碱性化学着色过程中不锈钢电势的测定

着重介绍了不同温度时碱性着色过程中不锈钢电势与着色时间的关系,并讨论了温度和添加剂亚硫酸钠对碱性着色过程的影响．     

真空钎焊不锈钢接头重熔温度的研究

利用金相试验和差热分析方法,系统地研究了用镍基钎料钎焊１Ｃｒ１８Ｎｉ９Ｔｉ时钎缝的重熔温度随钎焊工艺变化的规律。研究结果表明,熔化钎料与母材间的相互扩散是影响钎缝重熔温度的主要因素。当通过扩散使钎缝组织变成纯固溶体时,钎缝的重熔温度将大幅度提高。ＢＮｉ１ａ、ＢＮｉ２和ＢＮｉ５钎缝的重熔温度可分别提高到１２３５℃,１２３０℃和１３９７℃。ＢＮｉ７钎缝的重熔温度提高幅度较小,在试验条件下仅提高到９４５℃     

紧凑型X-pinch装置探头标定

 介绍了紧凑型X-pinch脉冲功率装置的电流电压测量设计方法。根据该装置的同轴传输线结构特点,研制了一种利用金属膜连接传输线外筒与负载外筒,构成回路测量负载电流的探头。在传输线末端设计电容分压器作为测量负载电压的探头,并利用电路模拟软件对此过程进行模拟,同时这两个探头需要进行在线标定。实验研究结果表明,该探头性能稳定、响应快,是测量负载电流与电压的理想工具。     

奥氏体不锈钢钻削变形系数的实验研究

以奥氏体不锈钢1Cr18Ni9Ti为工件材料,应用最新研制的涂层钻头进行大量切削实验,研究钻削参数对变形系数的影响以及变形系数与轴向力、转矩和钻削温度之间的关系．结果表明,不锈钢钻削变形系数反应了轴向力的变化趋势．实验还揭示了奥氏体不锈钢钻削加工中切削速度和进给量的变化对变形系数的影响规律．研究结果为奥氏体不锈钢钻削刀具选择及其参数的优化提供了依据．     

Characterizations of dissimilar S32205/316L welds using austenitic,super-austenitic and super-duplex filler metals

UNS S32205 duplex stainless steel plates were welded to AISI 316L stainless steel using the pulsed gas tungsten arc welding process with three different filler metals: ER2594, ER312, and ER385. The microstructures of the welds were characterized using optical and scanning electron microscopy, and all of the specimens were evaluated by ferrite measurements. The mechanical properties were studied through hardness, tensile, and impact tests. In addition, the pitting resistance equivalent number was calculated and cyclic polarization tests were performed to evaluate the corrosion resistance of the weld metal. The results showed that chromium nitride was formed in the heat-affected zone of the duplex side, whereas no sigma phase was detected in any of the specimens. The ferrite number increased from the root pass to the final pass. The absorbed energies of the impact test decreased with increasing ferrite number, whereas the tensile strength was enhanced. The fully austenitic microstructure of the specimen welded with ER385 exhibited the highest resistance to pitting corrosion at 25°C, and the super-duplex weld metal presented superior corrosion resistance at 50°C.     

碳扩散对非真空热轧不锈钢复合板结合性能的影响

采用非真空热轧方法制备304不锈钢/Q235碳钢复合板材,利用OM、SEM、EDS等研究了不同压下率和轧后冷却方式下复合界面夹杂物、界面组织及力学行为的演变,并分析了C扩散对复合板界面组织形成及结合强度的影响。结果表明,随着轧制压下率的增加,界面夹杂物由块状向线型、连续点状乃至弥散点状分布变化。当压下率较低(28%)时,复合板剪切断裂位于结合界面处,随着压下率增加至47%及以上,复合板断裂位置为脱碳铁素体区。另外,热轧复合板经水冷工艺处理后,由于冷却速率较快,要抑制碳钢侧C元素的扩散,避免复合界面处脱碳区域的形成,从而提高了复合界面的结合强度。     

