Dual Process Welding of Steel Plate

2002 ◽  
Author(s):  
Clint Wildash ◽  
Steve Webster
Keyword(s):  
Laser Welding ◽  
Weld Pool ◽  
Welding Speed ◽  
Welded Joint ◽  
Laser Beam Welding ◽  
Dual Process ◽  
Dual Processing ◽  
Laser Weld ◽  
Stage 1 ◽  
Welding Processes

Large scale fabrication and welding industries, such as those involved in offshore construction, are continuously striving to improve productivity, while maintaining quality levels required by the applicable design codes and standards. To achieve this, new improved welding technologies are regularly being evaluated. One area of development is to combine different welding processes to produce a welded joint exhibiting properties and productivity benefits that neither process could achieve individually. One promising combination is the use of both arc and laser beam welding for products such as pipeline. The welding procedure development work described, was carried out in two stages. Stage 1 (discrete dual processing) investigated the production of a welded joint using both arc and laser welding at separate times. The welds produced for this work, demonstrate that significant increases in welding speed are achievable in comparison to using either process individually. Stage 2 (simultaneous dual processing) investigated arc and laser welding of the joint at the same time from opposing plate faces, with the laser weld pool trailing the arc weld pool so that the former was positioned in the area of highest preheat temperature. The use of arc preheat significantly reduced the hardness of the laser welds to more acceptable levels. The main disadvantage identified for both stages of work was that fit up of the laser welded part of the joint needed to be good to accommodate the autogenous laser weld. Both Stages were shown to be capable of producing full penetration welds at higher productivity than using either process individually. It has been demonstrated that for 19 mm thick plate, an overall doubling of welding speed could be achieved using dual process as opposed to submerged arc welding, which is currently widely used to weld fabricated products such as pipeline. Future work to be carried will include extensive destructive testing on the welds to assess the benefits of Stage 1 and 2, which will be reported in another paper.

scholarly journals Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle

2020 ◽  
Vol 326 ◽  
pp. 08005
Author(s):  
Mete Demirorer ◽  
Wojciech Suder ◽  
Supriyo Ganguly ◽  
Simon Hogg ◽  
Hassam Naeem
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Input ◽  
Thermal Cycle ◽  
Laser Beam Welding ◽  
Base Material ◽  
High Strength ◽  
Cooling Rates ◽  
Aa 2024 ◽  
Welding Processes

An innovative process design, to avoid thermal degradation during autogenous fusion welding of high strength AA 2024-T4 alloy, based on laser beam welding, is being developed. A series of instrumented laser welds in 2 mm thick AA 2024-T4 alloys were made with different processing conditions resulting in different thermal profiles and cooling rates. The welds were examined under SEM, TEM and LOM, and subjected to micro-hardness examination. This allowed us to understand the influence of cooling rate, peak temperature, and thermal cycle on the growth of precipitates, and related degradation in the weld and heat affected area, evident as softening. Although laser beam welding allows significant reduction of heat input, and higher cooling rates, as compared to other high heat input welding processes, this was found insufficient to completely supress coarsening of precipitate in HAZ. To understand the required range of thermal cycles, additional dilatometry tests were carried out using the same base material to understand the time-temperature relationship of precipitate formation. The results were used to design a novel laser welding process with enhanced cooling, such as with copper backing bar and cryogenic cooling.

Determination of Heat Input in Tungsten Inert Gas and Laser Welding of Type Optim 960 QC Structural Steel Using Adams’ Equation for 2-D Heat Distribution

2017 ◽  
Vol 750 ◽  
pp. 45-52
Author(s):  
Sveto Cvetkovski
Keyword(s):  
Laser Welding ◽  
Heat Input ◽  
Arc Welding ◽  
Research Work ◽  
Laser Beam Welding ◽  
Peak Temperature ◽  
Efficiency Coefficient ◽  
Zone Recrystallization ◽  
Welding Processes

