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Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

《机械工程前沿（英文）》 2016年第11卷第3期页码 242-249 doi: 10.1007/s11465-016-0397-7

摘要：

Laser hot wire cladding, with the prominent features of low heat input, high energy efficiency, and high precision, is widely used for remanufacturing metal parts. The cladding process, however, needs to be improved by using a quantitative method. In this work, volumetric defect ratio was proposed as the criterion to describe the integrity of forming quality for cladding layers. Laser deposition experiments with FV520B, one of martensitic stainless steels, were designed by using the Taguchi method. Four process variables, namely, laser power (P), scanning speed (V_s), wire feed rate (V_f), and wire current (I), were optimized based on the analysis of signal-to-noise (S/N) ratio. Metallurgic observation of cladding layer was conducted to compare the forming quality and to validate the analysis method. A stable and continuous process with the optimum parameter combination produced uniform microstructure with minimal defects and cracks, which resulted in a good metallurgical bonding interface.

关键词： process optimization Taguchi method signal-to-noise (S/N) ratio volumetric defect ratio laser hot wire cladding

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Construction of nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically

《化学科学与工程前沿（英文）》 2023年第17卷第12期页码 2050-2060 doi: 10.1007/s11705-023-2343-7

摘要： Reducing the dissolution of Mn from LiMn₂O₄ (LMO) and enhancing the stability of film electrodes are critical and challenging for Li⁺ ions selective extraction via electrochemically switched ion exchange technology. In this work, we prepared a nitrogen-doped carbon cladding LMO (C-N@LMO) by polymerization of polypyrrole and high-temperature annealing in the N₂ gas to achieve the above purpose. The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode. The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42% compared to the LMO film electrode after 10 cycles. The cladding layer not only acted as a protective layer but also functioned as a conductive shell, accelerating the migration rate of Li⁺ ions. The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li⁺ ions, which was 33% less compared to the pure LMO film electrode. Meanwhile, the C-N@LMO film electrode retained evident selectivity toward Li⁺ ions, and the separation factor was 118.38 for Li⁺ toward Mg²⁺ in simulated brine. Therefore, the C-N@LMO film electrode would be a promising candidate for the recovery of Li⁺ ions from salt lakes.

关键词： LiMn₂O₄ lithium extraction surface coating cyclic stability Mn dissolution

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Steady-state thermal-hydraulic analysis of SCWR assembly

LIU Xiaojing, CHENG Xu

《能源前沿（英文）》 2008年第2卷第4期页码 475-478 doi: 10.1007/s11708-008-0093-3

摘要： Among the six gen-IV reactor concepts recommended by the gen-IV international forum (GIF), supercritical water-cooled reactor (SCWR), the only reactor with water as coolant, achieves a high thermal efficiency and, subsequently, has economic advantages over the existing reactors due to its high outlet temperature. A thermal-hydraulic analysis of the SCWR assembly is performed in this paper using the modified COBRA-IV code. Two approaches to reduce the hot channel factor are investigated: decreasing the moderator mass flow and increasing the thermal resistance between moderator channel and its adjacent sub-channels. It is shown that heat transfer deterioration cannot be avoided in SCWR fuel assembly. It is, therefore, highly required to calculate the cladding temperature accurately and to preserve the fuel rod cladding integrity under heat transfer deterioration conditions.

关键词： cladding temperature assembly temperature coolant resistance

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Hybrid forming mechanism of patternless casting and laser cladding

Zhongde SHAN, Fuzhen SUN, Yang LIU

《机械工程前沿（英文）》 2019年第14卷第4期页码 393-401 doi: 10.1007/s11465-019-0550-1

摘要： In accordance with the requirement of manufacturing dies quickly and economically, a hybrid forming method of stamping dies for automobile panels is proposed. The method combines digital patternless casting and high-power laser cladding. An experimental study is conducted on the hybrid forming process and its trial production and application in the manufacturing of stamping dies for typical panels. Results prove that the laser cladding layer exceeds HRC60 (Rockwell hardness) and thus meets the production efficiency requirement of automobile dies. The rate of defects is well controlled. Compared with traditional technology, this technology has remarkable advantages and advancement.

关键词： patternless casting laser cladding hybrid forming rapid tooling

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The Application and the Prospect of Remanufacturing Technologies in the Metallurgical Industry

Jie Xiong,Jian-cheng Fan,Jv Yuan

《工程管理前沿（英文）》 2016年第3卷第2期页码 165-170 doi: 10.15302/J-FEM-2016023

摘要： Metallurgical equipment is subjected to severe working conditions and the components suffer from various types of physical damages such as abrasion, corrosion and crack. Advanced surface engineering technologies and resistant coatings on the damaged surface can improve surface properties, extend service lives, reduce maintenance costs and improve product quality in the metallurgical industry. This paper introduces remanufacturing technologies, including electroplating, overlaying welding, thermal spraying and laser surface cladding and their applications in the metallurgical industry, and analyzes the development tendency and prospect of remanufacturing technologies.

