铸造用砂芯粘结剂粘度研究及应用

探讨了铸造用砂芯粘结剂粘度试验方法，分析了转子选择、操作方式、转速、时间等对粘度的影响，列出了粘度测试及指标制定需注意的事项，为机器人自动涂覆粘结剂的稳定应用提供借鉴和参考。     

制冷压缩机铝合金铸件的低压铸造

对汽车空调制冷压缩机铸件的结构及工艺性进行综合分析,应用树脂砂砂芯金属型低压铸造的工艺成功的生产了复杂耐压铝合金铸件;阐述了复杂耐压铝合金铸件低压铸造的设备、合金材料、工艺及生产中的实际操作问题。     

直列发动机缸体制芯工艺参数的共性与个性特征研究

通过利用UG软件对四种直列缸体的砂芯结构进行分析,寻找不同砂芯成形的共性及个性难点,进而分析不同砂芯的射砂及固化、表干等工艺参数与砂芯总重及砂芯结构之间的关系,得出上述工艺参数的共性与个性原理。结果表明,砂芯总重是缸体制芯工艺参数的首要影响因素,不同缸体不同砂芯的制芯工艺参数可以迁移使用,但同时砂芯结构特征对工艺参数也有一定影响。     

专利

大型铝合金壳体铸件的模具、制备铝合金壳体铸件的方法，包括砂芯底部连接底盘。底盘上设有与坩埚升液管相连的导入口，与导入口相连的是设在砂芯底部的直浇道，直浇道与横浇道一端相连，横浇道另一端深入到砂芯内部，横浇道上部连接内浇道；砂芯中部侧端面设有镶块；砂芯外部包裹金属型模具，包括左模、右模以及顶端的冒口。制备方法包括铝合金熔炼、装配模具、低压铸造、取出铸件。本发明操作简单，便于控制，产品表面质量高，工艺出品率高，气密性检查合格率高，成本低。     

金属型铸造铝合金用水溶芯的试验研究

针对金属型铸造铝合金铸件时砂芯溃散性差的问题，研究了用水溶性热芯盒水玻璃砂芯代替树脂砂芯和油砂芯，改善砂芯溃散性的制芯工艺和水溶溃散工艺，降低了铸件生产成本，改善了劳动条件和环境质量。     

铝合金框架铸造砂芯的分块成型设计

以某铝合金框架为例,依据复杂铸件铸造砂芯分块设计的简单分块原则,结合框架的结构和材料,以及砂芯的制造特点,论述了基于Pro/E的铸造砂芯分块成型设计过程,总结了行之有效的方法和经验.结果表明,采用Pro/E软件辅助设计,可提高铸造砂芯的设计效率,并为分块砂芯的模具和成型设计提供依据.     

C11下缸体铸造工艺分析及断芯解决措施

为生产出高品质的发动机缸体,在分析铸件结构的基础上,对缸体进行砂芯设计,确定浇注方式及熔炼工艺。为解决铸件出现的断芯问题,采用MAMGA软件进行模拟,分析充型速度;采用"8"字试块,检验表干时间和表干温度对砂芯抗拉强度的影响。通过增加阻流截面积,调整砂芯成分,设定表干温度和时间及更改油道芯固定方式解决了断芯问题。     

喷丸对低压铸造A356铝合金转向节组织与性能影响

在低压铸造A365铸造铝合金转向节过程中引入局部表面喷丸强化工艺,测试并分析表层残余应力分布情况及加热温度对其影响、表层显微硬度并观察喷丸截面的金相组织。结果表明,通过喷丸处理可使表层组织中的共晶Si细化并显著提高铝合金的表层硬度。喷丸时间为0～30 min时,随喷丸时间延长铝合金表层硬度逐渐增大,喷丸30 min时表层硬度(HV)约为230,与合金心部相比提高了约1.35倍。由于喷丸效果在超过100℃时会消失,因此喷丸处理后的铸件工作温度建议不超过100℃。     

电动客车水冷机壳低压铸造工艺设计与优化

针对电动客车电动机壳体直径较大、内壁筒状水套范围广和壁厚不均匀等特点,分析了水冷机壳的复杂结构及筒状砂芯对铝合金低压铸造顺序凝固的影响。设计了低压铸造浇注系统、模具结构和工艺参数。通过AnyCasting软件模拟铸件凝固过程,预测壁厚不均匀产生的热节和砂芯分隔作用形成的孤立液相情况,以及由此引发部分位置容易出现的缩松、缩孔等缺陷。探究如何采用铍铜镶件、水冷镶件和气冷管等优化措施调整凝固速度,提高铸件内部组织成形致密度及生产质量。     

