Question: Heat Treat Hatchet 1045/1075

[teclis22]

Hi all

i just got interested in steel recently. And i would like to know more about heat treatment in general.

The specific scenario here is a hatchet/tomahawk made with a body of 1045 and a cutting bit of 1075. Is the following heat treatment outline somewhat correct ? :

- Smithing:
forgewelding and finishing the form

- sharp Normalizing (2 cycles):
a) At 800°C (1470F), hold time 1 minute, quench in warm oil
b) At 800°C (1470F), hold time 1 minute, quench in warm oil

- Annealing:
at 700 °C (1290F) letting it cool down *very* slowly to 600°C(1110F in the oven
then let it cool down at room temperature

- Polishing/Grinding:
Removing forging scale and the first grind to give the form to the hawk

- Stress reduction:
at 640°C (1180F)for 3 hours then letting it slowly cool down to room temperature

- Hardening:
at 840°C(1540F), hold time 5 minutes
quench in oil

- Tempering (while the steel is still warm after quench):
1) at 200°C (390F)for 2 hours (1st cycle)
2) quench in water immediately
3) at 200°C (390F)for 2 hours (2nd cycle)
4) quench in water immediately
5) at 170°C (330F)for 2 hours (3rd cycle)
6) let it cool at room temperature

- sharpening
Convex main edge

With this I would expect an end result of about 60 HRc at the hawks cutting edge and a very strong and durable martensitic structure with close to 0% remaining austenite.

Looking for tweaks and feedback.

Thanks a lot in advance

tec

edit: added F's

 

[Stacy E. Apelt - Bladesmith]

Looks like sound numbers to me.

 

[teclis22]

Thanks Stacy.
Much appreciated.

Here is the slightly modded version, as i forgot normalizing *blush*

>>- Smithing:
>> Forming the back spike, finishing the form
>>
> - normalizing (3 cycles)[temperature is Ac3 + 40°C]
> a) at 750°C, hold time 5 min, cool down slowly
> b) at 750°C, hold time 5 min, cool down slowly
> c) at 750°C, hold time 5 min, cool down slowly
>
>>- sharp Normalizing (2 cycles):
>> a) At 800°C, hold time 1 minute, quench in warm oil
>> b) At 800°C, hold time 1 minute, quench in warm oil
>>
>>- Annealing:
>> at 700 °C letting it cool down *very* slowly to 600°C in the oven
>> then let it cool down at room temperature
>>
>>- Polishing/Grinding:
>> Removing forging scale and the first grind to give the form to the
>>hawk
>>
>>- Stress reduction:
>> at 640°C for 3 hours then letting it slowly cool down to room
>>temperature
>>
>>- Hardening:
>> at 840°C, hold time 5 minutes
>> quench in oil
>>
>>- Tempering (while the steel is still warm after quench):
>> 1) at 200°C for 2 hours (1st cycle)
>> 2) quench in water immediately
>> 3) at 200°C for 2 hours (2nd cycle)
>> 4) quench in water immediately
>> 5) at 170°C for 2 hours (3rd cycle)
>> 6) let it cool at room temperature
>>
>>- sharpening
>> Convex main edge