Microstructural characterization and formation of α′ martensite phase in Ti–6Al–4V alloy butt joints produced by friction stir and gas tungsten arc welding processes

2013 ◽  
Vol 47 ◽  
pp. 143-150 ◽  
Author(s):  
M. Esmaily ◽  
S. Nooshin Mortazavi ◽  
P. Todehfalah ◽  
M. Rashidi
Keyword(s):  
Arc Welding ◽  
Microstructural Characterization ◽  
Martensite Phase ◽  
Gas Tungsten Arc Welding ◽  
Butt Joints ◽  
Friction Stir ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Welding Processes

Friction Stir and Gas Tungsten Arc Welding of ZM21 Magnesium Alloy

2014 ◽  
Vol 909 ◽  
pp. 77-82
Author(s):  
Hari Krishna Kallipudi ◽  
Rama Koteswara Rao Sajja ◽  
Venkata Subba Rao Veera
Keyword(s):  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Arc Welding ◽  
Welding Process ◽  
Gas Tungsten Arc Welding ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Welding Processes

Magnesium alloy ZM21 plates were welded using friction stir welding, a solid state process and gas tungsten arc welding which is a fusion welding process. Defect free, full penetration welds were obtained after several trials using different process parameters. The effect of welding processes on mechanical properties of Mg-Zn-Mn joints were evaluated using tensile tests, bend test, vickers micro hardness measurements and optical microscopy. Welds produced by Friction stir welding process exhibited superior tensile properties compared to Gas Tungsten Arc Welding process. Hardness reduction in the weld metals were observed for both the welding techniques. Friction stir welds showed finer grains in the weld nugget and in the heat affected zone. Both types of welds exhibited good bend ductility comparable to that of the base material. It has been concluded that both the processes are well suited to obtain sound welds of the magnesium alloy ZM21 and Friction stir welding process offers stronger welds.

Role of welding processes on microstructure and mechanical properties of nuclear grade stainless steel joints

2019 ◽  
Vol 233 (11) ◽  
pp. 2335-2351 ◽  
Author(s):  
R Rajasekaran ◽  
AK Lakshminarayanan ◽  
M Vasudevan ◽  
P Vasantharaja
Keyword(s):  
Stainless Steel ◽  
Base Metal ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Nuclear Grade ◽  
Lower Percentage ◽  
Weld Joints ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Welding Processes

Nuclear grade 316LN austenitic stainless steel weld joints were fabricated using conventional gas tungsten arc welding (GTAW), activated flux gas tungsten arc welding (AGTAW), laser beam welding (LBW) and friction stir welding (FSW) processes. Assessment of weld beads was done by mechanical and metallurgical characterizations. Bead geometry and weld zones were studied by taking macrographs along the transverse side of the weld joints. Metallurgical features of different weld joints were carried out using optical microscopy and scanning electron microscopy. Microhardness distribution across four weld joints was recorded and hardness variations were compared. All weld zone, heat affected zone (HAZ) of GTAW and LBW, thermo-mechanically affected zone (TMAZ) of FSW processes, exhibited higher hardness values than the base metal. Reduced hardness was recorded at HAZ of AGTAW process. This was the result of a considerable grain growth. LBW joint showed the highest hardness value at the center of the fusion zone due to fine equiaxed dendrite morphology. Tensile and impact properties of different welding processes were evaluated and comparisons were made at room temperature. All weld samples displayed high yield strength (YS) and ultimate tensile strength (UTS) with a lower percentage of elongation compared to that of the base metal. FSW joint showed improved YS, UTS and impact toughness compared to other weld joints. This is attributed to the formation of strain-free fine equiaxed grains at stir zone around 5 µm in size with subgrains of 2 µm in size by severe dynamic recrystallization mechanism. Among the fusion welding techniques, AGTAW process exhibited improved toughness, besides almost equal toughness of the base metal due to low δ-Ferrite with high austenite content. Fractography studies of the base metal and different weld samples were carried out by SEM analysis and features were compared.

Microstructure and Corrosion Behavior of Cast A356 and Wrought AA6061 Aluminium Alloy Welds

2010 ◽  
Vol 117 ◽  
pp. 37-42
Author(s):  
K.Ratna Kumar ◽  
G. Madhusudhan Reddy ◽  
K. Srinivasa Rao
Keyword(s):  
Corrosion Resistance ◽  
Electron Beam ◽  
Friction Stir Welding ◽  
Arc Welding ◽  
Electron Beam Welding ◽  
Gas Tungsten Arc Welding ◽  
Fusion Welding ◽  
Friction Stir ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

In this work, it was intended to improve the corrosion resistance of welds of A356 and AA6061 by adopting mainly a special welding techniques, viz., pulsed current gas tungsten arc welding (PCGTAW), electron beam welding (EBW) and friction stir welding (FSW). It was found that the corrosion resistance of A356 and AA6061 welds could be improved by PCGTAW technique rather than continuous current gas tungsten arc welding (CCGTAW). It can be further improved by using electron beam welding. Improved corrosion resistance in A356 welds could be obtained by selecting T6 temper rather than as cast condition. In the case of AA6061, improved corrosion resistance was achieved by selecting T4 temper rather than T6 temper. As for as the welding techniques, friction stir welding (FSW) is useful than fusion welding techniques like CCGTAW,PCGTAW and EBW for improving the corrosion resistance of both the welds.

Microstructure and Wear Characteristics of Fe-Based Hard-Facing Alloy Claddings Formed by Gas Tungsten Arc Welding

2012 ◽  
Vol 706-709 ◽  
pp. 3028-3033 ◽  
Author(s):  
C.M. Lin ◽  
W. Wu
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Arc Welding ◽  
Martensite Phase ◽  
Gas Tungsten Arc Welding ◽  
Abrasive Wear Resistance ◽  
Cladding Layer ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Cladding Layers

The current investigation discusses the effect of Mn and Si contents on the microstructure and abrasive wear characteristic in Fe-based hard-facing alloy. A series of Fe-based hard-facing alloys are successfully fabricated onto the S45C steel by gas tungsten arc welding (GTAW). Results reveal that microstructure contains great amounts of martensite phases and moderate amounts of austenite phases. Si element added into Fe-based hard-facing alloy can not obviously affect the properties of the claddings, such as martensite phase, hardness, and abrasive wear resistance. Nevertheless, Mn element added into Fe-based hard-facing alloy can efficiently affect the martensite phase, hardness, and abrasive wear resistance of the claddings. The martensite contents decreases with the increasing of Mn contents in the cladding layers. The hardness increases as the Mn contents decreases, because the martensite contents increases. The abrasive wear resistance is not only related to the hardness of the cladding layer but the martensite contents of the cladding layer. The abrasive wear resistance is an inverse proportion to Mn contents of the cladding layers. Especially, the cladding layers containing 1.4Si-0.3Mn has the highest hardness of HRC 60.1 and the lowest wear loss of 0.37g.

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