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

Author(s):  
SERAFINO CARUSO ◽  
DOMENICO UMBRELLO

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.

Author(s):  
Jaber Jamal ◽  
Basil Darras ◽  
Hossam Kishawy

The concept of “sustainability” has recently risen to take the old concept of going “green” further. This article presents general methodologies for sustainability assessments. These were then adapted to measure and assess the sustainability of welding processes through building a complete framework, to determine the best welding process for a particular application. To apply this methodology, data about the welding processes would be collected and segregated into four categories: environmental impact, economic impact, social impact, and physical performance. The performance of each category would then be aggregated into a single sustainability score. To demonstrate the capability of this methodology, case studies of three different welding processes were performed. Friction stir welding obtained the highest overall sustainability score compared to gas tungsten arc welding and gas metal arc welding.


2021 ◽  
Vol 9 (209) ◽  
pp. 1-32
Author(s):  
Vinícius de Albuquerque Santos

The article makes a general study of Gas Metal Arc Welding (GMAW) and Solid Metal Arc Welding (SMAW) welding, welded on structural steel under the American Society for Testing and Materials (ASTM) A606. The welding process and its applicability in the construction and mining industry are presented. This work has as a starting point, the concepts of welding processes, thermal aspects involved, metallurgy, Thermally Affected Zone (ZTA), recurrent discontinuities and the result of mechanical tests. The material was welded to specimens in both processes. The mechanical test was evaluated, the anchoring in the bending of the material in the weld bead and characteristics of the weld quality. It was found that the material welded with SMAW showed greater tensile strength. It is also concluded, the greater hardness in the ZTA of the material welded with GMAW.


Author(s):  
Rudreshi Addamani ◽  
Ravindra Holalu Venkatadas ◽  
Ugrasen Gonchikar ◽  
Y. D. Chethan

The Pulsed Gas Metal Arc Welding (P-GMAW) process is used in high-technology industrial applications and it is one of the most significant arc welding processes. The quality, productivity and cost of welding will be affected by the P-GMAW welding input process parameters and are considered to the most important factors. It is necessary to determine the input and output relationship of the welding processes in order to understand and control the P-GMAW welding process parameters. P-GMAW is widely used process, especially in thin sheet metal industries. It offers an improvement in quality and productivity over regular Gas Metal Arc Welding (GMAW). The process enables stable spray transfer with low mean current and low net heat input. This paper describes the estimation and comparison of welding process parameters viz., current, gas flow rate and wire feed rate on ultimate tensile strength, yield strength, percentage of elongation and hardness. Experiments have been performed based on Taguchi’s L27 standard orthogonal array. Estimation of welding performances have been carried out using sophisticated mathematical models viz., MRA and GMDH, and, compared. The GMDH algorithm is designed to learn the process by training the algorithm with the experimental data. Three different criterion functions, viz., regularity, unbiased and combined criterions were considered for estimation in GMDH. Different GMDH models can be obtained by varying the percentage of data in the training set and the best model can be selected from these, viz., 50%, 62.5% and 75%. Estimation and comparison of welding performances were carried out using MRA and GMDH techniques.


Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2491 ◽  
Author(s):  
Philipp Henckell ◽  
Maximilian Gierth ◽  
Yarop Ali ◽  
Jan Reimann ◽  
Jean Pierre Bergmann

Wire arc additive manufacturing (WAAM) by gas metal arc welding (GMAW) is a suitable option for the production of large volume metal parts. The main challenge is the high and periodic heat input of the arc on the generated layers, which directly affects geometrical features of the layers such as height and width as well as metallurgical properties such as grain size, solidification or material hardness. Therefore, processing with reduced energy input is necessary. This can be implemented with short arc welding regimes and respectively energy reduced welding processes. A highly efficient strategy for further energy reduction is the adjustment of contact tube to work piece distance (CTWD) during the welding process. Based on the current controlled GMAW process an increase of CTWD leads to a reduction of the welding current due to increased resistivity in the extended electrode and constant voltage of the power source. This study shows the results of systematically adjusted CTWD during WAAM of low-alloyed steel. Thereby, an energy reduction of up to 40% could be implemented leading to an adaptation of geometrical and microstructural features of additively manufactured work pieces.


1987 ◽  
Vol 109 (2) ◽  
pp. 172-176 ◽  
Author(s):  
E. Kannatey-Asibu

Control of arc length is an essential component of the automation of arc welding processes. It is even more critical in gas metal arc welding where the arc length can vary substantially since it is closely tied to the melting process. Variations in arc length can greatly affect the quality of the weld produced. Even though there are currently systems available for controlling arc length, the theory necessary for microprocessor control is not fully developed. This paper develops a model of the gas metal arc welding process as a basis for arc length control, using the input to the wire feed drive motor as the control signal. The weld process is found to be first order after linearization, and that, coupled with the drive motor dynamics, produces a second-order system. The model is verified experimentally and is found to correlate very well with experimental results, the calculated time constant for the welding system in the constant current mode being 1.7 s, while the measured value is approximately 1.5 s.


Data in Brief ◽  
2021 ◽  
Vol 35 ◽  
pp. 106790
Author(s):  
Rogfel Thompson Martinez ◽  
Guillermo Alvarez Bestard ◽  
Sadek C. Absi Alfaro

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1077 ◽  
Author(s):  
Seungmin Shin ◽  
Sehun Rhee

In this study, lap joint experiments were conducted using galvanized high-strength steel, SGAFH 590 FB 2.3 mmt, which was applied to automotive chassis components in the gas metal arc welding (GMAW) process. Zinc residues were confirmed using a semi-quantitative energy dispersive X-ray spectroscopy (EDS) analysis of the porosity in the weld. In addition, a tensile shear test was performed to evaluate the weldability. Furthermore, the effect of porosity defects, such as blowholes and pits generated in the weld, on the tensile shear strength was experimentally verified by comparing the porosity at the weld section of the tensile test specimen with that measured through radiographic testing.


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