有效去除电磁铸造中因电磁搅拌产生的氧化夹杂,而且使得电磁铸造过程简便而易于控制.     

Microstructure of aluminum twin-roll casting based on Cellular Automation

Nucleation and growth model based on Cellular Automation（CA） incorporated with macro heat transfer calculation was presented to simulate the microstructure of aluminum twin-roll casting. The dynamics model of dendrite tip （KGT model） was amended in view of characteristics of aluminum twin-roll casting. Through the numerical simulation on solidification structure under different casting speeds, it can be seen that when the casting speed is 1.3 m/min, that is, under conditions of conventional roll casting, coarse columnar grains dominate the solidification structure, and equiaxed grains exist in the center of aluminum strip. When the casting speed continuously increases to 8 m/min, that is, under the conditions of thin-gauge high-speed casting, columnar grains in solidification structure all convert into equiaxed grains. Experimental and numerical results agree well.