Surface morphology: Difference between revisions

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== See also ==
== See also ==
* [[Vision|The vision]]
* [[Third aiCAMstir Meeting, 2 December 2021|Proceeding of the '''Third aiCAM<sup>''stir''</sup> Meeting,''' 2 December 2021]]


== References ==
== References ==
<references />
<references />

Revision as of 17:40, 6 December 2021

Surface morphology is a subset of analytical imaging to describe the macroscopic and microscopic appearance of the top surface friction stir welds

In some cases, high spatial resolution imaging made with sophisticated microscopes is used to produce images of products, samples and objects that cannot be seen with the naked eye.

FSW of steel

WC-based composite tool during FSW of Ni base alloy[1]

Friction stir welding (FSW) of Ni base alloy and of carbon steel was conducted during the development of WC-based composite tools for FSW of high-softening-temperature materials at the Prince Sattam Bin Abdulaziz University in Saudi Arabia and the Suez University in Egypt et al.[1]

FSW tool parts after consolidation, grinding for the required geometries and insertion in the tool holder[1]

The FSW tool was made from WC-based composites with 5 wt% Ni and 2.5 wt% Y2O3.[1]

FSW of Ni base alloy using WC-Co-TaC-NbC tool with 2.5 wt-percent Y2O3 and 5 wt-percent[1]

A visually acceptable weld shows a homogeneous surface from the start to the stop. The annealing colors above the heat affected zone are superficial colorations that result from the application of heat. They can be used on some materials such as stainless steels and copper alloys to assess and monitor the heat input during and even after FSW.

FSW of Ni base alloy using WC-Co-TaC-NbC tool with 2.5 wt-percent Y2O3 and 5 wt-percent[1]

If large surface breaking voids, as at the start of this weld, or small surface breaking voids are visible, as at near the middle of this weld, the weld does not meet the acceptance criteria described in ISO 25239-1:2020(en) — Part 5: Quality and inspection requirements, which is, strictly speaking, only applicable to aluminium.[2]

Preliminary image processing of surface breaking voids in FSW of Ni base alloy using the Fuzzy Select Tool (Magic Wand) in GiMP 2.10

Image processing with Fuzzy Select Tool (Magic Wand) in GIMP 2.10. GIMP (GNU Image Manipulation Program) is a pixel-based graphics program that includes functions for image editing and digital painting of raster graphics. The programme is free software and can be used free of charge.

FSW of Ni base alloy using WC-Co-TaC-NbC tool with 2.5 wt-percent Y2O3 and 5 wt-percent[1]

When welding carbon steel the annealing colors are less visible as shown here on a weld that shows some surface anomalities at the start.

Flash generation during FSW of 7050-T651

Visually acceptable weld in 10mm thick aluminum alloy 7050 as-cast plates

A study on friction stir welding of 10mm thialuminum-scandium alloy 7050-T651 castings (Al–5.6Zn–2.5Mg–1.6Cu) alloyed with 0.12 wt.% scandium was conducted at University of Applied Sciences of Southern Switzerland. The welds were made at a travel speed of 140 mm/min. The pin length was approximately 9.5 mm and the rotation speed was 240 rpm. Weld A was made as cast with acceptable visual appearance.[3]

Flash generation during FSW of 10mm thick artificially aged aluminum alloy 7050-T651 plates

Flash was expelled, while making weld A' in the artificially aged T651 condition.

Flash generation during FSW of 10mm thick aluminum alloy 7050-T651 plates

The flash was different on the advancing and retreating side of the weld. Gerenerating excessive flash is not a problem per se, as the flash can easily be removed with a milling cutter in the FSW machine or a grinding wheel of a manually operated angle grinder. However, in some cases excessive flash might be an indication for undercut, i.e. the weld being thinner than the plates, or for the pin being damaged by contacting the backing bar.

Flash generation during FSW of 10mm thick aluminum alloy 7050-T651 plates

Above photo shows the flash from a different point of view. Therefore, some FSW machines have several cameras installed, e.g. one in front of the FSW tool and two behind the FSW tool (looking at the weld from above and at an angle).

Deformation of the start region of friction stir welded 10mm thick aluminum alloy 7050-T651 plates

Significant deformation occured in the start region of the weld, so that the unwelded region is clearly visible in the area, which had not been stirred by the traversing pin.

See also

References