alloy steel up to heat . This is a piece of stock that is very similar (if not the actual alloy) to 4130/4140 steel , in spark test and workability/hardenability . So I lit the burner at 9 this morning , flame set on medium/low , and put this piece 2.75" diameter and 3.5" long in to soak . I kinda forgot about it until 9:30 , when I checked the piece was red hot shading to oranges right under the flame . I don't know how long it had been at red heat , but I consider the test a complete success . Just checked , the chunk is still too hot to touch . Furnace opening and burner baffle were both closed when I shut it off at
9:30 , so apparently it holds the heat well too .
'