Exotic vs Carbon Steel Kitchen Knives

L

LedSled

Joined
Jul 16, 2007
Messages
164
Forgive me if this has been discussed before, but my searches on BladeForums came up "page not found."

I'm quite curious if anyone has seriously compared the old carbon steels, carefully heat treated, to the new exotic steels for kitchen knives.

The reason I ask, is that I've been comparing my expensive new Shun's Elite-series SG2 Santoku with (choke!) an old stamped-out $8 Walmart-special chef's knife. My observations:
1) Cheap carbon steel may be soft, but it wears well and the edge straightens up nicely with a strop or smooth steel. Give it points for maintainability.
2) Shun's SG2 powder steel has better wear characteristics, but it needs re-honing once the edge is lost. The edge seems to break, rather than bending over.
3) My old WW2 bayonet in 1095 steel, with its excellent heat treat, makes me wonder if kitchen cutlery in the carbon steels might not be a better choice. I'm thinking mainly, but not exclusively, about carefully heat-treated A2 or 52100.
4) Stainless is nice, but put a patina on carbon steel and it doesn't rust that readily.
5) Debate sharpness and edge retention all you like, but an easily maintained edge matters most for daily kitchen use. I want shaving-sharp knives every time out of the block.

Comments anyone? I'll apologize in advance to the forum's materials snobs. It would also be nice to hear if anyone actually offers quality carbon steel cutlery.

Edit on 10/17/07 to summarize the discussion:
At a terminal bevel of 15 degrees per side, the edge on Shun's SG2 steel at Rockwell 64 has a tendency to micro-crumble. It's still usefully sharp, and continues to be extremely stable and durable. The responses suggest that, go a little steeper, and it won't be a problem. However, the best carbon steels hold an edge at much shallower angles. They also cost less, but can leave a metallic taste on your food. AEB-L steel (I'm not quite sure what it is) got some impressive plugs for kitchen knives, and a steel called SB1 (also at this moment for me an unknown), and gunmike1 gave Takeda's AO an enthusiastic rave. One unresolved point is which steels, like the old straight razors, allow you to let the metal relax, then straighten and polish the edge with a strop.
 
LedSled said:
Forgive me if this has been discussed before, but my searches on BladeForums came up "page not found."

I'm quite curious if anyone has seriously compared the old carbon steels, carefully heat treated, to the new exotic steels for kitchen knives.

The reason I ask, is that I've been comparing my expensive new Shun's Elite-series SG2 Santoku with (choke!) an old stamped-out $8 Walmart-special chef's knife. My observations:
1) Cheap carbon steel may be soft, but it wears well and the edge straightens up nicely with a strop or smooth steel. Give it points for maintainability.
2) Shun's SG2 powder steel has better wear characteristics, but it needs re-honing once the edge is lost. The edge seems to break, rather than bending over.
3) My old WW2 bayonet in 1095 steel, with its excellent heat treat, makes me wonder if kitchen cutlery in the carbon steels might not be a better choice. I'm thinking mainly, but not exclusively, about carefully heat-treated A2 or 52100.
4) Stainless is nice, but put a patina on carbon steel and it doesn't rust that readily.
5) Debate sharpness and edge retention all you like, but an easily maintained edge matters most for daily kitchen use. I want shaving-sharp knives every time out of the block.

Comments anyone? I'll apologize in advance to the forum's materials snobs. It would also be nice to hear if anyone actually offers quality carbon steel cutlery.
Click to expand...
There is a form on knifeforums.com that is dedicated to kitchen knives, there is a lot to learn on there. There are lots of knifemakers that use carbon steels that do so in the Japanese method, as well as a few forgers who make kitchen knives (though not many). My favorite kitchen knife steel is AEB-L, because of the fact that it is very easy to sharpen, has the carbide size of 52100, and it's stainless. My dad could make you one of those if that's what you're interested in.

I agree that carbon steels are much easier to sharpen than the modern "super steels", of which AEB-L isn't. Also, even with powder metallurgy, those PM stainless steels will lose their initial sharpness quickly because the average carbide size is larger than a very thinly sharpened edge. As for the best comparisons I've seen of how the super stainlesses do, here it is: http://www.knifeforums.com/forums/showtopic.php?tid/802103/

Edit: there's also an interesting steel we're looking into called SB1, which has greater wear resistance than AEB-L (and slightly larger carbides), but still lower carbide volume and carbide size than the current PM stainlesses, so it provides somewhat of a tradeoff between ultimate in edge stability (ability to hold a fine edge), and the ultimate in wear resistance.
 
