CrNiNRE奥氏体耐热钢的电解活化热浸扩散渗铝研究

采用表面电解活化助镀技术在渗碳炉辐射管用CrNiNRE奥氏体耐热钢表面进行了热浸扩散渗铝试验研究.应用SEM电镜和能谱分析及显微硬测试等方法分析CrNiNRE耐热钢热浸扩散渗铝层的成分、组织和形貌.试样经电解活化助镀后,在735℃铝浴中浸镀5min,获得了良好的热浸镀铝过渡层.以NH4Cl为活化剂,添加少量CeO2稀土混合物,在960℃密封扩散6h,随炉冷却,在耐热钢表面获得了结合良好的扩散渗铝层.     

熔剂法热浸镀铝工艺研究现状及发展

介绍了熔剂法热浸镀铝法的表面处理,碳钢和铸铁助镀工艺的方法和区别,助镀剂和覆盖剂的选择,浸镀铝温度及浸镀时间的选择、浸铝后工件的热处理及热浸渗铝工件的性能和微观组织等方面;阐述了当前国内外热浸渗铝工艺的新方法.     

稀土铝合金热浸镀渗工艺研究

对稀土铝合金的热浸镀渗工艺及渗铝后的耐腐蚀性进行了研究。结果表明，稀土对于热浸镀渗铝具有良好的催渗作用。钢表面热浸镀渗稀土铝后，具有良好的耐腐蚀性，其中含0．3％LPC混合稀土的铝合金具有更好的耐腐蚀性，其耐腐蚀性3倍于纯铝。     

1Cr18Ni9Ti不锈钢渗铝层结构及其抗氧化性能

在1Cr18Ni9Ti奥氏体不锈钢表面进行了热浸扩散渗铝试验研究.试样在730 ℃铝浴中浸镀5 min,先获得良好的热浸镀铝层.以NH4C1为活化剂,在960℃密封扩散6 h,获得了与基体结合良好的扩散渗铝层.应用SEM和能谱分析等方法分析了耐热钢热浸扩散渗铝层的成分、组织和形貌.获得的奥氏体钢的扩散渗铝层具有明显的双层特征,内扩散层主要由Fe,Al相和NiAl析出相组成,在外扩散层内为MeAl结构,并观察到气泡状孔穴;奥氏体不锈钢经扩散渗铝后的抗高温氧化性能优于未处理态.     

富Ce混合稀土铝合金热浸镀渗工艺研究

对富Ce混合稀土铝合金的热浸镀渗工艺及渗铝后的耐腐蚀性进行了实验研究。结果表明，稀土对于热浸镀渗铝具有良好的催渗作用。钢表面热浸镀渗稀土铝后，具有良好的耐腐蚀性，其中含0.3％富Ce混合稀土的铝合金具有更好的耐腐蚀性，其耐腐蚀性2～3倍于纯铝。     

Q235钢热浸渗铝复合渗硼层耐磨性的研究

用MM2型磨损试验机,在实验室条件下,对热浸渗铝和热渗铝复合渗硼试样进行了耐磨性的对比试验,并采用扫描电镜对磨损后的形貌进行观察分析.结果表明,在干摩擦条件下,热浸渗铝复合渗硼较单独热浸渗铝具有更好的耐磨性能.热浸渗铝的磨损机制以粘着磨损为主;而热浸渗铝复合渗硼以磨粒磨损为主要机制,同时伴有粘着磨损.     

渗铝钢的抗氢损伤性能

采用钝化助镀法在30CrMo钢表面获得热浸铝层,通过扩散渗铝和调质处理获得了渗铝钢试片和试棒.用氢渗透电化学技术测量了渗铝钢在饱和H2S盐水中的渗氢曲线,得到了不同温度(T)下氢在渗铝钢中的扩散系数(D),拟合得到了T与D的关系式,并研究了溶液中NaCl和CO2对稳态氢渗透电流(Imax)的影响.比较了30CrMo渗铝钢在饱和H2S盐水中腐蚀前后的机械性能.结果表明：热浸渗铝钢对氢扩散有明显的阻滞作用,其抗氢损伤性能好于基体钢材.     