铝合金机匣体叶片砂芯制芯工艺的优化

该机匣体为航空类产品,其材质为铝合金,该铸件的特点是结构复杂、薄壁且砂芯众多,该机匣体需用50多个砂芯才能完成其组芯造型.其叶片砂芯即为其中最主要的砂芯之一,因该砂芯为细薄的环状加层状结构,因而在热芯盒类芯盒的设计中其具有较为典型的代表性.     

大型铝合金支持筒简易金属型工艺研究

对于无法上设备的大型铝合金支持筒,采用简易金属型树脂砂芯,重力铸造工艺方法生产,质量高性能好,生产效率更高,成本也更低。     

Non-standard tests for process control in chemically bonded sands

Chemically bonded sand cores and molds are more commonly referred to as precision sand systems in the high production automotive powertrain sector. Their behavior in contact with molten metal can lead to casting defects. Consequently, the interaction is of great interest and an important part of metal casting technology. The American Foundry Society(AFS) sand testing is based on physical, mechanical, thermal and chemical properties of the sand system. Foundry engineers have long known that certain AFS sand tests provide limited information regarding control of molding and casting quality. The inadequacy is due to the fact that sand casting processes are inherently thermo-mechanical, thermo-chemical and thermo-physical. Non-standard foundry sand testing has proven useful for laboratory measurement of these characteristics in foundry sand using a disc-shaped specimen. Similarly, the equivalent disc-shaped specimens are used for casting trials. In order to accomplish near-net-shape casting with minimal defects, it is necessary to understand both the properties of the sand system, as well as the interface of molten metal when different binders, additives and/or refractory coatings are used. The methodology for the following non-standard chemically bonded sand tests is described:(1) disc transverse;(2) impact;(3) modified permeability;(4) abrasion;(5) thermal distortion;(6) quick loss on ignition. The data related to the non-standard sand tests were analyzed and interpreted. The test results indicate that there is relatively lower test-to-test variability with the disc-shaped specimens. The non-standard tests were able to discriminate between the chemically bonded polyurethane cold box sand specimens. Further studies should be conducted on various other sand and binder systems as well as on different specimen thicknesses.     

树脂砂型热物性值的测试

设计制作了适宜浇注法的测试砂型热物性值的装置,通过浇注铸铝实验,采集到离铸件—铸型界面不同距离的六个点的温度随时间的变化值,经过微机处理得出树脂砂型的表观热扩散率和导热系数随温度变化曲线,为研究铸铝件铸造工艺CAD提供了参数。     

Construction and analysis of dynamic solidification curves for non-equilibrium solidification process in lost-foam casting hypoeutectic gray cast iron

Most lost-foam casting processes involve non-equilibrium solidification dominated by kinetic factors, while construction of a common dynamic solidification curve is based on pure thermodynamics, not applicable for analyses and research of non-equilibrium macro-solidification processes, and the construction mode can not be applied to nonequilibrium solidification process. In this study, the construction of the dynamic solidification curve (DSC) for the nonequilibrium macro-solidification process included: a modified method to determine the start temperature of primary austenite precipitation (TAL) and the start temperature of eutectic solidification (TES); double curves method to determine the temperature of the dendrite coherency point of primary austenite (TAC) and the temperature of eutectic cells collision point (TEC); the "technical solidus" method to determine the end temperature of eutectic reaction (TEN). For this purpose,a comparative testing of the non-equilibrium solidification temperature fields in lost-foam casting and green sand mold casting hypoeutectic gray iron was carried out. The thermal analysis results were used to construct the DSCs of both these casting methods under non-equilibrium solidification conditions. The results show that the transformation rate of non-equilibrium solidification in hypoeutectic gray cast iron is greater than that of equilibrium solidification. The eutectic solidification region presents a typical mushy solidification mode. The results also indicate that the primary austenite precipitation zone of lost-foam casting is slightly larger than that of green sand casting. At the same time, the solid fraction (fs) of the dendrite coherency points in lost-foam casting is greater than that in the green sand casting.Therefore, from these two points, lost-foam casting is more preferable for reduction of shrinkage and mechanical burntin sand tendency of the hypoeutectic gray cast iron. Due to the fact that the solidification process (from the surface to center) at primary austenite growth area in the lost-foam cylinder sample lags behind that in the green sand casting,the mushy solidification tendency of lost-foam casting is greater and the solidification time is longer.     

