Japanese Makers Quenching

[_THS_]

Hi all,

In a quest to dial down what kind of heat treatment I like for future purchases, I'm trying to figure out how some of my favourite blades are heat treated.

For instance one of my favourite steel to sharpen is Raquin sc145, I know it get hardened to 64-65 with water quenching.

Some steels I like a lot:
Munetoshi San-mai
Watanabe gyuto (iron clad version)
Kenji togashi honyaki (blue1 version)

Thanks for your contribution

Fede.

 

[lemeneid]

Toyanabes are 63-65 HRC, little to very slight distal taper only. Grind is zero grind with just a slight convexing right above the cutting edge.
Love the cutting power of the knife, but don't love the sharpenability of it.

 

[_THS_]

Toyanabes are 63-65 HRC, little to very slight distal taper only. Grind is zero grind with just a slight convexing right above the cutting edge.
Love the cutting power of the knife, but don't love the sharpenability of it.

I own a Watanabe and I honestly love it, think the taper is just about enough... goes from 4.2 at handle to 1.9 at 2cm from the tip. Where did you get the info about the 63-65? Any clue if it is oil or water quenched?

 

[bahamaroot]

I think you're getting a little to hung up on the type of quenching. There is sooo much more that goes into heat treating than water or oil.

 

[milkbaby]

It's not a simple matter of water is better than oil; one should choose the quenchant based on whether a faster or slower quenchant is most appropriate for the particular steel. And the quenchant is only a small part of what goes into heat treatment. The results can vary depending on the structure of the steel prior to austenitizing and quenching to form martensite, what temperature one uses for austenitizing, how long the steel is soaked/held at this temperature, etcetera. Read the article below by @Larrin for more info if you're really interested.

https://knifesteelnerds.com/2019/02/25/how-fast-do-you-have-to-quench-hardenability-of-steel/
I wouldn't choose a knife based on one minor detail like which quenchant was used. It might be interesting to know but not very informative.

 

[_THS_]

I'm not sure I've ever mentioned water being better than oil. I have a Comet honyaki that's actually tits and it is oil quenched.
My question is wich quenchant is being used on the treatment I like on specific japanese knives...
IE: heiji and Shigefusa supposedly share the same steel, why is then heiji much more glassy and easier to chip?

 

[GorillaGrunt]

Haven’t used a Shig but my Heiji chipped so I thinned out the chips and sharpened it, that totally cured the problem. I only put on a tiny edge bevel so I’m pretty confident the problem was the initial edge not the steel.

 

[Runner_up]

I definitely feel like Heiji takes the steel a little harder than shigefusa does. Munetoshi are also made of very hard steel, which is water quenched.

 

[lemeneid]

I'm not sure I've ever mentioned water being better than oil. I have a Comet honyaki that's actually tits and it is oil quenched.
My question is wich quenchant is being used on the treatment I like on specific japanese knives...
IE: heiji and Shigefusa supposedly share the same steel, why is then heiji much more glassy and easier to chip?

Thats because if you take a look at the grind, Heijis are ground really thin while Shigs are fat bastards generally.

HT definitely plays a part, but assuming both Heiji and Shig heat treat their knives decently, its mostly a grind thing.

 

[Corradobrit1]

TF san mai blades are water quenched. W#1 to 64-65 and AS 65-66. The latter is easily my favourite steel with TF's HT.

 

[_THS_]

TF san mai blades are water quenched. W#1 to 64-65 and AS 65-66. The latter is easily my favourite steel with TF's HT.

This is the kind of information I was looking for. I believe both heiji and Watanabe are water quenched, less sure about togashi.