An alternative approach to thermal analysis using inverse problems in aluminum alloy welding

2017 ◽  
Vol 27 (3) ◽  
pp. 561-574 ◽  
Author(s):  
Elisan dos Santos Magalhaes ◽  
Cristiano Pedro da Silva ◽  
Ana Lúcia Fernandes Lima e Silva ◽  
Sandro Metrevelle Marcondes Lima e Silva
Keyword(s):  
Thermal Analysis ◽  
Heat Flux ◽  
Aluminum Alloy ◽  
Inverse Problems ◽  
Welding Process ◽  
Experimental Methodology ◽  
Function Technique ◽  
Content Type ◽  
Radiation Coefficient ◽  
Welding Processes

Purpose The purpose of this article is the determination of the temperature fields in a weld region has always been an obstacle to the improvement of welding processes. As an alternative, the use of inverse problems to determine the heat flux during the welding process allows an analysis of these processes. Design/methodology/approach This paper studies an alternative for the thermal analysis of the tungsten inert gas welding process on a 6,060 T5 aluminum alloy. For this purpose, a C++ code was developed, based on a transient three-dimensional heat transfer model. To estimate the amount of heat delivered to the plate, the specification function technique was used. Lab experiments were carried out to validate the methodology. A different experimental methodology is proposed to estimate the emissivity (radiation coefficient). Findings The maximum difference between experimental and numerical temperatures is lower than 5 per cent. The determined emissivity value for the aluminum 6,060 T5 presented a good agreement with literature values. The thermal fields were analyzed as function of the positive polarity. The specification function method proved to be an adequate tool for heat input estimation in welding analysis. Originality/value The proposed methodology proves to be a cheaper way to estimate the heat flux on the sample. The estimated power curves for the welding process are presented. The methodology to calculate the emissivity (radiation coefficient) was validated.

scholarly journals Comparative in Mechanical Behavior of 6061 Aluminum Alloy Welded by Pulsed GMAW with Different Filler Metals and Heat Treatments

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4157 ◽  
Author(s):  
Isidro Guzmán ◽  
Everardo Granda ◽  
Jorge Acevedo ◽  
Antonia Martínez ◽  
Yuliana Dávila ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Weld Joint ◽  
Welding Process ◽  
Mechanical Resistance ◽  
6061 Aluminum Alloy ◽  
Β Phase ◽  
Welding Processes ◽  
Filler Metals

Precipitation hardening aluminum alloys are used in many industries due to their excellent mechanical properties, including good weldability. During a welding process, the tensile strength of the joint is critical to appropriately exploit the original properties of the material. The welding processes are still under study, and gas metal arc welding (GMAW) in pulsed metal-transfer configuration is one of the best choices to join these alloys. In this study, the welding of 6061 aluminum alloy by pulsed GMAW was performed under two heat treatment conditions and by using two filler metals, namely: ER 4043 (AlSi5) and ER 4553 (AlMg5Cr). A solubilization heat treatment T4 was used to dissolve the precipitates of β”- phase into the aluminum matrix from the original T6 heat treatment, leading in the formation of β-phase precipitates instead, which contributes to higher mechanical resistance. As a result, the T4 heat treatment improves the quality of the weld joint and increases the tensile strength in comparison to the T6 condition. The filler metal also plays an important role, and our results indicate that the use of ER 4043 produces stronger joints than ER 4553, but only under specific processing conditions, which include a moderate heat net flux. The latter is explained because Mg, Si and Cu are reported as precursors of the production of β”- phase due to heat input from the welding process and the redistribution of both: β” and β precipitates, causes a ductile intergranular fracture near the heat affected zone of the weld joint.

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.

Study on the Solid Welding Conditions of Hollow Extrusion of 7075 Aluminum Alloy

2010 ◽  
Author(s):  
Quang-Cherng Hsu ◽  
Shu-Ping Shi ◽  
Chi-Peng Hsu
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Welding Process ◽  
High Strength ◽  
Outer Ring ◽  
Protective Atmosphere ◽  
Taper Angle ◽  
Flow Through ◽  
Direct Pressing ◽  
Welding Processes

