易切削变形Zn-Cu-Bi合金的显微组织与性能

采用力学性能测试、光学显微镜、扫描电镜和能谱分析技术及切削性能测试对自行研制的含Bi易切削变形Zn-Cu合金铸态及挤压态的组织与性能进行研究.结果表明:Mn在Zn-Cu合金中易形成大而硬的块状相,对于提高锌合金的综合力学性能作用不明显,且可能产生不良影响;低熔点Bi相在Zn-Cu合金中铸态时以针状弥散分布,挤压态时以点状弥散分布,改善了Zn-Cu合金的切削性能;自行配制的Zn- 1.2％Cu-0.5％Bi-X合金,切削性能良好,抗拉强度达到405 MPa,伸长率为19.0％,表现出较优的综合性能,可作为部分铜合金替代材料,用于制造轴承、连接件、五金和家电等结构件.     

基于全寿命管理电网设备资产墙预测模型研究

随着我国电网事业的蓬勃发展,电网企业设备资产全寿命管理和资产墙模型分析方法逐渐得到重视。基于价值链管理理论,提出了一种基于全寿命管理资产墙模型投资预测方法,该方法引入全寿命管理设备资产价值函数,克服了经典资产墙简单平移推演的弊端。通过对湖北电网主变设备投资预测实例分析表明,采用此模型的预测结果比采用经典资产墙方法的预测结果更准确,可为电网企业设备资产管理提供参考。     

半导体离子注入用离子束加速管的聚焦特性

讨论了离子注入机用三间隙强流离子加速管的聚焦特性，计算了各种能量离子束聚焦情况，并分析了抑制空间电荷效应所需要的电场强度。最后总结了三间隙加速管设计和调试应注意的问题。     

输电线路多源异构数据处理关键技术研究综述

输电线路多源异构数据的处理对提升智能电网时代输电线路运维水平具有重要意义。为了解决输电线路上不同来源数据的结构差异性问题,介绍了多源异构数据的概念及其与传统大数据之间的异同,列举了输电线路上各种多源异构数据的来源和特征。在介绍数据处理一般框架的基础上,从数据集成、数据分析的角度分析了输电线路多源异构数据处理的关键技术,并给出一个应用实例。最后阐述了目前多源异构数据处理的发展方向包括文本挖掘、数据实时性处理和数据可视化。输电线路多源异构数据处理技术可望为线路智能运维能力的发展提供新的技术手段。     

预热对HG70钢CO2气体保护焊焊接接头组织与性能的影响

在焊前不预热、预热100℃和预热150℃的条件下进行HG70钢CO2气体保护焊,分析了预热对焊接接头显微组织和力学性能的影响。结果表明：焊前预热使HG70钢焊接接头组织改善,硬度下降,淬硬倾向降低,塑性、韧性提高,强度稍有降低。     

Effects of process parameters and die geometry on longitudinal welds quality in aluminum porthole die extrusion process

By using the rigid-visco-plasticity finite element method, the welding process of aluminum porthole die extrusion to form a tube was simulated based on Deform-3D software. The welding chamber height (H), back dimension of die leg (D), process velocity and initial billet temperature were used in FE simulations so as to determine the conditions in which better longitudinal welding quality can be obtained. According to K criterion, the local welding parameters such as welding pressure, effective stress and welding path length on the welding plane are linked to longitudinal welds quality. Simulation turns out that pressure-to-effective stress ratio (p/σ) and welding path length (L) are the key factors affecting the welding quality. Higher welding chamber best and sharper die leg give better welding quality. When H=10 mm and D=0.4 mm, the longitudinal welds have the best quality. Higher process velocity decreases welds quality. The proper velocity is 10 mm/s for this simulation. In a certain range, higher temperature is beneficial to the longitudinal welds. It is found that both 450 and 465 °C can satisfy the requirements of the longitudinal welds.     

Effect of low temperature thermo-mechanical treatment on microstructures and mechanical properties of TC4 alloy

The effects of low temperature thermo-mechanical treatment (LTTMT) on microstructures and mechanical properties of Ti-6Al-4V (TC4) alloy were studied by optical microscopy (OM), tensile test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results confirm that the strength of TC4 alloy can be improved obviously by LTTMT processing, which combines strain strengthening with aging strengthening. The effect of LTTMT on the alloy depends on the microstructure of the refined and dispersed α+β phase on the basis of high dislocation density by pre-deformation below recrystallization temperature. The tensile strength decreases with the increase of pre-deformation reduction. The optimal processing parameters of LTTMT for TC4 alloy are as follows:solution treatment at 900 ℃ for 15 min, pre-deformation in the range of 600-700 ℃ with a reduction of 35%, finally aging at 540 ℃ for 4 h followed by air-cooling.     

基于改进GM(1,1)模型的变电站检修运维费用预测

针对变电站因设备的缺陷而引起的全寿命周期成本（life cycle cost,LCC）中检修运维费用拨付波动现象,分别采用传统的灰色GM(1,1)模型和组合改进的灰色GM(1,1)模型,对未来3年地市A的变电站检修运维费用进行预测,优化现有的成本拨付策略。结果表明,2种模型的预测精度等级均为一级,但改进后模型的平均相对误差及后验差比值均低于传统模型,说明改进模型比传统模型具有更高的预测精度,能够更好地预测变电站的检修运维费用。最后,利用改进的预测模型对某地市A的2019—2021年变电站检修运维费用进行预测。     

硬质相对6061铝合金异型散热型材表面质量的影响

采用化学成分分析、金相分析、扫描电镜、力学性能测试、能谱分析及PoDFA杂质分析等技术对国产6061铝合金异型散热型材和进口同种优质6061铝型材进行对比分析.结果表明:国产型材的杂质总含量为0.195mm2/kg,明显高于进口型材的杂质总含量(0.016 mm2/kg),且其中存在较多的MgAl2O4尖晶石和MgO硬质杂质相,这些物相具有特殊的形态和较高的硬度,在加工过程中易划伤模具表面而降低型材的表面质量;国产6061铝型材中Mg和Si元素的含量均高于进口试样的,但由于形成了较多大块状、硬而脆的Fe2Si2Al9相,导致国产型材的强度虽稍高于进口型材的,但其伸长率却大幅度下降,也影响型材的表面质量.     

预热对HG70钢C02气体保护焊焊接接头组织与性能的影响

在焊前不预热、预热100℃和预热150℃的条件下进行HG70钢C02气体保护焊,分析了预热对焊接接头显微组织和力学性能的影响.结果表明:焊前预热使HG70钢焊接接头组织改善,硬度下降,淬硬倾向降低,塑性、韧性提高,强度稍有降低.