高压开关压气缸热挤压模具设计

在设备闭合高度有限的情况下 ,设计了1副结构新颖的组合式挤压模具 ,使3150kN油压机设备能力得到了有效的发挥。所述压气缸毛坯生产工艺具有高效节材的特点 ,对类似零件的热挤压工艺及模具结构设计有重要的参考价值。     

Al-Pb-Si-Sn-Cu轴瓦合金的微观结构及特征

采用机械合金化、冷压与热挤压法制备了Al-15％Pb-4％Si—1％Sn—1．5％Cu(质量分数，％)轴瓦合金。试验结果表明，块体材料的组织分布很均匀。Pb粒子细小均匀弥散分布在Al基体上，呈纳米晶粒。Al基体晶粒大小约1．2μm，在其晶界和晶粒内都有粒子析出。在Al基体上还分布着由非晶和亚微米晶粒构成的混合相。研究表明，该工艺是制备Al-Pb系列轴瓦合金的较佳方法；并为制备室温不互溶、高温存在很宽固溶间隙、有较大密度差异的合金组元且组织均匀的合金奠定了工艺基础。     

轿车铝合金油泵壳体液态挤压工艺

采用液态挤压代替压力铸造及热模锻生产轿车铝合金油泵壳体,不仅克服了压铸件内部容易形成气孔和氧化夹杂的缺陷,而且减少了热模锻的投资及提高了材料利用率。本文介绍了铝合金油泵壳体液态挤压的模具结构及设计参数、技术经济分析。     

1 250 mm五机架六辊冷连轧工艺控制系统核心技术

简要介绍了自主设计制造、具有完全自主知识产权的1 250 mm五机架六辊冷连轧产线工艺及设备特点。重点阐述了冷连轧工艺控制系统的硬件配置、软件架构及核心技术。采用基于简易有限元的轧制力模型及基于成本函数的多目标负荷分配模型，实现了高精度的轧制规程计算。开发了原料板快速启车技术与板形多变量综合最优控制技术，实现了冷轧产品的尺寸精准控制。现场实际应用效果表明，机组稳定运行率达到99.8%以上，不同规格的产品厚度控制精度均达到±0.8%以内，板形控制精度均达到5I以内。     

液锻连挤硅线石粒子/铝复合材料的摩擦磨损行为

采用液锻连挤成形工艺获得了一种新型硅线石颗粒增强LY12铝基复合材料,其性能可与常规热挤压件媲美.摩擦磨损性能测试表明:硅线石颗粒增强铝基复合材料具有优良的摩擦磨损性能,且其耐磨性能随粒子体积分数增加而增加.材料经液锻连挤后,硅线石粒子在强大三向压应力作用下嵌镶于基体内,粒子很难拉脱,承受摩擦力的作用时,硅线石粒子起支承作用,粒子硬度高,故使复合材料整体耐磨性能提高.     

挤出工程和挤出理论发展史研究

在回顾挤出工程和挤出理论发展历史的基础上,作出了4点结论与建议。明确地提出要坚决打破我国存在的树脂及材料工业、制品加工工业和塑机制造工业等行业界限,根据当前知识经济时代的特点,坚持走依靠自我力量技术创新、产学研相结合的道路。     

Structural changes and mechanical performance of recycled poly(vinyl chloride) bottles exposed to ultraviolet light at 313 nm

The structural changes and mechanical performance of virgin poly(vinyl chloride) (PVC) bottle (VB) compounds blended with postconsumer PVC bottles collected from a specified factory (RB‐F) and houses (RB‐H), were examined before and after UV irradiation at 313‐nm UV wavelength for different periods of time up to 28 days. The results indicated that, when exposed to UV light, the RB‐F/VB blends containing greater conjugated double bonds with higher yellowness index appeared to exhibit better mechanical performance than that of the RB‐H/VB blends. It was found that the amount of conjugated double bonds was not a linear function of the discoloration level of PVC compounds. Tensile strength of the VB compounds was not affected when incorporated with RB‐F recyclate, but progressively decreased with increasing RB‐H recyclate. An optimum concentration for RB recyclates to be added into the virgin compound was recommended for obtaining a maximum impact strength. Both tensile and impact strengths decreased with increasing UV exposure time, a severe degradation being obvious after a UV exposure time of 21 days. Hardness was not affected significantly by the addition of PVC recyclate, but increased with increasing UV exposure time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 84–94, 2004     

基于单片机的PID温控系统在塑料挤出机中的应用

针对在塑料挤出过程中温度控制的重要性，介绍了一种新型的PID温度控制系统。该系统采用高性能单片机芯片，可以方便地对系统加热、冷却周期及PID的各个参数进行在线设定和修改，提高了塑料挤出机的温控精度。     

Biodegradable extruded starch blends

We prepared biodegradable extruded starch blends by first mixing starch with additives and then processing the mixture in an extruder. The mechanical properties, including tensile strength and elongation at break, solubility, biodegradability, rheological properties, molecular weight, and glass‐transition temperature of the extruded blends were studied. Glycerol and urea, to some extent, could both decrease the tensile strength and increase the percentage elongation at break because the former acts as a plasticizer and the latter can break down interactions among starch macromolecules. The extruded starch blends showed thermoplasticity, and their melts behaved as pseudoplastic liquids at a comparatively low shear rate. The biodegradability of the extruded starch was slightly higher than that of native starch. The molecular weight of starch displayed a decreasing tendency after extruding modification. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 627–635, 2003     

不同螺杆组合对聚乙烯交联反应挤出的影响

从20世纪60年代到现在,在国外,反应挤出取得了相当巨大的进步,其应用相当广泛。而在国内,对于反应挤出研究得很少,最突出的表现在利用平行同向双螺杆、采用两步法的生产工艺来反应挤出聚乙烯交联料。这主要是由于影响交联质量的因素很多,如配方、生产工艺和反应挤出设备等等,而本文着重讨论挤出设备,通过对现有的挤出设备进行改进,以期得到一组最佳的螺杆组合和生产工艺条件。