骨架材料对全钢载重子午线轮胎性能的影响

讨论骨架材料的规格、结构分布及工艺控制对全钢载重子午线轮胎性能的影响。胎体帘布采用带有外缠丝的 3 + 9+ 15× 0 2 2 + 0 15规格钢丝、胎体帘线密度在 45 0～ 65 0根·m- 1 范围内 (帘线直径大于 1 2mm)以及胎体反包端点在成品外轮廓曲线的第 2或 3条装配线上等措施均有利于保证胎体强度 ;合理设计带束层结构 ,端点与胎侧肩部花纹距离取 10mm左右有利于消除应力过度集中 ;采用钢丝增强带有利于提高胎圈刚性。     

碳钢贮热水箱的模拟腐蚀试验及涂层耐蚀性能研究

碳钢贮热水箱长期在30～80°C温变的热水环境中工作,易受到热水及水中杂质的腐蚀。研究了不同温度下Q235钢在自来水及含100μg/mLNaCl的自来水中的腐蚀速率。对裸钢及其涂覆相同厚度的不同涂层──酚醛环氧(自制)、钛纳米聚合物和改性聚乙烯后在70°C自来水中的极化曲线进行了比较。采用动电位扫描极化曲线测量和电化学交流阻抗谱法(EIS)分别对涂覆不同涂层的Q235钢进行了耐蚀性能研究。结果表明,3种防腐涂层均具有较佳的抗热水性,耐蚀能力较强,适宜对Q235钢贮热水箱进行防护。     

Synergistic Influence of Poly(4-Vinylpyridine) and Potassium Iodide on Inhibition of Corrosion of Mild Steel in 1M HCl

The corrosion and inhibition behavior of mild steel in 1 M HCl in the presence of poly(4-vinylpyridine)(P4VP) and potassium iodide (KI) was investigated using weight loss measurements, potentiodynamic polarization studies and impedance measurements. The inhibition efficiency increased with increasing P4VP concentration. The inhibiting action of P4VP is considerably enhanced by the addition of potassium iodide. The adsorption of this compound either alone or in combination with iodide ions on the metal surface is found to obey Lamgmir's adsorption isotherm. The experimental results suggest that the presence of iodide ions in the solution increases the surface coverage and, therefore, indicate the joint adsorption of P4VP and iodide ions. On the other hand, it was found that the inhibiting effect of P4VP and (P4VP + KI) increased with increasing temperature of the corrosion medium. The presence of these species in the solution decreases the double layer capacitance and increases the charge transfer resistance, both derived from Nyquist plots obtained from a.c. impedance studies. The variation of charge transfer resistance with time suggests that the inhibitive action of (P4VP + KI) depends mainly on the protective inhibitor film formed on the steel surface.     

不锈钢转化器在中小型硫酸装置上的应用前景

分析了传统碳钢转化器存在的缺点。相对于碳钢转化器，不锈钢转化器具有结构简单、安装方便、耐高温、不易漏气、维护工作量小等优点。通过碳钢转化器和不锈钢转化器结构和造价的比较，表明不锈钢转化器在中小型硫酸装置中也有良好的应用前景。     

Polyaniline for corrosion prevention of mild steel coupled with copper

Polyaniline emeraldine base/epoxy resin (EB/ER) coating was investigated for corrosion protection of mild steel coupled with copper in 3.5% NaCl solution. EB/ER coating with 5-10 wt% EB had long-term corrosion resistance on both uncoupled steel and copper due to the passivation effect of EB on the metal surfaces. During the 150 immersion days, the impedance at 0.1 Hz for the coating increased in the first 1-40 days and subsequently remained constant above 10⁹ Ω cm², whereas that for pure ER coating fell below 10⁶ Ω cm² after only 30 or 40 days. Immersion tests on coated steel-copper galvanic couple showed that EB/ER coating offered 100 times more protection than ER coating against steel dissolution and coating delamination on copper, which was mainly attributed to the passive metal oxide films formed by EB blocking both the anodic and cathodic reactions. Salt spray tests showed that 100 μm EB/ER coating protected steel-copper couple for at least 2000 h.     