The heat input during conventional arc welding processes can be readily calculated knowing the power taken from the power source. The efficiency coefficient can be taken from the appropriate literature standards. Here, the intention of the performed research work was to develop a procedure for determination of heat input in arc and laser welding processes implementing Adams equation - modified Rykalin equation for two dimensional heat distributions (2-D). To realize this idea, it is necessary to determine two characteristic temperatures points in the HAZ with known peak temperature, and to determine distance between them. Implementing measured values for distance in Adams’ equation, heat input in arc welding can be directly determined in arc welded joints.In laser beam welding, the absorption of the beam in the metal is not known, so that the welding heat input cannot be calculated directly, and direct implementation of Adam’s equation is not possible i.e. absorption coefficient has to be determined first, and after that calculation of heat input is possible.The peak temperatures corresponding to specific microstructures can be obtained by performing welding simulation, by the Gleeble 1500 simulator in our case. As one of the peak temperatures, the melting temperature can be used corresponding to the fusion line, so that at least one characteristic peak temperature such as coarse grain zone, fine grin zone, intercritical zone, recrystallization, has to be determined by the simulation.Performed research showed that obtained values for heat input using Adam’s equation correspond pretty well with standard equation for heat input in arc welding.

Numerical Analysis of Solidification Behavior during Laser Welding Nickel-Based Single-Crystal Superalloy Part: II Crystallography-Dependent Supersaturation of Liquid Aluminum

2021 ◽  
Vol 1018 ◽  
pp. 13-22
Author(s):  
Zhi Guo Gao
Keyword(s):  
Laser Welding ◽  
Single Crystal ◽  
Weld Pool ◽  
Welding Speed ◽  
Heat Input ◽  
Laser Power ◽  
Liquid Aluminum ◽  
Dendrite Growth ◽  
Solidification Cracking ◽  
Solid Liquid Interface

The thermal metallurgical modeling of liquid aluminum supersaturation was further developed through couple of heat transfer model, dendrite selection model, multicomponent dendrite growth model and nonequilibrium solidification model during three-dimensional nickel-based single-crystal superalloy weld pool solidification. The welding configuration plays more important role in supersaturation of liquid aluminum, morphology instability and nonequilibrium partition behavior. The bimodal distribution of liquid aluminum supersaturation along the solid/liquid interface is crystallographically symmetrical about the weld pool centerline in (001) and [100] welding configuration. The distribution of liquid aluminum supersaturation along the solid/liquid interface is crystallographically asymmetrical throughout the weld pool in (001) and [110] welding configuration. Optimum low heat input (low laser power and high welding speed) with (001) and [100] welding configuration is more favored to predominantly promote epitaxial [001] dendrite growth to reduce the metallurgical factors for solidification cracking than that of high heat input (high laser power and slow welding speed) with (001) and [110] welding configuration. The lower the heat input is used, the lower supersaturation of liquid aluminum is imposed, and the smaller size of vulnerable [100] dendrite growth region is incurred to ameliorate solidification cracking susceptibility and vice versa. The overall supersaturation of liquid aluminum in (001) and [100] welding configuration is beneficially smaller than that of (001) and [110] welding configuration regardless of heat input, and is not thermodynamically relieved by gamma prime γˊ phase. (001) and [110] welding configuration is detrimental to weldability and deteriorates the solidification cracking susceptibility because of unfavorable crystallographic orientations and alloying aluminum enrichment. The mechanism of asymmetrical solidification cracking because of crystallography-dependent supersaturation of liquid aluminum is proposed. The eligible solidification cracking location is particularly confined in [100] dendrite growth region. Moreover, the theoretical predictions agree well with the experiment results. The useful modeling is also applicable to other single-crystal superalloys with similar metallurgical properties for laser welding or laser cladding. The thorough numerical analyses facilitate the understanding of weld pool solidification behavior, microstructure development and solidification cracking phenomena in the primary γ phase, and thereby optimize the welding conditions (laser power, welding speed and welding configuration) for successful crack-free laser welding.

scholarly journals Reduced finite-volume model for the fast numerical calculation of the fluid flow in the melt pool in laser beam welding

2021 ◽  
Vol 1135 (1) ◽  
pp. 012010
Author(s):  
Jonas Wagner ◽  
Peter Berger ◽  
Philipp He ◽  
Florian Fetzer ◽  
Rudolf Weber ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Laser Beam ◽  
Finite Volume ◽  
Weld Pool ◽  
Welding Speed ◽  
Laser Beam Welding ◽  
Melt Flow ◽  
Finite Volume Model ◽  
Volume Model ◽  
Weld Pool Geometry

