Analysis of Intermetallic Phases Formed on Surface Vapor Oxidized H13 Hot Work Steels in Molten Aluminum

In this paper, the author dipped surface vapor oxidized H13 steel specimens into 700℃ molten aluminum liquid for a certain period of time. Analyze the intermetallic phases formed on the H13 samples surface with optical microscope and X-ray diffraction method. The observation of immersion test sample's cross-section shows that Fe3O4 film will protect die substrate from molten aluminum erosion. The identification of the intermetallic phases reveals that they consist of 2parts, which is named as the composite layer and the compact layer. Further investigations are made in order to know the phase constituents of the 2 layers, they are Al8Fe2Si (outer composite layer), (AlCuMg) and Al5Fe2 (compact layer),respectively. The experimental results show that on the same specimen, a convex surface with bigger radius of curvature is more likely to be molten and the melting loss speed is also faster than a flat and smooth surface. The thickness of compact layer on a smooth surface is much bigger than that of the convex surface. Therefore, the author supposes the compact layer is favorable in stabilizing the die surface material from further melting loss, as their formation on the die surface, the melting loss speed will decrease.     

刚塑性有限元模拟中体积变化问题处理方法

分析了在塑性有限元分析金属体积成形问题中引起体积变化的原因 ,指出在采用罚函数方法引入体积不可压缩条件的刚塑性有限元模拟中惩罚因子、增量步长、节点调整、网格密度和重划次数等是引起体积变化的主要原因。针对所分析原因 ,在现有的方法基础上提出基于三维有限元的节点调整和体积补偿新方法 ,并在实际模拟中应用 ,得到较好的效果 ,提高了模拟的精度和可信度。     

低温熔体获得方式对熔体温度处理效果的影响

利用熔体温度处理工艺研究了A3 5 6铝合金低温熔体的不同获得方式对其凝固组织的影响 ,用直接炉内保温和机械搅拌 2种方式改变低温熔体的结构 ,以获得理想的凝固组织。实验结果表明 ,熔体温度处理过程中 ,对低温熔体机械搅拌可以明显改善混合后熔体的组织形貌 ,使组织形貌由树枝晶转变为等轴晶 ;在搅拌基础上选取较低的低温熔体温度 ,能够得到很好的凝固组织。     

浅述我国电液锤技术的发展与应用

通过对国外电液锤技术的引述，介绍了目前国内电液锤技术的发展与应用状况，并展望了电液锤发展前景。     

富康轿车电喷缸体、缸盖加工自动线的电气设计

文章介绍了富康轿车电喷缸体、缸盖加工自动线的布局设计、PLC的选型及配置、编程方法与技巧、自动线的显示画面及优点等.     

4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cu(Ⅱ) determination by differential pulse volt-ammetry

A differential pulse voltammetric method was developed for the sensitive and selective determination of Cu(Ⅱ) at 4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-l,3,5-triazine modified carbon paste electrode in 0.05 mol/L KHC8H4O4 solution (pH = 4.02). The oxidation peak of Cu(Ⅱ) was observed at 0.065 V(vs Ag/AgCl) by scanning the potential in positive direc-tion. The analysis procedure consisted of an open circuit accumulation step in stirred sample solution. It was followed by medium exchange to a clean solution and subsequently an anodic potential scan was affected to obtain the voltammetric peak. The current was proportional to the concentration of the Cu(Ⅱ) ion in a range of 1× 10-7-1×10-4 mol/L for 6 min accumulation; the most of metal ions did not interfere with the determination. The developed method was applied to Cu(Ⅱ) determination in coal-ash sample, the results agreed with that of atomic adsorption spectroscopy(AAS).     

飞边槽结构形式对模锻成形的影响

开式模锻中飞边槽的形式对锻件成形过程的影响较大。本文通过大型体积成形有限元模拟软件DEFORM对采用不同形式飞边槽的锻件锻造过程进行了模拟，通过比较模拟结果得出不同形式飞边槽对模锻成形的影响，并就不同形式飞边槽在开式模锻中对模具型腔的填充性和模锻力的影响进行了详细分析。     

车床静刚度计算机测试系统研制

在分析了车床的结构特点和车削工艺系统的受力情况和借鉴传统车床静刚度仪优点的基础上，研制了一套基于计算机控制的车床静刚度测试系统。系统由计算机作为信号检测、数据处理和控制核心，并配以精密位移传感器、压力传感器和步进电机及其驱动器等。实现了自动加载、卸载，采样，数据处理，直接绘制、显示和打印刚度曲线等功能。系统的成功研制为车床静刚度的测试提供了一种先进手段。实测结果表明，该系统具有自动化程度高、测试效率高、精度高、可靠性高、测试性能稳定的优点。     

高吸水树脂研究进展

综述了高吸水树脂的制备、结构及吸水机理,介绍了高吸水树脂国内外发展现状及其在各方面的应用,并提出了目前的主要研究趋势。     

细菌纤维素合成过程中的影响因素

研究了接种量、pH值、培养液深度、培养液表面积和发酵时间等因素对形成细菌纤维素膜的产量、厚度及比表面积的影响。结果表明:接种量在7%、初始pH值在5～6范围内细菌纤维素的产量最大;厚度主要取决于发酵时间和初始pH值;培养液表面积对单位面积细菌纤维素产量有比较大的影响;膜的比表面积与发酵时间的长短无关。