scholarly journals A study on use of wobble features in laser welding of low alloy steel joint with butt joint configuration

2021 ◽  
Vol 1135 (1) ◽  
pp. 012021
Author(s):  
Timo Kankala ◽  
Antti Salminen
Keyword(s):  
Laser Welding ◽  
Focal Point ◽  
Beam Quality ◽  
Welding Process ◽  
Butt Joint ◽  
Air Gap ◽  
Low Alloyed Steel ◽  
Tool Diameter ◽  
Welding Processes ◽  
Beam Manipulation

Abstract Laser welding is modern digital welding process, which thanks to several advantages over traditional welding processes, is gaining ever growing role in manufacturing. The process has still some weaknesses. The better the beam quality the smaller the focal point, the actual welding tool, diameter is. Typically, because of this the welding of joints with lesser quality e.g. larger air gap is difficult or even impossible. So-called beam manipulation opens opportunities to deal with the problem. The dynamic beam manipulation gives opportunities to control the weld dimensions during the welding process by the requirements of individual locations of weld joint. This study used the two dimensional scanner to manipulate beam during welding with so called wobble function. Four different wobble configurations were tested in welding of low-alloyed steel with different joint qualities. The wobble typically made the welds wider, provided typically higher heat input and thus lowered the hardness of the joint. Wobble increased typically the root quality, but there are differences between different wobble parameters. It was possible to weld joints with wider air gaps in the selected material thickness, but the wider air gap and wobble caused finally, when wide enough the sagging of the joint.

The characteristics of high power fibre laser welding

2010 ◽  
Vol 224 (5) ◽  
pp. 1019-1029 ◽  
Author(s):  
A Salminen ◽  
H Piili ◽  
T Purtonen
Keyword(s):  
Laser Welding ◽  
High Power ◽  
Focal Point ◽  
Beam Quality ◽  
Welding Process ◽  
High Energy ◽  
High Energy Density ◽  
Fibre Laser ◽  
Line Energy ◽  
Laser Welding Process

Laser welding has an ever growing role in manufacturing technology. Keyhole laser welding is the most important laser welding process in metal industry when exceeding the 1 mm weld penetration. This process uses efficiently the high energy density of a laser beam to vaporize and melt materials, thus producing a keyhole in the material via which the energy is brought to it. The requirements from customer side and the development of new materials have been giving justification for the development of new laser types suitable for material processing with ever higher power values. In contrast, the development of laser technologies has made it possible to build more powerful lasers with excellent beam properties and good electrical efficiency. New laser sources with good absorption and beam quality make the laser welding even more efficient when throughput and efficiency are considered. They show their ability to produce narrower welds with lower line energy. However, the validation of actual keyhole shape, size, and behaviour against the models is still lacking because of the difficulties in performing the measurements of the actual dimensions. It has been shown that the better the beam quality the higher the welding speed. When welding with high power, good beam quality, and wavelength close to 1000 nm, there are some obstacles to overcome, which are caused by high absorption and power density. Typically, problems, such as thermal lensing, can be avoided with proper parameter and tool selection. Typically, the size of the keyhole is according to the focal point size, and the stability of the keyhole plays a major role when considering the ability of the laser welding process to produce high quality welds.

scholarly journals The Welding Processes of Rolled Homogeneous Armour Steel

2019 ◽  
Vol 9 (2S2) ◽  
pp. 361-366
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Arc Welding ◽  
Focal Point ◽  
Welding Process ◽  
Butt Joint ◽  
Vehicle Body ◽  
Flux Cored Arc Welding ◽  
Welding Processes ◽  
Armour Steel

