how does 3v do in the abs js test

[Rick Marchand]

Thanks, Butch.

 

[me2]

No matter the steel they all get lower impact resistance as they get harder. .

As a very general rule, that is true, but in the relatively high hardness range used for knives, it is not that simple.

 

[Neo]

Here's charpy numbers from the datasheets...
S7 at 57Rc is 125 ft-lbs energy
3v at 58Rc is 85 ft-lbs (note this is significantly harder than 57Rc)
3V at 60Rc is still 70 ft-lbs
L6 at 57Rc is approx 92 ft-lbs inferred from knowing hard numbers for others and using Latrobe's relative table....

Wear resistance in standardized test show that S7 and L6 are both about 1/10 that of 3V..

What do you think of Böhler K890 or better Böhler K490?

impact energy unnotched in joule

K890 at 60Rc is 105 j
K890 at 62Rc is 95 j
K490 at 62Rc is 80 j with the almost the same wear resistance as M4

http://www.bohler-edelstahl.com/files/K890DE.pdf
http://www.bohler-edelstahl.com/english/files/K490DE.pdf


Uddeholm Vanadis 4E ( Crucible has now created cpm 4V with the same make-up)

at 58 Rc is 70j
at 60 Rc is 60j
at 62 Rc is 50j
at 64 Rc is 40j

http://www.uddeholm.com/files/PB_Uddeholm_vanadis_4_extra_english.pdf

See for comparison : http://corse76.altervista.org/col.php?noti2=resilienza

I believe wear resistance is slightly less than M4

 

[Rapt_up]

I should have been clearer....

Originally Posted by Rapt_up

No matter the steel they all get lower impact resistance as they get harder. .

As a very general rule, that is true, but in the relatively high hardness range used for knives, it is not that simple.

Actually I meant more brittle, and typically this is represented by lower impact values. There are potentially exceptions if comparing steels of significantly different ultimate strengths. See below about its a characterisitic of steel and hold true within a given grade.

Any given steel gets more brittle as it gets harder...
Neo's example:
Uddeholm Vanadis 4E ( Crucible has now created cpm 4V with the same make-up)

at 58 Rc is 70j
at 60 Rc is 60j
at 62 Rc is 50j
at 64 Rc is 40j

Increasing hardness, decreasing energy in impact which is used as an indicator of brittleness.

Yes a given grade may be tougher at a specific hardness than another grade, thats the point of selecting the right grade for the job. BUt once you select that grade it get more brittle as you harden it. There is no free lunch.

Also un-notched energy number will be MUCH higher than notched, I presented notched test numbers.

How this works all become clear as you study force elongation curves for steel in material science.

 

[me2]

Many steels show localized peaks in toughness in the hardness range of knives, or in the very lowest tempering temperatures. The classic example is 4340 low alloy steel. It has a peak toughness at a tempering temperature of around 400 deg F. It drops after that to an impact toughness of not much more than as quenched. As the temperature rises it's toughness recovers and goes up dramatically. Many steels, but not all, show this behavior. Certain tempering ranges are avoided industrially because of these localized peaks and troughs in toughness. This is the classic example of tempered martensite embrittlement. Other mechanisms are possible, and steel cleanliness has a large role. That is why I said it's not that simple. And just to be a huge PITA, your impact values are from a chart labeled "Unnotched Impact Energy" from the Vanadis 4 link. I do agree that unnotched values will be much higher than notched values, since v-notched values for such steels as Vanadis 4E would likely be less than 10 J. Unnotched values are somewhat scatter prone, and must be used carefully.

 

[wnease]

Just looking at the numbers posted and tests suggested, keep in mind that at its working hardness the v notch and unnotched charpy numbers of S7 are not comparable to the other alloys that have data (L6, 3V). It's comparable but better than S5 in notched tests and both are way better than non-shock steels.

That said there is no impact in the testing described. Chopping soft pine with a short 10" blade does not inflict much impact and the bend test inflicts NONE.

Hossom has 3V camp knives that have been flexed past 90 degrees.

I passed the test at the ABS Intro to Bladesmithing with 5160... but it think I could do it with a dollar store cleaver, and if I had to heat treat by eye instead of my oven I would use 1080.

 

[crimsonfalcon07]

I'm glad to see this thread, because I was just popping in to ask a very similar question about these steels. I do most of my choppers in 5160 right now, but I'd like to try out 3V. I noticed on the previous page a comment that for chopping, 5160 is still better? I guess I'm curious what exactly 3V does better (edge retention under slicing and light cutting tasks? Is it better at chopping? Obviously better at rust prevention, but not at bending, if I get the flavor of this thread right?).

I'd be looking at a 24" OAL piece (a gladius/machete, to be exact). Being pretty much an utter noob at this sort of thing, I don't even know if length matters for which kind of steel you choose. Would it be different for the camp knife proposed by the OP as compared to a big honking blade aimed at smiting and stabbing?

I guess I'm confused as to why 5160 would be a better choice, outside of cost and lack of bendability, for an application involving chopping and other high impact stresses? Or did I just read that wrong? Is the advantage to 3V just for smaller knives that are aimed more at cutting than at high impact stresses? Or am I totally off base? Thanks in advance.

 

[james terrio]

I noticed on the previous page a comment that for chopping, 5160 is still better?

I very strongly doubt that. 3V is at least as tough and certainly has better edge retention at "big knife" hardnesses, which I put right at 56 (minimum) to 58Rc (just about perfect). 3V's reasonably high level of corrosion-resistance is purely a bonus in my book.

