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ARC welding method for bonding steel with aluminum

Zhenyang LU, Pengfei HUANG, Wenning GAO, Yan LI, Hanpeng ZHANG, Shuyan YIN

《机械工程前沿（英文）》 2009年第4卷第2期页码 134-146 doi: 10.1007/s11465-009-0033-x

摘要： When welding steel with aluminum, the appearance of intermetallic compounds of Fe and Al will decrease tenacity and increase rigidity, which leads to bad joint performance. A new type of low energy input (LEI) welding technology is introduced which can be used to weld steel with aluminum. Using the technology, brazing was located on the steel side and arc fusion welding on the aluminum side. The less heat input reduces the thickness of intermetallic compounds to 3-4 μm. Tensile strength tests prove that the joint breaks at the heat-affected zone and the strength is higher than 70% of the aluminum’s. Thus, the method can lead to a good performance joint.

关键词： joining of steel and aluminum low energy input welding arc welding fusion welding – brazing

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Wide gap active brazing of ceramic-to-metal-joints for high temperature applications

K. Bobzin,L. Zhao,N. Kopp,S. Samadian Anavar

《机械工程前沿（英文）》 2014年第9卷第1期页码 71-74 doi: 10.1007/s11465-014-0291-0

摘要：

Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based active filler metals cannot fulfill these requirements, if application temperatures higher than 600°C occur. Au and Pd based active fillers are too expensive for many fields of use. As one possible solution nickel based active fillers were developed. Due to the high brazing temperatures and the low ductility of nickel based filler metals, the modification of standard nickel based filler metals were necessary to meet the requirements of above mentioned applications. To reduce thermally induced stresses wide brazing gaps and the addition of Al₂O₃ and WC particles to the filler metal were applied. In this study, the microstructure of the brazed joints and the thermo-chemical reactions between filler metal, active elements and WC particles were analyzed to understand the mechanism of the so called wide gap active brazing process. With regard to the behavior in typical application oxidation and thermal cycle tests were conducted as well as tensile tests.

关键词： wide gap active brazing nickel filler metals high temperature application WC Al₂O₃

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Application of cold spraying for flux-free brazing of aluminium alloy 6060

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA,

《机械工程前沿（英文）》 2010年第5卷第3期页码 256-260 doi: 10.1007/s11465-010-0095-9

摘要： In the present study, samples of aluminium alloy 6060 were coated by cold spraying with a powder of brazing alloy Al12Si. The influence of the process gas temperature on particle velocities and coating build-up was investigated. The coated samples were heat-treated in air and under argon atmosphere to investigate the wetting behaviour of the deposited Al12Si and the diffusion processes between Al12Si coatings and substrates. Coated samples were brazed flux-free under argon atmosphere by an induction heating system. The microstructure of the coated, heat-treated, and brazed samples was investigated. The shear strength of the brazed joints was determined. The results show that the brazing alloy Al12Si could be very well deposited on the substrate by cold spraying. The particle velocity increased with increasing process temperature. Correspondingly, the thickness of Al12Si coatings increased with increasing process temperature. The heat treatments showed that a very good metallurgical bond between the Al12Si coatings and the substrate could be realized by the deposition using cold spraying. The coated samples could be well brazed without fluxes. The coating thickness and overlap width influenced the shear strength of the brazed joints. The highest shear strength of brazed joints amounts to 80 MPa.

关键词： aluminium alloy flux-free brazing cold spraying shear strength

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Influence of the filler materials on flux-free brazing of pure aluminium (1050)

