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Water-Driven Malleable,Weldable and Eco-Friendly Recyclable Carbon Fiber Reinforced Dynamic Composites

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Chinese Journal of Chemistry 2024年第5期42卷 516-522页

作者： Ping Yu Qirui Huang Yi Wang Wan Peng Zichen Jia Haiyue Wang Juanjuan Ma Chunyu Wang Xuzhou Yan School of Environmental and Chemical Engineering Jiangsu Key Laboratory of Function Control Technology for Advanced MaterialsJiangsu Ocean UniversityLianyungangJiangsu222005 China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai200240 China

Traditional carbon fiber-reinforced polymers based on thermoset matrix have been extensively used in the fields of wind turbine blades,automotive sector,and aerospace,among many others.However,there is still a major challenge of recycling those polymers due to the high cost and adverse impacts on the environment.In this work,we apply a polyimine network as matrix,which possess considerable tensile and thermal properties,to prepare the carbon fiber reinforced polyimine materials with trifluoromethyl diphenoxybenzene units(CFRFP)using a prepreg-based compression molding method.The CFRFP can be reshaped or reprocessed by heat or with water rapidly,and exhibited multifunction,including welding,chemical recycling,etc.These unique findings gained from our study will facilitate the manufacturing capability and enrich the types of fiber-reinforced composites.

关键词： Dynamic chemistry Green chemistry Fiber-reinforced composites Fluoropolyimine welding Reshaping Recycling Renewable resources

WeldNet:A voxel-based deep learning network for point cloud annular weld seam detection

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Science China(Technological Sciences) 2024年第4期67卷 1215-1225页

作者： WANG Hui RONG YouMin XU JiaJun XIANG SongMing PENG YiFan HUANG Yu State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Weld seam detection is an important part of automated welding.At present,few studies have been conducted on annular weld seams,and a lot of defects exist in the point cloud model of the tube sheet obtained by RGB-D cameras and photography methods.Aiming at the above problems,this paper proposed an annular weld seam detection network named WeldNet where a voxel feature encoding layer was adaptively improved for annular weld seams,the sparse convolutional network and region proposal network(RPN)were used to detect annular weld seam position,and an annular weld seam detection loss function was designed.Further,an annular weld seam dataset was established to train the network.Compared with the random sampling consistency(RANSAC)method,WeldNet has a higher detection accuracy,as well as a higher detection success rate which has increased by 23%.Compared with U-Net,WeldNet has been proven to achieve a better detection result,and the intersection over the union of the weld seam detection is improved by 17.8%.

关键词： deep learning point cloud weld seam detection welding annular weld seam

Influence of parameters on the microstructure of a duplex stainless steel joint welded by a GMAW welding process

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Progress in Natural Science:Materials International 2022年第4期32卷 415-423页

作者： Sandra Chacón-Fernández Antonio Portolés García Gerardo Romaní Labanda Universidad Politécnica de Madrid Escuela Técnica Superior de Ingenieros Industriales UPM

Duplex stainless steels(DSSs) are widely used in industry for their desirable properties. Any fusion welding technique modifies the microstructure and, consequently, the properties of the material. This paper presents a parametric study of the variables that determine the energy contribution(current, voltage and welding speed) and the structural modifications produced during gas metal arc welding. The analysis comprises metallographic study,phase balance, dimensioning of the weld beads and tensile and hardness tests. The influence of the variables studied on the thermal cycles obtained(temperatures reached and cooling rate) was determined by using a finite element model. The results showed that, in addition to the indicated parameters, the parameter power transfer per volume(W/m3) and the geometry in the bead must be controlled due to their influence on the heat flow distribution and phase balance.

关键词： welding Heat input GMAW Duplex stainless steels (DSS) Finite element model (FEM)

Microstructure Evolution of Heat‑Affected Zone in Submerged Arc welding and Laser Hybrid welding of 690 MPa High Strength Steel and its Relationship with Ductile–Brittle Transition Temperature

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Acta Metallurgica Sinica(English Letters) 2023年第4期36卷 623-636页

作者： Xuelin Wang Wenjuan Su Zhenjia Xie Xiucheng Li Wenhao Zhou Chengjia Shang Qichen Wang Jian Bai Lianquan Wu Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Guangdong Laboratory for Materials Science and Technology(Yangjiang Advanced Alloys Laboratory) Yangjiang BranchYangjiang 529500China Xiangtan Iron and Steel Co. Ltd of Hunan ValinXiangtan 411101China CIMC Raffles Offshore Limited Longkou 265700China CIMC Offshore Engineering Institute Limited Yantai 264670China Yangjiang Yichuan Metal Technology Co. LtdYangjiang 529533China

