Why do simple stainless steels preform so differently?

[MG74]

My question is regarding what I think is very very simple stainless steels yet they seem to perform way better than what their composition would suggest they should. The steels, in particular, I'm wondering about are AEB-L, 12C27, and 14C28N. I really want to know why AEB-L who's composition seems about as simple as a stainless steel can get with a relatively unimpressive carbon content can reach high hardness levels and compete and seemingly defeat VG-10 and outperform 12C27 and 14C28N and for that matter why are 12C27 and 14C28N even remotely comparable to VG-10?

I'm quite confused about how these simple Swedish steels which are lower in carbon and chromium and contain essentially little to no alloying elements or carbide formers other than chromium have comparable and even superior edge retention when compared to much more alloyed stainless steels. I'm also wondering why AEB-L the simplest of all of the steels above is both the best performer (from what I can tell) and the most expensive by a fair margin. Does it have to do with a special heat treatment or a manufacturing process like CPM or what exactly is going on here?

For reference, I'm comparing the alloys on the Znkives website.

 

[Stacy E. Apelt - Bladesmith]

In a very short explaination, AEB-L is 1070 steel with a healthy dose of chromium. Being slightly hypo-eutectiod, ther is no extra carbon for chromium carbides, so the chromium remains elmental, and provides stainless assets. 1070 will harden to Rc66, so hardness is high. It is prtetty much as simple as that.

 

[MG74]

Why then do lower classes of stainless steel even exist? If they're more complex and perform worse why are they still around and why is AEB-L so expensive if it's that simple? Why bother with all the complexity of a steel like VG-10 or 154cm if it doesn't improve wear resistance over AEB-L or really any other property as far as I can tell?

 

[Willie71]

Aeb-l is one of the cheapest steels out there.

Other steels may prioritize other traits, such as toughness, wear resistance, or corrosion resistance. Aeb-l is designed for razor blades. Pretty hard to find a better application than fine edged knives.

 

[MG74]

AEB-L is fairly cheap to obtain here in Canada as far as I can tell but in production knives, the cheapest AEB-L pocket knife I am able to find is just over a hundred dollars. 440C is actually slightly more expensive to obtain from my supplier in Canada. If it's a cheaper and superior material I just can't wrap my head around why production knives made from it would be so expensive and why there seemingly aren't any budget AEB-L pocket knives or kitchen knives for that matter. AEB-L seems well suited to that as well.

 

[MG74]

If AEB-L is just that good while also being cheap why hasn't someone started producing budget AEB-L knives and disrupted the whole bottom end of the knife market? If you can make stuff out of AEB-L for about the same price or lower than 440c and the other Chinese cheap steels why does that segment of the market even exist?

 

[Larrin]

My question is regarding what I think is very very simple stainless steels yet they seem to perform way better than what their composition would suggest they should.

What does simplicitly have to do with performing well?

The steels, in particular, I'm wondering about are AEB-L, 12C27, and 14C28N. I really want to know why AEB-L who's composition seems about as simple as a stainless steel can get with a relatively unimpressive carbon content can reach high hardness levels...

Hardness is related to how much carbon is dissolved into austenite prior to quenching to form martensite, or in other words, how much carbon is in “solution.” In general, stainless steels with higher carbon end up with carbon tied up in carbides rather than being in solution, so the hardness ends up the same. The carbides in the higher carbon steels give increased wear resistance.

..and compete and seemingly defeat VG-10 and outperform 12C27 and 14C28N and for that matter why are 12C27 and 14C28N even remotely comparable to VG-10?

I’m not sure what you mean by comparable to VG-10.

I'm quite confused about how these simple Swedish steels which are lower in carbon and chromium and contain essentially little to no alloying elements or carbide formers other than chromium have comparable and even superior edge retention when compared to much more alloyed stainless steels.

That depends on what kind of edge retention test you are performing. Higher carbon and alloy stainless steels have greater wear resistance meaning they will perform better on tests like rope cutting or the CATRA test.

I'm also wondering why AEB-L the simplest of all of the steels above is both the best performer (from what I can tell) and the most expensive by a fair margin.

AEB-L isn’t more expensive.

Does it have to do with a special heat treatment or a manufacturing process like CPM or what exactly is going on here?

