Microstructural Analysis of Fusion Zone in Gas Tungsten Arc-Welded Newly Developed Co-Based Superalloy

2021 ◽  
Author(s):  
H. R. Abedi ◽  
O. A. Ojo
Keyword(s):  
Fusion Zone ◽  
Microstructural Analysis ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

INVESTIGATION OF PULSE FREQUENCY ON FUSION ZONE CHARACTERISTICS OF GTA WELDED AZ31B MAGNESIUM ALLOY JOINTS

2020 ◽  
Vol 15 (2) ◽  
Author(s):  
Subravel V
Keyword(s):  
Magnesium Alloy ◽  
Tensile Properties ◽  
Fusion Zone ◽  
Welding Speed ◽  
Pulse Frequency ◽  
Pulsed Current ◽  
Az31b Magnesium Alloy ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Different Levels

In this investigation an attempt has been made to study the effect of welding on fusion characteristics of pulsed current gas tungsten arc welded AZ31B magnesium alloy joints. Five joints were fabricated using different levels of welding speed (105 mm/min –145 mm/min). From this investigation, it is found that the joints fabricated using a welding speed of 135 mm/min yielded superior tensile properties compared to other joints. The formation of finer grains and higher hardness in fusion zone and uniformly distributed precipitates are the main reasons for the higher tensile properties of these joints

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.

The characterization of corrosion resistance in the Ti-6Al-4V alloy fusion zone using a gas tungsten arc welding process

2009 ◽  
Vol 24 (12) ◽  
pp. 3680-3688 ◽  
Author(s):  
L.M. Wang ◽  
H.C. Lin
Keyword(s):  
Corrosion Resistance ◽  
Oxide Layer ◽  
Fusion Zone ◽  
Arc Welding ◽  
Welding Process ◽  
Heat Treatments ◽  
Gas Tungsten Arc Welding ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Arc Welding Process

The Ti-6Al-4V sheet alloys were welded by using a common gas tungsten arc welding process. In this work, we study the correlation of corrosion resistance and oxide layer structure produced after commonly used industrial heat treatments. We also study the oxide scales that were formed as a result of the heat-related treatment/aging process. The results indicate that better corrosion resistance of the Ti-6Al-4V alloy weldment can be obtained and significantly improved by a solution treatment plus an artificial aging (ST+AA) treatment, owing to the enhanced intensity of TiO2, V2O5, and Al2O3 oxides that compacted and grew on the surface of fusion zone. The newly found γ-TiAl and α2-Ti3Al particles that nucleated in the fusion zone due to different heat treatments do affect the composition of the oxide layer. The possible mechanism for this oxide layer formation in the fusion zone is discussed.

Microstructural Evolution during Gas Tungsten Arc, Laser and Resistance Spot Welding of Al-Containing Transformation Induced Plasticity (TRIP) Steel

2010 ◽  
Vol 89-91 ◽  
pp. 23-28 ◽  
Author(s):  
M. Amirthalingam ◽  
M.J.M. Hermans ◽  
I.M. Richardson
Keyword(s):  
Microstructural Evolution ◽  
Trip Steel ◽  
Spot Welding ◽  
Microstructural Analysis ◽  
Spectroscopy Analysis ◽  
Delta Ferrite ◽  
Trip Steels ◽  
Resistance Spot ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

In this work, the microstructural evolution of aluminum containing commercial grade TRIP steels during gas tungsten arc (GTA), Laser beam (LB) and resistance spot (RS) welding have been studied. Microstructural analysis was carried out using optical and scanning electron microscopy. Results show that fusion zones of welded TRIP steels contain complex inclusions with similar size distribution. The energy dispersive spectroscopy analysis of inclusions indicated that these inclusions are primarily oxides of aluminum with epitaxial enrichment of manganese and phosphorous. The fusion lines of GTA and LB welded aluminum containing TRIP steel contain a zone of polygonal ferrite with a size of about 200 m and 50 m respectively. It is found that aluminum partitioned from the liquid weld to the solidified delta ferrite in the fusion line causing enrichment and resulting in ferrite stabilisation. This ferrite zone was not found in the case of resistance spot welded samples due to faster cooling rates.

