Fe、Zn含量对渗铜剂性能的影响

采用扩散部分预合金化的方法制备不同成分的渗铜剂,以Fe-2Cu-0.8C烧结钢为基体,在1 120℃下保温30 min进行渗铜,研究Fe、Zn含量对渗铜剂熔渗表面性能和熔渗效率的影响。结果表明:Fe含量是影响熔渗表面性能的重要因素,当其低于1.6%时,表面出现腐蚀但无残留;当其高于2.2%时,表面无腐蚀但出现残留;Fe含量为1.9%时,表面无腐蚀和残留。Zn含量对熔渗表面性能影响小,锌会在熔渗过程中挥发而导致熔渗效率降低。经综合比较,Cu-1.9Fe-2.0Zn渗铜剂熔渗表面性能优异,综合力学性能好。     

渗铜烧结钢用高性能渗铜剂的研究及应用

介绍了国内外烧结钢用渗铜剂的研究现状,对国内外渗铜剂的性能进行了对比,分析了渗铜剂成分对熔渗性能的影响,指出了渗铜时的基体侵蚀和表面残留(粘附)产生的原因,提出了解决方法,对国内高性能渗铜剂的开发和应用提出了一些建议.     

钨渗铜材料力学性能和组织的批次稳定性研究

采用3批不同厂家的钨粉，通过烧结-熔渗法制备了钨渗铜材料，分析了材料的密度、金相组织和断口形貌，测试了不同温度下的拉伸强度，对比研究了高温钨渗铜材料的批次稳定性。结果表明：3个批次材料烧结性能一致，渗铜均匀性良好。组织相近，晶粒度相近，断口形貌相近，基本无差异；不同温度点的拉伸强度互有交叉，趋势一致，没有明显差异。对钨渗铜材料批生产过程中，原材料的供方选择和质量管控提出了方法和建议。     

金属原型零件渗铜烧结及其放电加工行为

研究了激光烧结快速成形技术制备金属原型零件的渗铜烧结处理工艺。通过放电加工试验以及对原型零件表面组织结构的分析，讨论了原型零件的放电加工行为，结果表明，经渗铜烧结处理的原型零件可获得与常规电极相近的加工性质，并且表现出优于常规电极的特性。     

钼粉粒度均匀性对钼渗铜材料组织的影响

采用熔渗法制备了钼渗铜材料。采用超声波探伤的方法对钼渗铜材料进行了无损检测，采用SEM和金相分析对钼渗铜材料进行了微观组织观察，分析了钼粉的粒度均匀性对钼渗铜钼材料组织的影响。研究结果表明：粉末粒度均匀性对钼骨架的渗铜性能有影响；粉末中存在的细颗粒较多或者有粉末团聚现象时，钼骨架局部细小孔隙聚集，铜难以渗入这些聚集的小孔隙，造成超声波探伤渗铜均匀性不佳；超声波探伤发现的“面积型渗铜不均”实际是“密集微孔聚集”。     

稀土对硼铝共渗过程及渗层性能的影响

本文研究了双涂层法稀土硼铝共渗工艺及渗层的性能,考察了稀土对渗层厚度、渗层表面硬度和渗层组织形态的影响,获得了稀土加入量的最佳值。试验结果表明:加入稀土后渗速可提高近1倍,改善了渗层的组织形态及性能。     

固态扩渗对低碳钢表面不锈钢化的研究进展

不锈钢具有抛光性能好、耐热性能好、焊接性能好、耐腐蚀性能好、抗疲劳性强等优点。本文综述了固态扩渗对低碳钢表面不锈钢化的研究现状。重点介绍了固态扩渗的工作原理、渗剂对低碳钢作用机理及组织与性能的影响,展望了固态扩渗对低碳钢表面不锈钢化未来发展方向的影响。     

