输电铁塔热浸镀锌层表面呈色机理研究

输电铁塔普遍采用热浸镀锌的方式进行防腐,铁塔热浸镀锌后表面为光亮的银白色,由于大部分铁塔安装在野外,光亮的银白色与自然环境不相协调,为了使铁塔热浸镀锌后的表面颜色与自然协调,本文主要从热镀液合金成分的选取和含量控制方面对热浸镀锌表面呈色机理进行研究,找出了镀锌表面变换色彩的方法,实现了黄、绿等色彩的呈现.     

极好的耐腐蚀Zn-Al-Mg-Si合金热浸镀锌薄钢板

建筑用热浸镀锌薄钢板产品多种多样，用w(Zn)5％Al系列合金镀层的薄钢板由于其耐腐蚀性好和镀层重量相对较轻而得到广泛使用。事实上其镀层的耐蚀性在盐雾试验中是传统热浸镀锌钢板的两倍。     

钢管热浸镀锌生产工艺及设备

描述了钢管从酸洗、漂洗、烘干、热浸镀、内吹、外吹、钝化和水漂洗的整个工艺过程,结合传统镀锌方法,对烘干设备、镀锌锅的拨料机构和浸锌机构等设备进行优化和改良。在节能、环保的前提下,生产出镀层质量优良的镀锌钢管。     

热浸镀锌作业线最新进展

将镀锌作业线与酸洗或彩涂作业线合并为一条联合作业线，是一种降低成本，满足高附加值市场需要的技术方案。     

低碳钢热浸镀锌的研究

为了进一步提高低碳钢镀锌层的表面质量和耐腐蚀能力，通过在传统热浸镀锌液中添加少量稀土，获得了一种耐蚀力好、结合力强和光滑的热浸镀锌层。研究了稀土对镀层厚度、表面质量、镀层硬度和耐腐蚀性的影响。     

热浸镀锌钢板镀层织构与耐蚀性

用X射线衍射和动电位扫描方法研究了热浸镀锌钢板镀层织构、相分布和耐蚀性的关系.实验结果表明,镀锌层中纯锌相的主要织构组分为{0002}基面织构,当镀锌层厚度增加时,纯锌相中{0002}基面织构密度水平增加,纯锌相自腐蚀电位升高、腐蚀电流密度减小以及耐蚀性增加.X射线衍射分析电化学剥离后的铁锌相,结果表明,镀锌层由纯锌相和合金相组成;电化学实验表明,镀锌层各相耐蚀性不同,合金相的耐蚀性高于纯锌相的耐蚀性,且Fe-Zn合金相的耐蚀性随铁含量的增加而增加.     

钢管热浸镀锌生产工艺线中的速度控制技术

本文重点阐述采用普通交流异步电动机配以变换器变频进行无级广泛的调速,从而使机械传动装置简化,满足了作业线对热镀锌钢管控制缓冷的要求,获得了较好的效果     

热浸镀锌生产线平整方法的新发展

在安装专用力矩控制系统和采用湿式平整操作法后，已将因锌粘附而使平壁机工作辊非计划更换次数减少约８０％。     

工况条件下锌基合金表面张力测定及极化曲线分析

从锌液本身的物理性能着手,通过引进焦利秤测量微小力的原理,利用吊片法测定热浸镀锌中锌液及其合金在420～480℃的表面张力,确定微量铝的加入,使由锌铝组成的理想稀溶液的自由能降低,引起锌液的表面张力下降,进而使锌液的化学位降低。并通过电化学实验测定了纯Zn及Zn-0.2%Al的极化曲线,证实了由表面张力降低所引起的锌液化学位的降低对提高镀锌层的耐腐蚀性能起很大的作用。     

原位TiC颗粒细化喷射沉积7075铝合金组织的机理

采用原位反应喷射沉积法制备TiCP/7075(TiCP体积分数为2·91%)铝合金,观察其微观组织.应用I mage Tool软件及平均截线法统计平均晶粒尺寸,并与喷射沉积7075铝合金进行对比.发现前者的晶粒尺寸比后者减小50%左右,表明原位TiC颗粒对喷射沉积7075铝合金组织具有显著的细化作用.从形核的属性、速度以及过程的晶体学分析对其细化机理进行了解释.     

Solidification and microstructure analysis of rapidly solidified melt-spun Al-Fe alloys

Aluminum-iron alloys with Fe contents of up to 8 wt pct were rapidly quenched from the melt using the planar-flow melt-spinning technique. Microstructural changes that occur across the thickness of melt-spun ribbons were investigated as a function of initial melt composition and ribbon thickness. A transition exhibiting a dramatic change in the cell spacing from a microcellular to a coarse cellular region was observed for all the alloys examined. For a given alloy, the volume fraction of the microcellular region decreases significantly with increasing ribbon thickness. A theoretical explanation for the observed behavior is presented in which the heat flow and solidification characteristics are related to the undercooling achieved before the onset of nucleation.     

