Ambient Temperature Temperbead Welding Using the Underwater Laser Beam Welding Process

2010 ◽  
Author(s):  
Bruce Newton
Keyword(s):  
Laser Beam ◽  
Ambient Temperature ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Nuclear Industry ◽  
High Quality ◽  
Gas Tungsten Arc ◽  
Class 1 ◽  
Gtaw Process ◽  
Underwater Laser

Ambient temperature temperbead welding using the Machine Gas Tungsten Arc Welding (GTAW) process is widely accepted in the nuclear industry. GTAW machine ambient temperature temperbead welding, addressed in ASME Code Case N-638, has been used to repair ASME Class 1 components in numerous safety related applications. Underwater laser beam welding (ULBW) is gaining increasing industry recognition as a method for producing high quality welds in high radiation environments. Since ULBW enables high quality weld deposition in underwater environments, the process enables water to serve as a radiation moderator, reducing personnel exposure levels. ULBW’s advantages go beyond radiation exposure reductions, and this paper will provide the reader a better understanding of the ULBW process’s capabilities and properties. A recently formed ASME Task Group is preparing a new Code Case that will delineate specific requirements and essential variables governing use of ULBW to repair ASME Class 1 components. In addition, this Code Case will provide specific rules for use of the ULBW process for ambient temperature temperbead welding. Extensive testing has been performed to demonstrate ULBW’s capabilities with regard to ambient temperature temperbead welding in an underwater environment, and this paper summarizes testing and test results. It also provides a technical summary of the new Code Case, it’s requirements, and summarizes several of the bases for these requirements.

Dissimilar and Similar Laser Beam and GTA Welding of Nuclear Fuel Pin Cladding Tube to End Plug Joint

2017 ◽  
Vol 24 ◽  
pp. 40-47
Author(s):  
Aravind Murugan ◽  
R. Sai Santhosh ◽  
Ravikumar Raju ◽  
A.K. Lakshminarayanan ◽  
Shaju K. Albert
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
High Energy ◽  
Optical Microscope ◽  
High Energy Density ◽  
Fuel Pin ◽  
Gtaw Process ◽  
Welding Processes

The end plug to cladding tube of fast reactor fuel pin is normally welded using Gas Tungsten Arc Welding (GTAW) process. The GTAW process has large heat input and wide heat-affected-zone (HAZ) than high energy density process such as laser welding. In the present study Laser Beam Welding (LBW) is being considered as an alternative welding process to join end plug to clad tube. The characteristics of autogenous processes such as GTAW and pulsed Nd-YAG laser welding on fuel cladding tube to end plug joints have been investigated in this study. Dissimilar combinations of modified stainless steel (SS) alloy D9 cladding tube to SS316L end plug, and similar combinations of SS316L cladding tube to SS316L end plug were successfully welded using the above two welding processes. The laser welding was performed at the butting surfaces of the cladding tube and the end plug, and also by shifting the laser beam by 0.2 mm towards the end plug side to compensate the heat balance and for improving the Creq/Nieq ratio in the molten pool. Helium Leak Test (HLT) and Radiography Test (RT) were carried out to validate the quality of the welds. The microstructures of the weld joints were analysed using optical microscope. In the present study, it has been demonstrated that it is possible to obtain welds free from hot cracks by shifting the laser beam by 0.2 mm towards end plug side, while the weld produced using the beam positioned at the interface shows cracks in the weld.

scholarly journals Spectroscopic closed loop control of penetration depth in laser beam welding process

2012 ◽  
Author(s):  
Teresa Sibillano ◽  
Antonio Ancona ◽  
Domenico Rizzi ◽  
Francesco Mezzapesa ◽  
Ali Riza Konuk ◽  
...  
Keyword(s):  
Laser Beam ◽  
Penetration Depth ◽  
Closed Loop ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Closed Loop Control ◽  
Loop Control

scholarly journals Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets

2018 ◽  
Author(s):  
Iñigo Hernando ◽  
Jon Iñaki Arrizubieta ◽  
Aitzol Lamikiz ◽  
Eneko Ukar
Keyword(s):  
Numerical Model ◽  
Laser Beam ◽  
Inconel 718 ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Bead Geometry ◽  
Predictive Tool ◽  
Melt Pool ◽  
Dendritic Arm Spacing ◽  
Weld Seams

A numerical model was developed for predicting the bead geometry and microstructure in Laser Beam Welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams and a specific tooling was manufactured for supplying protective Argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features as bead upper and bottom final shapes, weld penetration and dendritic arm spacing were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.

scholarly journals Hybrid laser-arc welding of laser- and plasma-cut 20-mm-thick structural steels

2022 ◽  
Author(s):  
Ömer Üstündağ ◽  
Nasim Bakir ◽  
Sergej Gook ◽  
Andrey Gumenyuk ◽  
Michael Rethmeier
Keyword(s):  
Laser Beam ◽  
Arc Welding ◽  
Laser Beam Welding ◽  
Digital Camera ◽  
Welding Process ◽  
Beam Power ◽  
Beam Diameter ◽  
Hybrid Laser Arc Welding ◽  
Single Pass ◽  
New Findings

AbstractIt is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.

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