重型翻转式起模机的开发应用

重型翻转式起模机应用于大件铸造造型生产线模型翻转起模单元中,适合的最大砂箱外形尺寸4 200 mm×2 400 mm×800 mm。本文介绍了重型翻转式起模机的开发与应用。     

活块移出模外利用开模力抽芯的压铸模

铝合金压铸件如图1所示,材质为ZL104。该铸件为立方体形状,右侧有一个大孔,尺寸为70 mm×54 mm×140 mm。开模时,所需要的侧抽芯力大。为了解决抽芯力大的难题,采用活块移出模外,利用开模     

GF166气冲造型自动线搬运车的国产化改造

一汽铸造公司铸造二厂于上世纪80年代末从瑞士GF公司引进了一条双主机气冲造型自动线。其砂箱内尺寸为1200mm×800mm×400/350mm,设计生产率150整型/h。 该线采用间歇开放式铸工带,由于设计生产率高,铸工小车及铸型的横向搬运共设置了9台搬运车(图1)。搬运车1、搬运车2将铸工小车及其上砂箱搬运至小车带;搬运车3将铸工小车及其上砂箱运至移出捅箱机后再将空铸工小车运回小车带;搬运车4将砂箱由移出箱     

浇注系统大孔出流技术在床鞍铸件上的应用

车床床鞍铸件外形尺寸620 mm×555 mm,主要壁厚45 mm,属板类铸件,双面导轨,铸件重98 kg,材质HT200,导轨面加工后不允许有任何铸造缺陷。采用大孔出流技术设计浇冒系统,设计准100 mm×200mm压边冒口,准50 mm直浇道,缓流式横浇道,并在搭接处设置滤渣网,压边缝隙式内浇道,获得成功,铸件工艺出品率92%,铸件废品率1.4%以下。     

浸入式水口侧孔结构对板坯结晶器流场的影响

对断面为850 mm×200 mm、1 150 mm×200 mm、1 400 mm×200 mm的板坯进行1∶1的物理模拟。通过改变浸入式水口的结构,从而对结晶器内流场、保护渣的分布,以及结晶器表面波动情况进行分析研究。实验结果表明,在断面为850 mm×200 mm时,两孔和三孔水口液面波幅的方差分别为0.27和0.03,大约相差10倍,同时由流场图看出三孔水口有效的减少了偏流现象;在断面为1 150 mm×200 mm时,在形成上回流区的3 s内,两孔水口上回流区的面积已经覆盖了2/3,保护渣覆盖面积为钢液表面的4/5且有波动情况,而三孔水口上回流区的覆盖面积只有1/5,保护渣完全覆盖且表面保护渣的波动不明显,因此得出两孔水口更优于三孔水口,使保护渣更容易融化。     

广东亚铝2025mm彩涂线涂机自动控制系统的研究

介绍了广东亚铝2025mm彩涂线涂机的设备组成、自动控制系统配置、人机界面、PLC硬件组态及伺服传动参数设置。     

运用均衡凝固模数法设计铸铁箱体补缩式浇注系统

轧环机下箱体,材质HT 250,重9 500 kg,轮廓尺寸4 100 mm×2 500 mm×577 mm,干砂型,冲天炉熔炼.运用均衡凝固模数法设计补缩式顶注雨淋浇注系统,以大孔出流作充填校核.采用2个浇包同时浇注,2套独立对称的浇注系统,设计结果为:直浇道φ80 mm,横浇道56/60 mm×50 mm,18只内浇道φ18 mm,浇注温度1 320～1 380 ℃.浇注出的铸件形状完整,机加后没有缩孔、缩松、夹渣、气孔等缺陷,工艺出品率93%.表明均衡凝固模数法设计补缩式浇注系统是实用的.     

运用均衡凝固理论设计液压机上横梁底雨淋式浇注系统

400 t液压机上横梁,材质HT200,铸件重4 670 kg,主要壁厚55 mm,轮廓尺寸1 818 mm×1 262 mm×730 mm,普通粘土砂手工造型,干型、干芯。运用大孔出流理论设计底雨淋式浇注系统,直浇道直径φ85 mm,位于55/65 mm×52 mm横浇道中间,两侧横浇道上均布12 mm×60 mm、长40 mm底雨淋内浇道共14只。用均衡凝固收缩模数法核算浇注系统当冒口的补缩能力。生产结果表明,铸件没有气孔、夹砂、夹渣、收缩等铸造缺陷,铸件品质稳定。实测浇注时间平均92 s,与计算值偏差1%,工艺出品率94%。生产实践证明,采用大孔出流理论设计浇注系统,用均衡凝固收缩模数法校核浇注系统的补缩功能,可以满足铸件充型和补缩要求,具有实用价值。     