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA,

《机械工程前沿（英文）》 2010年第5卷第1期页码 47-51 doi: 10.1007/s11465-009-0079-9

摘要： In the present study, samples of pure aluminium (1050) were deposited by cold spraying with filler materials such as Al12Si, Al7Si, Al12Si-4%Cu, and the Al-Si-based filler material A, which was especially developed for flux-free brazing by the Surface Engineering Institute. Besides, pure Si powder was also sprayed. The coated samples were heat-treated under different conditions and were brazed under an argon atmosphere without fluxes or with the flux Nokolok by an induction heating system. The shear strength of the brazed joints was determined. The results show that the filler materials could be well deposited by cold spraying. A thin layer of brittle Si could also form due to the strong deformation of the substrate surface. The heat treatments showed that a very good metallurgical bond between the filler materials and the substrate could be realized by the deposition by cold spraying. The Al7Si deposited samples could not be brazed without fluxes under the given conditions. The samples deposited with other filler materials could be brazed without fluxes. The in-situ diffusion process made it possible to braze the Si-deposited samples at 580°C. The joints of the samples deposited with the filler material showed the highest shear strength of 41 MPa, whereas the values of the Al12Si and Si deposited samples were less than 20 MPa. The employment of the flux Nikolok significantly increased the shear strength of the Al12Si deposited samples to more than 53 MPa.

关键词： aluminium flux-free brazing cold spraying shear strength

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Study of mechanism of activating flux increasing weld penetration of AC A-TIG welding for aluminum alloy

HUANG Yong, FAN Ding, FAN Qinghua

《机械工程前沿（英文）》 2007年第2卷第4期页码 442-447 doi: 10.1007/s11465-007-0076-9

摘要： When multi-component flux AF305 is used as surface activating flux for an aluminum alloy, the weld pene tration of activating flux-tungsten inert-gas (A-TIG) welding is over two times more than that of conventional TIG welding. Using A-TIG welding with the modes of alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), respectively, the flux differently affects weld penetration when the polarity is different. After studied the effect of compelled arc con striction on weld penetration of AC welding, it is believed that the constriction of the whole arc root is not the main mechanism that flux AF305 dramatically improves weld penetration. The penetration has a relationship with the separate distribution of slag on the weld surface. Then, an observation of scanning electron microscopy (SEM) and an electronic data systems (EDS) analysis of slag were performed respectively. The separate distribution of slag on the weld pool during welding and the great constriction of arc spots were confirmed by TIG welding with helium shielding gas. The relationship between slag distribution and weld penetration was studied by adding aluminum powder into flux AF305 to change the distribution of slag. During welding, the separate distribution of slag on the weld pool results in the great constriction of arc spots, an increase in arc spot force, and an increase in Lorentz force within the arc and weld pool. Finally, the weld penetration is increased.

关键词： A-TIG welding surface DCEN electrode negative increase

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基于DBN模型的激光焊接状态在线监控研究 Article

张艳喜, 游德勇, 高向东, Seiji Katayama

《工程（英文）》 2019年第5卷第4期页码 671-678 doi: 10.1016/j.eng.2019.01.016

摘要：

本文开发了集辅助激光成像系统、紫外/可见波段视觉成像系统（波长小于780 nm）、光谱测量仪、光电传感器的多传感器系统，用以观察和分析激光焊接过程中的焊接状态信息。本文采用小波包分解方法对通过光电传感器获得的可见光波段传感信号和激光反射传感信号进行分解并提取相关特征。光谱仪采集到的信号的主要波长为400~900 nm，将其分为25个子带并采用统计方法来提取光谱信号特征。利用紫外/可见波段视觉成像系统采集的图像获取金属蒸气和飞溅的特征，而辅助照明视觉传感器系统主要是用来采集匙孔特征。本文基于上述焊接过程的实时量化特征建立了焊接状态监测的深度信念网络（DBN），并采用遗传算法对所提出的DBN模型参数进行优化。与传统的反向传播神经网络（BPNN）模型相比，本文建立的DBN模型在焊接状态监测方面具有更高的精度和鲁棒性。最后，本文通过三个附加焊接试验验证了该方法在激光焊接状态监控中的有效性和泛化能力。

关键词：在线监控多传感小波包分解深信度网络

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Flux-free brazing of Mg-containing aluminium alloys by means of cold spraying

BOBZIN Kirsten, ZHAO Lidong, ERNST Felix, RICHARDT Katharina

《机械工程前沿（英文）》 2008年第3卷第4期页码 355-359 doi: 10.1007/s11465-008-0055-9

摘要： In the present study, AlSi12 and AlSi10Cu4 were deposited onto Mg-containing aluminium alloys 6063 and 5754 by cold spraying. The influences of the two brazing alloys and spray parameters on coating formation were investigated. The microstructure of the coatings was characterized. Some coated samples were heat-treated at 590°C and 560°C in air to investigate the effect of the rupture of oxide scales on the diffusion of elements during heat-treatment. Some coated samples were brazed under argon atmosphere without any fluxes. The results show that AlSi12 had much better deposition behaviour than AlSi10Cu4. Due to the rupture of oxide scales, Cu and Si diffused into the substrate and a metallurgical bond formed between the brazing alloys and the substrates during heat-treatment. The coated samples could be brazed without any fluxes. Because the oxide scales prevented the formation of a metallurgical bond locally, the brazed samples had relatively low shear strengths of up to 43 MPa.

