The effects of peak temperature and cooling rate on the susceptibility to intergranular corrosion of alloy 690 by laser beam and gas tungsten arc welding

2009 ◽  
Vol 51 (3) ◽  
pp. 439-445 ◽  
Author(s):  
Hwa Teng Lee ◽  
Jia Lin Wu
Keyword(s):  
Laser Beam ◽  
Cooling Rate ◽  
Intergranular Corrosion ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Peak Temperature ◽  
Gas Tungsten Arc ◽  
Alloy 690 ◽  
Gas Tungsten

scholarly journals Comparison of Ti-5Al-5V-5Mo-3Cr Welds Performed by Laser Beam, Electron Beam and Gas Tungsten Arc Welding

2013 ◽  
Vol 63 ◽  
pp. 397-404 ◽  
Author(s):  
T. Pasang ◽  
J.M.Sánchez Amaya ◽  
Y. Tao ◽  
M.R. Amaya-Vazquez ◽  
F.J. Botana ◽  
...  
Keyword(s):  
Electron Beam ◽  
Laser Beam ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Beam Electron ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

scholarly journals The Mechanism for HAZ Liquation of Nickel-Based Alloy 617B During Gas Tungsten Arc Welding

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 94
Author(s):  
Shanlin Li ◽  
Kejian Li ◽  
Mengjia Hu ◽  
Yao Wu ◽  
Zhipeng Cai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Holding Time ◽  
Peak Temperature ◽  
Eutectic Microstructure ◽  
Gas Tungsten Arc ◽  
Nickel Based Alloy ◽  
Gas Tungsten ◽  
M23c6 Carbides

The mechanism for HAZ (heat-affected zone) liquation of alloy 617B during gas tungsten arc welding (GTAW) was investigated. Welding thermal simulation work was conducted to investigate the effects of thermal parameters (peak temperature, holding time, and thermal cycle numbers) on M23C6 carbides’ evolutionary behavior in nickel-based alloy 617B. OM (optical microscopy), SEM (scanning electron microscopy), TEM (transmission electron microscopy), and SIMS (secondary ion mass spectrometry) were employed to characterize HAZ carbides. It was found that the constitutional liquation of M23C6 carbides is responsible for HAZ liquation in alloy 617B. Rapid heating meant that solute atoms released from partially dissolved M23C6 carbides did not have enough time to sufficiently diffuse into the matrix, resulting in eutectic reaction M23C6 + γ → liquid in the temperature range from 1250 °C to 1300 °C. In the following cooling process, the liquid phase transformed into γ and M23C6 (or M6C) carbides simultaneously, creating a eutectic microstructure. Subsequent thermal cycles with peak temperature 1100 °C and proper holding time brought about a tempering effect to precipitate fine M23C6 carbides from the Cr supersaturated zone around the eutectic microstructure. Boron was found to be enriched in carbides and was expected to promote HAZ liquation by two mechanisms. No cracking caused by HAZ liquation has been found, indicating that GTAW is a suitable method for joining alloy 617B.

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.

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