Influence of Small Volumetric Flaws on the Measurement of Crack Growth and Tearing Resistance in SENT Tests

2020 ◽  
Author(s):  
Vitor Adriano ◽  
Eleine Cardon ◽  
Wim De Waele ◽  
Stijn Hertelé ◽  
Matthieu Boone
Keyword(s):  
Crack Opening ◽  
Gas Metal Arc Welding ◽  
Measurement Techniques ◽  
Welding Parameters ◽  
Resistance Curve ◽  
Metal Arc Welding ◽  
Measured Resistance ◽  
X Ray Computed ◽  
Set Up ◽  
Tearing Resistance

Abstract This study evaluates the influence of volumetric discontinuities on the SENT tearing resistance curve as measured using DCPD and UC techniques. In order to do that, a series of SENT tests was carried out on specimens containing small drilled holes in different locations to simulate the presence of volumetric weld flaws. In addition, porous welds were produced by robotic Gas Metal Arc Welding (GMAW). Welding parameters were fine-tuned in order to obtain specimens with different porosity levels. Afterward, the pores were characterized by means of X-ray Computed Tomography (CT) scans and their position, shape and location were determined. SENT tests were performed in a servo-hydraulic machine using a double clip gauge set up to measure crack opening and DCPD and UC for crack sizing. The results indicated that volumetric discontinuities can influence the accuracy of crack measurement techniques in particular, and the measured resistance curve as a whole.

Solid Freeform Fabrication of Al-Li 2199 via Controlled-Short-Circuit-MIG Welding

2011 ◽  
Vol 409 ◽  
pp. 843-848
Author(s):  
David W. Heard ◽  
Julien Boselli ◽  
Raynald Gauvin ◽  
Mathieu Brochu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Solid Freeform Fabrication ◽  
Short Circuit ◽  
Lithium Concentration ◽  
Gas Metal Arc Welding ◽  
Fusion Welding ◽  
Welding Parameters ◽  
Freeform Fabrication ◽  
Metal Arc Welding ◽  
Welding Processes

Aluminum-lithium (Al-Li) alloys are of interest to the aerospace and aeronautical industries as rising fuel costs and increasing environmental restrictions are promoting reductions in vehicle weight. However, Al-Li alloys suffer from several issues during fusion welding processes including solute segregation and depletion. Solid freeform fabrication (SFF) of materials is a repair or rapid prototyping process, in which the deposited feedstock is built-up via a layering process to the required geometry. Recent developments have led to the investigation of SFF processes via Gas Metal Arc Welding (GMAW) capable of producing functional metallic components. A SFF process via GMAW would be instrumental in reducing costs associated with the production and repair of Al-Li components. Furthermore the newly developed Controlled-Short-Circuit-MIG (CSC-MIG) process provides the ability to control the weld parameters with a high degree of accuracy, thus enabling the optimization of the solidification parameters required to avoid solute depletion and segregation within an Al-Li alloy. The objective of this study is to develop the welding parameters required to avoid lithium depletion and segregation. In the present study weldments were produced via CSC-MIG process, using Al-Li 2199 sheet samples as the filler material. The residual lithium concentration within the weldments was then determined via Atomic Absorption (AA) and X-ray Photoelectron Spectroscopy (XPS). The microstructure was analyzed using High Resolution Scanning Electron Microscopy (HR-SEM). Finally the mechanical properties of welded samples were determined through the application of hardness and tensile testing.

Effect of the Heat Input in the Transformation of Retained Austenite in Advanced Steels of Transformation Induced Plasticity (TRIP) Welded with Gas Metal Arc Welding

2013 ◽  
Vol 339 ◽  
pp. 700-705 ◽  
Author(s):  
Victor Lopez ◽  
Arturo Reyes ◽  
Patricia Zambrano
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Residual Austenite ◽  
Welding Parameters ◽  
Transformation Induced Plasticity ◽  
Metal Arc Welding

The effect of heat input on the transformation of retained austenite steels transformation induced plasticity (TRIP) was investigated in the heat affected zone (HAZ) of the Gas Metal Arc Welding GMAW process. The determination of retained austenite of the HAZ is important in optimizing the welding parameters when welding TRIP steels, because this will greatly influence the mechanical properties of the welding joint due to the transformation of residual austenite into martensite due to work hardening. Coupons were welded with high and low heat input for investigating the austenite transformation of the base metal due to heat applied by the welding process and was evaluated by optical microscopy and the method of X-Ray Diffraction (XRD). Data analyzed shows that the volume fraction of retained austenite in the HAZ increases with the heat input applied by the welding process, being greater as the heat input increase and decrease the cooling rate, this due to variation in the travel speed of the weld path.