Abstract In this paper we propose a reduced two-dimensional finite-volume model for the fast calculation of the melt flow. This model was used to determine the influence of the welding speed, viscosity in the melt and vapour flow inside of the keyhole on the fluid flow field, the temperature distribution, and the resulting weld-pool geometry for laser beam welding of aluminium. The reduced computational time resulting from this approach allows the fast qualitative investigation of different aspects of the melt flow over a wide range of parameters. It was found that the effect of viscosity within the melt is more pronounced for lower welding speeds whereas the effect of friction at the keyhole walls is more pronounced for higher welding speeds. The weld-pool geometry mainly depends on the welding speed.

scholarly journals Real time control of curved laser welding processes by cellular neural networks (CNN): first results

2010 ◽  
Vol 8 ◽  
pp. 117-122 ◽  
Author(s):  
L. Nicolosi ◽  
R. Tetzlaff
Keyword(s):  
Control System ◽  
Laser Welding ◽  
Real Time ◽  
Laser Beam Welding ◽  
Recent Analysis ◽  
Feedback Signal ◽  
Real Time Control ◽  
Loop Control ◽  
Time Control ◽  
Welding Processes

Abstract. In the last decades the laser beam welding (LBW) has outclassed older welding techniques in the industrial scenario. Despite the improvement in welding technology, sophisticated methods of fault detection are not commonly used in commercially available equipments yet. A recent analysis of process images have revealed the possibility to build up a real time closed loop control system. By the use of image based quality features, a feedback signal can be provided to maintain the process in the desired state. The development of the presented visual control system has been focused on the adjustment of the laser power according to the detection of the so called full penetration hole. Due to the high dynamics of the laser welding, a fast real time image processing with controlling rates in the multi kilo Hertz range is necessary to have a robust feedback control. In this paper an algorithm for the real time control of welding processes is described. It has been implemented on the Eye-RIS v1.2, a visual system which mounts a cellular structure. By applying this algorithm in real time applications, controlling rates of about 7 kHz can be reached. In the following some real time control results are also described.

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.

On the issue of selecting and optimizing parameters of continuous laser welding of cast iron

2021 ◽  
Vol 23 (3) ◽  
pp. 20-30
Author(s):  
Dmitry Ilyushkin ◽  
◽  
Valery Soldatov ◽  
Oleg Petrakov ◽  
Irina Kotlyarova ◽  
...  
Keyword(s):  
Cast Iron ◽  
Laser Welding ◽  
Weld Pool ◽  
Process Parameters ◽  
Welding Speed ◽  
Optimization Problem ◽  
Radiation Power ◽  
Geometric Parameters ◽  
Continuous Laser ◽  
Passive Experiment

Introduction. Cast iron extremely poorly tolerate thermal welding cycles, and therefore it is necessary to choose carefully the technological parameters. The main parameters of continuous laser welding are: the power of laser radiation, the welding speed, the parameters of the focusing system. The aim of the work is to determine the optimal power and speed of continuous laser welding of cast iron, depending on the geometry of the weld. In this paper, the welding seams obtained on samples of gray alloyed cast iron with a pearlitic metal base, using an LS-1 ytterbium fiber laser, are studied. Research methods. The geometric parameters of the joints were quantified in the program for quantitative analysis and image processing ImageJ. The obtained data were processed by regression analysis. To optimize the process parameters, an orthogonal plan of the passive experiment was developed, including nine experiments in which the factors varied at three equally spaced levels. The quality parameters in the passive experiment were the geometric dimensions of the weld pool and the size of the quenched zone. To solve the optimization problem, we used the methods of gray relational analysis and linear programming. Results and Discussions. The obtained regression models explain a significant proportion of the variance of the dependent variables, the regression coefficients, as well as the models themselves, are statistically significant, which indicates a close linear relationship between the seam geometry and the process parameters. The calculated shape of the weld pool depending on the radiation power and welding speed shows that the required welding seam of the required dimensions can be obtained at various process parameters which allow solving a multi-criteria optimization problem. The gray relational evaluation of the geometric parameters of the seam shows that the most correct parameters in terms of obtaining the seam of the maximum depth with the minimum width, convexity (concavity) and the quenched zone are the minimum power and maximum welding speed. The calculation of the optimal radiation power and welding speed depending on the seam depth showed that welding of small thicknesses is optimally carried out with minimal power, and the seam depth is adjusted by changing the beam speed. Welding of large thicknesses is optimal at high speed, and to increase the depth of the seam, the power must increase.