Vertical-Up Gas Tungsten Arc Welding of Ti6Al4V Alloy and Characterization

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
R. K. Gupta ◽  
Paul G. Panicker ◽  
Vinu Paul ◽  
G. Radhakrishnan ◽  
L. Rajesh ◽  
...  
Keyword(s):  
Microstructural Analysis ◽  
Welding Process ◽  
Ductile Failure ◽  
Gta Welding ◽  
Parent Material ◽  
Ti6al4v Alloy ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Weld Parameters ◽  
Vertical Up

Gas tungsten arc (GTA) welding of Ti alloy Ti6Al4V is carried out in vertical-up direction. Weld parameters for the Ti6Al4V alloy were developed using Ti6Al4V (ELI) alloy filler wire and following two pass welding process. X-ray radiography was carried out to ensure the soundness of the weld. Tensile strength of the weldment was evaluated and microstructure characterization was carried out. It is observed that specimens mostly failed in heat affected zone (HAZ) area toward parent material with occasional failure at the weld. Microhardness mapping and microstructural analysis revealed HAZ as the weaker zone, where dissolution of α and formation of β have initiated. Due to moderate cooling rate at this zone, microstructure remained α–β, whereas weld microstructure is found to have martensitic α′ resulting in an increase in the microhardness. Yield strength (YS) of weldment is found to be more than 90% of parent metal (PM) and also reduction in elongation is noted. Fractography observations of failed specimen away from the weld show mainly ductile failure. Weldment failure fractography shows the presence of dendrite indicating failure near the fusion line.

The Influence of Gas Tungsten Arc Welding Parameters on Mechanical and Microstructure Properties of the TC4 Titanium Alloy

2019 ◽  
Vol 969 ◽  
pp. 895-900 ◽  
Author(s):  
Muralimohan Cheepu ◽  
D. Venkateswarlu ◽  
P. Nageswara Rao ◽  
S. Senthil Kumaran ◽  
Narayanan Srinivasan
Keyword(s):  
Titanium Alloy ◽  
Fusion Zone ◽  
Welding Speed ◽  
Welding Parameters ◽  
Bead Geometry ◽  
Box Behnken Design ◽  
Gas Tungsten Arc ◽  
Tc4 Titanium Alloy ◽  
Gas Tungsten ◽  
Zone Microstructure

In the present study, TC4 titanium alloy was gas tungsten arc welded to evaluate the mechanical and metallurgical properties of the welds. The welds were carried out at different welding conditions such as welding speed and current to identify their effect on microstructural changes and strength of the welds. The results of bead geometry measurements suggests that the fusion zone width and depth was greatly varying with the welding speed and current. It is also observed that the fusion zone microstructure and heat affected zones are greatly controlled by welding conditions. Therefore the mechanical properties of the welds were improved with the changes in welding conditions and are correlated with the metallurgical features of the welds. The optimal welding conditions were analysed using Box-Behnken design and analysis of variance technique for identifying strength of the welds and better bead geometry parameters.

Weldability Characteristics of Sintered Hot-Forged AISI 4135 Steel Produced through P/M Route by Using Pulsed Current Gas Tungsten Arc Welding

2016 ◽  
Vol 35 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Joby Joseph ◽  
S. Muthukumaran ◽  
K.S. Pandey
Keyword(s):  
Fusion Zone ◽  
Heat Input ◽  
Arc Welding ◽  
Testing Machine ◽  
Gas Tungsten Arc Welding ◽  
Filler Materials ◽  
Pulsed Current ◽  
Rectangular Plates ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

AbstractPresent investigation is an attempt to study the weldability characteristics of sintered hot-forged plates of AISI 4135 steel produced through powder metallurgy (P/M) route using matching filler materials of ER80S B2. Compacts of homogeneously blended elemental powders corresponding to the above steel were prepared on a universal testing machine (UTM) by taking pre-weighed powder blend with a suitable die, punch and bottom insert assembly. Indigenously developed ceramic coating was applied on the entire surface of the compacts in order to protect them from oxidation during sintering. Sintered preforms were hot forged to flat, approximately rectangular plates, welded by pulsed current gas tungsten arc welding (PCGTAW) processes with aforementioned filler materials. Microstructural, tensile and hardness evaluations revealed that PCGTAW process with low heat input could produce weldments of good quality with almost nil defects. It was established that PCGTAW joints possess improved tensile properties compared to the base metal and it was mainly attributed to lower heat input, resulting in finer fusion zone grains and higher fusion zone hardness. Thus, the present investigation opens a new and demanding field in research.

INVESTIGATION OF WELDING SPEED ON FUSION ZONE CHARACTERISTICS OF GTA WELDED AZ31B MAGNESIUM ALLOY JOINTS

2019 ◽  
Vol 14 (4) ◽  
Author(s):  
Subravel V ◽  
Thambidurai M
Keyword(s):  
Magnesium Alloy ◽  
Tensile Properties ◽  
Fusion Zone ◽  
Welding Speed ◽  
Pulsed Current ◽  
Az31b Magnesium Alloy ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Different Levels

In this investigation an attempt has been made to study the effect of welding on fusion characteristics of pulsed current gas tungsten arc welded AZ31B magnesium alloy joints. Five joints were fabricated using different levels of welding speed (105 mm/min –145 mm/min). From this investigation, it is found that the joints fabricated using a welding speed of 135 mm/min yielded superior tensile properties compared to other joints. The formation of finer grains and higher hardness in fusion zone and uniformly distributed precipitates are the main reasons for the higher tensile properties of these joints.

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