Fatigue Behaviour of Laser Beam Welded Circular Weld Seams under Multi-Axial Loading

2014 ◽  
Vol 891-892 ◽  
pp. 1397-1402 ◽  
Author(s):  
Martina Zimmermann ◽  
Jörg Bretschneider ◽  
Gunter Kirchhoff ◽  
Uwe Stamm ◽  
Jens Standfuss ◽  
...  
Keyword(s):  
Cast Iron ◽  
Laser Beam ◽  
Welding Process ◽  
Axial Loading ◽  
Fatigue Behaviour ◽  
Test System ◽  
Cyclic Strength ◽  
Hardened Steel ◽  
Torsional Loading ◽  
Welding Processes

With modern laser beam sources welding processes can be developed, that allow the joining of otherwise barely realisable material and geometrical constellations such as dissimilar welded, thick-walled shaft-hub joints for powertrain systems. Current design recommendations do not offer solutions to account for the cyclic strength under torsional loading for welded structures. In order to bridge the gap between cost and time consuming prototype testing and laboratory tests of basic homogeneous material samples, a test system combining axial and torsional loading was used. For this purpose application oriented test parts are designed to mimic the weld seam geometry, stiffness and heat dissipation conditions of the real structural part at its best. The dissimilar joints were realised for two material combinations: cast iron GJS-600-3 with case hardened steel 16MnCr5 and 42CrMo4 with 16MnCr5. The latter combination showed only a slightly higher cyclic strength compared to the cast iron/steel combination. A systematic optimization of the laser beam welding process leads to a fatigue behaviour under multi-axial loading conditions, where the cast iron/case hardened steel combination still met the strength specification required.

Evaluation of High Penetration Hybrid Laser-GMAW Welding Process Productivity Applied in the Joining of Thick Plates and Pipelines

2022 ◽  
Author(s):  
Rafael Gomes Nunes Silva ◽  
Max Baranenko Rodrigues ◽  
Milton Pereira ◽  
Koen Faes
Keyword(s):  
Laser Beam ◽  
Arc Welding ◽  
Manufacturing Industry ◽  
Operating Time ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Major Influence ◽  
Thick Plates ◽  
High Penetration ◽  
Welding Processes

Abstract Welding processes are present in all sectors of the industry, highlighting the manufacturing industry of thick plates and pipelines. In these applications, welding processes have a major influence on costs, schedules, risk analysis and project feasibility. Conventional arc welding processes, such as the gas metal arc welding (GMAW) process, have limitations when applied to high thickness joints due to their maximum achievable penetration depth. On the other hand, the laser beam welding (LBW) welding process, despite reaching high penetration depths, has several limitations mainly regarding the geometric tolerance of the joint. In this regard, the hybrid laser-arc welding (HLAW) process emerges as a promising bonding process, combining the advantages of the GMAW and LBW processes into a single melting pool. Despite the many operational and metallurgical advantages, the HLAW process presents a high complexity due to the high number of parameters involved and the interaction between the laser beam and the electric arc. The present work discusses the challenges involved in the parametrization of the HLAW process applied to the joining of thick plates and pipes, and empirically evaluated a comparison between the HLAW and GMAW processes, showing a reduction of operating time of approximately 40 times, and a reduction of consumption of shielding gas and filler material of approximately 20 times, evidencing the technical and financial contribution of the hybrid process.

Hybrid realization of fillet weld

2018 ◽  
Vol 37 (4) ◽  
pp. 1315-1327 ◽  
Author(s):  
Václav Kotlan ◽  
Roman Hamar ◽  
Lenka Šroubová ◽  
Ivo Doležel
Keyword(s):  
Laser Beam ◽  
Welding Process ◽  
Physical Parameters ◽  
Additional Material ◽  
Content Type ◽  
Heating And Cooling ◽  
Proposed Model ◽  
Materials Used ◽  
Physical Phenomena ◽  
Welding Processes