The comparative study of submerged arc welding(SAW)and laser hybrid welding(LHW)was carried out for a 690 MPa high strength steel with thickness of 20 mm.Microstructure and ductile–brittle transition temperature(DBTT)evolution in welded zone were elucidated from the aspect of crystallographic structure,particularly,digitization and visualization of 24 variants.The impact toughness of each micro zone in LHW joint is better than that of SAW,in which the DBTT of equivalent fusion line and heat-affected zone(HAZ)can reach−70 and−80℃,while that of SAW is only−50℃.LHW technology induces narrowing of the HAZ and refining of the microstructure obtained in weld metal and HAZ.Meanwhile,the austenite grain size and transformation driving force in the coarse grained heat-affected zone(CGHAZ)are reduced and increased,respectively.It makes variant selection mechanism occurring in CGHAZ of LHW dominate by close-packed plane grouping,which promotes lath bainite formation with high density of high angle grain boundary,especially block boundary dominated by V1/V2 pair.While for SAW,the lower transformation driving force inferred from the large amount of retained austenite in CGHAZ induces Bain grouping of variants,and thus triggers the brittle crack propagating straightly in granular bainite,resulting in lower impact toughness and higher DBTT.

关键词： High strength steel welding Microstructure Variant selection Ductile-brittle transition temperature

Comparison of feasibility,microstructure and performance of hybrid laser arc,activated flux tungsten inert gas and friction stir welding for thick plate of innovative ultra-pure ferritic stainless steel

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Journal of Iron and Steel Research(International) 2022年第4期29卷 665-676页

作者： Jian Han Lian-meng Liu Xin-ya Chen Min-fang Chen Lei Cui Yang-chuan Cai Yin-bao Tian School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China School of Materials Science and Engineering Tianjin UniversityTianjin 300072China

An innovative grade of ferritic stainless steel,ultra-pure 18Cr–2Mo thick plate,was designed and produced for special industrial application.In order to maintain its mechanical properties after joining,three advanced joining methods,hybrid laser arc welding,activated flux tungsten inert gas welding and friction stir welding,were selected and conducted to connect the thick plates.The feasibility of three joining methods,the microstructure and mechanical properties were compared,and the results have demonstrated that the sound joint was successfully produced using the selected parameters through friction stir welding.The obtained hardness and impact toughness of the weld zone were satisfying.In terms of activated flux tungsten inert gas welding,the crack will be created due to microstructural brittleness.And as for hybrid laser arc welding,the weld zone is narrow,and the addition of wire during welding for the top weld metal area leads to higher formation ratio of low-angle grain boundaries,which is beneficial to performance of the joint.However,there is still a weak area in the fusion line of the welded joint.The result has illustrated that the welding of innovative ultra-pure ferritic stainless steel thick plate by friction stir welding is feasible.

关键词： Ultra-pure ferritic stainless steel Hybrid welding Activated flux tungsten inert gas Friction stir welding Microstructural evolution Mechanical property

welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

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Defence Technology（防务技术） 2017年第2期13卷 59-71页

作者： Raffi Mohammed G.Madhusudhan Reddy K.Srinivasa Rao Department of Metallurgical Engineering Andhra University Visakhapatnam India Defence Metallurgical Research Laboratory Hyderabad India

High nitrogen stainless steel(HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance.Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poor mechanical properties.The above problems can be overcome by proper selection and procedure of joining process. In the present work, an attempt has been made to correlate the microstructural changes with mechanical properties of fusion and solid state welds of high nitrogen steel. Shielded metal arc welding(SMAW), gas tungsten arc welding(GTAW), electron beam welding(EBW) and friction stir welding(FSW) processes were used in the present work. Optical microscopy, scanning electron microscopy and electron backscatter diffraction were used to characterize microstructural changes. Hardness, tensile and bend tests were performed to evaluate the mechanical properties of welds. The results of the present investigation established that fully austenitic dendritic structure was found in welds of SMAW. Reverted austenite pools in the martensite matrix in weld zone and unmixed zones near the fusion boundary were observed in GTA welds. Discontinuous ferrite network in austenite matrix was observed in electron beam welds.Fine recrystallized austenite grain structure was observed in the nugget zone of friction stir welds.Improved mechanical properties are obtained in friction stir welds when compared to fusion welds. This is attributed to the refined microstructure consisting of equiaxed and homogenous austenite grains.