铜杀菌性能及金属过敏的研究

通过试验研究表明，铜的杀菌性能是由于在其表面上的铜离子与水产生Cu和H2O2（双氧水），二者在化学反应中生成OH，而铜的杀菌性能主要取决于OH。另外，经过试验研究认为，在不同的环境使用金属铜制成的各种器材，基本上不会发生接触性皮炎等金属过敏反应。铜在今后生活中会发挥更大作用。     

烧结钢熔渗铜影响因素的研究

研究了原料铁粉、基体骨架密度、熔渗温度和熔渗时间等因素对于渗铜烧结钢力学性能和组织结构的影响。实验表明,上述诸因素对合金的组织和性能具有显著影响。利用该工艺可以制造出密度为7.4~7.9g/cm3,强度与45号钢和20Cr钢相当或更高的粉未冶金结构零件。     

稀土对模具钢钒硼共渗层组织和性能的影响

本文研究了模具钢盐浴钒硼共渗工艺中，添加适量稀土对共渗层组织和性能的影响。并探讨了稀土元素对共渗层催渗作用机理，以及盐浴稀土钒硼共渗工艺在模具表面强化处理中的实际应用。应用结果表明，冷作模具经盐浴稀土钒硼共渗处理后比常规热处理的模具使用寿命提高３～７倍。     

Studies on the Effect of Alloying Element in Iron Base Hardfacing Alloy

Hardfacing, a surface modification technique, is used to rebuild the surface of a workpiece. The economic success of the process depends on selective application of hardfacing material and its chemical composition for a particular application. In this context, two hardfacing electrodes having different chemical compositions have been selected with addition of alloying elements and their hardness and microhardness responses were compared with that of mild steel. The emphasis has been to realize the effect of microstructure and chemical composition on the hardness and microhardness response of the hardfacing material with respect to mild steel. It has been observed that the hardness of hardfacing alloys is varied with addition of alloying elements compared to that without addition of alloying elements.     

Induction Heat Treatment of Sheet‐Bulk Metal‐Formed Parts Assisted by Water–Air Spray Cooling

In order to produce components with massive secondary functional elements from sheet metal bulk forming operations, termed sheet‐bulk metal forming, can be applied. Owing to high, three‐dimensional stress and strain states present during sheet‐bulk metal forming, ductile damage occurs in the form of micro‐voids. Depending on the material flow properties, tensile residual stresses can also be present in the components' formed functional elements. During service, the components are subjected to cyclic loading via these functional elements, and tensile residual stresses exert an unfavorable influence on crack initiation and crack growth, and therefore on the fatigue life. Following the forming process, temperature and microstructurally related compressive residual stresses can be induced by local heat treating of the surface. These residual stresses can counteract potential crack initiation on the surface or in the subsurface regions. In the present study, the adjustability of the residual stress state is investigated using a workpiece manufactured by orbital cold‐forming, which possesses an accumulation of material in its edge region. Based on residual stress measurements in the workpiece's edge region using x‐ray diffractometry, it is possible to verify the compressive residual stresses adjusted by varying the cooling conditions.     

Fluorescence histochemistry of the surface epithelium and stroma in the rhesus monkey ovary

The surface epithelium and stromal elements in the ovary of the rhesus monkey were studied with a variety of fluorescence-histochemical procedures to determine the relative distribution of specific chemical moieties. The surface (germinal) epithelium displayed high levels of cytoplasmic RNA and specifically intense fluorescence with methods that demonstrate basic, SH and SS groups of protein. The underlying basement membrane demonstrated an intense reaction when fluorochromed with hydroxynaphthoic acid hydrazide directed toward side-chain carboxyl groups of protein. The fluorescence pattern displayed by the underlying connective tissue was heterogeneous and related to its anatomical localization. It is suggested that this heterogeneity reflects specific, but as yet undefined, chemical differences in the fibrous elements of the ovary.     

