Real-time nondestructive monitoring of the gas tungsten arc welding (GTAW) process by combined airborne acoustic emission and non-contact ultrasonics

2018 ◽  
Author(s):  
Didem Ozevin ◽  
Lu Zhang ◽  
Alexandra-Del-Carmen Basantes-Defaz ◽  
Donald E. Yuhas ◽  
Zeynab Abbasi ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Real Time ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Nondestructive Monitoring ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Gas Tungsten

scholarly journals Arc Characteristics and Weld Bead Microstructure of Ti-6Al-4V Titanium Alloy in Ultra-high Frequency Pulse Gas Tungsten Arc Welding (UHFP-GTAW) Process

2020 ◽  
Vol 26 (4) ◽  
pp. 426-431
Author(s):  
Wei LI ◽  
Gaochong LV ◽  
Qiang WANG ◽  
Songtao HUANG
Keyword(s):  
Titanium Alloy ◽  
Fusion Zone ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Weld Bead ◽  
Gas Tungsten Arc ◽  
Arc Characteristics ◽  
Arc Pressure ◽  
Gtaw Process ◽  
Gas Tungsten

To resolve the problem of grain coarsening occurring in the fusion zone and the heat-affected zone during conventional gas tungsten arc welding(C-GTAW) welded titanium alloy, which severely restricts the improvement of weld mechanical properties, welding experiments on Ti-6Al-4V titanium alloy by adopting ultra-high frequency pulse gas tungsten arc welding (UHFP-GTAW) technique were carried out to study arc characteristics and weld bead microstructure. Combined with image processing technique, arc shapes during welding process were observed by high-speed camera. Meanwhile the average arc pressure under various welding parameters were obtained by adopting pressure measuring equipment with high-precision. In addition, the metallographic samples of the weld cross section were prepared for observing weld bead geometry and microstructure of the fusion zone. The experimental results show that, compared with C-GTAW, UHFP-GTAW process provides larger arc energy density and higher proportion of arc core region to the whole arc area. Moreover, UHFP-GTAW process has the obviously effect on grain refinement, which can decrease the grain size of the fusion zone. The results also revealed that a significant increase of arc pressure while increasing pulse frequency of UHFP-GTAW, which could improve the depth-to-width ratio of weld beads.

Real-time observation of cathodic cleaning during variable-polarity gas tungsten arc welding of aluminium alloy

2009 ◽  
Vol 223 (9) ◽  
pp. 1143-1157 ◽  
Author(s):  
R Sarrafi ◽  
D Lin ◽  
R Kovacevic
Keyword(s):  
Real Time ◽  
Process Parameters ◽  
Arc Welding ◽  
Molten Pool ◽  
Gas Tungsten Arc Welding ◽  
Process Conditions ◽  
Current Electrode ◽  
Gas Tungsten Arc ◽  
Variable Polarity ◽  
Gas Tungsten

Online observation is expected to provide a better understanding of the cathodic cleaning of oxides from the molten pool during variable-polarity gas tungsten arc welding (VP GTAW) of aluminium alloys. In this paper, a machine-vision system with appropriate illumination and filtering is used to monitor in real time the effect of different process parameters on the cleaning of oxides from the molten pool during VP GTAW of Al 6061. Based on the observations, the process conditions under which a clean molten pool can be achieved are determined. In addition, the control of the welding process to maintain the consistency of cathodic cleaning is discussed. The results showed that in order to have an oxide-free molten pool, the solid surface in front of the molten pool should be cleaned from oxides by the electric arc. The choice of process parameters to satisfy this condition has been discussed. It was found that the percentage of direct current electrode positive (DCEP) polarity in the cycle of current has the highest impact on the cathodic cleaning, with the arc current having less influence, and the welding speed showing the least effect. Furthermore, in order to keep the consistency of oxide cleaning, process parameters should be set or controlled to maintain the cleaned zone larger than the molten pool.

In-Situ Neutron Diffraction Study of Gas Tungsten Arc Welding of a 1018 Plain Carbon Steel

2007 ◽  
Vol 1027 ◽  
Author(s):  
Michael Gharghouri ◽  
Michael J Watson ◽  
David Dye ◽  
Ronald B Rogge
Keyword(s):  
Neutron Diffraction ◽  
Arc Welding ◽  
Neutron Diffraction Study ◽  
Plain Carbon Steel ◽  
Gas Tungsten Arc Welding ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Gas Tungsten ◽  
In Situ Neutron Diffraction

AbstractIn-situ neutron diffraction measurements of a dynamic Gas Tungsten Arc Welding (GTAW) process have been performed using a unique instrument that establishes steady-state conditions by translating and rotating a cylindrical specimen past a stationary weld torch. The fixed neutron sampling volume is at a constant location with respect to the torch as new material is brought into the fusion zone. We present maps of lattice spacing and integrated intensity as a function of location about the weld torch, which provide insight into the temperature and phase distributions around the weld.

