scholarly journals Evaluation of Heat Sources for the Simulation of the Temperature Distribution in Gas Metal Arc Welded Joints

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1142 ◽  
Author(s):  
Andrea Chiocca ◽  
Francesco Frendo ◽  
Leonardo Bertini
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Welded Joints ◽  
Initial Temperature ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Experimental Measurements ◽  
Thermal Methods ◽  
Simple Method ◽  
Metal Arc Welding

Residual stresses can affect both the static strength and the fatigue endurance of welded joints. Residual stresses can be assessed by numerical simulation; however, the simulation of the welding process is a complex task that requires knowledge of several parameters, many of which can only be estimated with some uncertainty. The reduction in the number of these parameters can lead to a more feasible and efficient study. In this work, the finite element method is used to assess the capability of different thermal methods used to simulate a single pass of the gas metal arc welding process in reproducing the temperature distribution around the weld. Results of the simulations are compared to experimental measurements of the surface temperature close to the welding area. The thermal techniques analyzed adopt different levels of complexity, from the basic implementation of a constant initial temperature assigned to a given material volume, to the more comprehensive and widespread Goldak’s double-ellipsoid model. The study shows that, close to the weld seam, very similar thermal behaviors can be achieved by employing each one of the analyzed methods. Secondly, considering the constant initial temperature method, the comparison between experimental measurements and numerical simulations showed a fairly good agreement, suggesting that a relatively simple method (i.e., requiring the setting of only one parameter) can be used to efficiently reproduce the thermal history of a welding process.

Evaluation by FEM of the Influence of the Preheating and Post-Heating Treatments on Residual Stresses in Welding

2014 ◽  
Vol 627 ◽  
pp. 93-96 ◽  
Author(s):  
Raffaele Sepe ◽  
Enrico Armentani ◽  
Giuseppe Lamanna ◽  
Francesco Caputo
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Element Model ◽  
Butt Joint ◽  
Temperature Fields ◽  
Heating Process ◽  
Butt Weld ◽  
Metal Arc Welding

During the last few years various experimental destructive and non-destructive methods were developed to evaluate residual stresses. However it is impossible to obtain a full residual stress distribution in welded structures by means of experimental methods. This disadvantage can be solved by means of computational analysis which allows to determine the whole stress and strain fields in complex structures. In this paper the temperature distribution and residual stresses were determined in a single-pass butt joint welded by GMAW (Gas Metal Arc Welding) process by finite element model (FEM). A 3D finite parametric element model has been carried out to analyze temperature distribution in butt weld joints and thermo-mechanical analyses were performed to evaluate resulting residual stresses. Temperature fields have been investigated by varying an initial preheating treatment. Moreover the technique of “element birth and death” was adopted to simulate the process of filler metal addition The high stresses were evaluated, with particular regard to fusion zone and heat affected zone. The influence of preheating and post-heating treatment on residual stresses was investigated. The residual stresses decrease when preheating temperature increases. The maximum value of longitudinal residual stresses without pre-heating can be reduced about 12% and 38% by using the preheating and post-heating process respectively.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

scholarly journals The Influence of the Welding Process on the Ultrasonic Inspection of 9%Ni Steel Pipe Circumferential Welded Joints

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 961
Author(s):  
João da Cruz Payão Filho ◽  
Elisa Kimus Dias Passos ◽  
Rodrigo Stohler Gonzaga ◽  
Daniel Drumond Santos ◽  
Vinicius Pereira Maia ◽  
...  
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Ultrasonic Inspection ◽  
Welding Process ◽  
Oil And Gas Industry ◽  
Co2 Injection ◽  
Shielded Metal Arc Welding ◽  
Scanning Angle ◽  
Metal Arc Welding

