标码机下支架注射成型的模拟分析

以标码机下支架为例,应用MoldFlow软件分析了浇口位置、熔体温度、模具温度和保压压力对熔接痕和翘曲变形的影响,分析熔接痕和翘曲变形产生的原因,通过优化设计方案,消除了产品正面及背面的熔接痕,减小了翘曲变形,分析结果与生产实际吻合。     

不同分散剂对水系流延氧化铝基片的影响

研究了2种不同类型的分散剂对水系流延氧化铝基片的影响。研究发现：从浆料的分散性、所流延坯片的质量、烧结后基片的密度及其微观结构的比较，流延氧化铝浆料以聚丙烯酸（PAA）为分散剂明显优于以阿拉伯树胶为分散剂。以阿拉伯树胶为分散剂的浆料分散性较差，流延出的坯片生坯密度较低、坯片的柔软性较差，烧结后相对密度较低，同时，由于分散剂对塑化剂的影响，使得粘结剂PVA在浆料中没有凝胶化，从而在坯片上表面产生C富集层。     

低介低温烧结玻璃／钙长石复合绝缘材料的研究

通过对低介电常数 CaO-Li2O-B2O3-SiO2-Al2O3玻璃设计及与钙长石晶体的复合优化，制备了具有低温、低介、与硅相匹配的低热膨胀系数的新型绝缘复合材料。样品在970℃烧结0．5h后，介电常数5．125，介质损耗2．48×10^-3，抗折强度105．8MPa，热膨胀系数（25～500℃）3．38×10^-6℃^-1。并研究了玻璃与钙长石加入量、显微结构等因素对材料性能的影响。     

Solid-state phase equilibria in the Gd–Co–Al ternary system at 1173 K

A portion of the isothermal section (1173 K) of the phase diagram of the Gd–Co–Al ternary system (up to 33.3 at.% Gd) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. Fourteen single-phase regions (including solid solution regions of the binary compounds), twenty-five two-phase regions and twelve three-phase regions were found to exist at this isothermal section. In the GdCo₂–GdAl₂ system, the existence of the GdCo_0.74Al_1.26 phase is identified and it has a composition range of 30–45 at.% Al, the maximum solid solubility of Al in GdCo₂ is about 15 at.%, and Co in GdAl₂ is about 16 at.%. Besides, the maximum solid solubility of Al in Co, Gd₂Co₁₇ and GdCo₅ is about 6, 17 and 25 at.%, respectively, the maximum solid solubility of Gd in Co, CoAl is below 2 at.% and the solid solubility range is from 47 to 61 at.% Al in CoAl phase. In this work, no new ternary compounds were observed.     

Preparation of ceramic coatings on inner surface of steel tubes using a combined technique of hot-dipping and plasma electrolytic oxidation

A new method for inner surface modification of steel tubes, named a combined technique of hot-dipping and plasma electrolytic oxidation (PEO) was proposed and demonstrated in this paper. In this work, metallurgically bonded ceramic coatings on inner surface of steel tubes were obtained using this method. In the combined process, aluminum coatings on steel were firstly prepared by the hot-dip process and then metallurgically bonded ceramic coatings were obtained on the aluminum coatings by PEO. The element distribution, phase composition and morphology of the aluminide layer and the ceramic coatings were characterized by SEM/EDX and XRD. The corrosion resistance of the ceramic coatings were also studied. The results show that, after hot-dip treatment, the coating layers consist of two layers, where Al, Fe_xAl _(1−x) were detected from external topcoat to the aluminide/steel substrate. Then after PEO process, uniform Al₂O₃ ceramic coatings have been deposited on inner surface of steel tubes. The ceramic coatings are mainly composed of -Al₂O₃ and γ-Al₂O₃ phase. The compound coatings show favorable corrosion resistance property. The investigations indicate that the combination of hot-dipping and plasma electrolytic oxidation proves a promising technique for inner surface modification of steel tubes for protective purposes.     

The Structure Stability of Carbide-Free Bainite Wheel Steel

Metallographic structures of carbide-free bainite steel wheel rim are mainly composed of supersaturated lath ferrite and retained austenite film among bainitic ferrite laths. It is suspected that supersaturated ferrite and retained austenite are likely to decompose under the influence of temperature change and mechanical stress. Stability of wheel rim structure is studied by means of x-ray diffraction, dye microscopy, and micro-hardness test. When the samples are tempered in the range of 150-350 °C, the retained austenite films are at the state of relative stability. Fifty percent of retained austenite is decomposed when the sample is tempered at 400 °C. Microhardness increases when the sample is tempered at 150 °C. The decrease in hardness is mild when the samples are tempered from 200 to 500 °C. The mechanical stability of retained austenite film is studied with tensile sample under the effect of tensile stress. The retained austenite appears to be stable in low and middle degree of deformation, and decomposition occurs at great amount of deformation. Diffraction peak of carbide is not found in all above experiments. The steel enriched silicon prevents the carbide precipitation during the transformation. It indicates the carbide-free bainite wheel steels have an excellent thermal and mechanical stability.     

人字形转向支架压铸件的工艺设计研究

介绍了转向支架铝合金压铸件的结构，分析了合金液体的流态变化、涡流的发生及气孔的形成机理，提出的解决方案主要是：对浇注系统进行较大的改动，严格规定内浇道在模具型腔上的起始位置点，内浇道在模具型腔所采取的喷射角度，以及内浇道的厚度和长度；内浇道的连接采用圆滑过渡，以减少铝液在浇道内产生的紊流；采用较长的分流锥，控制铝液在压室内的充满度；注重铝液浇注温度的恒定。     

RE对ZA43合金组织、力学性能及抗磨性的影响

通过RE对ZA43合金进行变质处理,研究了该合金的显微组织、力学性能及抗磨性能。结果表明,在ZA43合金中加入适量RE,能有效地阻止树枝状晶长大,优化组织结构,细化晶粒,使合金的抗拉强度提高20%、硬度提高10%,抗磨性能也大幅度改善。这为进一步改善该合金的力学性能及抗磨性能提供了一条有效途径,从而使锌合金代替铜合金成为可能和现实。     

国内外酸洗热轧板的生产及发展

介绍国内外酸洗热轧板的生产及发展,并就我国当前酸洗热轧板的发展谈了几点认识。     

Li2O-MgO-Al2O3-SiO2系高温低膨胀釉的制备及性能研究

以焦炉炉门堇青石衬砖的使用情况为依据，得出适合堇青石衬砖高温低膨胀釉的体系为Li2O-MgO-Al2O3-SiO2系。釉料在合理的化学组成范围内生成堇青石与口．锂辉石固溶体晶体。试验成功的研制出适用于堇青石衬砖的高温低膨胀釉，釉料在1350℃与堇青石砖共同烧成，釉层能均匀光滑的铺展在堇青石衬砖表面，它能在1200℃下使用而不融化，它的热膨胀系数为2．85×10^-4，在20℃～1000℃并且还有待于进一步降低。釉与堇青石衬砖热膨胀相匹配，因此釉层经五次热震（1100℃，水冷）后的没有裂纹出现。XRD物相分析得出釉有堇青石与口．锂辉石固溶体晶体相生成。釉能填充堇青石衬砖表面的气孔并以自身的高致密性防止了有害物质向砖内部渗透，起保护层作用。