Limitations of the Schlieren technique for shielding gas flow visualization in arc welding processes

2021 ◽  
Author(s):  
Mateus Barancelli Schwedersky ◽  
Álisson Fernandes da Rosa ◽  
Marcelo Pompermaier Okuyama ◽  
Régis Henrique Gonçalves e Silva
Keyword(s):  
Flow Visualization ◽  
Arc Welding ◽  
Gas Flow ◽  
Shielding Gas ◽  
Schlieren Technique ◽  
Welding Processes

scholarly journals Numerical Simulation of the Behavior of Hydrogen Source in a Novel Welding Process to Reduce Diffusible Hydrogen

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1619 ◽  
Author(s):  
Shinichi Tashiro ◽  
Naoki Mukai ◽  
Yoshihide Inoue ◽  
Anthony B. Murphy ◽  
Tetsuo Suga ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Arc Welding ◽  
Gas Flow ◽  
Operating Conditions ◽  
Shielding Gas ◽  
Diffusible Hydrogen ◽  
Welding Torch ◽  
Deposited Metal ◽  
Suction Nozzle ◽  
Gas Nozzle

This study aims to reduce the diffusible hydrogen content in deposited metal during gas metal arc welding (GMAW) and flux-cored arc welding (FCAW) which induces cold cracking. To achieve this, a novel welding torch with a dual gas nozzle has been developed. This special welding torch decreases the hydrogen source gas evaporated from a welding wire by the suction from the inner gas nozzle. In order to improve the suction efficiency of this evaporated gas, precise control of the suction gas flow is indispensable. In this paper, a simplified numerical simulation model of this process has been described. This model can take account of the evaporation of the hydrogen source gas from the wire while simulating the behavior of the shielding gas and the arc. Using this model, the effect of suction nozzle structure and torch operating conditions on suction gas flow pattern and suction efficiency was also investigated to understand the process mechanism. Furthermore, the diffusible hydrogen content in deposited metal was measured by chromatography as a validation step. Results show that some of the shielding gas introduced from a shielding nozzle was drawn inward and also branched into an upward flow that was sucked into the suction nozzle and a downward flow to a base metal. This branching height was defined as the suction limit height, which decisively governed the suction efficiency. As a result, in order to reduce the diffusible hydrogen, it was suggested that the suction limit height should be controlled towards below the wire position, where the evaporation rate of the hydrogen source gas peaks through optimization of the suction nozzle design and the torch operating conditions.

scholarly journals Characteristics of Welding and Arc Pressure in the Plasma–TIG Hybrid Welding Process

2018 ◽  
Author(s):  
Bo Wang ◽  
Xunming Zhu ◽  
Hongchang Zhang ◽  
Hongtao Zhang ◽  
Jicai Feng
Keyword(s):  
Arc Welding ◽  
Gas Flow ◽  
Welding Process ◽  
Hybrid Welding ◽  
Plasma Arc ◽  
Arc Pressure ◽  
Arc Current ◽  
Arc Welding Process ◽  
Welding Processes

In this article, a novel hybrid welding process called plasma-TIG coupled arc welding was proposed to improve the efficiency and quality of welding by utilizing the full advantage of plasma and TIG welding processes. The two arcs of plasma and TIG were pulled into each other into one coupled arc under the effect of Lorentz force and plasma flow force during welding experiments. The arc behavior of coupled arc was studied by means of it’s arc profile, arc pressure and arc force conditions. The coupled arc pressure distribution measurements were performed. The effects of welding conditions on coupled arc pressure were evaluated and the maximum coupled arc pressure was improved compared with single-plasma arc and single-TIG arc. It was found that the maximum arc pressure was mainly determined by plasma arc current and plasma gas flow. According to the results, the proposed coupled arc welding process have both advantages of plasma arc and TIG method, and it has a broad application prospect.

A mathematical model of the arc in electric arc welding including shielding gas flow and cathode spot location

1995 ◽  
Vol 28 (9) ◽  
pp. 1840-1850 ◽  
Author(s):  
R Ducharme ◽  
P Kapadia ◽  
J Dowden ◽  
M Thornton ◽  
I Richardson
Keyword(s):  
Mathematical Model ◽  
Arc Welding ◽  
Cathode Spot ◽  
Gas Flow ◽  
Electric Arc ◽  
Shielding Gas ◽  
Electric Arc Welding

Estimation and Comparison of Welding Performances Using MRA and GMDH in P-GMAW for SS 316L Material

2018 ◽  
Author(s):  
Rudreshi Addamani ◽  
Ravindra Holalu Venkatadas ◽  
Ugrasen Gonchikar ◽  
Y. D. Chethan
Keyword(s):  
Process Parameters ◽  
Arc Welding ◽  
Gas Flow ◽  
Gas Metal Arc Welding ◽  
Thin Sheet ◽  
Welding Process ◽  
Industrial Applications ◽  
Metal Arc Welding ◽  
Welding Processes ◽  
Gmaw Welding

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.