Larrin said:
. . . My favorite kitchen knife steel is AEB-L ...
Click to expand...
Now, why doesn't that surprise me? :D I've toned down my praise of 13C26 (a/k/a AEB-L) lately because I'm sure people were getting bored of hearing it, but it would indeed make a wonderful kitchen knife.

IMO it's really a matter of having the right balance of steel properties and characteristics for the particular knife and use. New, high carbon "super" steels run at high hardness should be expected to have excellent edge holding, but they fall short in other qualities that many of us want in a kitchen knife, especially durability and corrosion resistance. Traditional carbon steel blades can suffer rapid edge degradation due to rust/corrosion unless well cared for, as well as react unpleasantly with certain foods like cabbage.

With a steel like AEB-L you get a nice "package" of qualities for kitchen use, including toughness, edge stability, and decent corrosion resistance. The fact that it should cost far less than a super steel laminate just sweetens the deal.
 
Ledsled - I purchase vintage, well made, carbon steel kitchen knives on Ebay and then clean them up. I like to rehandle them with some nicely figured stabalized wood and then give them away as presents. Everyone loves them. They sharpen easily, do not chip, and hold an edge just fine. Of course I have to "train" folks on how to care for them, like no dish washers, clean and wipe dry, don't let them sit around with water or acidic food juices on them, but otherwise these old carbon steel knives are great.

I don't own any AEB-L kitchen knives so I cannot speak to them.
 
Larrin, Isn't R2 a bearing steel with more similarities to 52100 than VG10, CPM 154cm, CoweryX/Y, etc.? A very clean, powder steel, bearing steel with small carbides should do pretty well in these tests. I'd bet it can get pretty good initial sharpness.BTW, I still use Old Hickory knives over Forschiners, and some others which were considered good when purchased. I even gun blued a couple of them to see how they'ed turn out, and replaced them in the kitchen for about $7. Joe
 
The Mastiff said:
Larrin, Isn't R2 a bearing steel with more similarities to 52100 than VG10, CPM 154cm, CoweryX/Y, etc.? A very clean, powder steel, bearing steel with small carbides should do pretty well in these tests. I'd bet it can get pretty good initial sharpness.BTW, I still use Old Hickory knives over Forschiners, and some others which were considered good when purchased. I even gun blued a couple of them to see how they'ed turn out, and replaced them in the kitchen for about $7. Joe
Click to expand...
I dont' know anything about R2, they don't release any information about it. It's not a common steel.
 
Carbon steel kitchen knives lose their edges more through corrosion than through wear. If you use them on fruit or onions they can corrode very fast. I like them best for slicing meat or cutting vegetables that are pretty neutral. Another issue is that carbon steel blades can leave a metallic taste on acidic foods.
 
LedSled,

If a carbon steel kitchen knife is carefully heat treated, it won't be available for $8, nor will steeling help it much. Carbon steel can be made to equal or outperform many of the new super steels, but people that use it will have to be very careful with it, and the general public just isn't into knives that much, which is too bad.
 
No doubt you're correct, sodak. I'd guess that all the inexpensive kitchen knives, carbon or stainless, don't even get a heat treat, let alone a good one. Also, my Forschner smooth steel, hand polished by me, now sits unused in a drawer. Its hole in my knife block got milled into a slot to hold another knife.

If I can find a decent carbon chef's knife that won't break the bank, I'll buy it and write up a comparison to the Shun. It'll be interesting.

Jeff, your comment on metallic taste is disturbing. Thanks for bringing it up.
 
if the general population had a choice between a cheap stainless and 52100, they would go with the stainless. Ok, you cut a lime, then set your knife down to go drink margarita with your party friends, tomorrow morning you do your dishes and your carbon steel knife is corroded! this is what people think about. I love carbon steel though.
 
If AEB-L and 13C26 didn't exist I would agree about preferring 52100.
 
AO Super Steel is a tremendous performer in my Takeda 240mm Gyuto, but you have to wash and wipe it down frequently to avoid rust. It takes very acute angles and has great edge retention, but with it's tremendously thin and acute edge (9 degrees included from the factory, I took it to about 8 included) and very hard, brittle steel, it can microchip if you bang it hard off of a poly cutting board (easy to do when it cuts through food as if it isn't there). I need a quality wood cutting board soon, and I microbeveled it to about 12 or so included and I'll have to see if the microchipping stops. I would love to try some AEB-L at 63-65 RC in a kitchen knife, it should make for a lot of the thin edged goodness and cutting ability of my Takeda, with the huge bonus of being stainless and tougher. That would be a hard combo to beat. We just need to get Larrin to make us some!