This work aims to compare the ultrasonic inspection of 9%Ni steel joints welded with the Gas Metal Arc Welding (GMAW) process and Shielded Metal Arc Welding (SMAW) process. These are the two most widely used processes used to weld pipes for CO2 injection units for floating production storage and offloading (FPSO) in the Brazilian oil and gas industry. The SMAW equipment is simple and portable, which is convenient for the FPSO; however, the GMAW process has the advantage of welding with high productivity. In this study we performed a numerical simulation using the software CIVA, 11th version, to analyze the behavior of ultrasonic longitudinal wave beams through GMAW and SMAW dissimilar weld joints. Ultrasonic tests were performed on calibration blocks drawn from both welded joints to evaluate the simulation results. The results are discussed with regard to the microstructure of the weld metal via electron backscatter diffraction (EBSD) analyses. The SMAW process presented better inspection performance than the GMAW process in terms of attenuation and dispersion effects. Although the SMAW had a better outcome, for both processes the configuration of 16 active elements and a scanning angle of 48° resulted in an optimized inspection of the entire joint.

scholarly journals Influence of Alloying Element in Filler Metal on Mechanical Properties of A6061 Al Alloy Welded Joints

2020 ◽  
Vol 9 (3) ◽  
pp. 661-666
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Al Alloy ◽  
Fine Grain ◽  
Metal Arc Welding ◽  
Arc Welding Process ◽  
Filler Metals

The current work is intended to study the influence of using ER4043 and ER5356 filler metals on mechanical properties of A6061 Al alloy welded joint made by gas metal arc welding process (GMAW). For this study, 12mm plates of these materials were joint using a type single V groove butt joints with four layers and five passes configurationof welded joints. The soundness of the quality of the weld joint was investigated by X-ray Ct-Scan technique. The joint made with the ER4043 presented an enhancement of mechanical properties. In comparisonwith the joint made with ER5356, Al A6061 with ER4043 welded joint shows to have an advantage due to the formation of very fine grain and have uniformly distributed porosity in the weld region area.

The Effect of Filler ER4043 and ER5356 on Porosity Distribution of Welded AA6061 Aluminum Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 987-990
Author(s):  
Che Lah Nur Azida ◽  
Muhammad Faizol Ahmad Ibrahim ◽  
Azman Jalar ◽  
J. Sharif ◽  
Norinsan Kamil Othman ◽  
...  
Keyword(s):  
Welded Joints ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Butt Joint ◽  
Hardness Profile ◽  
Porosity Formation ◽  
Metal Arc Welding ◽  
Arc Welding Process ◽  
Filler Metals

The filler metal used during welding process is believed to play an important role on porosity formation in aluminium alloy welded. The present investigation is aimed to study the effect of different fillers ER4043 (Al-5%Si) and ER5356 (Al-5%Mg) on porosity formation of AA6061 alloy welded joints. Butt-joint welds were made on 6 mm thick plates using 21 – 22 V arc voltages by using Gas Metal Arc Welding process (GMAW). The hardness profile of each types of AA6061 welded joints for both fillers were characterized by the Vickers microhardness test. In order to study the formation and distribution of porosity, the images of analysis were obtained using the X- ray CT-Scan. It was observed that, more porosities were found in the alloy AA6061 using ER4043 compared to ER5356 filler metals with the percentage area value of porosity about 18.3 and 8.4%, respectively. The hardness profile of ER5356 and ER4043 welded materials exhibited the similar hardness pattern profile. It is proposed that Si and Mg contents in the filler metal could play significant role in the distribution of porosity. No significant effect was observed on the hardness profile for both filler metals of welded materials.

scholarly journals Numerical and Experimental Validation of Gas Metal Arc Welding on AISI 441 Ferritic Stainless Steel Through Mechanical and Microstructural Analysis

2022 ◽  
Author(s):  
SERAFINO CARUSO ◽  
DOMENICO UMBRELLO
Keyword(s):  
Grain Size ◽  
Residual Stresses ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Microstructural Analysis ◽  
Welding Process ◽  
Production Costs ◽  
Metal Arc Welding ◽  
Residual Stresses And Strains ◽  
Welding Processes