关键词： remanufacturing technology electroplating overlaying welding thermal spraying laser surface cladding

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Wind tunnel test study on the wind pressure coefficient of claddings of high-rise buildings

Yong QUAN, Yi LIANG, Fei WANG, Ming GU

《结构与土木工程前沿（英文）》 2011年第5卷第4期页码 518-524 doi: 10.1007/s11709-011-0128-4

摘要： The area-averaged most unfavorable wind pressure coefficients (MUWPCs) on various regions of building surfaces and the influence of the side ratio and the terrain category were studied based on wind tunnel test data of scale models of typical high-rise buildings with rectangular cross-sections. The negative area-averaged MUWPCs in the middle-height edge areas generally increased with an increasing / side ratio. The area-averaged MUWPCs can be well fitted with a function of the average area reduced by the square of the building depth, . In addition, no unique pattern was found for the effect of the terrain category on the MUWPCs.

关键词： side ratio area-averaged pressure coefficients cladding terrain category

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激光表面改性技术发展研究

张群莉,王梁,梅雪松,姚建华

《中国工程科学》 2020年第22卷第3期页码 71-77 doi: 10.15302/J-SSCAE-2020.03.010

摘要：

激光表面改性技术利用高能量密度的激光束对零部件局部易损易耗区域进行快速处理，获得材料表面所需性能，进而大幅延长零部件使用寿命，已在航空航天、石油化工、能源、交通、冶金等领域获得应用。本文针对激光冲击强化、激光淬火、激光熔覆3 种典型的激光表面改性技术，梳理了相应技术特点及国内外应用现状，凝练我国相关技术领域面临的差距与问题，总结激光表面改性技术的重点发展方向：专用合金材料制备、多能场激光复合表面改性、面向现场的激光再制造、激光冲击强化控形控性、激光表面改性智能化、激光表面微结构化。从政府引导、国产化创新、产业链完善、质量评价标准体系、人才培养等方面提出发展建议，以期为我国激光表面改性技术发展提供参考借鉴。

关键词：激光表面改性冲击强化淬火熔覆发展趋势

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Influence of the field humiture environment on the mechanical properties of 316L stainless steel repaired with Fe314

Lianzhong ZHANG, Dichen LI, Shenping YAN, Ruidong XIE, Hongliang QU

《机械工程前沿（英文）》 2018年第13卷第4期页码 513-519 doi: 10.1007/s11465-018-0503-0

摘要：

The mechanical properties of 316L stainless steel repaired with Fe314 under different temperatures and humidities without inert gas protection were studied. Results indicated favorable compatibility between Fe314 and 316L stainless steel. The average yield strength, tensile strength, and sectional contraction percentage were higher in repaired samples than in 316L stainless steel, whereas the elongation rate was slightly lower. The different conditions of humiture environment on the repair sample exerted minimal influence on tensile and yield strengths. The Fe314 cladding layer was mainly composed of equiaxed grains and mixed with randomly oriented columnar crystal and tiny pores or impurities in the tissue. Results indicated that the hardness value of Fe314 cladding layer under different humiture environments ranged within 419–451.1 HV_0.2. The field humiture environment also showed minimal impact on the average hardness of Fe314 cladding layers. Furthermore, 316L stainless steel can be repaired through laser cladding by using Fe314 powder without inert gas protection under different temperatures and humidity environments.

关键词： laser cladding repaired performance tensile strength temperature and humidity environment

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激光熔覆NiCrAl-陶瓷涂层的显微组织研究

陈庆华,魏仑,龙晋明,李俊昌

《中国工程科学》 2001年第3卷第10期页码 64-71

摘要：

运用激光熔覆技术在40Cr钢表面制备了(TiO₂+B₂O₃+Al₂O₃+TiB₂)/NiCrAl金属陶瓷涂层，其中的TiB₂和Al₂O₃陶瓷颗粒在激光加工过程中原位反应生成；对熔覆层的组织、物相、元素分布和显微硬度分布特征进行了分析研究；熔覆层中的主相依次分别是γ-Ni,γ′,Al₂O₃和TiB₂，熔覆层的微观结构和硬度主要和激光处理参数和熔覆层化学组成有关^［1～9］；陶瓷相的原位生成和加入，大大改善了熔覆层的硬度和覆层/基体界面的结合性能。