scholarly journals Application of Cold Wire Gas Metal Arc Welding for Narrow Gap Welding (NGW) of High Strength Low Alloy Steel

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 335 ◽  
Author(s):  
Rafael Ribeiro ◽  
Paulo Assunção ◽  
Emanuel Dos Santos ◽  
Ademir Filho ◽  
Eduardo Braga ◽  
...  
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Parameters ◽  
Narrow Gap ◽  
Dynamic Features ◽  
Narrow Gap Welding ◽  
Cold Wire ◽  
Metal Arc Welding ◽  
Welding Processes

Narrow gap welding is a prevalent technique used to decrease the volume of molten metal and heat required to fill a joint. Consequently, deleterious effects such as distortion and residual stresses may be reduced. One of the fields where narrow groove welding is most employed is pipeline welding where misalignment, productivity and mechanical properties are critical to a successful final assemblage of pipes. This work reports the feasibility of joining pipe sections with 4 mm-wide narrow gaps machined from API X80 linepipe using cold wire gas metal arc welding. Joints were manufactured using the standard gas metal arc welding and the cold wire gas metal arc welding processes, where high speed imaging, and voltage and current monitoring were used to study the arc dynamic features. Standard metallographic procedures were used to study sidewall penetration, and the evolution of the heat affected zone during welding. It was found that cold wire injection stabilizes the arc wandering, decreasing sidewall penetration while almost doubling deposition. However, this also decreases penetration, and incomplete penetration was found in the cold wire specimens as a drawback. However, adjusting the groove geometry or changing the welding parameters would resolve this penetration issue.

Feasibility of narrow gap welding using the cold-wire gas metal arc welding (CW-GMAW) process

2017 ◽  
Vol 61 (4) ◽  
pp. 659-666 ◽  
Author(s):  
Paulo D’Angelo Costa Assunção ◽  
R. A. Ribeiro ◽  
Emanuel B. F. Dos Santos ◽  
Adrian P. Gerlich ◽  
Eduardo de Magalhães Braga
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Narrow Gap ◽  
Narrow Gap Welding ◽  
Cold Wire ◽  
Metal Arc Welding

scholarly journals Globular-to-Spray Transition in Cold Wire Gas Metal Arc Welding

2021 ◽  
Vol 100 (4) ◽  
pp. 121-131
Author(s):  
R. A. RIBEIRO ◽  
◽  
P. D. C. ASSUNÇÃO ◽  
E. B. F. DOS SANTOS ◽  
E. M. BRAGA ◽  
...  
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Electrical Current ◽  
Feed Speed ◽  
High Speed Imaging ◽  
Transition Mechanism ◽  
Cold Wire ◽  
Metal Arc Welding

The electrical current required for a transition from globular to spray droplet transfer during gas metal arc welding (GMAW) is determined by the specified wire feed speed in the case of constant-voltage power supplies. Generally, in narrow groove welding, spray transfer is avoided, be-cause this transfer mode can severely erode the groove sidewalls. This work compared the globular-to-spray transition mechanism in cold wire gas metal arc welding (CW-GMAW) vs. standard GMAW. Synchronized high-speed imaging with current and voltage samplings were used to characterize the arc dynamics for different cold wire mass feed rates. Subsequently, the droplet frequency and diameter were estimated, and the parameters for a globular-to-spray transition were assessed. The results suggest that the transition to spray occurs in CW-GMAW at a lower current than in the standard GMAW process. The reason for this difference appears to be linked to an enhanced magnetic pinch force, which is mainly responsible for metal transfer in higher welding current conditions.

scholarly journals Silicate Island Formation in Gas Metal Arc Welding

2021 ◽  
Vol 100 (01) ◽  
pp. 13-26
Author(s):  
RICHARD DERRIEN ◽  
◽  
ETHAN MICHAEL SULLIVAN ◽  
STEPHEN LIU ◽  
ELODIE MOINE ◽  
...  
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Formation Rate ◽  
Welding Process ◽  
Electromagnetic Levitation ◽  
Welding Parameters ◽  
Silicate Formation ◽  
Metal Arc Welding ◽  
Initial Melting

Because formation of silicate islands during gas metal arc welding is undesirable due to decreased productivity and decreased quality of welds, it is important to understand the mechanism of the formation of these silicate islands to mitigate their presence in the weld. The effects of welding parameters on the silicate formation rate were studied. Results showed that the applied voltage and oxidizing potential of the shielding gas were the parameters that most strongly influenced the amount of silicates formed on the surface of the weld bead. High-speed video was used to observe the formation of silicate islands during the welding process, which showed that the silicates were present at each stage of the welding process, including the initial melting of the wire electrode, and grew by coalescence. A flow pattern of the silicate islands was also proposed based on video analysis. An electromagnetic levitation system was used to study the growth kinetics of the silicate islands. Silicate coverage rate was found to increase with increasing oxidizing time, increasing oxidizing potential of the atmosphere, and increasing content of alloying elements except for Ti.

