Smith Castings LLC was nearing the completion of a casting project, the completed castings were actually in the shipping department ready to go when the customer contacted Smith to request one of the castings be sent out for x-ray inspection. X-ray inspection was not factored in as a requirement for that particular job. Looking back into the original request for quote there was no designation regarding the requirement for x-ray inspection; nor on the purchase order. Smith looked back into all the records to make sure they hadn’t missed a requirement. They were unable to find any record indicating an x-ray requirement for this part.
Beyond the simple cost of paying for a casting to be x-rayed there is also the potential consequence of the determined outcome of the x-ray inspection. If the inspector deems the castings to fail, they fail. Since there weren’t any standards for x-ray defined prior to casting the part, the question arose, what standard would be used now? Smith asked themselves, “if we knew the standard would we have rigged the pattern differently to guard against every potential?”
With the understanding that ultimately their customer was seeking to provide a quality product to their customer Smith had a conference call and discussed the concerns and challenges with changing the standards and expectations for quality and inspection after the castings had already been produced. The customer was understanding but still wanted to see that their castings meet the desired quality. It was agreed that Smith would share the casting simulation results in an effort to alleviate any concerns and demonstrate the integrity of the castings that were produced.
Additionally, Smith directed their customer to an article published in the International Journal of Cast Metals Research, 2001 “Analysis of ASTM X-ray Shrinkage Rating for Steel Castings”. This article states and assess the capabilities of x-ray inspection. Smith’s experience with x-ray inspection has varied; there have been instances where x-ray is dead-on, and other instances where shrinkage was truly present in a casting but not initially identified until cut-sectioned, and still other circumstances where x-ray identified a concern but when cut sectioned, the issue did not exist in the casting. X-ray is a useful tool within the known inherent limitations.
As promised, a presentation of all the pertinent MAGMASOFT® simulation results was compiled and provided to the customer. These results demonstrated that the castings would meet the soundness quality requirement they were seeking. Shrinkage porosity was present in two locations of the castings but at levels within the allowable limit of the x-ray specification they would have otherwise utilized.