Non - Cryro Stainless ??

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AEB-L & similar steels have a very fine array of small carbides. It can have no carbides if you want, but the hardening temps are not usually high enough.
 
From what I understand, AEB-L has just enough Carbon to get hard but not formulate any carbides. It was formulated specifically for that reason, which is why it takes such a keen edge and is so easy to sharpen. Maybe someone more astute than me can correct me if I'm wrong but taking this into consideration, LN is probably overkill on AEB-L.

That's my understanding as well..I really like the steel. My personal carry knife is AEB-L heat treated to about 61rc..I cut up fish all the time and have no problems with chipping.
 
From what I understand, AEB-L has just enough Carbon to get hard but not formulate any carbides. It was formulated specifically for that reason, which is why it takes such a keen edge and is so easy to sharpen. Maybe someone more astute than me can correct me if I'm wrong but taking this into consideration, LN is probably overkill on AEB-L.

Exactly correct, you will get the basic iron carbides, but you get those anyway, but other than that there is zero carbide formation because the carbon content just isn't high enough to pull any of the alloy into the matrix.

So what you end up with is a basic carbon steel that happens to be stainless also.

So we end up with a fine grained stainless steel with no real carbide content other than the basic iron carbides.
 
So we end up with a fine grained stainless steel with no real carbide content other than the basic iron carbides.

iron carbides are real carbides. sandvik and uddeholm make a steel that allows the chromium present to stay as pure chromium. pure chromium is stain resistant, chromium carbides are not stain resistant. if you start here and look at the various programs recommended, http://www.smt.sandvik.com/en/produ...ife-steel/hardening-guide/hardening-programs/, there is a gain of hardness and reduction of RA by cooling in the deep freezer(-5F) and more hardness and reduction of RA by going to -95F(dry ice and solvent). they also recommend quenching in oil for best results.
 
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Jim wasn't saying that Iron carbides aren't real. He was just pointing out that there are no other carbides formed which makes it perform a lot like a simple carbon steel yet manages to be stainless.
They recommend oil because plate quenching is mostly used only by custom knifemakers. Plate quenching works just as well without all the mess.
 
There won't be any iron carbides either. Chromium is a stronger carbide former than iron, and with as much of it as there is in these types of stainless, if there isn't any chromium carbide, there won't be any iron carbide either. This is also all heavily dependent on heat treatment. Standard heat treatments give small chromium carbides, with enough chromium still free to provide stainless properties. This can all be adjusted by the heat treater.
 
There won't be any iron carbides either. Chromium is a stronger carbide former than iron, and with as much of it as there is in these types of stainless, if there isn't any chromium carbide, there won't be any iron carbide either. This is also all heavily dependent on heat treatment. Standard heat treatments give small chromium carbides, with enough chromium still free to provide stainless properties. This can all be adjusted by the heat treater.


NOT IN AEB-L / 13C26 there won't be any Chromium carbides no matter how you heat treat it.

But yes there will be iron carbides.
 
How can you get iron carbides without chromium carbides? The various micrographs of AEB-L/13C26 I've seen show very fine carbides, and the standard heat treatments put the austenization temperatures right in the area of a mixture of austenite + chromium carbides, which will produce martensite plus chromium carbides upon quenching. You can vary the amount of carbides by varying the austenizing temperature. Higher temperature - fewer carbides. This is a basic principle which applies to everything from 1095 to M4.
 
How can you get iron carbides without chromium carbides? The various micrographs of AEB-L/13C26 I've seen show very fine carbides, and the standard heat treatments put the austenization temperatures right in the area of a mixture of austenite + chromium carbides, which will produce martensite plus chromium carbides upon quenching. You can vary the amount of carbides by varying the austenizing temperature. Higher temperature - fewer carbides. This is a basic principle which applies to everything from 1095 to M4.


Those are iron carbides, not chromium.

There isn't enough carbon in AEB-L / 13C26 to pull the chromium into the matrix no matter how it's heat treated.
 