Effect of Welding Speed on CO2 Laser Beam Welded Aluminum-Magnesium Alloy 5083 in H321 Condition

2013 ◽  
Vol 685 ◽  
pp. 259-263 ◽  
Author(s):  
K. Subbaiah ◽  
Geetha Manivasagam ◽  
B. Shanmugarajan ◽  
S.R. Koteswara Rao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Laser Beam ◽  
Welding Speed ◽  
Welded Joint ◽  
Laser Beam Welding ◽  
Tensile Tests ◽  
Micro Hardness ◽  
Microstructural Characteristics ◽  
Hardness Tests

Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO2 laser beam welding at 3.5 kW incident power was conducted autogenously on 5 mm thick 5083-H321 aluminum alloy plates at different welding speeds. The mechanical properties and microstructural characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy (SEM). Both yield stress and tensile strength of the laser beam welded joint at the optimum welding speed were 88 % of base metal values. Experimental results indicate that the tensile strength and hardness of laser beam welds are affected by the variation of the intermetallic compounds.

scholarly journals SEM and XRD Characterisation of Fusion Lines Obtained on Austempered Ductile Iron by Laser Beam Welding without Preheating

2021 ◽  
Vol 13(62) (2) ◽  
pp. 1-8
Author(s):  
I.C. MON ◽  
Mircea Horia ȚIEREAN ◽  
Liana Sanda BALTEȘ
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Ductile Iron ◽  
Laser Power ◽  
Laser Beam Welding ◽  
Xrd Analysis ◽  
Austempered Ductile Iron ◽  
Melted Zone

This study highlights the weldability of austempered ductile iron (ADI) using laser welding. SEM, EDS and XRD analysis were performed on fusion lines, heat affected zone (HAZ) and melted zone (MZ). Welding speed (Ws) and laser power (P) were varied. The heat affected zone is composed of graphite, perlite and martensite; the melted and solidified zone contains graphite, ferrite and cementite. XRD results are in accordance with SEM micrographs.

scholarly journals Improvement weldability of dissimilar joints (Ti6Al4V/Al6013) for aerospace industry by Laser beam welding

2021 ◽  
Author(s):  
Anderson C. N. Clayton Nascimento Ribeiro ◽  
Rafael Humberto Mota de Siqueira ◽  
Milton Sergio Fernandes de Lima ◽  
Rafael Arthur Reghine Giorjão ◽  
Antônio Jorge Abdalla
Keyword(s):  
Intermetallic Compound ◽  
Laser Beam ◽  
Heat Input ◽  
Welded Joint ◽  
Aerospace Industry ◽  
Laser Beam Welding ◽  
Intermetallic Compound Layer ◽  
Al Alloy ◽  
Second Phase ◽  
Welding Processes

Abstract The discovery of new metal alloys and the technological advancement in welding processes are key resources for the aerospace industry to obtain cost reduction and better reliability. Thus, welded joints of dissimilar materials such as aluminum and titanium alloys has been explored due to its combined low density and high mechanical performance. Otherwise, welding of dissimilar metals may present deleterious factors to the welded joint as the formation of intermetallic and/or brittle second phase and residual stress. This project investigates the weldability of dissimilar welded joint (Al6013/Ti-6Al-4V) by Laser beam welding. The approach will be done in terms of mechanical properties and microstructural characterization. For this purpose, optimal laser offset from the joint line and the related heat input has been found. It was observed that offset controls the amount of the intermetallic compound layer in the fusion zone. Large pores were observed on the Al side of the weld metal when the offset is zero. The microstructure on the aluminum side consisted of \(\alpha\)-Al grains and the dispersed precipitates. Heat input and offset also influenced in the volumetric fraction of the precipitates. Martensite \({{\alpha }}^{{\prime }}\) and secondary acicular \({\alpha }\) phase was found in the titanium side. Furthermore, intermetallic compound of TiAl base phase such as TiAl, Ti3Al4, and Ti2Al3 was formed. Tensile strength of welded joint was 60% of the Al alloy. In addition, for the same offset and higher heat input, there was an increase in the hardness of the interface.

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