Guys,
When forging steel, either high carbon spring steel or low carbon mild steel the temperature can be in the orange hot range, and as the smith forges, the color of the metal cools to the temperature where the steel is black. At this point the steel can still be forged a little - cold forging, but it is better to reheat at this point. Heating the steel to much higher temperatures can result in interesting things - like the metal giving off sparks and the metal popping like in welding - it really can misbehave as you found out. 0-1 tool steel is more finicky as it does have a higher alloy content of elements other than iron & carbon. This alloy is to allow the steel to stay hard & strong at the higher temperatures we find the tool bit is subjected to in modern machining practice. This is of no advantage to parts for an flintlock. Personally I like to forge 1095 (a straight carbon steel, iron and 1% carbon) at no more than red hot to avoid things like your adventure. It does require a short forging time - only a few hammer smacks - and then return to the fire. The annealing - transition - hardening temperature is much hotter than the forging temperature.
Forging wrought iron is much different than steel as the material is in two distinct parts - pure iron and slag. If you forge wrought iron the same way as you forge steel it will again misbehave, but not like steel, wrought will split or "broom straw" at the free end. So wrought iron must be kept at least orange hot and when it cools to red returned to the fire for another heat. In fact when I forge the small lock parts I always try to allow for some extra length that is later cut back to trim away my inevitable broom straw end splits.
Happy New Year to all
Jim Everett