Modeling and Optimization of Gas Metal Arc Welding (GMAW) Process

2012 ◽  
pp. 339-367
Author(s):  
R. Venkata Rao
Keyword(s):  
Process Parameters ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Optimization Methods ◽  
Optimization Techniques ◽  
Modeling And Optimization ◽  
Metal Arc Welding ◽  
Process Output ◽  
Set Up

Weld quality is greatly affected by the operating process parameters in the gas metal arc welding (GMAW) process. The quality of the welded material can be evaluated by many characteristics, such as bead geometric parameters, deposition efficiency, weld strength, weld distortion, et cetera. These characteristics are controlled by a number of welding process parameters, and it is important to set up proper process parameters to attain good quality. Various optimization methods can be applied to define the desired process output parameters through developing mathematical models to specify the relationship between the input parameters and output parameters. The method capable of accurate prediction of welding process output parameters would be valuable for rapid development of welding procedures and for developing control algorithms in automated welding applications. This chapter presents the details of various techniques used for modeling and optimization of GMAW process parameters. The optimization methods covered in this chapter are appropriate for modeling and optimizing the GMAW process. It is found that there is high level of interest in the adaptation of RSM and ANN techniques to predict responses and to optimize the GMAW process. Combining two optimization techniques, such as GA and RSM, would reveal good results for finding out the optimal welding conditions. Furthermore, efforts are required to apply advanced optimization techniques to find out the optimal parameters for GMAW process at which the process could be considered safe and more economical.

scholarly journals Effects of High Frequency Mechanical Impact on Fatigue Life of Semi-Automated Gas Metal Arc Welding (GTAW) of HSLA Butt Weld

2019 ◽  
Vol 269 ◽  
pp. 06002
Author(s):  
Salina Saidin ◽  
Dahia Andud ◽  
Yupiter H. P. Manurung ◽  
Muhd. Faiz Mat ◽  
Noridzwan Nordin ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Steel Structure ◽  
Welding Parameters ◽  
Butt Weld ◽  
Metal Arc Welding ◽  
Life Enhancement ◽  
Fatigue Life Enhancement

This paper deals with a comprehensive investigation of fatigue life enhancement on semiautomated Gas Metal Arc Welding (GTAW) butt weld joint which is found almost everywhere in Malaysia welding structure steel sectors. The selected material in this study was high strength low alloy steel S460G2+M commonly used extremely in steel structure due to its outstanding mechanical properties. In this investigation, the method for joining the butt weld was conducted by unprofessional welder using semi-automated GMAW. At first, suitable welding parameters were identified and formulated into welding procedure specification (WPS) qualification conforming to AWS D1.1 standard. The test specimens were prepared and tested to ensure the welding quality. Further, the HFMI using Pneumatic Impact Treatment (PIT) technique were applied at the weld toe of the butt weld as tool for fatigue life enhancement. To investigate the influence of HFMI/PIT on the fatigue strength, the specimens were undergone fatigue test using universal fatigue machine using a constant amplitude loading. Finally, the comparison of the fatigue strength of as welded and treated specimens to indicate the beneficial influence of the treatment. Yes, the conduction by unprofessional welder using semi-automatic GMAW, the findings showed the improvement of fatigue strength and slope of S-N curves. In addition, the fracture location of test specimen shows physically affected by shifting from critical weld transition to base metal. The tensile test and hardness value also showed a slight difference as compared to untreated specimens.

scholarly journals Influence of welding method on microstructural creation of welded joints  

2011 ◽  
Vol 57 (Special Issue) ◽  
pp. S50-S56 ◽  
Author(s):  
P. Čičo ◽  
D. Kalincová ◽  
M. Kotus
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Structural Phase ◽  
Welding Parameters ◽  
Welding Method ◽  
Welding Technology ◽  
Metal Arc Welding

This paper is focused on the analysis of the welding technology influence on the microstructure production and quality of the welded joint. Steel of class STN 41 1375 was selected for the experiment, the samples were welded by arc welding including two methods: a manual one by coated electrode and gas metal arc welding method. Macro and microstructural analyses of the experimental welded joints confirmed that the welding parameters affected the welded joint structure in terms of the grain size and character of the structural phase.

Experimental Study on Tensile Strength of Butt Joints for Mild Steel with Thickness 6mm Using Gas Metal Arc Welding (GMAW)

2017 ◽  
Vol 740 ◽  
pp. 155-160 ◽  
Author(s):  
Z.A. Zakaria ◽  
K.N.M. Hasan ◽  
M.F.A. Razak ◽  
Amirrudin Yaacob ◽  
A.R. Othman
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Heat Affected Zone ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Welding Parameter ◽  
Welding Parameters ◽  
Low Carbon ◽  
Metal Arc Welding

In this study, the effects of various welding parameters on welding strength in low carbon steel JIS G 3101 SS400, welded by gas metal arc welding were investigated. Welding current, arc voltage and travel speed are the variable parameters were studied in this study. The ultimate tensile strength, hardness and heat affected zone were measured for each specimen after the welding operations, and the effects of these parameters on strength were examined. Then, the relationship between welding parameter and ultimate tensile strength, hardness and heat affected zone were determined. Based on the finding, the best parameter is formulated and used to calculate the heat input.

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