铝、镁合金真空低压消失模壳型铸造的缺陷分析

分析了采用泡沫模用精密铸造制壳,并用真空低压浇注成形铝、镁合金铸件的典型缺陷(主要是浇不足和冷隔、孔洞及粘砂缺陷)的行貌特征和形成机理,并提出相应的防治措施。结果表明,浇不足和冷隔缺陷主要由金属液充型速度慢、充型动力不足、浇注温度低等原因造成;孔洞缺陷主要由金属液浇注速度过快、保压压力小或保压时间短,浇注温度高,浇注系统设计不合理及型壳透气性差等原因造成。粘砂缺陷主要由型壳强度低、充型压力和真空度过大、造型型砂粒径大和激冷效果差等原因所致。     

湿度对壳型覆膜砂热裂倾向的影响

研究了环境湿度对壳型覆膜砂热开裂倾向及常温抗拉强度的影响，指出应结合生产实际对覆膜砂所生产的铸型、型芯适当存放，以减轻铸造缺陷，提高经济效益。环境湿度对覆膜砂铸型（芯）性能的影响是通过粘接桥界面上水分的积聚而起作用的。     

基于铜包铝复层圆坯水平连铸的数值模拟与试验研究

利用Fluent TM模拟软件研究芯部铝液浇注温度、拉坯速度等工艺参数对水平连铸铜/铝复层铸坯温度场、液相率及流场的影响,并进行试验验证。结果表明,芯部铝液浇注温度越高,与铜管接触的铝液温度越高,液穴深度越深,铝铜之间越易发生反应;拉坯速度越快,铝液液穴深度越深,液态铝与铜管壁接触时间越长。铝液浇注温度控制在710~730℃,拉坯速度为200mm/min时可以获得优质的铜/铝复层铸锭,模拟结果与试验结果具有较好的一致性。     

缸体、缸盖铸件生产的总体工艺路线——车用中小型发动机灰铸铁缸体缸盖铸件生产工艺(1)

介绍发动机缸体、缸盖铸件生产的总体工艺路线.目前大多数汽车发动机铸件生产企业都采用冲天炉-电炉双联熔炼,为防止铁液晶核减少、过冷度增加、白口化倾向较大,应控制电炉熔炼温度,避免长时间过热和保温;为确保铸件尺寸精度,铸型宜采用高密度造型,也可以采用呋喃树脂砂型或PEP-SET树脂砂型.根据国内目前情况,建议主体砂芯采用冷芯工艺,而水套等部位的砂芯采用覆膜砂工艺更为稳妥可靠.     

利用3D打印工艺生产V型燃气发动机缸体铸件

介绍了V型燃气发动机缸体铸件的结构及技术要求,分析了该铸件的生产难点,决定采用3D打印砂芯工艺:两侧砂芯形成铸件的侧面外观结构及冒口,中间整体砂芯则形成铸件的内腔结构和两端面结构,底部2块砂芯形成铸件缸口外观结构和浇注系统,砂芯之间通过凹凸定位台进行定位。生产结果显示:铸件尺寸精度可以达到CT9级,铸件关键区域RT最大为I级,1 MPa水压30 min无渗漏,检验均合格,金相组织和力学性能也均符合技术要求,使用3D打印技术提高了生产效率,提升了产品质量,降低了生产难度。     

铸造涂料在灰铸铁缸体上的选配及应用

从组芯工艺和砂芯复杂程度、铸件缺陷、芯砂类别及粒度方面介绍了铸造涂料的研配及选型,详细阐述了铸造涂料在不同系列轿车发动机缸体砂芯上的应用情况.最后指出:涂料的选择应根据不同铸件和砂芯的质量要求,选用适合铸件或砂芯特点的专用涂料,使涂料的性能与铸件质量相得益彰,既不使涂料性能过度优异造成成本浪费,又能满足铸件质量需求;供...