Jun 30

Titanium aerospace investment casting

In this work, a Titanium aerospace investment casting was analyzed by X-ray micro Computed Tomography (X-ray microCT). The geometry cast and evaluated was supplied by Boeing, and was supplied to CSIR as a design file. This geometry is used to benchmark titanium casting processes and suppliers against aerospace standards. Key features of interest are internal pockets, lugs, and varying thicknesses. Typical evaluations are dimensional, internal soundness, surface finish, and mechanical properties. The sample was supplied to the Stellenbosch University CT Scanner Facility for analysis. Traditional non-destructive test methods such as radiographic testing and ultrasound can be used to detect internal defects successfully, but X-ray microCT allows a more detailed view of the these defects as demonstrated in this technical note.

Ti casting xray image
Figure 1: Digital X-ray image of Titanium investment casting

casting 3d defects
Figure 2: Defect analysis indicating the location, shape and size of each defect larger than 1 mm.
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Front Stack0857
Figure 3: CT Slice image of the casting

wall thickness analysis 3d view
Figure 4: Wall thickness analysis of casting
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part to cad comparison
Figure 5: Part to CAD comparison of the casting
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It has been demonstrated that very useful information can be obtained from automatic analysis of X-ray microCT scans of a casting. Defect analysis, wall thickness analysis and part to CAD comparisons were demonstrated. It would be of particular interest to industrial companies that the nondestructive analysis reported here was performed in less than 4 hours. For lower quality and hence less stringent testing requirements, smaller components or large batches of samples, this time and hence cost can even be significantly reduced further.

THIS WORK WAS CARRIED OUT FOR THE CSIR AND WAS APPROVED FOR PUBLIC RELEASE BY BOEING
FURTHER DETAILS ARE AVAILABLE ON REQUEST

Analysis performed in Volume Graphics VGStudioMax 2.2

2 comments

    • ASHWANI KUMAR SRIVASTAVA on July 29, 2016 at 12:15 pm

    Dear sir,

    We are interpreting Titanium Castings(Ti6Al4V) as per ASTM E1320 , which is produced through Investment Casting route & hipped, .

    We are assuming that chances of inclusions in the castings are remote (casting is produced through Investment casting route) ,hence all the indications are shrinkage & accordingly we are interpreting the casting radiographs.

    We have seen one crack like indication but there is no mention of crack in ASTM E1320, should we assume that cracks are not possible in Titanium castings, further we wish to clarify that such a tight crack is difficult to pick up in RT. We are of the opinion that it is the shrinkage & the size is reduced due to hipping.

    My problem is that castings are already fitted , hence it is not available with us.

    We wish to know how to proceed further?

    Regards

    ashwani kumar srivastava

    1. Hi there
      Please email directly for detailed reply, anton2@sun.ac.za, but for ct scan we need the actual parts it’s the only way. There could be inclusions, not sure about cracks but not impossible especially if they are open to surface and not affected by hip

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