Abstract Residual stresses and strains, distortion, heat affected zone (HAZ), grain size changes and hardness variation during gas metal arc welding (GMAW), are fundamental aspects to study and control during welding processes. For this reason, numerical simulations of the welding processes represent the more frequently used tool to better analyse the several aspects characterizing this joining process with the aim to reduce lead time and production costs. In the present study an uncoupled 3D thermo-mechanical analysis was carried out by two commercial finite element method (FEM) software to model an experimental single bead GMAW of AISI 441 at different process set-up. The experimental HAZ and measured temperatures were used to calibrate the heat source of both the used numerical codes, then a validation procedure was done to test the robustness of the two developed analytical procedures. One software was used to predict the residual stresses and strains and the distortions of the welded components, while in the second software a user routine was implemented, including a physical based model and the Hall-Petch (H-P) equation, to predict grain size change and hardness evolution respectively. The results demonstrate that the predicted mechanical and microstructural aspects agree with those experimentally found showing the reliability of the two codes in predicting the thermal phenomena characterizing the HAZ during the analysed welding process.

Assessment of Weld Bead Performance for Pulsed Gas Metal Arc Welding (P-GMAW) Using Acoustic Emission (AE) and Machine Vision (MV) Signals Through NDT Methods for SS 304 Material

2020 ◽  
Author(s):  
Rudreshi Addamani ◽  
Holalu Venkatdas Ravindra ◽  
S. K. Gayathri Devi ◽  
Ugrasen Gonchikar
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Cost Effective ◽  
Weld Bead ◽  
Spray Transfer ◽  
Metal Arc Welding ◽  
Ss 304 ◽  
Wire Feed

Abstract To gain high cost effective products along with quality and productivity, Pulsed Gas Metal Arc Welding (P-GMAW) process is used in many highly developed industries for fabrication of welded joints. The input parameters are the most important factors which affects the productivity, quality and cost effective for the welding process. The processes enable low net heat input, stable spray transfer and with low mean current. To enhance efficiencies with constant voltage GMAW process, P-GMAW is an outstanding substitute for those industries which are looking to improve quality of welds since the process helps over varying operator’s skills. It is essential to determine the input/output relationship parameters, in order to recognize and control the P-GMAW welding process. P-GMAW applies waveform control logic to fabricate a very precise control of the arc during speed range and a broad wire feed. The power source switches between low background current and a high peak current between 30 to 400 times per second to obtain modified spray transfer process. The peak current pinches off wire droplets and drive it to the welded joints over this period. The process produces low heat input allowing weld pool to solidify, that metal transfer cannot occur but by the mean time, background current maintains the arc with stable spray transfer. Trials have been conducted on SS 304 material using copper coated filler wire of size 1.4 mm based on the Taguchi’s L27 standard orthogonal array. Current, Gas Flow Rate (GFR) and Wire Feed Rate (WFR) with a constant speed are the input parameters considered to carry out trials. The output parameters are Yield strength (YS, N/mm2), percentage of elongation and Ultimate Tensile Strength (UTS, N/mm2). Indirect response parameters are Viz., AE signals such as welding AERMS, welding AEENERGY, tensile AERMS and tensile AEENERGY along with MV signals like area and height of the weld bead are considered to assess the performance of the weld bead joint. It is clearly observed from the obtained results that an excellent relationship exists between welding AERMS welding AEENERGY with tensile AERMS and tensile AEENERGY along with MV signals which were taken at the time of tensile test to evaluate the performance of the weld bead joint. Verification of the results are carried out through performing different NDT testing methods on weld bead joint Viz., X–radiography, Scanning Electron Microscope (SEM) images to analyse external defects in the welded joints. On different zones of welded joint, Energy dispersive analysis (EDX) examination is carried out for elemental composition.

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