Purpose A model of hybrid fillet welding is built and solved. No additional material (welding rod, etc.) is used. Heating of the welded parts is realized by laser beam with induction preheating and/or postheating. The purpose of these operations is to reduce the temperature gradient in welded parts in the course of both heating and cooling, which reduces the resultant hardness of the weld and its neighborhood and also reduces undesirable internal mechanical strains and stresses in material. Design/methodology/approach The complete mathematical model of the combined welding process is presented, taking into account all relevant nonlinearities. The model is then solved numerically by the finite element method. The methodology is illustrated with an example, the results of which are compared with experiment. Findings The proposed model provided satisfactory results even when some subtle phenomena were not taken into account (flow of melt in the pool after irradiation of the laser beam driven by the buoyancy and gravitational forces and evaporation of molten metal and influence of plasma cloud above the irradiated spot). Research limitations/implications Accuracy of the results depends on the accuracy of physical parameters of materials entering the model and their temperature dependencies. These quantities are functions of chemical composition of the materials used, and may more or less differ from the values delivered by manufacturers. Also, the above subtle physical phenomena exhibit stochastic character and their modeling may be accompanied by non-negligible uncertainties. Practical implications The presented model and methodology of its solution may represent a basis for design of welding processes in various branches of industry. Originality/value The model of a complex multiphysics problem (induction-assisted laser welding) provides reasonable results confirmed by experiments.

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.

Influence of Surface Structured Filler Wires on Laser Beam Welding of Copper Alloys

2015 ◽  
Vol 805 ◽  
pp. 171-179 ◽  
Author(s):  
Vincent Mann ◽  
Fabian Gärtner ◽  
Florian Hugger ◽  
Konstantin Hofmann ◽  
Felix Tenner ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Laser Beam ◽  
Weld Seam ◽  
Copper Alloys ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Industrial Applications ◽  
Additional Amount ◽  
Infrared Wavelengths ◽  
Welding Processes

Compared to steel, the required amount of energy for conventional welding of copper is higher, due to its higher thermal conductivity. This problem is mainly solved by preheating the work pieces or welding processes with high intensities such as laser beam welding. As the absorption of copper for infrared wavelengths, which are commonly used in industrial applications today, is typically low, the energy efficiency of the laser welding process is low. Besides this, if filler wires are used in order to increase the bridgeable width of joining gaps, the energy consumption of the process is further increased due to the additional amount of energy required to melt the filler material.As roughened surfaces of copper parts are known to increase absorption and consequently energy efficiency of laser beam welding without filler wires, this paper investigates the influence of surface structured filler wires on laser beam welding of copper alloys. Thus, the correlation between knurling geometries, absorption, molten volume and the welding result is investigated. For this reason, the welding result is evaluated by means of geometrical, electrical and mechanical weld seam properties e.g. seam width, weld reinforcement, area of cross-section, electrical resistance, tensile strength and strain.

Analysis of Laser and Resistance Spot Weldments on Press-Hardened Steel

2011 ◽  
Vol 695 ◽  
pp. 202-205 ◽  
Author(s):  
Min Jung Kang ◽  
Cheol Hee Kim
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Simulation Models ◽  
High Strength ◽  
Hardened Steel ◽  
Forming Process ◽  
Resistance Spot ◽  
Mechanical Models ◽  
Welding Processes

For the manufacture of safe, lightweight vehicles, the demand for ultra-high-strength steel in the automotive industry is increasing. Although transformation-induced plasticity (TRIP) and dual-phase (DP) steels have a strength of under 1 GPa, boron-alloyed steel produced using the hot press forming process has a strength of more than 1500 MPa. Laser and resistance spot welding processes are used to join press-hardened steel, but the characteristics of the resulting weldments are not yet fully understood. In this study, the thermal cycles for both welding processes were investigated using finite element (FE) analysis. Resistance spot welding was analyzed using a combination of thermal, electric, and mechanical models, whereas the thermal behavior of laser welding was predicted using only a thermal model. The calculated bead shapes were compared with experimentally measured ones to validate the simulation models. The mechanical and metallurgical characteristics of the weldments were explained using the thermal history of each welding process.

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive 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.

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