Direct extrusion by port hole–bridge die configuration has been successfully used to fabricate products with hollow cross sections for 6000 series aluminum alloys. When these aluminum alloys flow through the upper die (with bridge and port hole) material flows separately. These separate materials contact together when they flow through the lower die (with welding chamber). The contacting and welding processes occurs naturally if the material temperature and contact pressure are suitable; then the product with hollow and complicated cross section will be obtained when the material flow through bearing regions in lower die. This solid welding process for 6000 series aluminum alloys is without any problem. However, if for 7000 series aluminum alloys this situation alerts since different alloy compositions such as Zn and Cu causing welding process in lower die failed. It will impede the success of industry application with light and high strength aluminum alloys. In order to determine the solid welding conditions during hollow extrusion with port-hole die structure for high strength aluminum alloy such as 7000 series, an easy tooling configuration has been designed. Based on this approach, two split and half die components with taper angle feature were inserted into an outer steel ring. In the beginning, some clearances happen between inner die and outer ring result from design in purpose. When the upper punch continues to press the testing billet, the clearance disappears gradually due to the designed taper angle of inner die and outer ring. However, when the pushing pressure from upper punch is over 350 Mpa and billet temperature is maintained at about 480C below melting temperature, small gaps between the two split half die components occur automatically. During this situation, two small flashes can flow into the opening gaps both from the upper and lower billets which then can weld together. However, these two upper and lower billets in direct pressing zone did not weld together. Several experiments at different pressure have been conducted and the best solid welding condition has been obtained. The proposed method (die configuration) is easy and cheap because there is no necessary to conduct experiment in controlled environment such as in vacuum chamber of Gleeble test or in a protective atmosphere. The grain size and grain structure as well as grain flow have been discussed in the proposed paper for testing parts in direct pressing zone and in flash zone. Some SEM photos and EDS analysis have been prepared and will be presented in this paper.

Optimization of CA-TIG welding parameters to predict and maximize tensile properties of super alloy 718 sheets for gas turbine applications

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tushar Sonar ◽  
Visvalingam Balasubramanian ◽  
Sudersanan Malarvizhi ◽  
Thiruvenkatam Venkateswaran ◽  
Dhenuvakonda Sivakumar
Keyword(s):  
Tensile Properties ◽  
Gas Turbine ◽  
Inconel 718 ◽  
Electron Beam Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Tig Welding ◽  
Welding Parameters ◽  
Content Type ◽  
Welding Processes

Purpose The primary objective of this investigation is to optimize the constricted arc tungsten inert gas (CA-TIG) welding parameters specifically welding current (WC), arc constriction current (ACC), ACC frequency (ACCF) and CA traverse speed to maximize the tensile properties of thin Inconel 718 sheets (2 mm thick) using a statistical technique of response surface methodology and desirability function for gas turbine engine applications. Design/methodology/approach The four factor – five level central composite design (4 × 5 – CCD) matrix pertaining to the minimum number of experiments was chosen in this investigation for designing the experimental matrix. The techniques of numerical and graphical optimization were used to find the optimal conditions of CA-TIG welding parameters. Findings The thin sheets of Inconel 718 (2 mm thick) can be welded successfully using CA-TIG welding process without any defects. The joints welded using optimized conditions of CA-TIG welding parameters showed maximum of 99.20%, 94.45% and 73.5% of base metal tensile strength, yield strength and elongation. Originality/value The joints made using optimized CA-TIG welding parameters disclosed 99.20% joint efficiency which is comparatively 20%–30% superior than conventional TIG welding process and comparable to costly electron beam welding and laser beam welding processes. The parametric mathematical equations were designed to predict the tensile properties of Inconel 718 joints accurately with a confidence level of 95% and less than 4.5% error. The mathematical relationships were also developed to predict the tensile properties of joints from the grain size (secondary dendritic arm spacing-SDAS) of fusion zone microstructure.

Prediction of heat affected zone and other mechanical properties of welded joints of HSLA A588-B of jet blast deflector

2019 ◽  
Vol 16 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Utkarsh Waghmare ◽  
A.S. Dhoble ◽  
Ravindra Taiwade ◽  
Jagesvar Verma ◽  
Himanshu Vashishtha
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Welding Process ◽  
High Strength ◽  
Generation Process ◽  
Content Type ◽  
Welding Processes ◽  
Scanning Electron

Purpose The purpose of this paper is to predict and optimize the width of heat affected zone (HAZ) with better mechanical properties using suitable welding process and parameters for the fabrication of jet blast deflector (JBD) (high strength low alloy material of grade A588-B was used for fabrication) so that the JBD can sustain high exhaust parameters, because there are different welding zones formed due to the rapid cooling of weld metals. Out of the various zones of welding, HAZ remains the weakest zone in the entire weldment. Design/methodology/approach The present work describes the modeling, simulation, Modeling of three-dimensional plate and mess generation process are carried out using ICEM CFD software. FLUENT 16.0 software is used for ANSYS simulation where various models are used for analysis and results are validated with the experimental outcomes. High strength low alloy plates are welded by using shielded metal arc welding and tungsten inert gas (TIG) welding processes with two different electrodes. Optical microscopy and scanning electron microscopy were used for metallurgical study. The mechanical properties were evaluated by tensile strength test, vickers microhardness test and impact test. The corrosion resistance was evaluated by performing the potentiodynamic polarization test. Findings The present study indicated for better mechanical properties and improved corrosion resistance for TIG welded joints with type 308 L filler. Practical implications In aeronautical, defense, space and research organizations. Originality/value It can be shown from the scanning electron microscope technique that sound weld joint is produced with very good mechanical properties and joint also showed better corrosion resistance.

