The "Ask Nathan a Question" Thread

SCTorrero said:
I think it is unlikely that the comparison regarding stain resistance (at least) accounts for the Delta protocol.
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I was talking about the raw properties of the steels. It is very difficult to compare two steels based on different heat treatments. And certainly I am not qualified to do so. However, I could speculate or entertain some ideas for the sake of a conversation.

If I was doing that, probably I would say that delta 3V would have considerably less wear resistance than Cruwear since it already has less wear resistance than regular 3V. Of course I do not know for sure if delta 3V has less wear resistance than regular 3V or not, but if it is more stainless than a regular 3V it might have less wear resistance. As far as I know, the increased corrosion resistance of delta 3V compared to 3V is because there is extra chromium left in the steel matrix after the heat treat compared to 3V heat treated by a standard protocol. Normally, that would mean that, since more chromium was left in the steel matrix, less chromium was used to make carbides. Of course one can argue that carbides in 3V is mostly vanadium which is correct but if one heat treat leaves more chromium carbides in the steel matrix compared to other, would not be the missing chromium would form a carbide if it was heat treated according to the industry standard heat treat? And we all know that more carbides means more wear resistance, right?
 
murat1983 said:
I was talking about the raw properties of the steels. It is very difficult to compare two steels based on different heat treatments. And certainly I am not qualified to do so. However, I could speculate or entertain some ideas for the sake of a conversation.

If I was doing that, probably I would say that delta 3V would have considerably less wear resistance than Cruwear since it already has less wear resistance than regular 3V. Of course I do not know for sure if delta 3V has less wear resistance than regular 3V or not, but if it is more stainless than a regular 3V it might have less wear resistance. As far as I know, the increased corrosion resistance of delta 3V compared to 3V is because there is extra chromium left in the steel matrix after the heat treat compared to 3V heat treated by a standard protocol. Normally, that would mean that, since more chromium was left in the steel matrix, less chromium was used to make carbides. Of course one can argue that carbides in 3V is mostly vanadium which is correct but if one heat treat leaves more chromium carbides in the steel matrix compared to other, would not be the missing chromium would form a carbide if it was heat treated according to the industry standard heat treat? And we all know that more carbides means more wear resistance, right?
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Out of curiosity ... have you run a D3V through some beat downs?

I'm not as awesome in knowledgeable things and charts and stats as a lot of members.. I'm just a dummy who uses stuff

I can say I've been very happy with D3V in what I use knives for!
 
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yoko said:
Out of curiosity ... have you run a D3V through some beat downs?
"
I'm not as awesome in knowledgeable things and charts and stats as a lot of members.. I'm just a dummy who uses stuff

I can say I've been very happy with D3V in what I use knives for!
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No I have not tested D3V wear resistance against 3V wear resistance, hence I said "I do not know for sure". And the point in this whole discussion is not whether D3V is good or not.
 
XtianAus said:
Hey Nate has magnacut been tougher than AEBL in your findings?
If not, what feature do you admire that has it replacing AEBL?
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I don't know, I haven't really compared the two in that regard. I'm not actually going to the ultimate in toughness, I'm looking for durability in rough use which can often be at a lower toughness. The ability of Magnacut to shrug off rough use is in line with my other offerings and is very good for a stainless steel. I like that it has more wear resistance and better stain resistance and that it holds up very well to careless use.
 
murat1983 said:
That is interesting.

When you said you tested the 3V,4V and MagnaCut at same hardness, is that hardness optimized for 3V (i.e. 60-61) or for 4V and Magnacut which is 63+? As you said 3V got dent rather than a fracture makes me think that you tested them all at 60-61?

