I have tried to heat treat a batch of 6 knives three times now (4 of 1095 and 2 5160).
All threes the have come out too soft (around 50HRC).
The first time, I normalized targeting 1550 to 1575F and hardened the 1095 at ~1450F and the 5160 at ~1500-1525F. I used a thermocouple and hand held IR thermometer gun to monitor temp. Soak times once at a semi-steady temp were a minimum of 5 minutes and up to 10 min. I quenched in parks 50 for about 10 seconds and then went straight to 1" thick AL plates in a vice to prevent warping. I used anti scale powder and cleaned up with a wire brush and water. Hardness testing was done with a set of hardness files.
The second time I went through the process I put a 2.5" diameter, 1/4" wall, 10.5" long pipe inside the forge centered between the two burners. I drilled a hole in the forge and through the center of the pipe and ran a K type thermocouple so the tip was in the center of the pipe. I watched the temp via a thermocouple but I am not sure how accurate it is. The IR gun read lower then the thermocouple.
I think I screwed up the second time by not normalizing and getting straight to hardening. Can you confirm that I would need to normalize again?
The third time I tired just heating to nonmagnetic and then air cool for normalization, then heat again to nonmagnetic and then quench in Parks 50 and then to the AL plates.
In all three cases I tempered in a toaster oven at 375F (verified with thermometers not trusting the oven settings) for 2 hours then turn off the oven and let cool to room temperature and then do that a seconding time.
I think that my problem lies in getting the steel normalized properly. Getting to the target temp in a forge and soaking for the right amount of time is very hard even with the pipe in the forge. I don't trust the thermocouple and IR gun to have an accurate temperature say to within 25 degrees F. And keeping the temperature inside the pipe low enough is hard. It rises to 1600 to 1700F with the propane flow as low as I could get it.
Any and all advice would sure be appreciated! I guess the real answer may be to get and Evenheat oven...
All threes the have come out too soft (around 50HRC).
The first time, I normalized targeting 1550 to 1575F and hardened the 1095 at ~1450F and the 5160 at ~1500-1525F. I used a thermocouple and hand held IR thermometer gun to monitor temp. Soak times once at a semi-steady temp were a minimum of 5 minutes and up to 10 min. I quenched in parks 50 for about 10 seconds and then went straight to 1" thick AL plates in a vice to prevent warping. I used anti scale powder and cleaned up with a wire brush and water. Hardness testing was done with a set of hardness files.
The second time I went through the process I put a 2.5" diameter, 1/4" wall, 10.5" long pipe inside the forge centered between the two burners. I drilled a hole in the forge and through the center of the pipe and ran a K type thermocouple so the tip was in the center of the pipe. I watched the temp via a thermocouple but I am not sure how accurate it is. The IR gun read lower then the thermocouple.
I think I screwed up the second time by not normalizing and getting straight to hardening. Can you confirm that I would need to normalize again?
The third time I tired just heating to nonmagnetic and then air cool for normalization, then heat again to nonmagnetic and then quench in Parks 50 and then to the AL plates.
In all three cases I tempered in a toaster oven at 375F (verified with thermometers not trusting the oven settings) for 2 hours then turn off the oven and let cool to room temperature and then do that a seconding time.
I think that my problem lies in getting the steel normalized properly. Getting to the target temp in a forge and soaking for the right amount of time is very hard even with the pipe in the forge. I don't trust the thermocouple and IR gun to have an accurate temperature say to within 25 degrees F. And keeping the temperature inside the pipe low enough is hard. It rises to 1600 to 1700F with the propane flow as low as I could get it.
Any and all advice would sure be appreciated! I guess the real answer may be to get and Evenheat oven...
