Tempering or drawing back consist of taking a little of the brittleness out.
With the metal clean and shiny it would be heated to a straw color. About 400 deg. I just set my kitchen oven to desired temp and lay it in. Bake for about an hour?? I like to let it cool down in the oven. This will take away a small amount of hardness but add a lot of toughness.
Kitchen ovens temp settings are suggestions. With my oven set at 400 the metal will come out blue. That means it got to about 500 deg. This reamer still cut good though.
This is my interpretation of tempering, I could be wrong, I often am.
