How to anneal mild steel?
As a supplement to barrow/m’s answer, For better results I would add that the mild steel should be heated to red heat in an oxygen free atmosphere(preferably but not essential) this will reduce or eliminate oxidization scale formation. For best results don’t allow it to cool naturally keep it in the furnace and slowly reduce the furnace temp. It may be sufficient simply to turn off the heat and allow everything to cool over a few hours.
