If it's triangular in cross section it's an older style deburring tool used in metalworking. Works fairly well on holes, not so much on edges made by two flat surfaces. It used to be fairly common 50 years ago but there's other deburring tools that work much better now.
I suppose it could also be used for scraping in a surface but it's a bit awkward for the ID of a bearing surface and I wouldn't reach for first. Something with a curve like this was what the old men used and what I was taught with.
For flat surfaces there's these
types that come in a variety of shapes/sizes per individual preference. There's also the Biax power scraper but that's not what the OP asked about.
The one the OP has is likely hardened very high on the Rc scale and can chip somewhat easily. High hardness for cutting metal (deburring) also means the metal is somewhat brittle, especially if it's made from W-1 like they used to. It should have a hollow grind, made by simply holding against the periphery of a pedestal grinder wheel to re-sharpen. Most were about 5" in length when new, many times they were shortened for better control or the one the OP has is just that old to have been ground to the nub length it is now. I have several and still find them to be a quick way to deburr plastic or other soft materials when a file just throws a fuzzy edge.