高拉速连铸保护渣的理化性能研究

高拉速连铸工艺要求连铸保护渣的溶化温度应适当降低，熔化速度应适当增大、粘度适当减小、凝固温度应适当降低、Al2O3吸收速率应适当增大。连铸保护渣的理化性能可以通过调整基料渣系的化学成分和骨架粒子的类型和含量而改变。利用溶化温度、凝固温度、粘度、Al2O3吸收速率与化学成分之间的关系，可以预测连铸保护渣的溶化性能、粘性特征和夹杂物吸收能力。     

汽车排气系统高温端用B441铁素体不锈钢研制

为了开发满足排气系统高温端零件使用要求的不锈钢产品,在实验室研究了化学成分、热处理制度对B441不锈钢性能的影响.结果表明,稳定化元素Nb、Ti的添加对改善B441不锈钢的综合性能有利.生产试制结果表明,生产的B441铁素体不锈钢产品具有优良的常温力学性能和耐高温性能,能够满足汽车排气系统高温端使用要求.     

淬火钢件冷却速度、显微组织和硬度分布的计算预报

 利用ANSYS有限元软件计算了多种钢端淬试样和圆柱体零件指定部位的冷却速度。分析了合金元素对冷却速度的影响,表明对于一些热物理性能参数值未知的材料,可以用成分相近的钢的对应参数代替来计算其指定部位的冷却速度。进而结合梅尼尔模型预测了零件指定部位的组织和硬度,所得结果与文献中的数据一致,表明此类方法可用于对钢种化学成分和热处理工艺的并行设计优化。     

On the transfer of protective coating elements on a metal surface from halide gaseous media

The processes occurring during the formation of multicomponent diffusion coatings on nickel alloys at the stage of delivery of elements on the article surface when chlorine, bromine, and iodine halides are used as activators are considered. Balance equations and calculated values are given for the partial pressures in the composition of a gas phase of components participating in chemical transport reaction; the possible reactions of delivering elements on the article surfaces and the structures of Ni–Al, Ni–Cr, Ni–Cr–Al, Co–Cr–Al coatings deposited on the ZhS26, ZhS6U, ZhS32, and VZhL12U alloys are presented.     

Metal-ceramic cohesion and the image interaction

A detailed understanding at the microscopic level of the strength of bonding at metal-ceramic interfaces, including its dependence on the crystallographic structure and chemical nature of the components, requires a model of the interatomic forces. Interatomic force models and computer simulation are widely used in the study of metal-metal and ceramic-ceramic boundaries but have not yet been applied to metal-ceramic. Recently however improvements in the microscopic modelling of metallic and ceramic cohesion together with the development of more powerful computers have opened possible ways of simulating the metal-ceramic interface which we are currently investigating. A particularly important component of the adhesive interaction across a metal-ceramic interface is believed to be the electrostatic image interaction which has no place in simple models of adhesion based on chemical bonding. This paradoxical situation is resolved. The image interaction is really a classical concept in the continuum electrostatics of point charges near a conducting surface, and makes no reference to discrete atoms. Nevertheless its equivalent attractive force close to a real metal surface can be calculated quantum mechanically for simple geometries. Fortunately, the results of these quantum mechanical calculations can be simulated by a classical interatomic force model, suggesting a way forward for atomistic simulation.     

聚焦辐射式烧结机点火器的开发与应用

针对当前烧结机燃油点火器能耗高、寿命短、点火不均匀等现状，研制开发了一种聚焦辐射式燃油节能点火器。这种新型节能点火器采用曲面聚焦并在炉壁上喷涂高黑度辐射涂料，在料面宽度方向上可以形成均匀的点火料带，从而实现快速、均匀点火。工业应用表明该点火器具有明显的节能效益。     

Detection of macrosegregation in a large metallic specimen using XRF

Abstract

The characterisation of macroscopic chemical segregation in engineering components over length scales of many metres can be an arduous task. This report investigates the implementation of a technique that is capable of mapping long range variations in the chemical composition of metal components, without the need for extensive sample preparation. The capability of the method is optimised for large production components in a setting where process parameters such as measurement time and minimal surface preparation are of importance. Hence, a readily available hand held X-ray fluorescence instrument and analysis software are used to map macrosegregation in a low alloy steel slab.