GCrl5轴承钢精炼渣对夹杂物祛除行为的研究

通过建立的夹杂物穿越钢渣界面运动模型,研究了精炼渣对夹杂物的吸附现象。结果表明,夹杂物 粒径、表面张力和熔渣粘度是影响夹杂物冲破钢渣界面的重要参数,大型夹杂物中粒径和熔渣粘度起决定作用,而 ≤ 20㎛ 级别的小型夹杂物中仅表面张力起决定作用;大型夹杂物冲破钢渣界面的能力远大于小型夹杂物。针对 小型夹杂物难以吸附的问题,运用了夹杂物运动模型和熔渣、钢液表面张力模型,研究了表面张力对吸附过程的影 响。结果表明,直径≤ 122.9 ㎛尺寸的夹杂物均无法穿越钢渣界面,回弹至钢液一侧,由此得出：无法通过调整精 炼渣用以吸附≤ 122.9 ㎛夹杂物以达到进一步降低钢中氧含量的目的。     

Multidisciplinary optimization of gas-quenching process

Distortion as a result of the quenching process is predominantly due to the thermal gradient and phase transformations within the component. Compared with traditional liquid quenching, the thermal boundary conditions during gas quenching are relatively simple to control. By adjusting the gas-quenching furnace pressure, the flow speed, or the spray nozzle configuration, the heat-transfer coefficients can be designed in terms of both the component geometry and the quenching time. The purpose of this research is to apply the optimization methodology to design the gas-quenching process. The design objective is to minimize the distortion caused by quenching. Constraints on the average surface hardness, and its distribution and residual stress are imposed. The heat-transfer coefficients are used as design variables. DEFORM-HT is used to predict material response during quenching. The response surface method is used to obtain the analytical models of the objective function and constraints in terms of the design variables. Once the response surfaces of the objective and constraints are obtained, they are used to search for the optimum heat-transfer coefficients. This process is then used instead of the finite-element analysis. A one-gear blank case study is used to demonstrate the optimization scheme.     

Improved corrosion protection of aluminum alloys by electrodeposited silanes

Organofunctional silanes recently have emerged as outstanding, environmentally friendly corrosion protectors for metal substrates, compared with conventional chromate treatments. A simple immersion technique is typically used to coat the metal surface with silane films. However, the thickness and uniformity of the films are uncontrolled in this process. This paper proposes a new deposition technique for the silane films on the metal surface, i.e., by electrodeposition. Hydrolyzed silanes are water-soluble, ionized molecules, so they can be deposited on metals by electrodeposition. Various combinations of silane mixtures were tested at different voltages, pH values, bath concentrations, and exposure times on panels of alloy aluminum and mirror-polished ferro-plate. The surface structure was characterized by scanning electron microscopy (SEM) and ellipsometry. The resistance of the film to corrosion was investigated by direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) techniques. Electrodeposition results in a more organized and uniform film with fewer pores, compared with immersed or dipped films. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 320–26 of the Proceedings.     

离心铸造汽缸套白斑产生机理

针对离心铸造汽缸套的白斑特征，以模拟试验手段探寻原因。用金属凝固理论解释白斑形成机理。经过装车试用，验证了白斑对摩擦性能的影响。     

添加硫酸锰对化学镀Co-Fe-P合金结构禾口磁性台皂的影响

借助扫描电镜、能谱分析、X射线衍射和振动样品磁强计研究了添加硫酸锰对Co-Fe-P合金沉积速率、结构和磁性能的影响.结果表明,少量的硫酸锰有利于Co-Fe-P镀层的沉积,但过量时会降低沉积速率.当镀液中添加的硫酸锰浓度小于0.02 mol-L-1时对镀层组成几乎没有影响,但随着其浓度进一步增大至0.04 mol·L-1,镀层组成发生显著的变化.硫酸锰对该镀层具有整平作用,而且可使镀层中颗粒细化;硫酸锰有利于镀层形成非晶或微晶态结构.硫酸锰还可以改善Co-Fe-P合金膜的磁性能.     

A NEW ELECTROMAGNETIC IMAGING SCHEME

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The distribution of grain boundary planes in polycrystals

During the last ten years, techniques have been developed to measure the distribution of grain boundaries in polycrystals as a function of both lattice misorientation and grain boundary plane orientation. This paper presents a brief overview of the techniques used for these measurements and the principle findings of studies implementing these techniques. The most significant findings are that grain boundary plane distributions are anisotropic, that they are scale invariant during normal grain growth, that the most common grain boundary planes are those with low surface energies, that the grain boundary populations are inversely correlated with the grain boundary energy, and that the coincident site lattice number is a poor predictor of the grain boundary energy and population.     

焊接船体接头设计指南（二）

（接上期） 8卷边和切口 尽量不要广泛使用卷边，因为切割不恰当的卷边有潜在的危险。在构件安装到位后，加强杆或横梁的坡口焊缝处总免不了要用卷边，就像纵向加强杆或舱底龙骨这种情况（图11）。     

稀土稳定氧化锆超细粉末的合成机理研究

依据Al(Ⅲ )、Zr(Ⅳ )的水解聚合机理 ,把锆、铝和钇的无机盐溶液按一定组成混合在一起 ,通过加入乙二醇作为络合剂和调节溶液的PH值来获得溶胶 ,并直接蒸馏溶胶来获得干凝胶 ,最后制得ZrO2 (Y2 O3 ) -Al2 O3 系粉末。研究结果表明 :该工艺不仅制粉时间快、成本低、产量大 ,而且粒子均匀 ,粒径在 2 0～ 5 0nm之间 ,具有一定的可行性     

Preparation of Protein-Stabilized β-Carotene Nanodispersions by Emulsification–Evaporation Method

This work was initiated to prepare protein-stabilized β-carotene nanodispersions using emulsification–evaporation. A pre-mix of the aqueous phase composed of a protein and hexane containing β-carotene was subjected to high-pressure homogenization using a microfluidizer. Hexane in the resulting emulsion was evaporated under reduced pressures, causing crystallization and precipitation of β-carotene inside the droplets and formation of β-carotene nanoparticles. Sodium caseinate (SC) was the most effective emulsifier among selected proteins in preparing the nanodispersion, with a monomodal β-carotene particle-size distribution and a 17-nm mean particle size. The results were confirmed by transmission-electron microscopy analysis. SC-stabilized nanodispersion also had considerably high ζ-potential (−27 mV at pH 7), suggesting that the nanodispersion was stable against particle aggregation. Increasing the SC concentration decreased the mean particle size and improved the polydispersity of the nanodispersions. Nanodispersions prepared with higher β-carotene concentrations and higher organic-phase ratios resulted in larger β-carotene particles. Although increased microfluidization pressure did not decrease particle size, it did improve the polydispersity of the nanodispersions. Repeating the microfluidization process at 140 MPa caused the nanodispersions to become polydisperse, indicating the loss of emulsifying capacity of SC due to protein denaturation.