Numerical Simulation and Experiment Analysis of MIG Welding for Aluminum Alloy Extrusion

2012 ◽  
Vol 430-432 ◽  
pp. 1311-1314
Author(s):  
Zheng Zhi Luo ◽  
Yi Su Pan
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Three Dimensional ◽  
Welding Process ◽  
Element Model ◽  
Mig Welding ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Welding Processes ◽  
Aluminum Alloy Extrusion

Welding characteristics of MIG welding for aluminum alloy extrusions are studied. In this article, the aluminum alloy is EN AW-6005A. The welding heat source and the welding processing of aluminum alloy extrusions are discussed. A three dimensional finite element model has been developed to dynamically simulate the welding process. The investigations focus on the comparison the welding heat resource of simulation and section of the experiments parts. And the residual stress of numerical simulation and tests are compared. It’s help to optimize the MIG welding processes and improve the welding quality for aluminum alloy extrusion.

scholarly journals Short-Pulse Resistance Spot Welding of Aluminum Alloy 6016-T4 - Part 1

2021 ◽  
Vol 100 (01) ◽  
pp. 41-51
Author(s):  
ERIC SCHULZ ◽  
◽  
MATTHIAS WAGNER ◽  
HOLGER SCHUBERT ◽  
WENQI ZHANG ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Short Pulse ◽  
Welding Process ◽  
Welding Current ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Pull Out ◽  
Welding Processes

Short-pulse welding parameters for resistance spot welding (RSW) of aluminum alloy AA6016-T4 using mediumfrequency direct current (MFDC) systems were developed to reduce the heat input required for nugget formation. Optimization of current and time parameters is critical during RSW of aluminum alloys for reducing energy requirements and avoiding weld imperfections, such as solidification cracking and expulsion, while maintaining weld quality, particularly given the high electrical and thermal conductivities of the materials. The welding time and the applied current level of the current pulse were varied systematically for thin sheets (1 mm or 0.04 in.) of AA6016-T4. The quality of the welds was evaluated by pull-out testing, ultrasound testing, and metallography techniques. Simulations of the same welding processes were performed with the finite element-based SORPAS® software. The results showed short-pulse MFDC RSW can reduce the energy required for sound welds in this alloy without requiring an increase in welding current. The simulations and experiments also showed the welding process had distinct weld nugget nucleation and growth phases.

Thermal Analysis to Evaluate Ageing Process in Heated Tool and Electrofusion Welding of Polymer Pipes

2013 ◽  
Vol 837 ◽  
pp. 190-195 ◽  
Author(s):  
Sorin Vasile Savu ◽  
I. Danut Savu ◽  
Ion Ciupitu
Keyword(s):  
Thermal Analysis ◽  
Stress Test ◽  
Base Material ◽  
Welding Process ◽  
Relaxation Modulus ◽  
High Energy ◽  
Welding Parameters ◽  
Heating Process ◽  
Welding Cycle ◽  
Welding Processes

Heated tool and electrofusion welding are the most used joining processes of higher than 2 mm thick polymer pipes. The two welding processes have different heating-cooling cycles and they produce different influences on the properties of the polymers. Exploitation of polymer pipes for water and gas distribution revealed ageing behaviour of the material in the welding area. The modification of the behaviour depends on the base material, on the applied welding process and on the used parameters. Thermal analysis can be used as tool to reveal and to evaluate the modification of the physical and mechanical properties. Such knowledge is important when prediction of the in use life is necessary to be predicted. Experimental programme was applied to HDPE 100 and HDPE 80, both welded using heated tool and electrofusion processes and different sets of parameters (factorial experiment principles were used to establish the welding parameters). Plasticity characteristics of the welds material, as elongation and relaxation modulus, were determined by using thermal analysis. Burst stress test, applied to the pipe, was considered. It has been observed important rate of the heating process of the surface in contact with the heater. The DSC analysis revealed a decreasing of the elongation with about 12% and decreasing of the relaxation modulus with amount up to 14%, for the material located at the interface between pipe and the heater. At 0.5 mm from the interface it was revealed an intensity of the modification up to half of the values recorded for the interface. That was explained on the poor thermal conductivity specific to the both materials. By using DSC thermal analysis it has been revealed that the polyethylene has high rate crystallization during welding cycle, after the heating to the viscous state. Such crystallization, together with potential non-uniformity of the heating provides modifications in the geometrical characteristics of the weld. For high energy input, the material experience large quantity of fluid material with important plastic distortion. That means high possibility to reject material during pressing step of the welding cycle. 10% increasing of the temperature, for the same heating pressure, involves 5-8% increasing of the dimensions of the fluid ring in the interface. About 10% difference between the relaxation modulus of the heated and non-heated HDPE and that means local ageing transformation of the HDPE. The material becomes more fragile than before the welding process.

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