He's already stated the service, that being H2SO4/sulfuric acid. In light of that, to my mind, there are more considerations to this than simply the wall thickness. The nature of what corroded it to begin with should be addressed. Depending on the nature of the corrosion, my concern would be how the sulfuric acid would interact with any remenants of the originating corrosion mechanism. Simply sand blasting may or may not have been enough to remove all traces. Based on grade etc listed, they can lose .047" from nominal (3/64th)
The shadows on the corrosion face edges imply something deeper than that.
All in all, If I saw something like that, I'd sure be looking for any valid reason to get rid of it given the service of sulfuric acid. If it were a water line or something like that, I probably would'nt worry about it if it's min wall wasn't violated, but acid?? Somebody could get hurt if it fails, and I sure wouldn't want to be the engineer who ok'd something like that if it failed with pictures like that floating around.
My opinion for what it's worth,
Gerald