Rolled Homogeneous Armour (RHA) steel is known as protective steel and it is utilized in a military vehicle, For example tanks, howitzers, heavily clad battle vehicles just as developments in armament. Weld quality straight forwardly decides the entire mechanical properties of the protective steel in vehicle body structures. Hybrid Optical Maser Arc welding (HOMAW) has a decent mechanical property and focal point of this exploration is considered to recover more energy than laser and Metal Active Gas Welding (MAGW) process. Manual Metal Arc Welding (MMAW) with low hydrogen ferritic filler (LHF) which performs better weldability on Armour steels with comparing MMAW with Austenitic stainless steel (ASS), and Flux cored arc welding (FCAW) with ASS/LHF. MMAW procedure is considered to reduce the expense through LHF consumable in workplace. The examination of MAGW method, a welding fringe of 54o V-narrow cut geometry has better mechanical property for tensile strength and also the welding narrow cut point of 48o X-trench cut geometry has better solution for compression strength of butt-joint Armour steel. This survey was embraced to grant a top-level view of the various categories of welding process and mechanical properties in welding of RHA steels.

Microstructure and mechanical property improvement of dissimilar metal joints for TC4 Ti alloy to Nitinol NiTi alloy by laser welding

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yan Zhang ◽  
DeShui Yu ◽  
JianPing Zhou ◽  
DaQian Sun ◽  
HongMei Li
Keyword(s):  
Tensile Strength ◽  
Laser Welding ◽  
Mechanical Performance ◽  
Niti Alloy ◽  
Welding Process ◽  
Ti Alloy ◽  
The One ◽  
Fusion Weld ◽  
Welding Processes ◽  
Cu Interlayer

Abstract To avoid the formation of Ti-Ni intermetallics in a joint, three laser welding processes for Ti alloy–NiTi alloy joints were introduced. Sample A was formed while a laser acted at the Ti alloy–NiTi alloy interface, and the joint fractured along the weld centre line immediately after welding without filler metal. Sample B was formed while the laser acted on a Cu interlayer. The average tensile strength of sample B was 216 MPa. Sample C was formed while the laser acted 1.2 mm on the Ti alloy side. The one-pass welding process involved the creation of a joint with one fusion weld and one diffusion weld separated by the remaining unmelted Ti alloy. The mechanical performance of sample C was determined by the diffusion weld formed at the Ti alloy–NiTi alloy interface with a tensile strength of 256 MPa.

scholarly journals Laser Welding of Titanium Alloys with an Yb: YAG Disk Source

2018 ◽  
Vol 941 ◽  
pp. 845-850 ◽  
Author(s):  
Jean Denis Beguin ◽  
V. Gazagne ◽  
Yannick Balcaen ◽  
Joel Alexis ◽  
Eric Andrieu
Keyword(s):  
Laser Welding ◽  
Fiber Type ◽  
Beam Quality ◽  
Butt Joint ◽  
Bead Geometry ◽  
Test Results ◽  
Full Penetration ◽  
Α Phase ◽  
Core Fiber ◽  
Cp Ti

In this paper, the laser welding of thin titanium sheet in a butt joint configuration are investigated using a continuous Yb: YAG disk source, with high beam quality and a particular fiber configuration, enable to provide a broad range of beam diameters with different intensity distribution. The thermal efficiency of the laser process is discussed as a function of the fiber type. The weldability results for the CP Ti grade 2 and the Ti-6Al-4V titanium alloy are expressed in terms of full penetration, and correct bead geometry (NF L06-395-2000). Full penetration welds are easily achieved with the core fiber, but the outer fiber produces welds with limited geometric defects. Butt joints microstructure consists of an acicular α phase in the fusion zone for CP Ti, and a martensitic α’ phase for the Ti-6Al-4V alloy. Tensile test results confirm a similar or slightly higher joint strength for the full penetration welds, compared with the parent metal.

