Cold Steel - Aus 8A Stainless VS. Carpenters CTS XHP Alloy?

[Comeuppance]

Putting studs on Tri Ad lock was a stroke of genius too. Can't wait to see that propagate to the rest of the line (someday, at least it looks amazing).

Can you post a link or a picture of what you're referring to here?

 

[BladeChick777]

It's definitely worth the extra cash. Like the Mini Lawman is a $60 knife in AUS-8, it's an $84 knife in CTS-XHP, well worth the difference in my opinion.

 

[Freman Bloodglaive]

Can you post a link or a picture of what you're referring to here?

The Tiger Claw has thumb studs on the lockbar allowing it to be unlocked with one hand.

 

[BonhamBlades]

It's not, but that doesn't mean that suddenly AUS 8A is suddenly bad, it just doesn't look as good compared to the current supersteels. AUS 8, VG10, and 154CM still cut fine for me.

I'll be picking up several AUS 8 Cold Steel folders at clearance prices as the vendors phase them out.

I wasn't calling AUS 8A bad, just that there is much better available these days. I still have the original three AUS 8A brass bolster tantos from Cold Steel and cherish them.

 

[Gaston444]

1. The difference in edge retention between AUS8A and CTS-XHP is much greater than you have said. Generally around an 80-100% improvement, depending on the material cut, the edge type used, and the heat treat. I would generally prefer a steel with higher edge retention for my EDC, and I usually end up carrying M390, Elmax, or similar, for my EDC knives.

Where's the scientific evidence that any of this is true? I've seen only one knife steel test in the mid-late '90s that used a truly scientific methodology: Every blade was made specifically for the test, controlling edge geometry, cut pressure and edge surface grit finish: 440C, an AUS-8 near-equivalent (as far as I know), blew away in raw edge-holding every steel of the time, and this in a wide variety of materials... This superiority including to greater or lesser extent D-2, ATS-34, 154 CM and the two earliest cutlery-used CPM steels. A particularly wide margin was found on manilla rope between 440C and the second best steel...

You hear so much talk how people can tell differences in steel: I've never had any confidence two identical knives ever performed the same for me, even with the same steel... So-called "Identical" knives can have huge differences in edge thickness at the top of the edge bevel from the factory, even within the same run of the same model: How do you even know what affects the performance you observe?

Once I fully re-sharpened the knife, I forget any significance to any edge-holding that happens: Whatever edge-holding objectivity there was is now lost in a sea of minute edge surface finish variations...

2. AUS8A has moderate corrosion reisistance, but is much lower than CTS-XHP. I have had several knives in AUS8 and AUS8A, and they started to corrode from the sweat in my pockets rather quickly, while none of the knives I have used in CTS-XHP have ever had those problems.

I only know AUS-8 as basically a 440C equivalent: 440C was sometimes used on dive knives (though 440A was more common)... If you need more corrosion resistance than that, you are in deep trouble...

I keep thinking of that custom knifemaker sharing his sadness of hearing another maker actually saying chrome lowers edge-holding and wear resistance... The nonsense when it comes to steel properties seems bottomless...

Gaston

 

[singularity35]

So here's your chance for scientific testing. Get both and do the tests.

 

[RBid]

Where's the scientific evidence that any of this is true? I've seen only one knife steel test in the mid-late '90s that used a truly scientific methodology: Every blade was made specifically for the test, controlling edge geometry, cut pressure and edge surface grit finish: 440C, an AUS-8 near-equivalent (as far as I know), blew away in raw edge-holding every steel of the time, and this in a wide variety of materials... This superiority including to greater or lesser extent D-2, ATS-34, 154 CM and the two earliest cutlery-used CPM steels. A particularly wide margin was found on manilla rope between 440C and the second best steel...

You hear so much talk how people can tell differences in steel: I've never had any confidence two identical knives ever performed the same for me, even with the same steel... So-called "Identical" knives can have huge differences in edge thickness at the top of the edge bevel from the factory, even within the same run of the same model: How do you even know what affects the performance you observe?

Once I fully re-sharpened the knife, I forget any significance to any edge-holding that happens: Whatever edge-holding objectivity there was is now lost in a sea of minute edge surface finish variations...




