Search results for "In-process"
showing 6 items of 6 documents
Residual stress measurement in innovative friction stir welding processes
2017
In recent years, important innovations have been introduced in Friction Stir Welding (FSW) technology such as, for example, the Laser assisted Friction Stir Welding (LFSW) and in-process Cooled Friction Stir Welding (CFSW). Residual stresses have a fundamental role in welded structures because they affect the way to design the structures, fatigue life, corrosion resistance and many other material properties. Consequently, it is important to investigate the residual stress distribution in FSW where, though the heat input is lower compared to traditional welding techniques, the constraints applied to the parts to weld are more severe. The aim of the present work is to verify the capabilities …
A flexible robotic cell for in-process inspection of multi-pass welds
2020
Welds are currently only inspected after all the passes are complete and after allowing sufficient time for any hydrogen cracking to develop, typically over several days. Any defects introduced between passes are therefore unreported until fully buried, greatly complicating rework and also delaying early corrections to the weld process parameters. In-process inspection can provide early intervention but involves many challenges, including operation at high temperatures with significant gradients affecting acoustic velocities and, hence, beam directions. Reflections from the incomplete parts of the weld would also be flagged as lack-of-fusion defects, requiring the region of interest (ROI) t…
Intentional weld defect process: From manufacturing by robotic welding machine to inspection using TFM phased array
2019
Specimens with intentionally embedded weld defects or flaws can be employed for training, development and research into procedures for mechanical property evaluation and structural integrity assessment. It is critical that the artificial defects are a realistic representation of the flaws produced by welding. Cylindrical holes, which are usually machined after welding, are not realistic enough for our purposes as it is known that they are easier to detect than the naturally occurring imperfections and cracks. Furthermore, it is usually impractical to machine a defect in a location similar to where the real weld defects are found. For example, electro-discharge machining can prod…
In-process calibration of a non-destructive testing system used for in-process inspection of multi-pass welding
2020
Abstract In multi-pass welding, there is increasing motivation to move towards in-process defect detection to enable real-time repair; thus avoiding deposition of more layers over a defective weld pass. All defect detection techniques require a consistent and repeatable approach to calibration to ensure that measured defect sizing is accurate. Conventional approaches to calibration employ fixed test blocks with known defect sizes, however, this methodology can lead to incorrect sizing when considering complex geometries, materials with challenging microstructure, and the significant thermal gradients present in materials during the inter-pass inspection period. To circumvent these challenge…
Structural investigation of crystallized Ge-Ga-Se chalcogenide glasses
2018
H. Klym thanks to the Ministry of Education and Science of Ukraine for support and Dr. P. Demchenko for the assistance in XRD experiments.
Continuous monitoring of an intentionally-manufactured crack using an automated welding and in-process inspection system
2020
Abstract Automated weld deposition coupled with the real-time robotic Non-Destructive Evaluation (NDE) is used in this paper. For performance verification of the in-process inspection system, an intentionally embedded defect, a tungsten rod, is introduced into the multi-pass weld. A partially-filled groove (staircase) sample is also manufactured and ultrasonically tested to calibrate the real-time inspection implemented on all seven layers of the weld which are deposited progressively. The tungsten rod is successfully detected in the real-time NDE of the deposited position. The same robotic inspection system was then used to continuously monitor an intentionally-manufactured crack for 20 h.…