奥氏体耐热钢的热浸扩散渗铝研究

采用表面电解活化助镀技术在奥氏体耐热钢表面获得了良好的助镀层，试样经电解活化助镀后，在735℃铝浴中浸镀5min，可获得良好的热浸镀铝过渡层。以NH4Cl为活化剂，添加少量和CeO2稀土混合物，在960℃密封扩散6h，随炉冷却，在耐热钢表面获得了结合良好的扩散渗铝层。应用SEM电镜分析和能谱分析等方法分析了热浸扩散渗铝层的成分、组织和形貌。     

热浸镀Galvalume熔池流动与传热的数值模拟

根据热浸镀Galvalume熔池的几何结构及工艺参数,建立了Galvalume熔池的数学模型,对不同速度、宽度和入池温度带钢热浸镀Galvalume过程中的熔池进行了数值模拟。结果表明:熔池内锌液流速与带钢速度成正比,随着带钢速度加快,熔池低速流动区域减少;带钢宽度影响熔池整体的流动形态,熔池内低温区域随着带钢宽度变大明显增多;带钢入池温度升高使得熔池内温度分布更均匀。     

《中国表面工程》2005年第4期主要文章摘要

装备维修技术的发展及表面工程技术的应用；类石墨碳膜的制备及其与类金刚石碳膜的区分；阴极电泳涂装用锌镍锰三元磷化液的研究；电刷镀Cu／Ni纳米多层膜镀液的研究；稀土镧对热浸渗铝钢耐H2S腐蚀性能的影响。     

热浸渗铝技术的研究应用发展

从浸铝前的表面处理、铝液成分、浸铝温度和时间的选择、浸铝后的热处理、热浸渗铝工件的性能及应用等方面，介绍了国内外热浸渗铝工艺的新进展。分析了目前的热浸渗铝工艺存在的问题，并提出了今后研究工作的重点。     

热镀锌钢板钝化工艺对耐蚀性的影响

为提高热镀锌钢板的耐蚀性,对热镀锌钢板铬酸盐钝化工艺进行了研究.采用盐雾试验、钝化膜的微观形貌等手段分析了钝化液浓度及钝化工艺参数(钝化液温度、烘干时间、烘干温度等)对热镀锌钢板铬酸盐钝化膜耐蚀性的影响.结果表明,采用试验确定的钝化工艺处理得到的钝化膜耐蚀性明显提高,对实际生产具有较好的指导意义.     

球铁浸镀微弧氧化陶瓷层的制备与组织分析

通过热浸镀铝及微弧氧化的方法在球墨铸铁表面上获得了陶瓷层,并对该涂层进行了XRD、SEM分析.研究结果表明:浸镀温度越高,镀层越厚,直到达到一峰值;浸镀时间越长,镀层越厚.球墨铸铁浸镀微弧氧化获得的涂层由涂层表面至基体依次为陶瓷层、纯铝层、扩散层、基体.陶瓷层主要为Al2O3相,扩散层由FeAl3、Fe2Al5相组成.     

Optimizing friction stir welding parameters to maximize tensile strength of AA2219 aluminum alloy joints

AA2219 aluminium alloy (Al-Cu-Mn alloy) has gathered wide acceptance in the fabrication of lightweight structures requiring a high strength-to-weight ratio and good corrosion resistance. In contrast to the fusion welding processes that are routinely used for joining structural aluminium alloys, the friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force etc., and the tool pin profile play a major role in determining the joint strength. An attempt has been made here to develop a mathematical model to predict the tensile strength of friction stir welded AA2219 aluminium alloy by incorporating FSW process parameters. A central composite design with four factors and five levels has been used to minimize the number of experimental conditions. The response surface method (RSM) has been used to develop the model. The developed mathematical model has been optimized using the Hooke and Jeeves search technique to maximize the tensile strength of the friction stir welded AA2219 aluminium alloy joints.     

