铝合金中厚板焊接工艺试验

采用MIG焊接方法，对5083、6061、6082铝合金中厚板进行焊接工艺试验，验证了所选焊接参数和焊接材料的可行性，分析了空气相对湿度、氩气含水量等对铝合金焊接的影响，以及铝合金焊接后接头强度下降的情况。     

铁路敞车中梁埋弧焊裂纹分析

采用埋弧焊焊接出口巴基斯坦的铁路敞车中梁时,产生了大量的裂纹.对其焊接工艺、焊接材料、工件表面污物、材料化学成分等进行了分析;确定了出现裂纹的原因是由两方面引起,一是硫化物偏析引起的热裂纹,二是焊接规范不合理.经工艺试验与分析,采用H08Mn2焊丝和合理焊接规范,有效防止了裂纹的产生.     

考虑夹具接触约束的FSW焊接变形的固有应变法预测

为高效高精度地预测大尺寸结构FSW焊接变形,基于考虑夹具接触约束的热弹塑性仿真结果,在分析塑性应变的区域分布特点的基础上运用固有应变法进行分区映射,发展了一种有效的焊接变形预测方法.针对小尺寸6061-T6铝合金板材FSW焊接,将接触约束状态和固定约束状态下的焊后变形预测值与实验值进行了对比分析,结果表明接触约束状态的...     

双电极焊条TE4303单弧焊接分析

从焊接效率与节能、微观组织、力学性能、断口形貌等方面对钛钙型双电极焊条(TE4303)单弧焊进行了研究.结果表明,与传统单芯焊条(E4303)电弧焊相比,当采用相同的焊接电流时,TE4303单弧焊熔化系数和熔敷系数可提高1倍,熔化单位重量焊条金属节省电能约20%～30%;TE4303单弧焊对母材热输入小,接头熔合比小,...     

Candidate materials for the sulfur electrode current collector—II. Aluminum and its alloys

In the continuing search for materials for the positive current collector/container of the high-temperature sodium-sulfur cell, the electrochemical behavior of aluminum alloys in polysulfide/sulfur melts has been examined. Electrochemical evidence coupled with SEM surface examination and chemical analysis of the melt have shown that aluminum materials studied remain passive within the 1.25–4.5 V potential range (Na/Na⁺ reference). The existence of the transpassive region currently reported in the literature has not been confirmed. Interpretation of the nature of the observed residual currents is suggested. The alloys studied can be used as self-healing substrates of conductive coatings or as matrices of composite materials in contact with the polysulfide/sulfur melts.     

正火轧制及后续正火工艺对S460NL高强度低温结构钢组织性能的影响

以EN10025-3标准为基本依据,采用中碳、低磷、低硫、低氮、低氢设计了正火高强度低温S460NL结构钢板的成分,通过高均质冶炼连铸工艺,生产了不同规格的正火轧制和正火轧制+正火钢板。结果表明,对于规格60 mm以下S460NL钢板,正火轧制工艺可以满足EN10025-3和EN10164 Z35标准性能要求,对于规格60 mm及以上S460NL钢板,需要增加正火工艺才能满足EN10025-3和EN10164 Z35标准的性能要求;正火轧制+正火态S460NL钢板经PWHT模拟焊热处理后的拉伸性能、－50 ℃冲击性能优异,符合标准要求。     

Influence of Welding Parameters on the Tensile Shear Strength of Aluminum Alloy Joint Welded by Resistance Spot Welding

Aluminum alloy A5052 sheets were welded using the technique of resistance spot welding with cover plates. The effects of welding parameters on the tensile shear strength of the joints were investigated. The results reveal that the technique is feasible to weld aluminum alloy, and that the enhanced electrode force is more effective than the extended down-sloping time for inhibiting pores formation and increasing the strength of the joint.     

An experimental and theoretical study of gas tungsten arc welding of stainless steel plates with different sulfur concentrations

During fusion welding, the presence of sulfur in steel often affects heat and fluid flow in the weld pool and its geometry. While the role of sulfur during welding of stainless steel plates with the same sulfur content is well understood, welding of stainless steel plates containing different concentrations of sulfur has not yet received proper attention. Here we report an experimental and modeling investigation of gas tungsten arc butt welding of stainless steel plates containing different sulfur concentrations. The main variables studied were sulfur concentrations in the two plates, welding current and welding speed. The results show significant shift of the fusion zone toward the low sulfur steel. The asymmetric fusion zone profile with respect to the original joint interface could be quantitatively explained through numerical modeling of heat transfer and fluid flow considering a bead shift observed experimentally.     

The Mechanical Behavior of Friction-Stir Spot Welded Aluminum Alloys

Aluminum and alloys are widely used in the automotive industry due to the light weight, good formability, and malleability. Spot welding is the most commonly used joining method of these materials, but the high current requirements and the inconsistent quality of the final welds make this process unsuitable. An alternative welding technique, the friction-stir spot welding process, can also be successfully used in joining of aluminum and alloys. In this study, 1-mm-thick AA5754 Al-alloy plates in the H-111 temper conditions were joined by friction-stir spot welding using two different weld parameters such as tool rotational speed and dwell time. Mechanical properties of the joints were obtained with extensive hardness measurements and tensile shear tests. The effect of these parameters on the failure modes of welded joints was also determined.     

