About the knifesteelnerds heat treatments recommended in the book

[PlumasDePan]

In the end of the book it puts heat treatment recommendation for each steel.

However I don't get something. In this article https://knifesteelnerds.com/2018/11/12/rockwell-hardness/
Larrin goes to show that is preferable a high temper temperature with low austerising.

Geting for example the best result for caldie steel at 1020c(1850F) austerising and 525C(1000F) temper. While in the book for the same steel he reccomends a low temper temperature of 400F

 

[Wild Willie]

This might be better in the knife Maker's forum. Or maybe Larrin could weigh in.

 

[Larrin]

I read through the article and I see that I said that a high temper is better at converting retained austenite but I don't see where I gave a general recommendation for a high temper. If using a sufficiently low austenitizing temperature, especially in combination with a cryo treatment, the retained austenite can be kept to reasonable levels.

As to why I recommend a low temper, that is covered in the book. However, one article to look at is the CPM-CruWear heat treatment study where we found the 400F temper to lead to superior toughness. That has been confirmed with a few other steels as well. https://knifesteelnerds.com/2018/06/04/toughness-testing-cru-wear-z-wear/

 

[Stacy E. Apelt - Bladesmith]

Thanks Larrin.

 

[PlumasDePan]

Thank you very much Larrin . I can't believe you responded my post in person.... You are the man!

 

[primecut]

Hi Larrin,
As compared to the results of the 400F low temper, is lowering the tempering temp to say 300 to 375F, increase hardness and reduce toughness?

 

[Larrin]

Reducing the tempering temperature generally reduces toughness along with an increase in hardness.