Effect of Gas Tungsten Arc Welding Condition on Hydrogen Absorption in a Duplex Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 536-541
Author(s):  
Bahram Mirzaei ◽  
Goroh Itoh ◽  
Alireza Khodabandeh
Keyword(s):  
Arc Welding ◽  
Thermal Desorption Spectroscopy ◽  
Gas Tungsten Arc Welding ◽  
Welding Condition ◽  
Gas Tungsten Arc ◽  
Three Samples ◽  
The Matrix ◽  
Gtaw Process ◽  
Gas Tungsten ◽  
The Relationship

The use of duplex stainless steels (DSSs) is steadily increasing. For many uses where joining is needed, gas tungsten arc welding (GTAW) is one of the most important joining methods for DSSs. Since hydrogen embrittlement (HE) occasionally occurs in DSSs, understanding the relationship between the extent of HE and the welding condition is crucial to prevent HE. In this research, the effect of the heat input of GTAW process on the microstructure and the extent of HE in a UNS S31260 (JIS SUS329J4L) has been investigated. For this purpose, three samples have been prepared with diffrent velosity. All the samples have been cathodically hydrogen-charged, and then subjected to tensile test at a strain rate followed by fractography observation. Thermal desorption spectroscopy (TDS) has been carried out on the samples welded at low and average velosities. The results showed that tensile properties of the welded specimens were lower than those of base metal due to coarsening of the matrix ferrite grains and loss in the fraction balance of ferrite and austenite phases in the weld metal zone, where fracture took place.

Development of New Weld Heat Input and Dilution Equations for Gas Tungsten Arc Welding: Part 1

2013 ◽  
Author(s):  
Jonathan K. Tatman ◽  
Steven L. McCracken ◽  
Trevor G. Hicks
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
Filler Metal ◽  
Welding Process ◽  
Gas Tungsten Arc Welding ◽  
Power Ratio ◽  
Gas Tungsten Arc ◽  
Welding Part ◽  
Gtaw Process ◽  
Gas Tungsten

Predicting weld dilution for machine gas tungsten arc welding (GTAW) is a challenge due to the number of variables associated with the welding process. Proper heat input and power ratio controls are critical in many welding applications to control weld dilution, such as for dissimilar metal welds where low weld dilution is necessary to prevent solidification cracking or for cladding where weld dilution is minimized to maintain corrosion resistance of the clad material. This paper discusses the preliminary development and validation of improved weld dilution, heat input, and power ratio equations for the GTAW process. The new equations incorporate power added for the hot wire GTAW process, filler metal material properties, and the heat used to melt the filler metal when added to the GTAW process. The weld dilution equation was validated by comparing calculated dilution values to measured values from bead-on-plate weld trials performed on a variety of filler metals and substrates. Results of the testing and validation along with limitations of the new equations are discussed.

scholarly journals Effect of Current on Mechanical Properties and Microstructure of Aluminum 6061 with Gas Tungsten Arc Welding Process

Kapal ◽  
2020 ◽  
Vol 17 (3) ◽  
pp. 107-113
Author(s):  
Tarmizi Tarmizi ◽  
Kevin Daniel Sianturi ◽  
Irfan Irfan
Keyword(s):  
Mechanical Properties ◽  
Arc Welding ◽  
Gas Flow ◽  
Welding Process ◽  
Butt Joint ◽  
Gas Tungsten Arc Welding ◽  
Welding Parameters ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Gas Tungsten

Aluminum 6061 is an aluminum alloy that is widely used in various industrial fields, which heat treatable. However, it can be joined using a welding process. Aluminum joining using the Gas Tungsten Arc Welding (GTAW) process has become the option to produce good quality joints. This research aims to get optimum welding parameters by knowing the mechanical properties and microstructure of the welding results. The GTAW process uses a 25-volt voltage, Argon protective gas flow rate of 15 liters per minute with filler rod ER 5356 with 2.4 mm diameter and electrodes tungsten 2.4 mm in diameter. This process uses a single V butt joint and groove angle of 60° with variations in the current of 100, 110 and 120 A. The results indicate that specimens with a variety of current of 110 A give better results in the absence of defects, have a tensile strength of 152 MPa, and get a hardness value of 87.55 HV, which is the highest compared to the other two specimens. Whereas specimens with the current variation of 100 and 120 A have defects in the weld area. The optimum parameters of the 6061 aluminum GTAW process with a thickness of 6 mm using a current of 110 A bring on better outcomes and mechanical properties than the use of currents of 100 and 120 A.

scholarly journals Effect of Heat Input on Distortions and Residual Stresses Induced by Gas Tungsten Arc Welding in SS 316L to INCONEL625 Multipass Dissimilar Welded Joints

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Harinadh Vemanaboina ◽  
B Sridhar Babu ◽  
Edison Gundabattini ◽  
Paolo Ferro ◽  
Kaushik Kumar
Keyword(s):  
Residual Stresses ◽  
Heat Input ◽  
Arc Welding ◽  
Elevated Temperatures ◽  
Welded Joint ◽  
Gas Tungsten Arc Welding ◽  
Average Value ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Gas Tungsten

In the present study, distortion and residual stresses in the multipass welded joint were analyzed with respect to heat input. The welded joint was produced using the gas tungsten arc welding (GTAW) process with dissimilar Ni-based filler of ERNiCrMo-3. This dissimilar joint is essential in power generating nuclear and thermal plants operating at elevated temperatures. The distortion and residual stress measurements were taken using the Vernier height gauge and XRD method. To evaluate the mechanical properties, tensile testing was carried out at room temperature. The welded joint qualified the tensile test with an average value of 593 MPa. In the weld metal, a significant variation of residual stresses is measured on the top surface of the weldment along with the thickness with peak magnitude of 145 MPa to 180 MPa at the fusion zone.

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