冷铁工艺在熔模精密铸造中的应用研究

1.概述 随着科学技术的发展,我国在铸造领域自主研发了许多先进的铸造成形技术,使铸造业有了飞速的进步。同时,铸件不断地向大型化、薄壁化、整体化发展,对铸件质量也提出了新的更高的要求。例如,对于存在热节的大型薄壁复杂铸件进行熔模精密铸造,由于铸件热节处成形困难,     

大型复杂薄壁铝合金铸件调压成形精密铸造技术

西北工业大学周尧和院士等针对大型复杂薄壁部件的铸造生产难题而发明了一种大型复杂薄壁铝合金铸件调压成形精密铸造技术。采用该技术生产大型复杂薄壁铸件，能够在金属液平稳进入铸型型腔的同时保持优异的充型能力和补缩能力，在保证大型复杂薄壁铸件成形精度的同时获得优异的冶金质量，使铸件晶粒细化，致密度提升，铸件性能提高。     

石膏型低压铸造工艺规程的研究与应用

基于低压铸造生产要求，对石膏型制备与烘干工艺、合金熔炼与浇注工艺进行研究，升液管预热有利于均匀喷涂涂料，升液管口平面上放置石棉垫板和过滤网片可提高服役寿命。旨在为薄壁叶片和大型复杂薄壁铸造铝合金铸件的生产提供科学依据。     

不规则薄壁铸件铣削加工工艺研究

铸件毛坯被广泛应用于工业生产当中,其中复杂、不规则薄壁铸件的铸件毛坯加工的一个难点。结合实际加工情况,介绍了此类铸件加工中的工序分配、装夹方案及刀具设置方法,旨在提升不规则薄壁铸件加工工艺水平。     

缸盖喷油器孔渗漏的解决措施

作为发动机的关键零件之一，气缸盖在工作中承受复杂的负荷，属于高强度、薄壁复杂铸件，不仅要有良好的理化性能，而且要有良好的铸造性能和切削性能，技术要求较高，铸造工艺难度较大，因此其生产质量控制尤为重要。     

大型薄壁高强度铝合金铸件成形研究

为节约原材料，降低生产成本，以高强度铝合金铸件代替铝合金棒制造大型薄壁铝合金件，应用金属型铸造和砂型铸造原理，对大型、薄壁回旋体高强度铝合金铸件的铸造工艺进行了试验研究。结果表明，采用金属型和砂型相结合的铸造工艺，能满足其铸件质量要求，这是一种简单、经济、实用的铸造新工艺方法。     

对压铸机压射缸建压增压系统的分析与改进

我在日本验收压铸机等设备过程中对压铸机压射系统因建压增压时间过长进行分析与改进,并取得良好效果。随着复杂形状和薄壁型压铸件的出现,压铸行业对压铸机的建压增压时间提出高的要求。如压铸薄壁型铸件时,要求建压增压时间     

黄铜薄壁铸件应用消失模铸造的工艺试验研究

冲厕阀黄铜铸件是一个薄壁且内腔复杂的铸件,重0.5kg,壁厚3～4mm,外形尺寸为80mm×40mm×80mm,铸件要求表面光洁不允许有任何缺陷,并要求能通过1MPa的水压试验不渗漏,且不允许浸渗修补。铸件表面经打磨和抛光后,送去电镀厂表面镀铬。     

薄壁铝合金铸件铸造工艺设计及优化

正1.铸件要求薄壁封闭开关外体铸件,结构比较复杂,且铸件的壁厚不均匀,薄壁区域尺寸很小,铸件中也存在尺寸很厚大的区域,在这些区域如果浇注系统和补缩系统不合理定会造成缩孔缺陷。为了保证铸件致密度提出了以下要求:铸件材质为ZL104合金,铸件要求组织致密,不能有缩松、缩孔、裂纹等缺陷,在0.5MPa煤油压力下进行气密性试验,要求     

低压铸造新技术应用

正低压铸造技术是实现铸件少余量、无余量加工,同时也是汽车铸件精密化、薄壁化、轻量化和节能化的重要措施。九十年代后期,世界各国对铸件要求越来越高,铸件的精密化、薄壁化、轻量化和省力化已成为铸造技术发展的主攻方向。而低压铸造技术和压铸恰巧能够满足上述要求。但低压铸造在设备、模具、工艺和自动化方面尚需进一步改进和提高。目前国产低压压铸造机在汽车铝合金轮毂等行业的应用比较成功,由于气缸盖低压铸造工艺难度较     

Vibration-assisted filling capability in thin wall investment casting

Understanding the mechanism of the vibration needed to fill thin section and clarifying the dominant control parameters of the vibration in thin wall investment casting are the keys to producing sound casting. The filling capability in thin wall investment casting method can be assessed by the metal head. It was found that the effect of the vibration on the metal head is markedly dependent on acceleration of applied vibration. Two potential mechanisms were observed from the experimental results during the filling process in thin wall casting: discontinuous propagation flow in vibration conditions and continuous propagation flow without vibration. These mechanisms can modify the contact angles between liquid metal and a wall of the mold. Experiments also showed that two features of the transition can be observed from the front of the morphology: coherent liquid metal front, this occurs in thin wall investment casting when the acceleration due to vibration is less than (1?g) and jetting at the free surface, this occurs in thin wall investment casting when the acceleration due to vibration exceeds 1?g.     