下拉式热型连铸工艺中的阻流研究

为了解决下拉式热型连铸过程中金属液静压头过高容易拉漏,从而迫使连铸速度必须降得很低这一问题,在铸型上游设置了过滤网式、窄缝式和小孔式三种不同形式的阻流器,分别进行阻流试验,以期降低压头。试验结果表明,过滤网式阻流器由于孔径过大,剩余压头太低,基本没有阻流作用。窄缝式阻流器主要利用摩擦阻力达到阻流,即使窄缝长度达50 mm,宽度为0.3 mm时,剩余压头也只有2～3 mm,阻流效果不显著。小孔式阻流器主要利用表面张力达到阻流,当小孔直径为0.5 mm时,剩余压头可达8 mm,可以显著降低铸型上游金属液的压头,从而防止下拉式热型连铸的拉漏。     

运用大孔出流理论设计磨齿机床身底注式浇注系统

Y7163-10-102磨齿机床身,材质HT200,轮廓尺寸1275mm×680mm×620mm,主要壁厚20mm,最大壁厚55mm,铸件重1300kg,树脂砂型。运用大孔出流理论,设计底注式浇注系统,1个直浇道,直径φ55mm,2个横浇道,截面38mm×40mm,14个内浇道,截面29mm×8mm。浇道比为A直∶∑A横∶∑A内=1.0∶1.2∶1.4。铸件顶部放2只侧冒口,直径φ80mm。实测浇注时间80s,型腔金属液面上升速度8mm/s。生产结果表明:铸件形状完整,轮廓清晰。机加工后,铸件没有缩孔、气孔、渣孔缺陷,达到技术要求。     

Investigation on microstructure and internal friction for low density TiB2/ZL114 composites

TiB₂/ZL114 composites with the density of 2.733 g/cm³ were fabricated through reaction of K₂TiF₄ and KBF₄ (LSM method). The composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The internal friction measurements were performed on DTM-II-J dynamic modulus damping analyzer and the mechanisms were investigated. Experimental results indicate that reinforced particles are well-distributed in the matrix and the internal friction value of TiB₂/ZL114 composites is up to a maximum of 9.04x10^-3, almost twice that of ZL114. The internal friction results form dislocation vibration within the material, the sliding of grain boundary and phase interface, and together with the micro-plastic deformation caused by difference in coefficients of thermal expansion and elasticity modulus of various phases. The average internal friction values of samples with the sizes of 40 mmx4 mmx2 mm, 40 mmx8 mmx2 mm and 40~mm$\times 25 mmx2 mm are 8.83x10^-3, 8.89x10^-3, and 8.93x10^-3, respectively. Thus, the developed composites are of low density, high internal friction, and the sizes of samples have no relation to the internal friction behavior.     

Deformed texture of copper processed by equal channel angular pressing via different angle routes

The commercially pure copper with dimension of 80 mm×20 mm×4 mm was used for equal channel angular pressing （ECAP）, of which their outward appearance coordinate is corresponded with that of rolling deformation modes. Cold-deformed texture was investigated. The results show that the texture character in pure copper processed by ECAP is related with intersection angle （Ф） of the die channel. When Ф is 90° and the sample is extruded for one pass, its texture consists of α and β orientation lines including mainly C, B, S and Goss components, moreover a little rotated cube is found. When Ф is 135°, as extrusion pass increases, the weak texture forms on the scope of deviation from rotated cube （ψ=0°, θ=0°, Ф=45°＋15°） and develops to the ψ=45° fiber mainly including rotated cube. When Ф is 120°, the texture is ψ=45° fiber mainly including rotated cube that is maintained constant as extrusion pass increases.     

大直径薄壁X60钢级管线用无缝钢管的开发

介绍了采用局部感应加热热扩工艺开发生产X60钢级Φ406.4 mm×7.92 mm管线用无缝钢管的工艺过程。通过检测成品的几何尺寸、机械性能以及金相组织分析,证明该产品尺寸符合标准要求,金相组织均匀,综合性能达到API Spec 5L标准PSL2水平。热扩成型的同时进行热处理,消除了钢管内应力,缩短了生产周期,降低了大直径薄壁高钢级管线用无缝钢管的生产成本。     

Al2O3/Al纳米复合材料的强化机制

将含氢等离子蒸发法制备的Al2O3/Al纳米复合粉体冷压成直径为25mm，厚度为2mm的块材，并通过620℃，40min热烧结和变形量为55％的冷轧形变处理使样品的相对密度达到99％。对官致密Al2O3/Al纳米复合材料的拉伸实验表明：其屈服强度σ0.2和断裂强度σb分别为粗晶Al的12－16倍和5－6倍，延伸率δ比同质冷轧粗晶Al约高28％。表征了Al2O3/Al纳米复合材料的结构和热稳定性，研究了晶粒细化的强化效应、非晶Al2O3弥散增强和冷变形加工硬化等对材料强度的影响。探讨了Al2O3/Al纳米复合材料的强化机制。     

