复合齿冠研究

通过采用比例镶铸硬质点支撑软基体以提高耐磨性的研究，实现了耐磨合金与钢基的可靠结合，研制成齿冠复合材料工作面，其使用寿命是原齿冠的两倍以上。     

铸造钢铁基耐磨复合材料制备工艺的研究进展

评述了铸造钢铁基耐磨复合材料的制备工艺和研究进展,重点分析了双液复合铸造、双金属镶铸及铸渗3种耐磨复合材料制备工艺,并对耐磨复合材料制备技术的未来发展方向和研究重点提出合理选材、提高冶金质量、应用数值模拟技术、探研界面结合机理等建议。     

碾压工艺因素对双金属复合减摩材料物理力学性能的影响

介绍了用烧结一回转冷碾压方法制造双金属复合减摩材料的新工艺,探讨了影响双金属复合减摩材料物理力学性能的工艺因素。     

双金属轧制复合技术及其研究的进展

对双金属轧制复合技术中的热轧复合、等辊径等辊速冷轧复合和异步冷轧复合三种主要的工艺方法进行了扼要的介绍，回顾了它们的发展历史及主要的研究成果，提出了未来研究工作的方向。     

电渣复合法制备双金属复合轧辐的研究进展

复合轧辊是一种以高耐磨性及高强韧性材料分别作为工作外层及芯材的双金属复合材料。本文对国内外采用电渣冶金技术进行双金属复合以制备复合轧辊的堆焊复合法、液态金属表面复合法、自耗结晶器复合法等工艺方法进行了系统介绍,分析了自耗电极形式、导电回路方案、外层金属供给方式及设备结构等对双金属复合过程及复合轧辊综合性能的影响。同时,对不同工艺的基本特点及其控制关键技术进行了概括。对各电渣复合工艺技术发展历程及复合轧辊综合性能的稳定控制进行了分析,对电渣复合法制备双金属复合轧辊的未来发展前景进行了展望。     

电渣复合法制备双金属复合轧辊的研究进展

复合轧辊是一种以高耐磨性及高强韧性材料分别作为工作外层及芯材的双金属复合材料。本文对国内外采用电渣冶金技术进行双金属复合以制备复合轧辊的堆焊复合法、液态金属表面复合法、自耗结晶器复合法等工艺方法进行了系统介绍,分析了自耗电极形式、导电回路方案、外层金属供给方式及设备结构等对双金属复合过程及复合轧辊综合性能的影响。同时,对不同工艺的基本特点及其控制关键技术进行了概括。对各电渣复合工艺技术发展历程及复合轧辊综合性能的稳定控制进行了分析,对电渣复合法制备双金属复合轧辊的未来发展前景进行了展望。     

高铬—40Cr复合锤头的研究和应用

采用无应力镶铸工艺研制出的高铬－４０Ｃｒ复合锤头，质量稳定，使用安全可靠，其有效寿命是高锰钢锤头的６．３倍。     

双金属离心复合轧辊开发研究

通过轧辊内、外套设计 ,离心工艺参数的确定及浇注工艺等几方面介绍了双金属离心复合轧辊的生产工艺。     

双金属复合铸造球磨机衬板工艺研究

介绍了用立浇双金属复合铸造工艺将高耐磨性的高铬铸铁和高韧性的优质碳素钢有机地融为一体,制成双金属复合球磨机衬板,并对其力学性能进行了试验研究.该双金属复合衬板兼具两种金属的优点,既有较高的耐磨性,又有良好的整体韧性,适用于大型球磨机.     