scholarly journals REPLACEMENT OF MANUAL GMAW WELDING BY FCAW SEMI-AUTOMATIC WELDING

2021 ◽  
Vol 2021 (2) ◽  
pp. 4342-4347
Author(s):  
MARIAN SIGMUND ◽  
◽  
TADEAS CICHA
Keyword(s):  
Carbon Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Parameters ◽  
Automatic Welding ◽  
Cored Wire ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Welding Procedure ◽  
Welding Processes

The article describes a replacement and benefits between manual gas metal arc welding (GMAW) with solid wire and semi-automatic flux-cored arc welding (FCAW) with metal flux-cored wire for a specific application of a welded steel compensator used for connecting piping systems to form larger units. For the replacement of the technologies and improvement of the welding efficiency and productivity a specific type of carbon steel mounting insert, DN300 PN16, was selected. Since these pressure parts are subject to the directive 2014/68/EU, both the welding processes have to meet the same welding quality requirements. In particular, they are the welding procedure qualification report (WPQR) and the welder’s or welding operator’s qualification in accordance with valid European standards. Based on this requirement, a sample was selected so that it would cover the widest possible range of carbon steel mounting inserts produced. This article describes the whole experiment including the selection of the right equipment and filler material, finding the ideal welding parameters, and the subsequent qualification of the welding procedure and the operator with emphasis on the largest possible increase in the welding speed and productivity for these specific weldments.

scholarly journals COMPUTER ANALYSIS OF THE GMAW AND GMAW-CW WELDING THERMAL CYCLES

2015 ◽  
Vol 14 (2) ◽  
pp. 37
Author(s):  
E. A. M. Mendonça ◽  
E. M. Braga ◽  
A. S. A. Ferreira ◽  
R. R. Maciel ◽  
T. S. Cabral ◽  
...  
Keyword(s):  
Experimental Data ◽  
Heat Input ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Parameters ◽  
Thermal Cycles ◽  
Complex Situation ◽  
Cold Wire ◽  
Metal Arc Welding ◽  
And Behavior

A novel process of welding GMAW-CW (Gas Metal Arc Welding-Cold Wire) had been developed with it resemblance to the GMAW (Gas Metal Arc Welding), the GMAW-CW has an additional wire fed into de weld pool, allowing better deposition rates, while maintaining weld characteristics. However, there is a more complex situation related to the HAZ (Heat Affected Zone) and weld geometry prediction than the GMAW conventional. The welding energy is a high metallurgical important parameter because together with the geometric characteristics of the gasket and the preheat level is decisive in thermal cycles imposed to the material, and therefore in the possible microstructural transformations and behavior of the joint. The behavior of representative curves of thermal cycling reflects important aspects regarding the conditions used in welding. Usually such factors as the type of process, use or non- pre or post- heating, heat input, multipass welding, are able to establish differences in the form of a heat cycle curve. In this work, it was applied the dual ellipsoidal model of heat input, adapted to the GMAW-CW and compared to the same model over the GMAW, using existing experimental data and predicting the HAZ dimensions in function of weld and welding parameters. The results found had less than 10% error from experimental data in a more refined version of the model, whereas the difficulties to predict cold wire addition influences were not trivial.

High Deposition Pulse Current GMAW Can Change Current Scenario of Thick Wall Pipe Welding

2009 ◽  
Author(s):  
P. K. Ghosh ◽  
Shrirang G. Kulkarni ◽  
Banshi Prasad Agarwal
Keyword(s):  
Arc Welding ◽  
Pulse Current ◽  
Gas Metal Arc Welding ◽  
Thick Wall ◽  
Narrow Gap ◽  
Shielded Metal Arc Welding ◽  
Narrow Gap Welding ◽  
Pulse Parameters ◽  
Metal Arc Welding ◽  
Pipe Welding

The high deposition pulse current gas metal arc welding (P-GMAW) with multiple drop transfer per pulse has been used to weld thick wall austenitic stainless steel pipe. Welding of the pipe was also carried by the commonly used shielded metal arc welding (SMAW) and conventional gas metal arc welding (GMAW) processes and compared. Utility of the P-GMAW to facilitate narrow gap welding of the thick wall pipe by appropriate control of pulse parameters has been discussed in reference to produce superior quality weld. The superiority of weld quality has been justified through the microstructure, mechanical properties, residual stresses and fracture mechanics properties of weld joints. Basic characteristics of the P-GMAW process changing the scenario of thick wall pipe welding have been closely studied with respect to its arc characteristics and behaviour of metal transfer. A precise control of the process in order to achieve desired thermal, mechanical and microstructural effects in the narrow gap welding has been achieved by regulation of summarised influence of pulse parameters, mean current (Im) and arc voltage. The summarised influence of pulse parameters is defined by a hypothetically defined dimensionless factor φ = [(Ib/Ip) f.tb] where, the Ib, Ip, f and tb are the base current, peak current, pulse frequency and pulse off (base) time respectively.

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.

Sign in / Sign up

Export Citation Format

Share Document