Real Time Weld Process Monitoring

Welding is a complex process, is increasingly automated, and operates at higher speeds in more difficult environments. Defects also need to be detected as they arise to ensure efficient, high-quality production. All these needs have led to a growing interest in the use of sensors to provide accurate, robust, real-time monitoring where this cannot be achieved by more traditional testing and inspection techniques. This important book reviews the range of monitoring techniques available and their applications. After an introductory chapter, the first part of the book reviews the range of sensor technologies in welding, from arc and optical sensors to infrared and ultrasonic techniques. Part two discusses the monitoring of particular aspects of welding such as weld seams and profiles, the analysis of weld penetration and weld pool surface, as well as monitoring of resistance and laser welding. With its distinguished editor and international team of contributors, Real-time weld process monitoring is a valuable reference to all those concerned with improving the quality of welding and welded components. Reviews the range of monitoring techniques available Examines the range of sensor technologies in welding from arc and optical sensors to infrared and ultrasonic techniques Discusses the monitoring of specific aspects of welding such as weld seams, resistance and laser welding

An improved method and apparatus are provided for real time weld monitoring. An infrared signature emitted by a hot weld surface during welding is detected and this signature is compared with an infrared signature emitted by the weld surface during steady state conditions. The result is correlated with weld penetration. The signal processing is simpler than for either UV or acoustic techniques. Changes in the weld process, such as changes in the transmitted laser beam power, quality or positioning of the laser beam, change the resulting weld surface features and temperature of the weld surface, thereby resulting in a change in the direction and amount of infrared emissions. This change in emissions is monitored by an IR sensitive detecting apparatus that is sensitive to the appropriate wavelength region for the hot weld surface.

This book discusses the latest advances in manufacturing and process control, with a special emphasis on digital manufacturing and intelligent technologies for manufacturing and industrial processes control. The human aspect of the developed technologies and products, their interaction with the users, as well as sustainability issues, are covered in detail. Development of new products using 3D printers, rapid prototyping systems, remote fabrication, and other advanced techniques, is described in detail, highlighting the state-of-the-art and current challenges. Other key topics include digital modeling systems and additive manufacturing, together with their applications in a number of fields, e.g in bioengineering/biomedicine, in the aerospace, maritime and military fields or for archeological and historical purposes, such as preserving structures, but not limited to this. The book is based on three AHFE 2018 affiliated conferences i.e. the AHFE 2018 International Conference on Advanced Production Management and Process Control, the AHFE 2018 International Conference on Human Aspects of Advanced Manufacturing, and the AHFE 2018 International Conference on Additive Manufacturing, Modeling Systems and 3D Prototyping, which were held on July 21-25, 2018, in Orlando, Florida, USA.

Many new, or relatively new, welding processes such as friction stir welding, resistance spot welding and laser welding are being increasingly adopted to replace or improve on traditional welding techniques. Before advanced welding techniques are employed, their potential failure mechanisms should be well understood and their suitability for welding particular metals and alloys in different situations should be assessed. Failure mechanisms of advanced welding processes provides a critical analysis of advanced welding techniques and their potential failure mechanisms. The book contains chapters on the following topics: Mechanics modelling of spot welds under general loading conditions and applications to fatigue life predictions, Resistance spot weld failure mode and weld performance for aluminium alloys, dual phase steels and TRIP steels, Fatigue behaviour of spot welded joints in steel sheets, Non-destructive evaluation of spot weld quality, Solid state joining - fundamentals of friction stir welding, Failure mechanisms in friction stir welds, Microstructure characteristics and mechanical properties of laser weld bonding of magnesium alloy to aluminium alloy, Fatigue in laser welds, Weld metal ductility and its influence on formability of tailor welded blanks, Joining of lightweight materials using reactive nanofoils, and Fatigue life prediction and improvements for MIG welded advanced high strength steel weldments. With its distinguished editor and international team of contributors, Failure mechanisms of advanced welding processes is a standard reference text for anyone working in welding and the automotive, shipbuilding, oil and gas and other metal fabrication industries who use modern and advanced welding processes. Provides a critical analysis of advanced welding techniques and their potential failure mechanisms Experts in the field survey a range of welding processes and examine reactions under various types of loading conditions Examines the current state of fatigue life prediction of welded materials and structures in the context of spot welded joints and non-destructive evaluation of quality

Despite the wide availability of literature on welding processes, a need exists to regularly update the engineering community on advancements in joining techniques of similar and dissimilar materials, in their numerical modeling, as well as in their sensing and control. In response to InTech's request to provide undergraduate and graduate students, welding engineers, and researchers with updates on recent achievements in welding, a group of 34 authors and co-authors from 14 countries representing five continents have joined to co-author this book on welding processes, free of charge to the reader. This book is divided into four sections: Laser Welding; Numerical Modeling of Welding Processes; Sensing of Welding Processes; and General Topics in Welding.

It has been shown both experimentally {2} and theoretically {2,3} that surface skimming SH waves propagating along symmetry axes of the texture have velocities that differ in proportion to the magnitude of any stress that lies along one of the symmetry axes. Specifically, the stress is directly proportional to the relative velocity difference through the equation -,--V ik=---V. -=ki) ( I) cr. = 2G (-V ~ ik where cr. is the stress in the direction i, G is the shear modulus and Vik is the ~elocity of an SH wave propagating in the i direction and polarized in the k direction. This rather simple relationship is particularly useful because the constant of proportionality involves only the well known shear modulus and the velocity term can be measured directly by observing the transit time shift when a transmitter-receiver pair of SH wave transducers are rotated through 90 degrees on the surface of the part. Experimentally, Equation (I) was tested on the web of railroad rails which had been loaded by a 200,000 pound mechanical testing machine {I}. The method of exciting and detecting the necessary surface skimming SH waves used electromagnetic acoustic transducers (EMATs) that operated through a magnetostrictive mechanism at high magnetic fields {4}. Wave velocities parallel and perpendicular to the axis of the rail on the web differed by the amount predicted by Equation (I) to an absolute accuracy of 30 percent in the worst case.

Advanced welding processes provides an excellent introductory review of the range of welding technologies available to the structural and mechanical engineer. The book begins by discussing general topics such power sources, filler materials and gases used in advanced welding. A central group of chapters then assesses the main welding techniques: gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), high energy density processes and narrow-gap welding techniques. Two final chapters review process control, automation and robotics. Advanced welding processes is an invaluable guide to selecting the best welding technology for mechanical and structural engineers. An essential guide to selecting the best welding technology for mechanical and structural engineers Provides an excellent introductory review of welding technologies Topics include gas metal arc welding, laser welding and narrow gap welding methods