钨钼复合双金属界面研究

采用粉末冶金法制备了钨钼复合双金属靶材,研究了不同工艺参数下复合材料的界面组织和结构。试验结果表明,控制适当工艺参数可以获得结合良好的平直界面。钨钼复合双金属界面结合形式主要为扩散结合,烧结温度和保持时间对复合材料结合界面结构均有明显影响。本文还讨论了钨钼复合双金属界面的缺陷及产生机理。     

Numerical Simulation on Carburizing and Quenching of Gear Ring

 The carburizing process of the gear ring was simulated by taking into account the practical carburizing and quenching techniques of the gear ring and by solving the diffusion equation. The carbon content distribution in the carburized layer was obtained. Based on the results, the quenching process of the gear ring was then simulated using the metallic thermodynamics and FEM; it was found that the carburization remarkably affects the quenching process. Microstructures and stress distributions of the gear ring in the quenching process were simulated, and the results are confirmed by experiments.     

高强度工程机械用钢铸坯夹杂物分析

为了解某厂高强度工程机械用钢Q550MD铸坯夹杂物来源,优化生产工艺,提高铸坯质量,采用大样电解和夹杂物自动扫描分析方法,对铸坯中夹杂物数量、尺寸、形貌及成分进行研究。结果表明,电解试样中大型夹杂物尺寸集中在80~140 μm,形状大多为球形,主要成分为铝酸钙。铸坯中大型夹杂物在形成最终复合夹杂物前均来自于钢包,且可能发生结晶器卷渣。检测的铸坯宽度方向1/4位置发现夹杂物聚集现象,夹杂物数量明显高于边部和1/2位置,这与结晶器流场不合理有关。     

双金属复合材料弯曲成形有限元模拟的材料模型研究

由于双金属材料中两层复合组织结构的非均质性,对其零件成形过程进行有限元模拟是一个比较复杂的过程,其中最关键的一点就是材料模型问题.本文在经典的复合材料层合板理论的基础上对双金属复合材料的本构关系进行了推导计算,根据材料具体的加工工艺,在有限元软件MSC Marc中,建立了等效层合板模型,可以较准确地描述双金属材料结构的真实情况.     

高强度工程机械用钢铸坯夹杂物分析

为了解某厂高强度工程机械用钢Q550MD铸坯夹杂物来源,优化生产工艺,提高铸坯质量,采用大样电解和夹杂物自动扫描分析方法,对铸坯中夹杂物数量、尺寸、形貌及成分进行研究。结果表明,电解试样中大型夹杂物尺寸集中在80~140 μm,形状大多为球形,主要成分为铝酸钙。铸坯中大型夹杂物在形成最终复合夹杂物前均来自于钢包,且可能发生结晶器卷渣。检测的铸坯宽度方向1/4位置发现夹杂物聚集现象,夹杂物数量明显高于边部和1/2位置,这与结晶器流场不合理有关。     

Melanoma-associated hypopigmentation: where are the antibodies?

The purpose of this study was to compare the changes in the degree of conversion in the various layers of composites after additional heat curing. Four types of composites and three types of inlay ovens were used in this study. Composite was placed in a 4 mm thick Teflon mold and light cured from the top for 60 seconds. Twenty samples were prepared for each composite; 10 of these were additionally heat cured in an inlay oven as the manufacturer recommended. After light curing or light and heat curing, the samples were sectioned into four parts and assigned to groups A, B, C, or D according to their distance from the light source. These sections were then thinned to 50 to 70 mm, and these wafers were analyzed with a Fourier Transform Infrared spectrometer to determine the degree of conversion. A standard baseline technique was used to calculate the degree of conversion. When the composites were heat cured, significant increases in the degree of conversion were noted throughout the samples, but the amount of increase differed among materials. Thus the clinical performance of a heat-treated composite inlay may be different depending on materials.     