A new shell casting process based on expendable pattern with vacuum and low-pressure casting for aluminum and magnesium alloys

A new shell casting process, with the adoption of the foam pattern of lost foam casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment casting and vacuum and low-pressure casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and low-pressure casting process. The few-layer compound thin shell of silica sol–sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250°C for 30 min, and the shell was roasted at 800°C for 1 h. Combined with the vacuum and low-pressure casting process, this new shell casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell casting, gravity casting, and LFC were also made to show the characterization of this new shell casting process.     

聚氨脂树脂砂性能研究

研究了HG、CP和NP三种聚氨脂树脂砂的透气性、发气量和在不同加热条件下的残留强度.结果表明:HG系列树脂砂透气性最高,CP系列树脂砂发气性总体上要优于其它两种树脂砂,发气量相对较低.树脂砂的高温残留强度随加热时间的增加而降低,加热温度越低,残留强度降低的幅度也越小;随着加热温度升高,树脂砂的残留强度显著下降,在500℃加热10min时,所有配比树脂砂的残留强度趋于零.CP2配比的树脂砂在透气性、发气性、溃散性和低温强度等方面有较好匹配,能更好地满足薄壁复杂铝合金件铸造成形需求.     

Die design optimization of die casting for fabrication of fuel cell aluminum bipolar plate with micro-channel through casting simulation and experimental investigation

In vacuum die casting, we require a high quality die design for fuel cell bipolar plates to prevent unfilled phenomena, turbulent flow, and porosity. We have designed a die for thin plate die casting using two geometric shapes. In addition, we propose a new overflow system based on numerical simulation, and conducted actual vacuum die casting experiments. An optimal die design consists of seven overflows at the end of the cavity and three overflows at each side wall of the cavity. In our experiment, the molten metal that passed the gate and reached the side wall flowed into the side overflow, no turbulent flow occurred, and the filling behavior and are uniform. In addition, partially solidified molten metal passing through the channel was perfectly eliminated by overflow without back-flow. To validate the proposed approach, a good quality sample was manufactured using the optimal die design with the proposed overflow system.     

簿板坯连铸结晶器振动参数的控制

在对普通板坯连铸结晶器正弦振动参数的理论研究及工业试验的基础上，针对薄板坯拉速快的特点提出了拉坯速度同振动参数的同步控制模型。该模型使薄板坯在高速浇注的条件下采用较低的振动频率能够获得最佳负滑动时间及所必需的负滑动率。     

铝材超薄快速铸轧状态下铸轧辊强度的有限单元法分析

运用有限元软件Algor和工程技术语言Matlab编程对两套正常使用的铸轧辊以及针对超薄快速铸轧而设计的铸轧辊进行了强度仿真计算，获得了超薄快速铸轧辊在热装配的预应力，轧制扭短以及轧制力等我应力场条件下的综合应力状态，并探讨了改善铸轧辊应力状态的策略及方法，为铸孔辊适应铝材超薄快速铸轧工艺提供了有效的分析方法，对改善铸轧辊的强度设计具有指导意义。     

低压铸造薄壁板件的流动与传热耦合数值模拟

采用 VOF法处理自由表面 ,达西源项法处理固 -液两相区流动 ,开发了铸造过程流动与传热耦合数值模拟软件。通过对流场及温度场分别采用不同的计算域和时间步长 ,大大提高了计算效率。利用该软件模拟了一薄壁板件的低压铸造过程 ,并进行了实验验证。数值模拟结果表明 ,对薄壁件而言 ,充型过程的流动对铸件初始温度分布影响较大 ,但充满后的残余流动对温度分布影响较小     

一种高强度、高稳定性铸铁的研究及应用

试验采用高Si/C比、Mo与Cu低合金化、强化孕育等工艺方法,生产低应力高强度铸铁,并用静态弯曲和开口环测应力法,对普通铸铁和高强度铸铁的弹性模量、应力松弛性能进行了对比试验。结果表明,高Si/C比、低合金化的高强度铸铁,能够满足大型精密仪器薄壁基础铸件的高刚度、高稳定性要求。     

Effect of vibration after filling on mechanical reliability in thin wall investment casting with fillability filling regime—part 1

A vibration technique is used in this study to explore the effect of low frequency vibration on the mechanical reliability of Al-7Si-Mg castings. The quality of castings is related to the number and the size of porosity and oxide film in thin wall investment casting. The quality of each method of casting (casting with and without vibration) was assessed by the density of the defects within the thin strips. Weibull distribution function is used to analyze the tensile strength data. The Weibull modulus is applied as a criterion to assess the mechanical reliability to identify the optimized casting condition. The results show that the effect of the vibration on the mechanical reliability is markedly dependent on acceleration of vibration, and the Weibull modulus is in the range of 12 to 12.7 when the acceleration is in range of 0 to 1 g; however, in more than 1 g, the range is 30–35.     

一种扫描式铸轧板带凸度检测方法

根据铸轧工艺的特点，文章提出了一种扫描式铸轧板带凸度检测的方法，即采用双束激光差动扫描测量板带的厚度分布，从而计算出板带的凸度。文章设计了激光板凸度检测装置，现场应用表明，系统可以满足铸轧板凸度检测与控制的要求，具有成本低、精度高等特点。