Where are you getting this information? Virtually every source I've seen is exactly backwards to that. The ability to form carbides depends on both (or all) elements involved. There is relatively low carbon (compared to most powder steels) but there is plenty of chromium. Increasing either increases the volume of chromium carbides. Carbon doesn't pull chromium into the matrix to form carbides. Carbides are formed when carbon and chromium dissolved in the matrix are pulled out of the matrix to form a carbide. Conversely, putting chromium and carbon into solution in the matrix means dissolving the carbides.
 
Where are you getting this information? Virtually every source I've seen is exactly backwards to that. The ability to form carbides depends on both (or all) elements involved. There is relatively low carbon (compared to most powder steels) but there is plenty of chromium. Increasing either increases the volume of chromium carbides. Carbon doesn't pull chromium into the matrix to form carbides. Carbides are formed when carbon and chromium dissolved in the matrix are pulled out of the matrix to form a carbide. Conversely, putting chromium and carbon into solution in the matrix means dissolving the carbides.

They are dead wrong as usual, you need to find some new sources. ;)

AEB-L / 13C26 was developed/designed so it wouldn't develop any chromium carbides at all, that the reason for the extremely low carbon content, just enough to get hard, but not enough to pull the chromium.
 
Let's remember to keep this thread civil and not personal. You are doing a fine job of that so far. There is nothing wrong with challenging a data source and questioning information and asserting your knowledge and experience.

When it gets snarky is when I shut threads down like this.
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"They are dead wrong, as usual..." That seems a little presumptive of my sources, don't you think? As it happens I did find some new ones though.

Verhoeven's paper on knife edge wear provides references where the steel manufacturer states steels such as AEB-L/13C26 can be heat treated to produce fine arrays of chromium carbides.

Verhoeven's book for blade smiths has an extensive section on heat treating similar steels, including the phase diagram for iron-carbon-chromium at both 1000 deg. C and 1100 deg. C. The composition of AEB-L puts it in the austenite + chromium carbide range when austenized in the 1000-1100 deg. C range.

Thermocalc is a program used to design alloys and heat treatments. It has been applied to AEB-L and the phase diagram is linked below. It is a diagram of the phases present at various temperatures and carbon contents, with the amount of chromium held constant at the nominal chromium content of AEB-L. This diagram also shows that the combination of AEB-L's alloy content and typical austenizing temperatures forms chromium carbides.

http://www.calphad.com/AEB-L.html (This one was new. I found it while looking for information from Uddeholm)

The PhD thesis linked below shows considerable chromium carbide in steels very similar to AEB-L when in the annealed condition. The steels (A & B) have slightly more carbon (0.69% and 0.7%) than AEB-L (0.65%), with similar chromium levels, along with trace elements. These chromium carbides remain after quenching, similar to the way iron carbide remains after quenching steels like 1095. Note also that the above diagrams also show that a high enough austenizing temperature will dissolve all the carbide, resulting in all austenite. For various reasons, this is not recommended.

http://iris.lib.neu.edu/cgi/viewcontent.cgi?article=1023&context=mech_eng_diss (This one was also new.)

A similar thesis shows chromium carbides present in 420HC type steel, which has less carbon than AEB-L, with similar chromium levels. I don't have a link to the full thesis. If I get one, I'll post it.

Now, to be clear, these carbides are not all chromium carbide. They will contain some iron mixed into the carbide, which replaces/substitutes for chromium. However, they are primarily chromium carbide, particularly since there are not other elements present to make carbides in AEB-L type steels. This is the reason the diagrams reference carbides as M7C3 and M23C6. The M stands for metal. It is also sometimes written as (Cr, Fe)7C3, where the first element is the primary carbide former.

Again, if you have sources that show iron carbide replaces chromium carbide, or that chromium carbide can't be formed with the steels being discussed, I would be very interested to see them.

Oh, and to be on topic to the original poster's question, there is a section in Verhoeven's book for blade smiths that outlines a procedure for heat treating stainless steels without the use of cryogenic or sub-zero treatment. I don't know of anyone that has explored it in knife making, but the information is out there.
 
I don't care what you think it said, the bottom line is that AEB-L / 13C26 can't be HT in any way so it will develop Chromium carbides period.

The carbon content just isn't high enough for that to happen, Period.

That is my finial say on this.
 
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