热丝化学气相沉积金刚石薄膜空间场的数值分析

根据热丝化学气相沉积(HFCVD)金刚石薄膜的几何特点和工艺参数,建立了该系统的二维温度场、速度场和密度场 的耦合模型.利用该模型对沉积大面积金刚石薄膜的空间场进行了模拟计算,研究了沉积参数对空间场的影响.结果表明,衬底处 的温度分布和质量流密度的计算值与实测值相吻合.只有气体进口速度对质量流密度的均匀性影响最大,其它沉积参数对衬底温度 的均匀性、质量流密度的均匀性影响不大.从热丝阵列的最低温度出发,优选出沉积100 mm×100 mm、高质量金刚石薄膜比 较适宜的热丝几何参数.     

利用数值模拟开发涡轮增压器壳体铸件

介绍了汽车发动机中涡轮增压器壳体铸件的结构及技术要求,利用自动化线壳型铸造,一型2件,水平分型,采用封闭式浇注系统,浇口比为ΣF直:ΣF横:ΣF内=2:1.5:1,其中,直浇道截面面积为1 200 mm2,横浇道截面面积为900mm2,内浇道截面面积为600 mm2。热侧冒口直径为65 mm,高度为100 mm,冒口颈尺寸为23 mm×33 mm;顶冒口直径为50 mm,高度为70 mm,冒口颈尺寸为10 mm×25 mm,并在涡轮室内部圆形平面处放置尺寸为50 mm×15 mm×15 mm的随型冷铁,使生产的铸件冒口颈区域微观缩松消除。     

回火温度对26CrMo4s/2钢钻杆用管性能的影响

测定了26CrMo4s/2钢钻杆用管在回火温度上升时的相变点,重点研究了不同回火温度对材料的拉伸强度、夏比冲击功的影响。研究结果表明,回火温度的提高会导致强度指标下降,塑性和韧性指标上升,当回火温度超过620℃时,材料强度降幅加大;26CrMo4s/2钢热处理后可以满足ANSI/APISpec5DP—2009标准中E、X、G等3个钢级的要求;选择合适的回火温度后,冲击功达到100J以上(7.5mm×10mm,21℃)。     

Time-Series Fluctuation Characteristics of Segregation Carbon Element Distribution Along Casting Direction in High Carbon Continuous Casting BilletEI北大核心CSCD

High carbon steel is prone to produce macroscopic/semi-macroscopic segregation, and C segregation along casting direction will have a serious impact on the quality of billet. Based on qualitative analysis (macroscopic quality rating and elemental macro content analysis) and relatively simple quantitative analysis (segregation index, mean square error), the existing technologies have judged the degree of segregation of billet in different levels, but with requirement of stricter quality stability standard, especially for the typical raw material of high-level rod-wire steel (e.g. 70 high carbon steel), it is very necessary to introduce a new method to measure the fluctuation characteristics more effectively. In this work, the ARMA (auto regressive moving average) model in the time series is firstly used to study the segregation degree of high carbon steel billet at different positions from the aspects of inherent period and damping rate in terms of the fluctuation characteristics (period and extremum) of C element along the casting direction. The size of the billet is 170 mmx170 mm and the sampling location is in the center longitudinal plane of the billet. The experiment is conducted by considering the effect of cooling strength (conventional cooling and strong cooling) on the fluctuation characteristics. Firstly, it is shown that the inherent period and the damping rate can quantitatively describe the inherent characteristics (periodic and extreme characteristics) of the C element along the casting direction. Secondly, strong cooling makes the average inherent period and the average damping rate of C element time series in the columnar grain region smaller, thus increasing the fluctuation degree and the segregation degree. However, strong cooling makes the average inherent period and the average damping rate of the C element time series in the equiaxed grain region larger, thus decreasing the fluctuation degree and the segregation degree. Finally, the period and the damping rate of the columnar grain region are respectively affected by the dendritic spacing and the temperature gradient, and the period and the damping rate of the equiaxed grain zone are respectively affected by the liquid flow in the solidification process (V-shaped segregation) and local cooling rate. By this research, a new theoretical basis may be supplied for delicacy control of element segregation and related quality fluctuation phenomenon.     

闭式压力机组合机身数值模拟与试验研究

针对闭式压力机组合机身传统设计计算方法存在的问题,利用接触分析理论与方法对机身接触面的接触非线性问题进行研究。对组合机身拉紧螺杆的预紧力进行分析计算,获得了较为可靠的机身计算模型。对计算模型进行数值模拟,得出其在受载状态下的应力与变形的计算结果。利用仪器对机床进行试验,将测试结果与计算结果进行对比,最终证明分析方法的可行性。     

轧辊锻造工艺分析

对轧辊的锻造工艺进行了分析。充分利用现有的设备,合理选择大钢锭进行一锭多件的生产实践。优化了轧辊的工艺并缩短了生产周期。