What AEB-L does well is in having good toughness, edge stability, ease in sharpness, and take very fine edges. It was designed to be a razor blade steel. I would think that it would make some intuitive sense that a lower carbon stainless would excel in toughness and ease in sharpening. The steel has a balanced composition to keep the amount of carbide low to achieve those properties. Other steels are designed to exhibit other properties, such as to maximize wear resistance or corrosion resistance.

For reference, I'm comparing the alloys on the Znkives website.

It can be difficult to predict how a steel performs based solely on its composition. You wouldn’t know how the various elements interact or how the steel is processed.

 

[Larrin]

If AEB-L is just that good while also being cheap why hasn't someone started producing budget AEB-L knives and disrupted the whole bottom end of the knife market? If you can make stuff out of AEB-L for about the same price or lower than 440c and the other Chinese cheap steels why does that segment of the market even exist?

There are low end knives that use various Swedish stainless steels without advertising the grade. If you go up another step in price you have Kershaw knives, though they have some models that are pretty cheap.

 

[Grayzer86]

Aeb-l is the cheapest usable stainless I have found. The qualities you are stating may be misrepresented. While it is tough, and takes a very fine edge, it’s edge retention is decent, not amazing. For abrasion resistance, it doesn’t compete with CPM154, and doesn’t come close to stuff like S30v and higher end steels. I use all of these steels for different purposes and they all perform quite differently. Currently AEB-L is avaialable in far fewer sizes than most other steels so manufacturers have less chance of getting the exact size they need. It needs cryo during heat treat which adds a step that they probably don’t use for 440. It also means that they would have to adjust their tried and tested heat treating procedure that they having been using for however long. Lastly it’s a fairly unknown steel still and many people who would see it in the knife specs would have no idea what it is.

 

[Geoff Flato]

Personally I much prefer 154cm and even 440c to aeb-L, and I've made at least 100 knives with each.
Aeb-L performs decently, but 440c holds an edge longer and is noticably nicer to work with. Compared to 154cm and CPM 154 there isn't really much contest in my opinion.
Personally I'll be ordering another big pile of 440c, and I won't be buying any aeb-L again.
A lot of it boils down to the kind of knives you make and what you look for in a steel. Aeb-L works great for a lot of people, but it isn't for everything.

 

[AVigil]

Steel is often the least expensive part of the knife .

 

[MG74]

Personally I much prefer 154cm and even 440c to aeb-L, and I've made at least 100 knives with each.
Aeb-L performs decently, but 440c holds an edge longer and is noticably nicer to work with. Compared to 154cm and CPM 154 there isn't really much contest in my opinion.
Personally I'll be ordering another big pile of 440c, and I won't be buying any aeb-L again.
A lot of it boils down to the kind of knives you make and what you look for in a steel. Aeb-L works great for a lot of people, but it isn't for everything.

I know 154cm is overall far better but with such high scores in edge-retention and for being such a cheap material I just don't get how nobody has made a budget line of folders or pocket knives that tend to be made from 440C but given very poor heat treatments. Perhaps it's the workability of the steel but I just don't feel like that's a satisfying answer. I don't think it'd be hard to get a profitable cheap production line of AEB-L so it just boggles my mind as to why as far as I can tell it isn't being done.

 

[Larrin]

Where are you getting these “scores” from?

 

[MG74]

Where are you getting these “scores” from?

I'm comparing alloy content from http://www.zknives.com/ but as far as scores go I've been comparing different users and online reviewer's tests of these steels, in particular, the Cedric and Ada channel on Youtube

.

I know his tests aren't super scientific or anything and there's no perfect way to compare steel performance his tests at least show that AEB-L in a production knife tested against an abrasive synthetic can have rather impressive edge retention especially when you compare it to the other steels he's tested.

 

[Geoff Flato]

Heat treated properly with cryo, 440c will be more wear resistant then aeb-L. Aeb-L will be tougher and take a finer edge. Its all tradeoffs once you take hype out and compare apples to apples

 

[Grayzer86]

I know 154cm is overall far better but with such high scores in edge-retention and for being such a cheap material I just don't get how nobody has made a budget line of folders or pocket knives that tend to be made from 440C but given very poor heat treatments. Perhaps it's the workability of the steel but I just don't feel like that's a satisfying answer. I don't think it'd be hard to get a profitable cheap production line of AEB-L so it just boggles my mind as to why as far as I can tell it isn't being done.