新能源汽车ABS粉末冶金感应齿圈的研制

采用粉末冶金工艺替代机械加工工艺, 通过分析产品结构, 精选材料配方, 优化控制模具模架设计、温模压制成形、高温烧结、精密整形及达克罗等工艺, 制备出了高质量的ABS感应齿圈成品零件, 并对其进行力学性能测试。结果显示, 材料组份为Fe-0.8Ni-3Co-0.2P的ABS粉末冶金感应齿圈成品密度为7.15g·cm-3, 表面硬度HRB55, 抗拉强度421MPa, 饱和磁感应强度1.12T, 中性盐雾试验240h无锈蚀。结果表明, ABS粉末冶金感应齿圈技术性能指标完全满足新能源汽车制动控制系统应用要求, 用户装机使用运行效果良好。     

双金属复合板矫直过程的弯曲及弹复解析

基于工程弹塑性力学建立了不同组坯方式下双金属复合板弯曲矫直过程截面弹塑性状态演变路径的解析模型.基于该模型分析不锈钢复合板矫直过程中的弯曲回弹特性,解释复合板弯曲回弹过程中截面的反向屈服现象,并将不锈钢复合板与单一材料板材弯曲过程进行对比.研究结果表明:双金属复合板在弯曲过程中截面会经历五种弹塑性状态,并伴随着不同的中性层偏移规律,弯曲回弹后的残余应力分布与单一材料板相比更加不均匀且可能进入反向屈服状态;复合板与单一材料板材的弯矩相对差值随着屈服强度比的增大而增大,其绝对值随着弯曲曲率先增大后减小.      

Influence of mold length and mold heat transfer on horizontal continuous casting of nonferrous alloy rods

The influence of mold length and mold heat transfer on the conventional hot-top D.C. continuous casting process was studied through numerical simulations and experiments with horizontally cast 20 mm diameter lead and zinc rods. The minimum casting speed was found to be a nonlinear function of the mold length. For short molds, an inverse relationship between mold length and minimum casting speed was observed. However, the minimum casting speed for zinc cast from molds longer than 12 mm was constant at 2.5 mm/s. For lead cast in molds longer than 12 mm, the minimum observed casting speed was constant at 4.0 mm/s. The observed nonlinear relationship between minimum casting speed and mold length was predicted using a numerical model of the process. For this, an analytical expression for the mold boundary conditions was derived which included the influence of gas gap formation between the rod and the mold due to thermoelastic deformations of both the rod and the mold. Correlation between observed and predicted behavior was demonstrated for both the lead and zinc rods. Maximum casting speed was observed to increase with increased mold length; however, this speed was found to be critically dependent on process attributes such as mold and pinch wheel alignment and mold lubrication.     

球磨机安装问题探析

磨矿作业是金属矿选矿工艺的重要工序,球磨机是磨矿作业的主要设备,球磨机能否长期稳定运行,其安装工程质量至关重要。从基础工作,中心标板和基准点的埋设,底座的安装,主轴承的安装,筒体、端盖、大齿圈的安装,大小齿轮的装配等方面详细介绍了球磨机的安装步骤及安装过程中需注意的问题,值得借鉴。     

Influence of mold length and mold heat transfer on horizontal continuous casting of nonferrous alloy rods

The influence of mold length and mold heat transfer on the conventional hot-top D.C. continuous casting process was studied through numerical simulations and experiments with horizontally cast 20 mm diameter lead and zinc rods. The minimum casting speed was found to be a nonlinear function of the mold length. For short molds, an inverse relationship between mold length and minimum casting speed was observed. However, the minimum casting speed for zinc cast from molds longer than 12 mm was constant at 2.5 mm/s. For lead cast in molds longer than 12 mm, the minimum observed casting speed was constant at 4.0 mm/s. The observed nonlinear relationship between minimum casting speed and mold length was predicted using a numerical model of the process. For this, an analytical expression for the mold boundary conditions was derived which included the influence of gas gap formation between the rod and the mold due to thermoelastic deformations of both the rod and the mold. Correlation between observed and predicted behavior was demonstrated for both the lead and zinc rods. Maximum casting speed was observed to increase with increased mold length; however, this speed was found to be critically dependent on process attributes such as mold and pinch wheel alignment and mold lubrication. Formerly Research Assistant, University of Waterloo