I only know AUS-8 as basically a 440C equivalent: 440C was sometimes used on dive knives (though 440A was more common)... If you need more corrosion resistance than that, you are in deep trouble...

I keep thinking of that custom knifemaker sharing his sadness of hearing another maker actually saying chrome lowers edge-holding and wear resistance... The nonsense when it comes to steel properties seems bottomless...

Gaston

It sounds as though the difference isn't worth it to you. I respect your right to have an opinion of your own. In my experience, there has been a notable difference in performance between AUS-8 and an assortment of higher end steels. I have had corrosion show up on AUS-8, and have had to touch it up more frequently than I've needed to maintain S30V, S35VN, or Elmax. Before it goes there, yeah, I understand edge geometry as a factor in terms of edge retention *and* cutting life. My experiences have not been measured or recorded. They may not carry any weight with you. That is OK. They do matter to me.

I think CS is taking a huge step forward.

 

[marthinus]

So much speculation on a steel........I wonder if XHP would get as much attention if it was called 440XH as it was initially.

For those that want to read the 1993 patent for the steel.

https://www.google.co.za/patents/US...a=X&ei=mNocVdz7MYK07Aag5YDIBw&ved=0CBsQ6AEwAA

XHP compares quite well to AUS-8.

From looking at the chemistry I would expect XHP to function very similar to AUS-8 in use and I could justify the cost due to the newer technology used to make the steel as the purity of the steel in theory would be higher and the chances of voids etc would be less.

 

[Skywalker31]

...

From looking at the chemistry I would expect XHP to function very similar to AUS-8 in use and I could justify the cost due to the newer technology used to make the steel as the purity of the steel in theory would be higher and the chances of voids etc would be less.

It's got more than double the carbon, almost double the vanadium, and slightly more chromium, and you'd expect it to function similarly?

Seems like it should at the very least be a higher carbide-volume steel, with the all the performance changes associated with that.

 

[ron finkbeiner jr]

I am still waiting for my XHP recon 1 spear point.

 

[Freman Bloodglaive]

440C is closer to AUS10 with its 1% carbon, but even then there are differences. The 440 series has 18% chromium which makes it very stainless, especially in the A and B variants where there isn't as much carbon to lock up the chromium in carbides. The AUS steels have vanadium which I understand is used as a grain refiner. They are about 14% chromium, which puts them on the low end of the stainless range.

Certainly AUS8 is stainless, and I've never had a problem with it, but some people report experiencing rusting, particularly with the bead blasted finish.

Buck have produced very good results with their lowly 420HC steel thanks to a good heat treatment and careful edge geometry, but that doesn't make 420HC a high wear steel.

 

[marthinus]

It's got more than double the carbon, almost double the vanadium, and slightly more chromium, and you'd expect it to function similarly?

Seems like it should at the very least be a higher carbide-volume steel, with the all the performance changes associated with that.

Yes I would. Apart from the higher attainable hardness and slightly improved corrosion resistance the differences in Vanadium is not that large compared to something like S30V.

Then again, I dull CPM-M4, M390 etc in a days use so improved "wear resistance" does not mean much to me.

 

[NJBillK]

I just looked at the Code 4 for example, there is this HUGE monstrous $12 difference in price going to XHP. LOL

If you want to negate that, there is an army navy store near my house with an aus8 code 4 for $99 and won't budge on the asking price... I tried to get him to lower it, but to no avail.

 

[craytab]

I am still waiting for my XHP recon 1 spear point.

That is the one I have my eye on as well. $20 more for upgraded American steel and an actual DLC? No brainer....

If you want to negate that, there is an army navy store near my house with an aus8 code 4 for $99 and won't budge on the asking price... I tried to get him to lower it, but to no avail.

My local Army Navy had a recon 1 in Aus8 for $120. Mean while the same knife I had in my pocket at the time cost half the price from and online dealer. Needless to say I never go there anymore.

 

[Ankerson]

Yes I would. Apart from the higher attainable hardness and slightly improved corrosion resistance the differences in Vanadium is not that large compared to something like S30V.

Then again, I dull CPM-M4, M390 etc in a days use so improved "wear resistance" does not mean much to me.

What are you cutting with M4 or M390 that you can dull them in a day of use?

 

[marthinus]

What are you cutting with M4 or M390 that you can dull them in a day of use?