5A06-O铝合金蒙皮的拼焊工艺

分析了4mm铝合金板5A06-O拼焊的焊接工艺特点，从焊前准备、焊接方法、焊接材料、焊接规范、焊后检查以及缺陷补焊等方面进行试验分析，确定了4mm铝合金板5A06-O的拼焊工艺，保证了铝合金顶盖蒙皮拼焊的焊接质量，满足出口电力机率的设计要求。     

超超临界高压主汽调节阀壳与接管用国产化P92钢焊条工艺评定

对超超临界高压主汽调节阀壳与接管用焊条进行工艺评定试验,评定试板母材为F92,CB2,焊材为国产化P92钢焊条CHH727,并对工艺评定试板进行力学性能测试及金相观察。工艺评定试验结果表明,国产化P92钢焊条CHH727完全满足超超临界高压主汽调节阀壳与接管的焊接使用要求。     

双电极焊条单弧焊的电弧特性

针对双电极焊条单弧焊焊接新工艺，作者研究了其电弧静特性和双电极焊条的熔化特性，并用高速摄像机对双电极焊条单弧焊的电弧形态进行了研究。结果表明。双电极焊条单弧焊具有上升的电弧静特性，静特性曲线随两焊芯间距的增大而上移；在两焊芯间距合适的情况下，双电极焊条阴、阳极熔化速度可以保持一致，故双电极焊条单弧焊可使用交、直流电源，其熔化速度比单芯焊条的大并随焊接电流的增大和两焊芯间距的减小而增大；双电极焊条单弧焊电弧有多种形态。     

压力容器焊接工艺制定与管理专家系统

以压力容器的生产制造为应用背景，在实现对焊接工艺评定报告PQR、焊接工艺指导书WPS等进行编制、捡索、管理的基础上．实现了根据JB4708—2000“钢制压力客嚣焊接工艺评定”和JB／T4709—2000“钢制压力容器焊接规程”等行业标准，由PQR或WPS智能推理生成焊接接头工艺卡以及对焊接材料消耗的计算和汇总，最终生成指导焊接生产的焊接工艺规程。同时．系统实现了用户管理和文档编制流程管理．使系统具有更强的实用性。     

低碳钢A-TIG焊活性剂的焊接性

利用自行研制的低碳钢A-TIG焊活性剂进行了各种焊接工艺试验。内容包括焊缝外观形貌、熔深效果、接头微观组织、化学成分及接头力学性能分析。结果表明，使用本活性剂可以使焊缝熔深比常规的TIG焊增加3倍，对12mm以下的低碳钢板对接无需开坡口可一次焊接完成，且单面焊双面成形，焊缝表面成形良好，接头微观组织、焊缝的化学成分、接头力学性能均不受影响。焊接电流、弧长、焊接速度、涂层厚度和保护气体种类等，对焊接熔深的增加产生影响。     

Constraints Based Modeling for Innovative Product & Process Designs

An innovative, constraints based modeling (CBM) approach proved successful for product developments and process improvements. The product developments involved specifying the chemical composition range for a set of chromium-free, high-performance consumable electrodes intended for gas-metal arc welding (GMAW) of high-strength steels used in hull constructions while significantly reducing energy costs. The process improvements involved selecting appropriate non-carcinogenic chemicals for a non-chromate conversion coating bath used with corrosion protection of aluminum alloys. In both cases, successful application of the CBM approach also led to the award of U.S. Patents. “A novel modeling approach is successful for product developments and process improvements” Dr. K. Sampath is a Technology/Business Consultant in Johnstown, PA. He received a Ph.D. degree in Welding Engineering from The Ohio State University and a MBA degree from Cornell University. He has pioneered the Constraints Based Modeling Approach to provide innovative, low-cost, low-risk solutions to persistent materials processing issues, and has received three U.S. Patent awards     

热锻模耐热层堆焊材料的实验研究

为适应热锻模耐热层材料使用性能的要求，研制了一种新型的热作模真钢堆焊焊条。对比分析了所研制焊条堆焊材料的硬度，显微组织及回火稳定性。从堆焊材料成分的角度，解释了所研制焊条堆焊材料所具备的特性。     

Numerical modelling and experimental determination of temperature distribution during manual metal arc welding

Abstract

Welding is a highly reliable and efficient metal joining process. Manual metal arc (MMA) welding is very widely used in industry. The temperature distribution that occurs during welding affects the material microstructure, hardness, and the residual stresses present in the material after welding. In the present work, the temperature distribution during bead on plate welding using MMA welding was experimentally determined for AISI type 304 stainless steel plates and low carbon steel plates of thickness 6 and 12 mm. A three-dimensional computer model based on the control volume method has been developed to predict the temperature distribution in the heat affected zone (HAZ) and in the base plate region of the bead on plate welds, using the weld parameters as input data to the computer model. In this computer model, the heat energy used to melt the electrode is considered as a separate heat flux term and the remaining heat supplied by the welding arc is considered as another heat flux term. A good match between the experimental results and the theoretical predictions was obtained. Using the computer model, the time taken to cool from 800 to 500°C in the coarse grained HAZ (close to the fusion line) of low carbon steel specimens was calculated. From this cooling time and the chemical composition of the material, the maximum hardness in the coarse grained HAZ was predicted. Microhardness measurement in the same region of the welded plates was carried out. The experimentally measured values and predicted results match closely.     

AI2O3/Cu复合材料制备工艺的优化

新型颗粒增强铜基复合电极材料Al2O3/Cu能较好地解决电阻点焊镀锌钢板时普通电极材料做电极寿命较短的问题。为了获得优化的Al2O3/Cu复合电极材料制备工艺,采用粉末冶金法制备Al2O3/Cu复合电极材料,通过改变制备过程中的工艺参数,以密度、显微维氏硬度、电导率、显微组织为检测内容,探讨压制力和烧结温度对Al2O3/Cu复合电极材料物理机械性能和显微组织的影响。结果表明,综合性能最优时的Al2O3/Cu复合电极材料制备工艺为:Cu-Al2O3混合粉末制坯压制力100 kN,烧结温度940℃。