The Effect of Laser Welding Process Parameters on the Mechanical and Microstructural Properties of V-4CR-4TI Structural Materials PDF Download
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Author: Publisher: ISBN: Category : Languages : en Pages : 24
Book Description
V-Cr-Ti alloys are among the leading candidate materials for the frost wall and other structural materials applications in fusion power reactors because of several important advantages including inherently low irradiation-induced activity, good mechanical properties, good compatibility with lithium, high thermal conductivity and good resistance to irradiation-induced swelling and damage [1]. However, weldability of these alloys in general must be demonstrated, and laser welding, specifically, must be developed. Laser welding is considered to be an attractive process for construction of a reactor due to its high penetrating power and potential flexibility. This paper reports on a systematic study which was conducted to examine the use of a pulsed Nd:YAG laser to weld sheet materials of V-Cr-Ti alloys and to characterize the microstructural and mechanical properties of the resulting joints. Deep penetration and defect-free welds were achieved under an optimal combination of laser parameters including focal length of lens, pulse energy, pulse repetition rate, beam travel speed, and shielding gas arrangement. The key for defect-free welds was found to be the stabilization of the keyhole and providing an escape path for the gas trapped in the weld. An innovative method was developed to obtain deep penetration and oxygen contamination free welds. Oxygen and nitrogen uptake were reduced to levels only a few ppm higher than the base metal by design and development of an environmental control box. The effort directed at developing an acceptable postwelding heat treatment showed that five passes of a diffuse laser beam over the welded region softened the weld material, especially in the root region of the weld.
Author: Publisher: ISBN: Category : Languages : en Pages : 24
Book Description
V-Cr-Ti alloys are among the leading candidate materials for the frost wall and other structural materials applications in fusion power reactors because of several important advantages including inherently low irradiation-induced activity, good mechanical properties, good compatibility with lithium, high thermal conductivity and good resistance to irradiation-induced swelling and damage [1]. However, weldability of these alloys in general must be demonstrated, and laser welding, specifically, must be developed. Laser welding is considered to be an attractive process for construction of a reactor due to its high penetrating power and potential flexibility. This paper reports on a systematic study which was conducted to examine the use of a pulsed Nd:YAG laser to weld sheet materials of V-Cr-Ti alloys and to characterize the microstructural and mechanical properties of the resulting joints. Deep penetration and defect-free welds were achieved under an optimal combination of laser parameters including focal length of lens, pulse energy, pulse repetition rate, beam travel speed, and shielding gas arrangement. The key for defect-free welds was found to be the stabilization of the keyhole and providing an escape path for the gas trapped in the weld. An innovative method was developed to obtain deep penetration and oxygen contamination free welds. Oxygen and nitrogen uptake were reduced to levels only a few ppm higher than the base metal by design and development of an environmental control box. The effort directed at developing an acceptable postwelding heat treatment showed that five passes of a diffuse laser beam over the welded region softened the weld material, especially in the root region of the weld.
Author: Swarup Bag Publisher: Springer Nature ISBN: 9811601828 Category : Technology & Engineering Languages : en Pages : 581
Book Description
This book presents the select proceedings of Conference on Research and Developments in Material Processing, Modelling and Characterization (RDMPMC 2020). It highlights the new technologies developed in the generation of rational materials for various applications with tailored properties. It covers fundamental research in emerging materials which includes biomaterials, composites, ceramics, functionally graded materials, energy materials, thin film materials, nanomaterials, nuclear materials, intermetallic, high strength materials, structural materials, super alloys, shape memory alloys and thermally enhanced materials. It includes the numerical modeling and computer simulation to investigate the properties and structure of materials. Few of the most relevant manufacturing techniques highlighted in this book are welding, coating, additive manufacturing, laser-based manufacturing, advanced machining processes, casting, forming and micro and nanoscale manufacturing processes. Given its contents, this book is beneficial to students, researchers and industry professionals.
Author: Publisher: ISBN: Category : Languages : en Pages : 11
Book Description
Mechanical properties and microstructural characteristics of laser and electron-beam welds of a 500-kg heat of V4Cr4Ti were investigated in as-welded condition and after postwelding heat treatment by impact testing, microhardness measurement, optical microscopy, X-ray diffraction, and transmission electron microscopy (TEM). Ductile-brittle transition temperatures of the laser and electron-beam welds were significantly higher than that of the base metal. However, excellent impact properties could be restored in both types of welds by postwelding annealing at 1000 C for 1 h in vacuum. Analysis by TEM revealed that annealed weld zones were characterized by extensive networks of fine V(C, O, N) precipitates, which clean away O, C, and N interstitial from the grain matrices. This process is accompanied by simultaneous annealing-out of the dense dislocations present in the weld zone. This finding could be useful in identifying an optimal welding procedure by controlling and adjusting the cooling rate of the weld zone by an innovative method to maximize the precipitation of V(C, O, N).