Development of circumferential TIG welding process model: a simulation model for welding of pipe and plate

Abstract

It is useful to develop a numerical model for various welding positions in order to understand welding phenomena. Welding simulation models for a particular application could help in offline robot programming and online robot control. The objective of this study was to develop a tungsten inert gas (TIG) welding simulation model for various workpieces of different shapes. The present model may be easily applied to several workpiece configurations. This article deals with a model for circumferential welding of a pipe to a plate of mild steel, and aluminium alloys. The calculated results clarify that a homogeneous weld is hardly obtained at a fixed pipe welding position due to gravity, and that weld bead shape varies sensitively with wall thickness in pipe to plate welding. It is concluded that the model proposed in this article is useful to simply simulate TIG welding and provides a powerful means to estimate the optimum process parameters in welding practice.     

复杂截面铝合金型材拉弯成形有限元模拟

本文对矩形管截面铝合金型材拉弯成形工艺进行了研究 ,建立了位移控制拉弯工艺的有限元模型 ,采用ABAQUS软件对几种不同截面的铝合金型材拉弯成形过程进行了数值模拟 ,分析了不同补拉量对型材的截面畸变和回弹的影响以及不同截面形状抵抗拉弯成形时截面畸变的能力。其结果和方法对铝合金型材的拉弯成形工艺具有参考价值。     

铝合金铸造工艺CAD/CAE技术的研究与应用

介绍了铝合金铸造工艺CAD/CAE技术研究的主要内容及其应用,并给出了实例。实践应用表明,铝合金铸造工艺CAD/CAE技术能有效地应用于铝合金铸件的工艺设计和模拟分析,很好地为实际铝合金铸件生产服务。     

Effect of pulsed current GTA welding parameters on the fusion zone microstructure of AA 6061 aluminium alloy

AA6061 aluminium alloy (Al−Mg−Si alloy) has gathered wide acceptance in the fabrication of food processing equipment, chemical containers, passenger cars, road tankers, and railway transport systems. The preferred process for welding these aluminium alloys is frequently Gas Tungsten Arc (GTA) welding due to its comparatively easy applicability and lower cost. In the case of single pass GTA welding of thinner sections of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current processes. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. In this investigation, an attempt has been made to develop a mathematical model to predict the fusion zone grain diameter incorporating pulsed current welding parameters. Statistical tools such as design of experiments, analysis of variance, and regression analysis are used to develop the mathematical model. The developed model can be effectively used to predict the fusion grain diameter at a 95% confidence level for the given pulsed current parameters. The effect of pulsed current GTA welding parameters on the fusion zone grain diameter of AA 6061 aluminium alloy welds is reported in this paper.     

La对热浸镀渗铝层抗冲蚀腐蚀磨损性能的影响

研究了稀土La及其加入量对热浸镀渗稀土铝合金渗层显微硬度及抗冲蚀腐蚀磨损性能的影响.结果表明,在相同的工艺条件下, 与渗纯铝相比,加入稀土La元素后,渗层的显微硬度和抗冲蚀腐蚀磨损性能均得到了不同程度的提高.且当La含量为0.5%时, 渗铝层的显微硬度和抗冲蚀腐蚀磨损性能均为最好.     

元胞自动机法模拟铝合金三维枝晶生长

以元胞自动机模型为基础,基于晶粒形核和生长的物理过程及热质传输过程,建立了铝合金凝固过程微观组织形成及枝晶形貌演化的三维元胞自动机模型.与传统的元胞自动机不同,该模型不仅考虑了温度场扩散而且考虑了固液相中的溶质扩散、曲率过冷等重要因素.枝晶尖端生长速度与局部过冷度的关系采用KGT(Kurz-Giovanola-Trivedi)模型,温度场和浓度场计算采用有限差分法.使用该模型模拟了单晶生长和多晶生长.模拟结果表明,所建立的模型能够合理反映质点形核、单晶粒生长和多晶粒生长,微观组织形貌的模拟计算结果合理.