You nailed it. It is the process used to clean off used hooks for powder coating. I found some tensile test data that showed an increase in tensile strength if tempered around 1000 F for 4 hours but this is nowhere near that long. It would be an interesting experiment, but not worth it this time. I think I will make up some samples and do some testing though. It would be nice to use it in the future as it’s fast and easy!