Author: Manjaiah M Publisher: CRC Press ISBN: 1003856780 Category : Technology & Engineering Languages : en Pages : 269
Book Description
This book covers advances in fusion and solid-state welding processes including basics, welding metallurgy, defect formation, and the effect of process parameters on mechanical properties. Details of the microstructural and mechanical behaviors of weldments are included. This book covers challenges encountered during dissimilar welding of metal by fusion and solid-state welding processes, including remedial solutions and hybrid processes to counter the same. Numerical and statistical simulation approaches used in the welding process for parameter optimization and material flow studies are described as well. Features: Provides details related to the microstructural and mechanical behaviors of welded joints developed by different welding processes. Covers recent research content, metallurgical analysis, and simulation aspects. Discusses the joining of plastics and ceramics. Includes a dedicated chapter on machine learning and digital twin in welding. Explores difficulties associated with the joining of dissimilar metals and alloys. This book is aimed at researchers and graduate students in material joining and characterization and welding.
Author: Publisher: ISBN: Category : Languages : en Pages : 8
Book Description
The authors are conducting a program to develop an optimal laser welding procedure for large-scale fusion-reactor structural components to be fabricated from vanadium-base alloys. Microstructural characteristics were investigated by optical microscopy, X-ray diffraction, transmission electron microscopy, and chemical analysis to provide an understanding of the mechanism of the drastic improvement of impact toughness of laser and electron-beam (EB) welds of V-4Cr-4Ti following postwelding annealing at 1000°C. Transmission electron microscopy (TEM) revealed that annealed weld zones were characterized by extensive networks of fine V(C, O, N) precipitates, which appear to clean away O, C, and N from grain matrices. This process is accompanied by simultaneous annealing-out of the dense dislocations present in the weld fusion zone. It seems possible to produce high-quality welds under practical conditions by controlling and adjusting the cooling rate of the weld zone by some innovative method to maximize the precipitation of V(C, O, N).
Author: João Pedro Oliveira Publisher: MDPI ISBN: 303928861X Category : Technology & Engineering Languages : en Pages : 260
Book Description
Laser welding is a high-energy process used in a wide range of advanced materials to obtain micro- to macro-sized joints in both similar and dissimilar combinations. Moreover, this technique is widely used in several industries, such as automotive, aerospace, and medical industries, as well as in electrical devices. Although laser welding has been used for several decades, significant and exciting innovations often arise from both the process and/or advanced materials side.
Author: Meysam Haghshenas Publisher: MDPI ISBN: 3039289977 Category : Technology & Engineering Languages : en Pages : 252
Book Description
As the Guest Editor of this Special Issue entitled "Science, Characterization, and Technology of Joining and Welding" of Metals, I am pleased to have this book published by MDPI. Joining, including welding, soldering, brazing, and assembly, is an essential requirement in manufacturing processes and is classified as a secondary manufacturing process. This Special Issue of Metals includes technical and review papers on, but not limited to, different aspects of joining and welding, including welding technologies (i.e., fusion-based welding and solid-state welding), characterization, metallurgy and materials science, quality control, and design and numerical simulation. This Special Issue also includes the joining of different materials, including metal and non-metals (polymers and composites), including 17 peer-reviewed papers from several researchers all around the globe (China, Germany, Brazil, South Koria, Slovakia, USA, Taiwan, Canada, and India). As of this date (April 2020), the papers in this Special Issue have been cited 47 times by other researchers, which I think is an eminent number and shows the high quality of the published papers in this Issue. This Special Issue includes a large diversity of various subjects in the field of joining: laser welding, friction stir welding, diffusion bonding, multipass welding, rotary friction-welding, friction bit joining, adhesive bonding, weldbonding, simulation and experimentation, metal/FRP joints, welding simulation, plasma–TIG coupled arc welding, liquation cracking, soldering, resin bonding, microstructural characteristics, brazing, and friction stir butt and scarf welding. I would like to sincerely thank all the researchers who contributed to this Special Issue for their high-quality research. I also would like to acknowledge Mr. Toliver Guo, Senior Assistant Editor at MDPI, who continuously and tirelessly contributed toward this Special Issue by assisting me with inviting the authors and the follow ups. I think this Special Issue will enhance our knowledge and understanding in the field of joining and assembly. I would like to dedicate this book to my wife, Mehrnoosh, for her continued support and encouragement.
Author: Publisher: ISBN: Category : Languages : en Pages : 4
Book Description
The authors are conducting a program to develop an optimal laser welding procedure that can be applied to large-scale fusion-reactor structural components to be fabricated from vanadium-base alloys. Results of initial investigation of mechanical properties and hardening behavior of laser and electron-beam (EB) welds of the production-scale heat of V-4Cr-4Ti (500-kg Heat 832665) in as-welded and postwelding heat-treated (PWHT) conditions are presented in this paper. The laser weld was produced in air using a 6-kW continuous CO2 laser at a welding speed of H"5 mm/s. Microhardness of the laser welds was somewhat higher than that of the base metal, which was annealed at a nominal temperature of H"050°C for 2 h in the factory. In spite of the moderate hardening, ductile-brittle transition temperatures (DBTTs) of the initial laser (H"0°C) and EB (H"0°C) welds were significantly higher than that of the base metal (H"170°C). However, excellent impact properties, with DBTT
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Author: Swarup Bag
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Author: João Pedro Oliveira
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