FWIW, I don't give a fat flying leap at a rolling donut if a knife can be bent without breaking; we've addressed that part of the ABS testing. Except for dedicated filet/boning knives, I much prefer knives that don't bend OR break.

Is the advantage to 3V just for smaller knives that are aimed more at cutting than at high impact stresses?

No, that's the beauty of it. Although I do love 3V for smaller knives with thinner geometry, it's important to remember that it was specifically designed for very high toughness with really good wear-resistance. That makes for a very serious chopper/"hard use"/"tactical" type of knife in my opinion. We need to keep in mind that alloys like the S-series were designed for jackhammer bits and the like, not cutting tools as we're thinking of here.

Thanks to Rapt-up, me2 and Neo for the info on other very interesting alloys; fascinating stuff!

 

[gga357]

If I may interject my thoughts. I have not pulled the trigger on 3v yet cause I wonder if its too difficult to sharpen in the field. 5160 is such an easy steel to deal with.

 

[crimsonfalcon07]

Thanks James. Was wondering why Rick had suggested 5160 for a beater blade. The formula one racer vs baja buggy example made me think that maybe there's some reason besides cost that you wouldn't use 3V for a beater blade or something taking serious use/abuse, since the formula one racer would do very poorly off-roading, and I seem to recall another comment about chopping being abuse.

That said.... Chopping, Batoning and Prying is "Beating" by conventional standards. You need a beater blade not a cutting tool.

So I took that analogy to mean that 3V would perform way better at normal knife-related tasks within the use category, which I guess would be what, light cutting and slicing? but not as well, and perhaps even would get wrecked at "beater" tasks like chopping, like a formula one racer would if you took it off road.

Sounds like I might just have to invest in some 3V for the next gladius. Stuff is really pricy in comparison to 5160. As gga was mentioning, is it harder to sharpen (and grind on, for that matter) than 5160?

 

[Dave Behrens]

I very which I put right at 56 (minimum) to 58Rc (just about perfect). thinner geometry, it's important to remember that it was specifically designed for very high toughness with really good wear-resistance. That makes for a very serious chopper/"hard use"/"tactical" type of knife in my opinion."

Even at 59+ HRC 3V make one hell of a chopper blade. And it also was made for high toughness and wear resistance at higher hardnesses AND thinner geometry. It is the absolute best blade steel IMHO, it has the best of all worlds.

If I may interject my thoughts. I have not pulled the trigger on 3v yet cause I wonder if its too difficult to sharpen in the field. 5160 is such an easy steel to deal with.

It is not at all difficult to sharpen in my experience, and under 61 HRC it can be fairly easy.

Thanks James. Was wondering why Rick had suggested 5160 for a beater blade. The formula one racer vs baja buggy example made me think that maybe there's some reason besides cost that you wouldn't use 3V for a beater blade or something taking serious use/abuse, since the formula one racer would do very poorly off-roading, and I seem to recall another comment about chopping being abuse.
So I took that analogy to mean that 3V would perform way better at normal knife-related tasks within the use category, which I guess would be what, light cutting and slicing? but not as well, and perhaps even would get wrecked at "beater" tasks like chopping, like a formula one racer would if you took it off road.
Sounds like I might just have to invest in some 3V for the next gladius. Stuff is really pricy in comparison to 5160. As gga was mentioning, is it harder to sharpen (and grind on, for that matter) than 5160?

I think what Rick meant was there is no need to pay for a premium steel like 3V for a "beater blade", when a more affordable( and easy to work with) steel such as 5160, which is also very tough, is available. The biggest noticeable difference between the two is corrosion resistance, but 3v is tougher( by how much is arguable) and has better wear resistance(again by how much is arguable). Annealed 3V is easy to work, once HT'd it is comparable to 154CM or 440c for grind-ability.

 

[james terrio]

I'll let Rick speak for himself. I will say that I'm pretty sure 5160 would make a very good, tough chopper at a low cost... I won't be able to say so for certain until I've worked with it.

I agree with Dave, 3V is not nearly as hard to sharpen as the "hype" might suggest; I haven't noticed a huge difference between it and any other moderate- to high-alloy steel. Yes, 3V is more time-consuming to sharpen than "plain" carbon steels. That's a big part of the whole point! I do know for a fact that 3V at the same Rockwell hardness and same geometry will keep cutting long after O1, 1095 and 1084 have given up.

I also agree that being able to grind edges thinner without fear of chipping counteracts any perceived difficulty regarding keeping the edge keen.

3V rocks. Try it.

 

[Rick Marchand]

I think what Rick meant was there is no need to pay for a premium steel like 3V for a "beater blade", when a more affordable( and easy to work with) steel such as 5160, which is also very tough, is available. The biggest noticeable difference between the two is corrosion resistance, but 3v is tougher( by how much is arguable) and has better wear resistance(again by how much is arguable). Annealed 3V is easy to work, once HT'd it is comparable to 154CM or 440c for grind-ability.

Dave has it right. 3V will outperform 5160, all HT's equal. (Wear, rust resistance, hardness to toughness ratio, etc...) If it boiled down to a serious everyday user, I would choose 3V over 5160. But if you just want to have fun and beat the crap out of a knife, 5160 pulls ahead with regard to cost and workability... in my opinion, at least

 

[crimsonfalcon07]

Thanks for the information. I, at least, am off to Aldo's to purchase a billet of 3V. Cheers!