Irrigation pipes filled with sand and other debris for one and anything else required on site and the farm.

Site can look like this.

Farm and other uses range quite a bit.

 

[Ankerson]

Irrigation pipes filled with sand and other debris for one and anything else required on site and the farm.

Site can look like this.

Farm and other uses range quite a bit.

Yeah, some of that would do it for sure, to any steel.

 

[Larry Turko]

Pretty darn relevant if you actually cut stuff frequently, particularly since the AUS8 might make 100 and the XHP somewhere in the neighborhood of 180. Glad to hear you don't have corrosion issues, I've had AUS8 develop rust spots sitting in a drawer. As for the transverse toughness, go watch the videos where CS knives are tested to failure. It's almost invariably the blade that breaks before the lock on any Triad lock folder.

You prefer what you prefer, but get your facts straight or you're just going to look foolish.

I'm sitting here with a bright red face because as you pointed out I made myself look so foolish. Nevertheless I'm going to soldier on and respond to your post; Have you actually compared Aus8 to XHP to come up with the figures above? I bet your claims are pure speculation... but even if they are true does it matter? How many people are going to make a hundred hard cuts with a folder even in a decade? Of course if Aus 8 does eventually dull it's easy to re-sharpen.
I've seen the Tatanka vs Voyager lock test but I've never seen a test where pressure is applied to a folder from the side. If the steel were to really break before the handle breaks off, then the Triad lock it's even better than I thought. Anyway have you seen any proof that XHP would survive longer than Aus 8 in that situation?
What I think is really going on here is that those who have drunk the kool-aid about "super" steels are desperate to justify spending much more money for steels that will be of little or no practical benefit. As someone else posted on this forum with regard to the Sebenza; the Emperor has no clothes.

 

[Charr]

Where's the scientific evidence that any of this is true? I've seen only one knife steel test in the mid-late '90s that used a truly scientific methodology: Every blade was made specifically for the test, controlling edge geometry, cut pressure and edge surface grit finish: 440C, an AUS-8 near-equivalent (as far as I know), blew away in raw edge-holding every steel of the time, and this in a wide variety of materials... This superiority including to greater or lesser extent D-2, ATS-34, 154 CM and the two earliest cutlery-used CPM steels. A particularly wide margin was found on manilla rope between 440C and the second best steel...

You hear so much talk how people can tell differences in steel: I've never had any confidence two identical knives ever performed the same for me, even with the same steel... So-called "Identical" knives can have huge differences in edge thickness at the top of the edge bevel from the factory, even within the same run of the same model: How do you even know what affects the performance you observe?

Once I fully re-sharpened the knife, I forget any significance to any edge-holding that happens: Whatever edge-holding objectivity there was is now lost in a sea of minute edge surface finish variations...




I only know AUS-8 as basically a 440C equivalent: 440C was sometimes used on dive knives (though 440A was more common)... If you need more corrosion resistance than that, you are in deep trouble...

I keep thinking of that custom knifemaker sharing his sadness of hearing another maker actually saying chrome lowers edge-holding and wear resistance... The nonsense when it comes to steel properties seems bottomless...

Gaston

On your first point, you are using outdated information, and there have been other tests performed since then, in order to be as scientific as possible in determining the qualities of each steel but you also have to take into consideration that heat treatment can play a very large role in the performance of most steels. Realistically speaking, I doubt that there were the same treatment processes for the steels more than 20 years ago, or that someone would be able to make a consistent and repeatable heat treat in their own personal setup across that many varieties of steel.
Then, yes, finishing qualities does become a major factor in the edge performance, but before any of that, we have a bigger issue:

AT NO TIME DID I MAKE THIS A CONVERSATION ABOUT 440C

First, AUS8's composition:



From the same source:
"AUS8(Aichi) - Aichi steel. Sometimes referred as A8, which isn't correct. More often it's called 8A, which is a common abbreviation. Similar to 440B steel. AUS8A is the same steel, except it's annealed. Apparently A stands for Annealed."