Properties and microstructure of aluminum-copper-magnesium-lithium alloys

The microstructure and mechanical properties of Al−Cu−Mg−Li alloy extrusions prepared from both rapidly cooled powder flakes and cast ingots have been determined. Embrittlement of the alloys by lithium was observed in both powder source and ingot source metarial. Fracture in all the powder source alloys was partly transgranular and partly along the boundaries of the original powder flakes. In the ingot source Al 2024 the fracture was transgranular but the addition of lithium changed the fracture path to predominantly integranular. The fatigue crack growth rate of powder source Al 2024 with and without lithium was found to be five to ten times slower than the growth rate of ingot source Al 2024.     

低Si和高Al冷轧TRIP钢的组织和性能分析

改变传统TRIP钢的Si或Al含量,结果表明,ω（Si）为0.61％的试验钢与传统的TRIP钢力学性能相当;ω（Al）为1.20％的试验钢抗拉强度略偏低,但其n值较高,达0.235。2种试验钢的组织均为铁素体＋小岛状马氏体。低Si或以Al代Si并通过适当的生产工艺,可以产生TRIP效应,低Si的试验钢残余奥氏体体积分数达6.20％,高Al的试验钢残余奥氏体体积分数达5.11％。扫描电镜观察断口形貌表明,2种试验钢拉伸试样断口均呈韧窝状,并且可避免高Si含量对钢板表面的不利影响。     

Effect of post weld heat treatment on the microstructure and tensile properties of dissimilar friction stir welded AA 2219 and AA 6061 alloys

In the present work, the effect of post weld heat treatment on the microstructure and mechanical properties of dissimilar friction stir weldments of Al alloys 6061and 2219 (in peak aged T6 temper) was investigated. The survey of microhardness profile in the as-welded samples showed fluctuations across the weld zone and a minimum in the hardness occurred in the heat affected zone (HAZ) of alloy 6061. After a post weld ageing treatment at 165°C for 18h, the hardness was found to increase in weld zone alone and there is no effective improvement in HAZ hardness. On the other hand, a post weld solution treatment at 520°C followed by ageing at 165°C for 18h resulted in significant improvement in hardness across the whole weldment. This is also reflected in the tensile strength of the joint. These results were correlated with microstructures, observed using optical, scanning and transmission electron microscopes.     

Effect of aging on microstructure of Mg-Zn-Er alloys

The effect of aging on microstructure of Mg-Zn-Er alloys at 473 K was investigated using hardness measurement,scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results indicated that both Mg3.8Zn1.5Er and Mg5Zn2.0Er alloys exhibited visible age-hardening effect,especially the latter alloy.Microstructure analysis showed that,after being aged,lots of fine MgZn2 phases with hexagonal structure were found in the α-Mg matrix.Comparing with Mg3.8Zn1.5Er alloy,the accelerated hardenin...     

Creep and microstructure of magnesium-aluminum-calcium based alloys

This article describes the creep and microstructure of Mg-Al-Ca-based magnesium alloys (designated as ACX alloys, where A stands for aluminum; C for calcium; and X for strontium or silicon) developed for automotive powertrain applications. Important creep parameters, i.e., secondary creep rate and creep strength, for the new alloys are reported. Creep properties of the new alloys are significantly better than those of the AE42 (Mg-4 pct* Al-2 pct RE**) alloy, which is the benchmark creep-resistant magnesium die-casting alloy. Creep mechanisms for different temperature/stress regimes are proposed. A ternary intermetallic phase, (Mg,Al)₂Ca, was identified in the microstructure of the ACX alloys and is proposed to be responsible for the improved creep resistance of the alloys. All concentrations in wt. pct, unless otherwise stated. RE stands for a combination of rare earth elements, i.e., misch metal, in this case.     

780MPa级热镀锌用TRIP钢退火工艺及组织演变

研究了热镀锌用高强TRIP钢的退火工艺对性能的影响和组织演变规律.结果表明:实验用钢可获得780.00MPa以上的抗拉强度和24.00%以上的断后延伸率;两相区加热温度和贝氏体保温时间对钢的力学性能具有显著影响,两相区加热温度为850℃,贝氏体保温时间为30s时,实验用钢能获得最佳的综合力学性能;在贝氏体中温相变后,仍有部分亚稳奥氏体(碳含量较低)在后续冷却过程中发生马氏体相变,从而导致钢退火后的微观组织由铁素体、贝氏体、残余奥氏体和马氏体组成.     

Effect of Ho-doping on microstructure and magnetostriction of TbDyFe alloys

Tb0.3Dy0.7HoxFe1.95 (x=0.00, 0.05, 0.10, 0.15, 0.20, 0.35, 0.50, 0.65) quaternary alloys were prepared by arc-melting and followed by annealing. The phases present and structure of the alloys were determined using a D8-Advance X-ray diffractometer. The magnetostriction of the alloys was studied by standard strain gauge technique. The dependence of Ho content on the structure, magnetostriction and density of the alloys was investigated in detail. The research results showed that Ho-doping did not change MgCu2-type cubic Laves structure in Tb0.3Dy0.7Fe1.95. When Ho content x≤0.2, rich rare earth phase presented in the alloys increased and magnetostriction of the alloys reduced evidently with increasing x, but for alloys with x>0.2, the content of rich rare earth phase started to reduce and the magnetostriction increased quickly, especially at low magnetic field in the alloy with x=0.65 due to separation of rich rare earth phases on the surface of the alloy.