Improved cell viability and hydroxyapatite growth on nitrogen ion-implanted surfaces

Stainless steel 306 is implanted with various doses of nitrogen ions using a 2?MV pelletron accelerator for the improvement of its surface biomedical properties. Raman spectroscopy reveals incubation of hydroxyapatite (HA) on all the samples and it is found that the growth of incubated HA is greater in higher ion dose samples. SEM profiles depict uniform growth and greater spread of HA with higher ion implantation. Human oral fibroblast response is also found consistent with Raman spectroscopy and SEM results; the cell viability is found maximum in samples treated with the highest (more than 300%) dose. XRD profiles signified greater peak intensity of HA with ion implantation; a contact angle study revealed hydrophilic behavior of all the samples but the treated samples were found to be lesser hydrophilic compared to the control samples. Nitrogen implantation yields greater bioactivity, improved surface affinity for HA incubation and improved hardness of the surface.     

快中子增殖反应堆燃料元件包壳材料的晶界工程技术应用展望

针对钠冷快中子增殖反应堆(简称快堆) 燃料元件包壳材料316 以及15-15Ti 奥氏体不锈钢, 讨论了通过晶界工程(grain boundary engineering, GBE) 技术进一步提高材料抗辐照肿胀以及抗蠕变性能的可行性. 通过GBE 技术能够大幅增加材料中与孪晶相关的低 重合位置点阵(coincidence site lattice, CSL) 晶界比例. 快堆燃料元件包壳在固溶退火处理后还要经过20% 左右的冷加工变形, 目的是在显微组织中引入大量位错, 吸收由辐照产生的点缺陷, 并增加吸收裂变产物的陷阱. 如果在这样的冷加工变形前大幅提高材料的低∑CSL 晶界比例, 使冷加工变形时的位错滑移在具有特殊取向关系的晶粒间的传播以及位错在特殊结构晶界处的堆积排列发生变化, 那么就有可能使冷加工后位错的分布状态有利于吸收更多的由辐照产生的点缺陷, 提高材料抗辐照肿胀的能力.     

Effect of thermal aging on the fatigue crack growth behavior of cast duplex stainless steels

The effect of thermal aging on the fatigue crack growth (FCG) behavior of Z3CN20-09M cast duplex stainless steel with low ferrite content was investigated in this study. The crack surfaces and crack growth paths were analyzed to clarify the FCG mechanisms. The microstructure and micromechanical properties before and after thermal aging were also studied. Spinodal decomposition in the aged ferrite phase led to an increase in the hardness and a decrease in the plastic deformation capacity, whereas the hardness and plastic deformation capacity of the austenite phase were almost unchanged after thermal aging. The aged material exhibited a better FCG resistance than the unaged material in the near-threshold regime because of the increased roughness-induced crack closure associated with the tortuous crack path and rougher fracture surface; however, the tendency was reversed in the Paris regime because of the cleavage fracture in the aged ferrite phases.     

Effect of tin addition on the microstructure and properties of ferritic stainless steel

This article reports the effects of Sn on the inclusions as well as the mechanical properties and hot workability of ferritic stainless steel. Precipitation phases and inclusions in Sn-bearing ferritic stainless steel were observed, and the relationship between the workability and the microstructure of the steel was established. Energy-dispersive X-ray spectroscopic analysis of the steel reveals that an almost pure Sn phase forms and MnS-Sn compound inclusions appear in the steel with a higher Sn content. Little Sn segregation was observed in grain boundaries and in the areas around sulfide inclusions; however, the presence of Sn does not adversely affect the workability of the steel containing 0.4wt% Sn. When the Sn content is 0.1wt%-0.4wt%, Sn improves the tensile strength and the plastic strain ratio and also improves the plasticity with increasing temperature. A mechanism of improving the workability of ferritic stainless steel induced by Sn addition was discussed:the presence of Sn lowers the defect concentration in the ultra-pure ferritic lattice and the good distribution of tin in the lattice overcomes the problem of hot brittleness that occurs in low-carbon steel as a result of Sn segregation.