Spectroscopic Measurements of Hydrogen and Oxygen in Shielding Gas During Plasma Arc Welding

1993 ◽  
Vol 115 (1) ◽  
pp. 145-148 ◽  
Author(s):  
Q. Pang ◽  
T. Pang ◽  
J. C. McClure ◽  
A. C. Nunes
Keyword(s):  
Flow Rate ◽  
Arc Welding ◽  
Gas Flow ◽  
Plasma Arc Welding ◽  
Plasma Arc ◽  
Shielding Gas ◽  
Gas Flow Rate ◽  
Average Temperature ◽  
Welding Arc

In Situ optical spectroscopy has been used on plasma arc welded 2219 aluminum to measure both the average temperature of and the amount of hydrogen and oxygen in the welding arc. Hydrogen and oxygen levels of less than 75 ppm can be readily detected. It is shown that below a critical shield gas flow rate, the rapid invasion of atmosphere can be readily detected by this technique, and that this critical flow rate is dependent on the temperature of the arc.

scholarly journals Shielding Gas and Inclusion Content Effects on Impact Toughness and Tensile Properties of 410NiMo Steel Welds

2021 ◽  
Vol 100 (01) ◽  
pp. 52-62
Author(s):  
BOUCHRA TENNI ◽  
◽  
MYRIAM BROCHU ◽  
STÉPHANE GODIN ◽  
DENIS THIBAULT
Keyword(s):  
Impact Toughness ◽  
Tensile Properties ◽  
Arc Welding ◽  
Postweld Heat Treatment ◽  
Weld Strength ◽  
Shielding Gas ◽  
Absorbed Energy ◽  
Inclusion Content ◽  
Flux Cored Arc Welding ◽  
Welding Processes

The effect of shielding gas on the mechanical and microstructural characteristics of ER410NiMo martensitic stainless steel weldments was investigated. Three weldments with various inclusion contents were manufactured using different shielding gas compositions and welding processes: gas metal arc welding (GMAW) with 100% argon (Ar), GMAW 85% Ar/15% carbon dioxide (CO2), and flux cored arc welding (FCAW) 75% Ar/25% CO2. The inclusions in each weldment were characterized by means of scanning electron microscope observations and energy-dispersive spectroscopy analysis. The weldments underwent postweld heat treatment, after which the chemical composition and reformed austenite proportion were measured to account for microstructural effects. Hardness measurements, tensile tests, and impact toughness tests using the Charpy method were performed. The results showed that the Charpy V-notch (CVN) absorbed energy decreases with increasing inclusion content. The highest CVN absorbed energy, 195 J, was obtained for the GMAW 100% Ar weld, which had the lowest inclusion content. GMAW 85% Ar/15% CO2, with four times more inclusions than the former, had a CVN absorbed energy of 63 J. The current manufacturing process, FCAW 75% Ar/25% CO2, was found to have an inclusion content three times higher than the GMAW 100% Ar weld but a CVN absorbed energy of 66 J, which is close to the GMAW 85% Ar/15% CO2 weld. The results showed that using GMAW 100% Ar as a replacement to FCAW 75% Ar/25 % CO2 would lead to a three-fold improvement in terms of absorbed impact energy. The effect of inclusions on tensile properties, which was not clearly identified as several factors, in addition to inclusion content, affects the weld strength and elongation. Overall, the yield and ultimate tensile strengths differed slightly: 724 and 918 MPa for GMAW 100% Ar, 746 and 927 MPa for GMAW 85% Ar/15% CO2, and 711 and 864 MPa for FCAW 75% Ar/25% CO2, respectively.

Prediction of Weld Bead Dilution in GMAW Process Using Fuzzy Logic

2011 ◽  
Vol 110-116 ◽  
pp. 3171-3175 ◽  
Author(s):  
Masood Aghakhani ◽  
Maziar Mahdipour Jalilian ◽  
Alimohammad Karami
Keyword(s):  
Fuzzy Logic ◽  
Arc Welding ◽  
Gas Flow ◽  
Gas Metal Arc Welding ◽  
Metal Arc Welding ◽  
And Performance ◽  
Welding Processes ◽  
St37 Steel ◽  
Central Composite ◽  
Plate Distance

Gas metal arc welding is one of the most important arc welding processes used in manufacturing and repair. In this process selecting appropriate values for process variables is essential in order to decide upon metal transfer and subsequently control the heat input into the workpiece from which reliable predictions could be made about the metallurgical, mechanical properties and performance of the welded joints. In this paper, the welding dilution in gas metal arc welding of ST37 steel has been predicted by fuzzy logic. A five level five factor rotatable central composite design was used to collect the welding data and the weld dilution was modeled as a function of wire feed rate, welding voltage, nozzle-to-plate distance, welding speed and gas flow rate.

Sign in / Sign up

Export Citation Format

Share Document