It’s entirely possible these budget 440 knives you are comparing are also 440 A or B not 440C. Like I said, and Larrin pointed out several times, it’s a decent steel, but it doesn’t beat very many other steels in wear resistance at all, much less being far superior. I feel like many reasons have been stated as to why they aren’t using it. Just because it’s cheap for us doesn’t mean it’s cheap for manufacturers. These huge companies making tens of thousands of knives are buying incredible amounts of steel. This volume combined with manufacturer incentives and loyalty all likely add up to considerable savings for them. Maybe they can’t get as large of a discount on it as they can on other more widely used steels. Maybe the mills won’t produce it in the thicknesses they want. Maybe it is not cost effective to purchase it and have it shipped to the factories in China or Taiwan, compared to using Chinese steel, or steel that is already comonly used and shipped to China. These large companies have far more things to consider when producing knives than we do, and probably have drastically different material costs and considerations than we do.

 

[MG74]

It’s entirely possible these budget 440 knives you are comparing are also 440 A or B not 440C. Like I said, and Larrin pointed out several times, it’s a decent steel, but it doesn’t beat very many other steels in edge retention at all, much less being far superior. I feel like many reasons have been stated as to why they aren’t using it. Just because it’s cheap for us doesn’t mean it’s cheap for manufacturers. These huge companies making tens of thousands of knives are buying incredible amounts of steel. This volume combined with manufacturer incentives and loyalty all likely add up to considerable savings for them. Maybe they can’t get as large of a discount on it as they can on other more widely used steels. Maybe the mills won’t produce it in the thicknesses they want. Maybe it is not cost effective to purchase it and have it shipped to the factories in China or Taiwan, compared to using Chinese steel, or steel that is already comonly used and shipped to China. These large companies have far more things to consider when producing knives than we do, and probably have drastically different material costs and considerations than we do.

I get that but if the material is cheap and rather promising it's still a huge seemingly unexplored opportunity. If it's not cost-effective to purchase and ship in large quantities it'd still be a promising candidate for a small production runs like Spyderco makes. I'm sure that if there was a huge potential for profit that potential would outweigh the difficulties in doing something like that. Deals would be struck, factories could be opened etc.. If there's a potential profit to be made I can't imagine large companies simply leaving money on the table unless there's some other factor that is at play. What is it about AEB-L that it's rarely used in production? Is it simply too new? I've gotten the impression from some of you that it's sort of a new steel and somewhat unknown.

 

[Willie71]

I get that but if the material is cheap and rather promising it's still a huge seemingly unexplored opportunity. If it's not cost-effective to purchase and ship in large quantities it'd still be a promising candidate for a small production runs like Spyderco makes. I'm sure that if there was a huge potential for profit that potential would outweigh the difficulties in doing something like that. Deals would be struck, factories could be opened etc.. If there's a potential profit to be made I can't imagine large companies simply leaving money on the table unless there's some other factor that is at play. What is it about AEB-L that it's rarely used in production? Is it simply too new? I've gotten the impression from some of you that it's sort of a new steel and somewhat unknown.

Aeb-l performs very well when heat treated in very specific ways. It’s quite unlikely that a mass produced knife will have that attention to care at a low price point. Custom makers heat treat it to Rc62, but production knives are typically under Rc60, where aeb-l is just ok, not great. It’s bad marketing to run blades hard and fine, then have people chip those edges using them as pry bars or screwdrivers. Outside of the custom knife world, aeb-l doesn’t have a lot of sex appeal.

 

[MG74]

Aeb-l performs very well when heat treated in very specific ways. It’s quite unlikely that a mass produced knife will have that attention to care at a low price point. Custom makers heat treat it to Rc62, but production knives are typically under Rc60, where aeb-l is just ok, not great. It’s bad marketing to run blades hard and fine, then have people chip those edges using them as pry bars or screwdrivers. Outside of the custom knife world, aeb-l doesn’t have a lot of sex appeal.

Is that really true though? I can tell you a cheap AEB-L folding knife would be extremely appealing to me. Most people seem to describe AEB-L as a tough steel that doesn't chip or roll too much and that holds a super fine edge with decent retention and stainlessness. I haven't really seen anyone complaining of it chipping out or anything along those lines and I don't think it'd be that big of a problem for a cardboard cutter sort of pocket utility knife.

 

[Lapedog]

I would think part of the reason is the fineness of the grain of these steels and the edge stability due to toughness. Steels like these seem to keep a razor edge for longer and then suddenly are dull as a butter knife.

Higher carbide steels lose that razor edge, but keep a working edge for a lot longer