Mike
 
gunmike1,

Did your gyuto's factory edge come at 9 degrees total, or per side? If it's total, that's razor blade territory, and I can't imagine any kitchen knife standing up with that thin of bevel.

Thanks for weighing in,
Ray
 
LedSled said:
gunmike1,

Did your gyuto's factory edge come at 9 degrees total, or per side? If it's total, that's razor blade territory, and I can't imagine any kitchen knife standing up with that thin of bevel.

Thanks for weighing in,
Ray
Click to expand...

9 degrees total, actually about 4.6 per side per my calipers and trig calculations. I asked for the thinnest and most acute one they had. I hear the Takedas generally run between 5 and 6 per side from the factory. The AO Super Steel can take a really thin and acute edge, but slamming it into a poly cutting board isn't recommended (this is the source of my microchipping, it just cuts through food with ease and slams the board). With a 6 per side micro I didn't run into any chipping with some cutting today on a wooden board, and it still cuts with ease, so the extra couple degrees didn't seem to negatively impact my cutting ability. The geometry on this knife compared to what I was using is a HUGE improvement, this knife just plain cuts. However, like I said, it can microchip (which actually will still allow it to slice at a high level for a really long time) and does require frequent rinsing and drying due to the lack of corrosion resistance, but the very good edge retention and incredible cutting ability are worth it to me.

Mike
 
woah, 4.6 is a tiny number! I take it that this never goes through bones in your kitchen.
 
gunmike1,

That's quite a testimonial to AO steel, but can you tell us more about the steel and its hardness/heat treat? You make it sound like a very high end carbon.

We're beginning to get to the heart of why I started this thread. At 15 degrees per side terminal bevel, Shun's SG2 at Rockwell 64 has a tendency to micro-crumble. It's tiny, but enough to take off the fine edge. It shows up easily with a 40x stereo microscope under collimated light. The carbides are big, and it takes a diamond-charged strop with a very light touch to lap a really fine edge. The slightest side force crumbles it right off. After that it's extremely stable and durable.

I'm still wondering if the older carbon stuff with a really good heat treat won't do better, as well as costing less. Also, like the old straight razors, you can let the metal relax, then straighten and polish the edge with a strop.
 
LedSled said:
gunmike1,

That's quite a testimonial to AO steel, but can you tell us more about the steel and its hardness/heat treat? You make it sound like a very high end carbon.
Click to expand...
There are several "blue (aogami)" steels. As you can notice, they contain high percentage of Tungsten, so they have quite high wear resistance and they are very "clean" (i.e. they do not contain any impurities that would degrade performance)

Hitachi Blue #1: C 1.2% - 1.4%, Si .10% - .20%, Mn .20% - .30%, P <= .025%, S <= .004%, Cr .30% - .50%, W 1.5% - 2.0%

Hitachi blue #2: C 1.0% - 1.2%, Si .10% - .20%, Mn .20% - .30%, P <= .025%, S <= .004%, Cr .20% - .50%, W 1.0% - 1.5%

Hitachi Blue Super: C 1.4% - 1.5%, Si .10% - .20%, Mn .20% - .30%, P <= .025%, S <= .004%, Cr .30% - .50%, W 2.0% - 2.5%, Mo .30% - .50%, V .30% - .50%
 
I think Takeda runs the Aogami Super around 63-64 RC, but know nothing of the heat treatment. I believe it is ran in the 62+ RC range by the knife companies that I have seen when I was shopping around. I do know it makes for a steel that is very high performance, but like I said it can microchip. And yes, I avoid bones at every corner. If you use proper care (so the edge doesn't corrode away) and technique (right cutting board, no bones, ect.) it seems to hold it's thin edge very well in my home use. If you went with a 10 per side microbevel you probably wouldn't have any issues with non-bone cutting, but part of why I like the knife so much is that the edge is so acute. Of course, as long as you reset the bevel every few sharpenings you probably wouldn't notice a great decrease in cutting ability, but I am going to try to use mine properly and keep it as thin as possible to avoid chipping in my use. A huge part of the reason I bought the knife was because I had heard how it can take a 5 per side edge, so I am reluctant to go any fatter than I have to on that knife.

Mike
 
You must log in or register to reply here.
Back
Top