Next, 440C, compared to that chart:



You can clearly see here, not only is the amount of Chromium much higher, the Carbon is as well. Though these differences seem minute, you will often find that it does not take a large difference in the amounts in relative percent to make a difference in the steel's performance. Also, you will find that Carbon is a key element, along with other metals, in forming carbides. Without those carbides, the majority of the steel's properties will not be at the desired level, primarily cutting performance.
You will also note that AUS8 also has much more Molybdenum in the matrix of the steel, which aids in making carbides, and allows Chromium to function more efficiently at preventing corrosion, since Chromium that is held in the carbides of the steel does not actively prevent corrosion.
So, as we have actively proven that AUS8 is NOT an equivalent to 440C, most of your argument becomes unsound.

Lastly, let's compare CTS-XHP, 440C, and Aus8 all together:



Now the differences become MUCH more apparent between all three of these steels.
This is a fairly common description of CTS-XHP:
"CTS-XHP is an air hardening, high carbon, high chromium, corrosion resistant alloy which can be described as either a high hardness Type 440C stainless steel or a corrosion resistant D2 tool steel. Possesses corrosion resistance equivalent to Type 440C stainless but can attain a maximum hardness of 64 HRC, approaching that of D2 tool steel."

So it is not AUS8 that is a comparison to 440C, but in fact XHP. So, you have, in fact, given an argument for why this steel IS as good as it is, with your praise of 440C. If we take your arguments for why 440C is a good steel, and replace your false statement that AUS8 is an analog to 440C with the truth; that CTS-XHP is essentially an improvement over 440C, then we are left with something closer to the overall truth, though still founded on old information.

So, you have inadvertently supported the fact that CTS-XHP is an improvement over AUS8, in your attempts to do the opposite.

Now, about your arguments that edge finish and sharpening affect edge retention, I will not actively argue, because you are presenting too many variables at once to actually be able to argue without needing a whole thread on them (of which there are already enough), and we have seen many researchers, knife makers, and testers, who have come with evidence for a variety or results and comparisons, all of which I am not fully versed with.
Basically, I do not have enough evidence to argue with you, but you do not present enough evidence to support your own claim either, and your claim is intentionally vague and subjective, to the point that you are in essentially discrediting your own previous statements, trying to say that the steel does make a difference based on edge retention tests (which once more were outdated), and then following it up by saying "once I sharpen it, it doesn't matter".
Your last claim about corrosion resistance is also more support for XHP as well, as you are again using 440C as your basis for evidence.
Oh, and the comment about a custom knife-maker's conversation about the properties of Chromium in knife steels is irrelevant to this discussion. I get the point you were trying to make, but you are much more similar to the mistaken maker than the one who was displeased about their mistake in this instance.


SO, we are left with this conclusion:
Not only have you presented evidence that is outdated, you have used it to try and support the qualities of AUS8, when in fact the two are not related directly. Not only that, your evidence (assuming its validity), is in fact much more suitable to support the positive performance of CTS-XHP, not AUS8, as CTS-XHP is much more analogous to 440C.
Lastly, you invalidated your own argument by proceeding to claim that "Once I fully re-sharpened the knife, I forget any significance to any edge-holding that happens: Whatever edge-holding objectivity there was is now lost in a sea of minute edge surface finish variations".
Congratulations, you have a very unsound argument, based on false and outdated evidence, that in no way disproves any of my claims or my evidence. IF you can find reputable sources of evidence that prove me wrong, then I have no issues with being wrong, but I do not tolerate being critiqued without the needed evidence or rationale, thank you.

I do not intend to be harsh or unreasonable in this assessment, but I will admit I did get a little angry when I read your response, so I do apologize for any offense taken.

 

[craytab]

I'm sitting here with a bright red face because as you pointed out I made myself look so foolish. Nevertheless I'm going to soldier on and respond to your post

You really should have stopped here.

I bet your claims are pure speculation... but even if they are true does it matter?

And your claims are proven fact right?

How many people are going to make a hundred hard cuts with a folder even in a decade?

My gosh man. You need to stop making ridiculous statements.

What I think is really going on here is that those who have drunk the kool-aid about "super" steels are desperate to justify spending much more money for steels that will be of little or no practical benefit. As someone else posted on this forum with regard to the Sebenza; the Emperor has no clothes.

As we all pointed out to you the first time you got all red faced the cost is not much at all. Again, $20 for better American made steel and actual DLC instead of paint. If you can't see the benefit of that then their just might not be any reasoning to be done here.

And a pot shot at CRK to end things off......