关于中压电缆网双环接线方式供电能力的分析

结合北京地区现阶段对相关技术的规定,以实际供用电方案为例,对中压电缆网双环接线方式的供电能力进行深入讨论。通过设计环网单元划分,发现某些条件下双环网供电能力可以得到进一步提升。     

直流电桥法测量电缆故障点的距离

迅速、准确地探测故障点的位置对保证故障电缆的及时修复有着重要意义。介绍了电缆故障的性质和直流电桥法测量电缆故障点距离的原理，着重阐述了几种常用的电缆接地故障的测量方法，并提出在实际生产、施工中，应根据具体情况选取合理的仪器及测量方法，迅速、准确地探测故障点的位置，以保证故障电缆的及时修复。     

Bulk and Interphase Effects in Aged Structural Joints

Although structural adhesives are becoming widespread in numerous applications, one important limitation at present is the long term behaviour of bonded assemblies under conditions of high humidity, especially at elevated temperatures. This study presents a comparison between bulk properties of a structural epoxy resin and its behaviour in a torsional joint consisting of a hollowed-out cylinder bonded to a plate—both substrates being in stainless steel. Exposure to ca. 100% relative humidity at 70°C leads to modification of the bulk properties of the polymer, notably reduction of its elastic modulus. Although this may explain some differences in behaviour of the torsional joint, premature failure is attributed to weaknesses in the interphase zone.

Auger Electron Spectroscopy (AES) has been employed to investigate both unbonded steel surfaces and fracture zones. Although prolonged exposure to water leads to a more extensive degree of (apparently) adhesive failure at the interface polymer/metal, AES has shown the presence of non-negligible quantities of carbon, attributed to residual polymer. Failure would seem to occur, at least partly, in a weak interphase of the polymer, near, but not at, the interface.

Various possible causes are evoked. For dry failure, residual polymer may be due to the topography of the metal surface and/or local modification of the adhesive during cure. In the case of aged joints, in addition there are potential effects due to swelling and differential stresses, secondary bond failure and molecular chain scission within the polymer, all provoked by the presence of water.     

Effect of fretting amplitudes on fretting wear behavior of steel wires in coal mines

Given that fretting wear causes failure in steel wires, we carried out tangential fretting wear tests of steel wires on a self-made fretting wear test rig under contact loads of 9 and 29 N and fretting amplitudes ranging from 5 to 180 μm. We observed morphologies of fretted steel wire surfaces on an S-3000N scanning electron microscope in order to analyze fretting wear mecha-nisms. The results show that the fretting regime of steel wires transforms from partial slip regime into mixed fretting regime and gross slip regime with an increase in fretting amplitudes under a given contact load. In partial slip regime, the friction coefficient has a relatively low value. Four stages can be defined in mixed fretting and gross slip regimes. The fretting wear of steel wires in-creases obviously with increases in fretting amplitudes. Fretting scars present a typical morphology of annularity, showing slight damage in partial slip regime. However, wear clearly increases in mixed fretting regime where wear mechanism is a combination of plastic deformation, abrasive wear and oxidative wear. In gross slip regime, more severe degradation is present than in the other regimes. The main fretting wear mechanisms of steel wires are abrasive wear, surface fatigue and friction oxidation.     

GCr15轴承钢连铸过程中热物性参数的研究

借鉴前人实验数据,采用一定的数学方法,对轴承钢的热物性参数进行了研究.结果表明：GCr15轴承钢的液相线温度为1 465.7℃,固相线温度为1 328.4℃,零强度温度为1 380℃左右,零塑性温度为1 330℃左右;在固相区、液固两相区、液相区分别采用不同的公式进行处理,可使结果更加准确,还避免了奇异性.研究结果可为轴承钢连铸工艺有限元模拟提供基础.