关键词： diffusion metallurgical substrate Mg-containing aluminium spraying

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Offline motion planning and simulation of two-robot welding coordination

Tie ZHANG, Fan OUYANG

《机械工程前沿（英文）》 2012年第7卷第1期页码 81-92 doi: 10.1007/s11465-012-0309-4

摘要：

This paper focuses on the two-robot welding coordination of complex curve seam which means one robot grasp the workpiece, the other hold the torch, the two robots work on the same workpiece simultaneously. This paper builds the dual-robot coordinate system at the beginning, and three point calibration method of two robots’ relative base coordinate system is presented. After that, the non master/slave scheme is chosen for the motion planning, the non master/slave scheme sets the poses versus time function of the point u on the workpiece, and calculates the two robot end effecter trajectories through the constrained relationship matrix automatically. Moreover, downhand welding is employed which can guarantee the torch and the seam keep in good contact condition all the time during the welding. Finally, a Solidworks-SimMechanics simulation platform is established, and a simulation of curved steel pipe welding is conducted. The results of the simulation illustrate the welding process can meet the requirements of downhand welding, the joint displacement curves are smooth and continuous and no joint velocities are out of working scope.

关键词： complex curve seam two robots coordinated welding motion planning

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Review on electromagnetic welding of dissimilar materials

K. SHANTHALA,T. N. SREENIVASA

《机械工程前沿（英文）》 2016年第11卷第4期页码 363-373 doi: 10.1007/s11465-016-0375-0

摘要：

Electromagnetic welding (EMW) is a high-speed joining technique that is used to join similar or dissimilar metals, as well as metals to non-metals. This technique uses electromagnetic force to mainly join conductive materials. Unlike conventional joining processes, the weld interface does not melt, thus keeping the material properties intact. Extremely high velocity and strain rate involved in the process facilitate extending the EMW technique for joining several materials. In this paper, the research and progress in electromagnetic welding are reviewed from various perspectives to provide a basis for further research.

关键词： electromagnetic welding impact dissimilar materials

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Structure and performance of welding joint of Q235 steel welded by SHS welding

Junzhi HU, Sumei WANG, Xiaoli ZHAO, Shilin ZHU, Botao YU,

《机械工程前沿（英文）》 2010年第5卷第2期页码 189-193 doi: 10.1007/s11465-010-0003-3

摘要： A self-propagating high-temperature synthesis (SHS) welding-pen that can weld steel workpiece from 6 to 10 mm is developed and welds the Q235 steel. The structure and properties of the welding joint are studied. The result indicates that this type of welding is melting and the fusion zone is clear. The tensile-strength of the welding joint is 283 MPa, flexural strength is 628 MPa, impact toughness is 46.43 J·cm, and the microhardness of the welding joint and fusion zone are 230 HV and 255.6€HV, respectively. The mircohardness of the fusion zone and the welding line are higher than that of the matrix.

关键词： self-propagating high-temperature synthesis (SHS) welding welding line structure and performance melting

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Processing parameter optimization of fiber laser beam welding using an ensemble of metamodels and MOABC

《机械工程前沿（英文）》 2022年第17卷第4期 doi: 10.1007/s11465-022-0703-5

摘要： In fiber laser beam welding (LBW), the selection of optimal processing parameters is challenging and plays a key role in improving the bead geometry and welding quality. This study proposes a multi-objective optimization framework by combining an ensemble of metamodels (EMs) with the multi-objective artificial bee colony algorithm (MOABC) to identify the optimal welding parameters. An inverse proportional weighting method that considers the leave-one-out prediction error is presented to construct EM, which incorporates the competitive strengths of three metamodels. EM constructs the correlation between processing parameters (laser power, welding speed, and distance defocus) and bead geometries (bead width, depth of penetration, neck width, and neck depth) with average errors of 10.95%, 7.04%, 7.63%, and 8.62%, respectively. On the basis of EM, MOABC is employed to approximate the Pareto front, and verification experiments show that the relative errors are less than 14.67%. Furthermore, the main effect and the interaction effect of processing parameters on bead geometries are studied. Results demonstrate that the proposed EM-MOABC is effective in guiding actual fiber LBW applications.

