# Benefits of good heat treat



## shinyunggyun (May 21, 2022)

What are some other benefits of a good HT besides sharpness, edge retention, and ease of sharpening?


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## jedy617 (May 21, 2022)

that's about it, but for stainless steels...stainlessness


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## McMan (May 21, 2022)

That the edge doesn't crumble like an old brick...


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## blokey (May 21, 2022)

Toughness, too.


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## superworrier (May 21, 2022)

Basically all the qualities of steel


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## McMan (May 21, 2022)

I think about steels as having multiple variables and HT as a way for a maker to prioritize these variables (or even to draw out potential).

IMO bad HT is pretty evident because the knife has shortcomings (I was only partly joking about good HT preventing the knife from crumbling like an old brick). 
But IMO “good” HT is more of a spectrum, and at a certain point represents more of a maker’s choices/tastes/knowledge of a given steel. After all, the same steel can be treated differently, for different reasons, based on different decisions and goals. It becomes about how a maker weighs variables.


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## Delat (May 21, 2022)

Also something Kamon points out regularly is in addition to the heat treat he minimizes the number of heat cycles when forging, I believe to maintain consistency and fine grain in the steel. I think Yu Kurosaki does the double-blade forging thing for the same reason. 

So processes leading up to the actual heat treat are also important.


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## T85 (May 22, 2022)

shinyunggyun said:


> What are some other benefits of a good HT besides sharpness, edge retention, and ease of sharpening?


No dude, that is everything you want out of a blade!


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## 213 (Jun 2, 2022)

I found it to be Stunnig how much influence the heat treat has. I Once made a comperative Review of a Watanabe White#2 vs. A Goko Hamono White#2. The results made the whole steel discussion kind of absurd for me. In the the end the same steels were like night and day compared to each other.


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## MSicardCutlery (Jun 2, 2022)

The steel's heat treat is the largest determinant variable in how a knife performs aside from the blade geometry. There's a reason the Japanese say that the katana receives its "soul" in the quench. With good temperature control the toughness and can be optimized, either to strike the best balance, or to get the most of one property out of a given steel. When it comes to stainless steels the corrosion resistance will also be influenced by the heat treat.


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## Barmoley (Jun 2, 2022)

As important as the heat treat is, the range of differences between 2 different steels would have to be greater than the range of difference of different heat treats in one steel. Heat treat can't change one steel into another, so for some applications one would have to jump to a different steel if he ran out of possibilities the different heat treats on the chosen steel provide.


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## Troopah_Knives (Jun 2, 2022)

There is a lot of mysticism surrounding heat treatment and grain size etc and its importance. I would actually say that HT is less important than material selection for a given knife as material selection has a much greater effect on properties like hardness, toughness, and wear resistance. Sure a bad heat treat can ruin a knife but picking mild steel for a chef's knife and picking Rex 121 for a cleaver will also ruin a knife. In the vast majority of cases on the scale of non-bad heat treatments, you are effectively picking where on the hardness toughness curve you want the steel to fall. Sure in some cases you can get up above that curve a bit with really good temp control and fine grain size (grain size is mostly relevant in low alloy steels) but these are incremental improvements. I can't put a number on it but think in the range of 10%. Most of the time when people say a knife has a really good HT I suspect that the maker has just picked the best hardness toughness balance for that particular geometry.


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## Barmoley (Jun 2, 2022)

Troopah_Knives said:


> There is a lot of mysticism surrounding heat treatment and grain size etc and its importance. I would actually say that HT is less important than material selection for a given knife as material selection has a much greater effect on properties like hardness, toughness, and wear resistance. Sure a bad heat treat can ruin a knife but picking mild steel for a chef's knife and picking Rex 121 for a cleaver will also ruin a knife. In the vast majority of cases on the scale of non-bad heat treatments, you are effectively picking where on the hardness toughness curve you want the steel to fall. Sure in some cases you can get up above that curve a bit with really good temp control and fine grain size (grain size is mostly relevant in low alloy steels) but these are incremental improvements. I can't put a number on it but think in the range of 10%. Most of the time when people say a knife has a really good HT I suspect that the maker has just picked the best hardness toughness balance for that particular geometry.


I would even argue that most of the time when end users say a knife has a really good heat treat they are attributing positive qualities of the knife to the heat treat that in reality come from something else, like geometry. I have a hard time believing that most end users, even enthusiasts could tell minute differences in performance that different, good heat treats provide. We have to assume decent heat treat since bad heat treat will ruin any steel. Besides, different users prefer different qualities anyway, some want harder edges and are willing to give up toughness and ease of sharpening others make feel on stones the most important quality or would rather have more toughness. The best heat treat would certainly be the best hardness toughness balance for a given geometry, but I don't even think we are seeing that when people rave about how good the heat treat is. Makers on the other hand should strive for this though.


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## Marcelo Amaral (Jun 3, 2022)

From the point-of-view of a cook, i find hard to tell how much some of the qualities i look for (toughness, sharpness, edge retention etc.) are due to HT, geometry or steel's type provided we are talking about good steels, like aogami, shirogami, aogami super, sc125, sc145, W2, 52100 etc. 

I feel geometry plays a huge role as thicker, more convex grind edges are noticeably tougher, but i remember one japanese gyuto that had a worse edge retention if compared to most japanese blades with similar steel (shirogami #2) and, at least in my mind, similar geometry (very thin behind the edge, convex grind). It looked to me like this worse edge retention could be, in this case, due to its HT? One day i would like to measure its hardness.

I usually favor sharpness and food release as my favorite traits as long as toughness and edge retention are not a problem, which is true for most blades i've used since getting aboard KKF.


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## captaincaed (Jun 4, 2022)

Troopah_Knives said:


> There is a lot of mysticism surrounding heat treatment and grain size etc and its importance. I would actually say that HT is less important than material selection for a given knife as material selection has a much greater effect on properties like hardness, toughness, and wear resistance. Sure a bad heat treat can ruin a knife but picking mild steel for a chef's knife and picking Rex 121 for a cleaver will also ruin a knife. In the vast majority of cases on the scale of non-bad heat treatments, you are effectively picking where on the hardness toughness curve you want the steel to fall. Sure in some cases you can get up above that curve a bit with really good temp control and fine grain size (grain size is mostly relevant in low alloy steels) but these are incremental improvements. I can't put a number on it but think in the range of 10%. Most of the time when people say a knife has a really good HT I suspect that the maker has just picked the best hardness toughness balance for that particular geometry.





Barmoley said:


> I would even argue that most of the time when end users say a knife has a really good heat treat they are attributing positive qualities of the knife to the heat treat that in reality come from something else, like geometry. I have a hard time believing that most end users, even enthusiasts could tell minute differences in performance that different, good heat treats provide. We have to assume decent heat treat since bad heat treat will ruin any steel. Besides, different users prefer different qualities anyway, some want harder edges and are willing to give up toughness and ease of sharpening others make feel on stones the most important quality or would rather have more toughness. The best heat treat would certainly be the best hardness toughness balance for a given geometry, but I don't even think we are seeing that when people rave about how good the heat treat is.


listen to these two. 
I think in the context of forge heat treating, there’s a large amount of judgement involved, and you can get into the realm of bad/wrong if you’re inexperienced. I don’t think many brands we talk about here fall into this camp.

If you use a temp-controlled kiln and follow basic guidelines, I think it’s harder to screw up.

You’ll probably stumble on particular knives you like to sharpen more than others, but that’s more serendipity than anything.


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