I certainly expect 3V to be more durable than 4V and MagnaCut at 60-61, but according to Larin's work 4V should have better toughness than 3V once the hardness goes beyond 61. I think I read it from several sources that the toughness of 3V nosedives after 61, whereas 4V and MagnaCut remains relatively less affected. I do not know what the reason is, I was expecting 3V to be more tougher than 4V regardless the hardness but it seems that is not the case. Probably the microstructure changes considerable once 3V goes over 61.
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I think that 3V is not naturally a good candidate for hardness above 61 or 62 because the aust temp required to put that much carbon into solution will make a plate martensite which is inherently less tough than a lath mix and 3V isn't well designed for this. And the lower tempering temperatures to retain that hardness is going to be highly tetragonal martensite. Not tough. So higher hardness dictate a steel with a higher hardness sweetspot.

I heard about a car magazine that pitted a Toyota Prius against a BMW on a high speed track and the BMW got better fuel mileage. Because the speeds they were running had the Toyota running flat out and the BMW was still in its normal range.





I don't think the optimal hardness for MC is 63+. You might be thinking of 4V, which MC is not. For example, you will not see MC used as a competitive blade sports steel. It really is not the same as 4V.



Those three sample pieces were between HRC 60.25-61.0 which is low for 4V but I had a test piece from an earlier HT trial and I wanted to see what would happen.



The lesson to be learned from that particular trial is that 3V is (obviously) the better choice if you're looking for high toughness. Which isn't a revelation. What was a revelation (in the since that I did not know what to expect until I tried it) is the relative durability of the three steels at around 60.5. I didn't know what to expect. Now I do.
 
murat1983 said:
To my knowledge, CruWear is tougher than 3V once the hardness goes beyond 61. I believe CruWear is noticeably tougher than 3V at 61.5-62.5 HRC which is the sweet spot for CruWear. CruWear has similar stain resistance to 3V perhaps little bit less with considerable increased wear resistance.

Also, many maker says that with CruWear it is much easier to get a good heat treat compared with 3V, but probably that is irrelevant for CPK knives.
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Yeah I have high hopes for Cruwear in high hardness applications. I don't think we'll get similar stain resistance, but I don't know.
 
murat1983 said:
I was talking about the raw properties of the steels. It is very difficult to compare two steels based on different heat treatments. And certainly I am not qualified to do so. However, I could speculate or entertain some ideas for the sake of a conversation.

If I was doing that, probably I would say that delta 3V would have considerably less wear resistance than Cruwear since it already has less wear resistance than regular 3V. Of course I do not know for sure if delta 3V has less wear resistance than regular 3V or not, but if it is more stainless than a regular 3V it might have less wear resistance. As far as I know, the increased corrosion resistance of delta 3V compared to 3V is because there is extra chromium left in the steel matrix after the heat treat compared to 3V heat treated by a standard protocol. Normally, that would mean that, since more chromium was left in the steel matrix, less chromium was used to make carbides. Of course one can argue that carbides in 3V is mostly vanadium which is correct but if one heat treat leaves more chromium carbides in the steel matrix compared to other, would not be the missing chromium would form a carbide if it was heat treated according to the industry standard heat treat? And we all know that more carbides means more wear resistance, right?
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I'm not sure is 3V has considerably less wear resistance than Cruwear. 3V has pretty good abrasive resistance due to the vanadium carbide content, which is pretty significant. Cruwear also has Vanadium carbide, among others and is also going to be pretty good. Even though Cruwear has a little less vanadium carbide than 3V I expect in the balance it will be better, but perhaps not "considerably" better.

CPM 3V with the industry standard heat treat (using the secondary hardening hump) will combine the carbon that leaks from the martensite with the free chrome, forming additional secondary chromium carbide. This carbide is not particularly hard (high 60's I think) but it would aid abrasive wear resistance in some applications and in some geometries, but I don't think it's going to pay much of a dividend in a knife application given the trade-offs needed in this material in our application.

In my own extensive testing with regular 3V and Delta 3V in cutting cardboard I got better edge retention with Delta 3V, which is one of the primary reasons we went that way. The additional corrosion resistance was a happy side effect, not the goal.

I think an important mechanism for better edge retention in Cruwear will be the higher working hardness. I expect we will give up some corrosion resistance and some toughness but gain some edge retention in Cruwear, which is why we're evaluating it as a steel offering.
 
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