关键词： laser beam welding parameter optimization metamodel multi-objective

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轻量化材料焊接车间智能化要素分析

周安亮,王德成

《中国工程科学》 2017年第19卷第5期页码 103-108 doi: 10.15302/J-SSCAE-2017.05.018

摘要：

本文从轻量化材料焊接最终目标和需求、数字化和智能化技术发展趋势、焊接车间柔性构建三个维度出发，结合先进制造车间智能化和焊接工艺数字化技术发展趋势，分析得出了轻量化材料焊接车间智能化需满足的焊接控制管理实时化、焊接过程质量控制闭环化、焊接性分析数据化、焊接工艺分析智能化、快速互换装夹（柔性化）、焊缝质量检测工具化、焊接生产管理数字化、焊接基础数据库无纸化八大基本要素，并对这些要素分别进行了阐述，相关结论可以作为焊接车间智能化改造或新建的参考。

关键词：焊接工艺焊接车间智能化轻量化材料战略研究

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Research on overlaying welding rod of high hardness maraging steel

PAN Yong-ming, CHEN Shao-wei

《机械工程前沿（英文）》 2006年第1卷第4期页码 465-467 doi: 10.1007/s11465-006-0060-9

摘要： The development of new maraging steel overlaying welding rod, which contains Co, Mo, W and V alloy, solved the problems of poor homogeneity of hardness and mechanical process, prolonged the service life of wear-resistant components and increased the productive efficiency of repairing, greatly benefiting the national economy.

关键词： development productive efficiency national homogeneity mechanical

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Magnetic confinement fusion: a brief review

Chuanjun HUANG, Laifeng LI

《能源前沿（英文）》 2018年第12卷第2期页码 305-313 doi: 10.1007/s11708-018-0539-1

摘要： Fusion energy is considered to be the ultimate energy source, which does not contribute to climate change compared with conventional fossil fuel. It is massive compared with unconventional renewable energy and demonstrates fewer safety features compared with unconventional fission energy. During the past several decades, never-ceasing efforts have been made to peacefully utilize the fusion energy in various approaches, especially inertial confinement and magnetic confinement. In this paper, the main developments of magnetic confinement fusion with emphasis on confinement systems as well as challenges of materials related to superconducting magnet and plasma-facing components are reviewed. The scientific feasibility of magnetic confinement fusion has been demonstrated in JET, TFTR, JT-60, and EAST, which instigates the construction of the International Thermonuclear Experimental Reactor (ITER). A fusion roadmap to DEMO and commercial fusion power plant has been established and steady progresses have been made to achieve the ultimate energy source.

关键词： fusion energy magnetic confinement tokamak structural material superconducting magnet

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Turbidity-adaptive underwater image enhancement method using image fusion

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-021-0669-8

摘要： Clear, correct imaging is a prerequisite for underwater operations. In real freshwater environment including rivers and lakes, the water bodies are usually turbid and dynamic, which brings extra troubles to quality of imaging due to color deviation and suspended particulate. Most of the existing underwater imaging methods focus on relatively clear underwater environment, it is uncertain that if those methods can work well in turbid and dynamic underwater environments. In this paper, we propose a turbidity-adaptive underwater image enhancement method. To deal with attenuation and scattering of varying degree, the turbidity is detected by the histogram of images. Based on the detection result, different image enhancement strategies are designed to deal with the problem of color deviation and blurring. The proposed method is verified by an underwater image dataset captured in real underwater environment. The result is evaluated by image metrics including structure similarity index measure, underwater color image quality evaluation metric, and speeded-up robust features. Test results exhibit that the method can correct the color deviation and improve the quality of underwater images.

关键词： turbidity underwater image enhancement image fusion underwater robots visibility