Application of Electromagnetic Force in Laser Welding

2007 ◽  
Author(s):  
J. Zhou ◽  
H. L. Tsai
Keyword(s):  
Laser Welding ◽  
Electromagnetic Force ◽  
Solid Phase ◽  
Numerical Models ◽  
Metal Flow ◽  
Welding Process ◽  
Weld Bead ◽  
Electromagnetic Forces ◽  
Laser Welds ◽  
Welding Processes

In recent years, lasers have been widely used in the welding processes for automotive, aerospace, electrical and heavy manufacturing industries due to their high power density, small heat-affected zone and high productivity. Especially, with high depth-to-width ratio and high welding efficiency, keyhole-mode laser welding is more promising compared to the conventional welding processes. However, a number of defects, such as porosity, irregular beads, undercut and humping are frequently observed in laser welds, which deteriorates the strength and quality of the welded parts. In current study, an externally controllable electromagnetic force is introduced into the laser welding process to prevent porosity formation and to control weld bead shape. Numerical models are developed to study the transport phenomena in laser welding and to accurately calculate the current density and magnetic flux fields and the resulting electromagnetic forces in three-dimensional weldments. Effects of the electromagnetic force on metal flow, heat and mass transfer and weld bead shape are investigated. The continuum model is used to handle the entire domain including solid phase, liquid phase and mush zone. The enthalpy method is employed to handle the absorption and release of latent heat during melting and solidification. Inverse Bremsstrahlung (IB) absorption, Fresnel absorption and multiple reflections of laser beam energy at the keyhole walls are considered for the study of laser-plasma interaction. Volume of Fluid (VOF) technique is adopted to calculate the free surface evolution in the computation. As indicated by this study, porosity-free laser welds with desired bead shapes can be achieved with appropriate applications of electromagnetic forces.

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.

Investigation on Porosity Content in 2024 Aluminum Alloy Welding by Yb:YAG Disk Laser

2011 ◽  
Vol 383-390 ◽  
pp. 6265-6269 ◽  
Author(s):  
V. Alfieri ◽  
F. Cardaropoli ◽  
F. Caiazzo ◽  
V. Sergi
Keyword(s):  
Aluminum Alloy ◽  
Laser Welding ◽  
Beam Quality ◽  
Welding Process ◽  
Porosity Formation ◽  
2024 Aluminum Alloy ◽  
Disk Laser ◽  
Aluminum Alloy 2024 ◽  
Slab Lasers

Aluminum alloy 2024 is extensively used in automotive and aerospace industries, but its application is limited due to the susceptibility to generate porosity during the welding process. Nevertheless, benefits from laser welding are clearly demonstrated. In addition, the use of a disk laser allows to obtain significant reduction in focus diameter and increased beam quality compared to traditional rod or slab lasers. The aim of the work is to discuss porosity formation as influenced by the thermal input provided, so bead-on-plate specimens in different conditions have been prepared. Porosity content is examined in relation to the fused zone extent and discussed considering interaction between laser and material. Higher thermal inputs are beneficial in full penetrative welds.

scholarly journals NUMERICAL STUDY OF THE TEMPERATURE FIELD FOR Fe3Al LASER WELDING

2021 ◽  
Vol 55 (3) ◽  
Author(s):  
Josef Bradáč ◽  
Jiří Hozman ◽  
Jan Lamač
Keyword(s):  
Temperature Field ◽  
Laser Welding ◽  
Numerical Scheme ◽  
Numerical Study ◽  
Welding Process ◽  
Beam Power ◽  
Welding Parameters ◽  
Original Experiment ◽  
Butt Weld ◽  
Welding Processes

The main objective of this paper was focused on a numerical study related to a proper evaluation of the temperature field during the laser-welding process. The investigated material used for the experiments was Fe3Al, given its properties and promising application potential. The original experiment was based on a 3D model of a butt weld. However, to reduce the computational complexity, a planar variant of the heat-transfer equation with suitable choices of surface and volumetric heat sources, given by modified Gaussian pulses, is used to model the temperature distribution in the fixed cross cut during the laser welding. Subsequently, the numerical scheme based on the discontinuous Galerkin method was employed to evaluate the temperature field more properly and to identify the main characteristics of the molten zone. Finally, the numerical study was performed for various combinations of the welding parameters, such as laser-beam power and welding speed. The obtained results were in good agreement with the expected behavior, and thus illustrate the optimization potential of the proposed numerical scheme in the similar issues of a laser-welding processes.

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