So I was digging around for suggested annealing after normalizing and lowering thermal cycles for grain refinement. I don't have temperature control, only a magnet and eyeballs at night.
Stacy wrote before (Help with annealing hypoeutectoid steels (5160, 1075 etc) in gas forge and others):
The home method of doing 5160, or other hypoeutectoid, with only a forge would be to heat to non-magnetic, and then increase about two or three shades of red hotter ( if the forge has a pyrometer, 1550-1600°F). Pull out and air cool until it becomes magnetic again. Immediately stick it in the vermiculite tub and let it cool for 6 hours. Remove and quench in water. It should be pearlitic and reasonably soft.
You can also do a sub-critical spheroidizing anneal. Heat to 1600°F and air cool to black. Quench in water. Heat to 1350°F and air cool to black. Quench. Heat to 1250°F and air cool to black. Quench in water. Repeat 1250°F step two more times.
Larrin wrote very similar (https://knifesteelnerds.com/2019/06/17/annealing-part-2/):
For low alloy steels heat treating with simple equipment, heat the steel to a little above nonmagnetic (not as high as for quenching for full hardness) and then place the steel in vermiculite for slow cooling. That will provide an anneal that is similar to the shortened DET anneal described by Verhoeven. That annealing treatment can be performed after cycling the steel for grain refinement. So the total process would be 1) high temperature (~1600-1700°F) normalize, air cool, 2) low temperature austenitize (just above nonmagnetic) and air cool 1-3 times for grain refinement, 3) anneal by heating to just above nonmagnetic and place in vermiculite.
So let's say I want to use a eutectoid or hypereutectoid steels (1084, 1095, 26c3 etc), what is the difference in the state of the steel between the slow cooling in vermiculite versus say trying to guesstimate sub-critical cycling anneal by eye? I'm going to get some vermiculite or other insulator, but I am curious as to what difference in the steel results from the two different methods (slow cooling vs subcritical cycling).
Stacy wrote before (Help with annealing hypoeutectoid steels (5160, 1075 etc) in gas forge and others):
The home method of doing 5160, or other hypoeutectoid, with only a forge would be to heat to non-magnetic, and then increase about two or three shades of red hotter ( if the forge has a pyrometer, 1550-1600°F). Pull out and air cool until it becomes magnetic again. Immediately stick it in the vermiculite tub and let it cool for 6 hours. Remove and quench in water. It should be pearlitic and reasonably soft.
You can also do a sub-critical spheroidizing anneal. Heat to 1600°F and air cool to black. Quench in water. Heat to 1350°F and air cool to black. Quench. Heat to 1250°F and air cool to black. Quench in water. Repeat 1250°F step two more times.
Larrin wrote very similar (https://knifesteelnerds.com/2019/06/17/annealing-part-2/):
For low alloy steels heat treating with simple equipment, heat the steel to a little above nonmagnetic (not as high as for quenching for full hardness) and then place the steel in vermiculite for slow cooling. That will provide an anneal that is similar to the shortened DET anneal described by Verhoeven. That annealing treatment can be performed after cycling the steel for grain refinement. So the total process would be 1) high temperature (~1600-1700°F) normalize, air cool, 2) low temperature austenitize (just above nonmagnetic) and air cool 1-3 times for grain refinement, 3) anneal by heating to just above nonmagnetic and place in vermiculite.
So let's say I want to use a eutectoid or hypereutectoid steels (1084, 1095, 26c3 etc), what is the difference in the state of the steel between the slow cooling in vermiculite versus say trying to guesstimate sub-critical cycling anneal by eye? I'm going to get some vermiculite or other insulator, but I am curious as to what difference in the steel results from the two different methods (slow cooling vs subcritical cycling).