关键词： High nitrogen austenitic stainless steel(HNS) Shielded metal arc welding (SMAW) Gas tungsten arc welding (GTAW) Electron beam welding (EBW) Friction stir welding (FSW)

welding solidification cracking susceptibility and behavior of a Ni-28W-6Cr alloy

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Journal of Materials Science & Technology 2019年第1期35卷 29-35页

作者： Shuangjian Chen Xiang-Xi Ye D.K.L.Tsang Li Jiang Kun Yu Chaowen Li Zhijun Li Center for Thorium Molten Salts Reactor System Shanghai Institute of Applied Physics Chinese Academy of Sciences

welding solidification cracking of alloys is associated with the range of solidification temperature that can be greatly affected by the amount of refractory metals and other additives. In this work, solidification cracking of Ni-28W-6Cr alloy with high W content was studied by gas tungsten arc welding, showing that the welding current, alloying elements and precipitates all affect the cracking susceptibility. The lengths of cracks increase linearly with the welding current in the range from 150 to 250 A. The relatively high cracking susceptibility is mainly attributed to the high content of Si, which tends to segregate with other elements including W, Cr, Mn as films or components with low melting point in the last solidification stage and weaken the binding force of grain boundaries. Moreover, the existence of precipitated continuous eutectic M_6C carbides in the grain boundaries also acts as nucleation sites of crack initiation, and the cracks often propagate along solidification grain boundary.

关键词： welding solidification cracking susceptibility Ni-W-Cr alloy Chemical composition Grain boundaries

welding Effect at the Heat Affected Zone by Joining a Gray Cast Iron with Stainless Steel E308-16

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Materials Sciences and Applications 2023年第6期14卷 336-345页

作者： Yajaira Curiel-Razo Enrique Curiel-Reyna Minerva Robles-Agudo Alberto Lara-Guevara Ignacio Rojas-Rodríguez Facultad de Estudios Superiores-Cuautitlán Universidad Nacional Autónoma de México Cuautitlán-Izcalli México División Industrial Universidad Tecnológica de Querétaro Querétaro México División de Posgrado Facultad de Informática Universidad Autónoma de Querétaro Querétaro México

Different investigations of the union of dissimilar materials such as stainless steel and different castings have been carried out, but rapid cooling immediately after welding has not been considered, in this work it was investigated how rapid cooling affects the metallurgical microstructure and consequently the mechanical properties. The effect of welding parameters on the microstructure and mechanical properties of the joint between dissimilar metals, an E-308-16 austenitic stainless steel and Gray Cast Iron was also analyzed. Gray cast iron samples (GCI) were fabricated, welded and cooled. The main welding parameters studied in this work are the welding technique and the type of filler electrodes. Flux-coated electrode E-308-16 was applied for this different joint. An experimental study was carried out for the analysis of welded joints of similar and dissimilar steels. The microstructure of the welded joints was analyzed using an optical microscope, in the base metals, heat affected zone (HAZ) and filler metal. The mechanical properties of the welded joints were evaluated by Vickers microhardness and tensile strength tests. The hardness profile showed differences in hardness between the base metals, the heat affected zone and the filler metal. The metallurgical microstructures observed along the welded areas corresponded to the profile. The hardness differences determined the effect on the mechanical and metallurgical characteristics of the welded samples as a result of the cooling rate differences. This research work is important because it allows us to analyze the possibility of reworking pieces of dissimilar materials by welding or, failing that, to determine if this may or may not be possible.

关键词： Gray Iron welding Hot Affected Zone Filler Metal Microstructure Dissimilar Metals

Experimental investigation and optimization of weld bead characteristics during submerged arc welding of AISI 1023 steel

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Defence Technology（防务技术） 2019年第1期15卷 72-82页

作者： Ankush Choudhary Manoj Kumar Deepak Rajendra Unune Department of Mechanical-Mechatronics Engineering The LNM Institute of Information Technology

Submerged arc welding(SAW), owing to its high deposition rate and high welding quality, is widely used in the fabrication of pressure vessel, marine vessel, pipelines and offshore structures. However, selection of an optimum combination of welding parameters is critical in achieving high weld quality and productivity. In this work, initially, the SAW experiments were performed using fractional factorial design to analyze the effect of direct and indirect input parameters, namely, welding voltage, wire feed rate,welding speed, nozzle to plate distance, flux condition, and plate thickness on weld bead geometrical responses viz. bead width, reinforcement, and penetration. The bead on plate technique was used to deposit weld metal on AISI 1023 steel plates. The effect of SAW input parameters on response variables were analyzed using main and interaction effects. The linear regression was used to develop the mathematical models for the response variable. Then, the multi-objective optimization of input parameters was carried out using desirability approach, genetic algorithm and Jaya algorithm. The Jaya algorithm offered better optimization results as compared to desirability approach, genetic algorithm.

关键词： Submerged arc welding Optimization Regression Genetic algorithm Jaya algorithm