Influence of external loads on a characteristic angle between grains and solidus line as an indicator for hot cracking susceptibility during GTA welding

Gollnow, Christian; Griesche, Axel; Weidemann, Jens; Kannengießer, Thomas

doi:10.1016/j.jmatprotec.2016.08.013

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…Tensile strength behaviors of TIG welded specimens were evaluated against three inside coated fillers at three levels of welding current; experiments include all possible combinations among these selected parameters. From the available literature, it is different to compare the results against this presented study because AA6061 filler was rarely used due to the susceptibility of hot cracking in the weld region [36,37]. The experimental results have shown an increasing trend in tensile strength properties; thus, this behavior is the outcome of the selected mechanism of the nano-induced coating as discussed in Sect.…”

Section: Tensile Strength Propertiesmentioning

confidence: 93%

Modified utilization of semi-sectioned tubes as filler coated with MWCNTs–TiO2 in TIG arc welding to recover fusion lost mechanical properties of the weldment

Muzamil

Samiuddin

2018

J Braz. Soc. Mech. Sci. Eng.

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The loss of mechanical properties in heat treatable aluminum alloys categories during arc fusion welding processes is a critical issue, which limits the direct application in contrast to different post-treatments methods. This work involved a strategy for the novel and distinctive formation of fillers using 3-mm-diameter (AA6061) tubes having MWCNTs and TiO 2 nanoparticles coating on the inner surface. A series of experiments were conducted using TIG welding to evaluate the effect of welding current and composition of inside coating (MWCNTs-TiO 2) contents on welding strength. Three gradually increasing current values (160 A, 180 A and 200 A) were selected and tested against three combinations of nanocomposite coatings that include 1 wt% MWCNTs-TiO 2 , 1.5 wt% MWCNTs-TiO 2 and 2 wt% MWCNTs-TiO 2. Acceptable qualified bonding between nanocomposite and inside surface is utmost important before conducting the experiments, Tape Test (ASTM-D3359-09 e2) was performed for the assessment of bonding conditions and led to qualitatively exceptional bonding conditions after applying vacuum heating cycle. Tensile test results have demonstrated a significant improvement of 34.20-45.65% strength using innovative nanocomposite coated semi-sectioned tube in comparison to tube fillers without coating. Meanwhile, a beneficial gradually forming W-shape microhardness profile in contrast to conventional U and V shape profiles was achieved at 1.5 and 2 wt% of MWCNTs, and the uplift of hardness in the WZ region up to 86.51% subjected to increase high MWCNTs contents in combination with the current. Therefore, it is concluded to be a virtuous strategy for reinforcing mechanism of weldments to encounter some fusion property loss in aluminum alloys.

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Section: Tensile Strength Propertiesmentioning

confidence: 93%

Modified utilization of semi-sectioned tubes as filler coated with MWCNTs–TiO2 in TIG arc welding to recover fusion lost mechanical properties of the weldment

Muzamil

Samiuddin

2018

J Braz. Soc. Mech. Sci. Eng.

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“…The direction of columnar dendritic grains changed periodically with the heat source oscillation, which made crack propagation difficult. Gollnow et al [ 25 ] reported that the angle between the fusion line and the predominant main axis grains is correlated to the probability of occurrence of hot cracking. Shinozaki et al [ 26 ] suggested that a coarse equiaxed grain structure resulted in high solidification cracking susceptibility, which was also confirmed by Tang and Vollertsen [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Solidification Crack Susceptibility of Al 6014 Molten Alloy Subjected to a Spatially Oscillated Laser Beam

2018

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Oscillating laser beam welding for Al 6014 alloy was performed using a single mode fiber laser and two-axis scanner system. Its effect on the microstructural evolution of the fusion zone was investigated. To evaluate the influence of oscillation parameters, self-restraint test specimens were fabricated with different beam patterns, widths, and frequencies. The behavior of hot cracking propagation was analyzed by high-speed camera and electron backscatter diffraction. The behavior of crack propagation was observed to be highly correlated with the microstructural evolution of the fusion zone. For most oscillation conditions, the microstructure resembled that of linear welds. A columnar structure was formed near the fusion line and an equiaxed structure was generated at its center. The wide equiaxed zone of oscillation welding increased solidification crack susceptibility. For an oscillation with an infinite-shaped scanning pattern at 100 Hz and 3.5 m/min welding speed, the bead width, solidification microstructure, and the width of the equiaxed zone at the center of fusion fluctuated. Furthermore, the equiaxed and columnar regions alternated periodically, which could reduce solidification cracking susceptibility.

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Influence of external loads on a characteristic angle between grains and solidus line as an indicator for hot cracking susceptibility during GTA welding

Cited by 2 publications

References 10 publications

Modified utilization of semi-sectioned tubes as filler coated with MWCNTs–TiO2 in TIG arc welding to recover fusion lost mechanical properties of the weldment

Modified utilization of semi-sectioned tubes as filler coated with MWCNTs–TiO2 in TIG arc welding to recover fusion lost mechanical properties of the weldment

Microstructure and Solidification Crack Susceptibility of Al 6014 Molten Alloy Subjected to a Spatially Oscillated Laser Beam

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