s30v

cptncavman

cptncavman

Joined
Dec 20, 2004
Messages
71
what is the range of rockwell hardnes and the hardness for s30v knives to have to hold an edge and ease of sharpening?
 
Edge-holding and ease of sharpening is relative to the task and user. I have S30V at 63 rc and I don't find it hard to sharpen.
 
cptncavman said:
ive been looking at a cris reeves green berret it says 55 to 57 is that right
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Probably so -- an actual combat knife needs to be tough beyond anything else, and the edge needs to be tough also - so it won't chip easily with use/abuse. Follow this up with the need for ease and speed of sharpening, and you simply cannot get all of those properties out of S30V at the higher hardness ranges. IIRC, combat Randall knives are roughly in this same hardness range.
 
Crucible recommends target hardness of 58 to 61 for S30V. I tend to agree. Having said that, I have great respect for CRK. If it was another manufacturer, I'd question if they were sacrificing optimum performance for optimal ease of finishing. With CRK, they will be doing it because their research shows it to be right.

CPMS30V gets most of it's edge retention from Vanadium carbides - so it doesn't have to be silly hard to perform.

Rob!
 
i've only tried it at RC 60... ridonkulous to sand and finish, sharpening not too bad on cheap diamond hones, and edge maintenance with a strop is all it has needed since my first test piece came back from ht.

sometimes softer isn't better. softer edges are less stiff and more likely to roll, usually require thicker edges to support them. my test knife is sharpened @ 23 degrees included.

hardness ratings aren't everything... heat treatment processes vary. my blades get an austenitizing temp lower than recommended on crucibles data sheet, but they get a 2 stage cryo so still reach full hardness
 
wnease

I accept that the manufacturer doesn't know it all. Tell us about your process. I'd like to try it out. What led you to it? S30V is an incredible steel and if there are ways to get more out of it, they sure warrant trying.

Rob!
 
sorry havent been on for awhile, so how does this compare to brittleness, the harder the knife the more brittle right. thats why the japanese sword uses hard and soft steel. the 55-57 rockwell is going to allow more flex in the blade before it snaps, than the 63 rockwell will allow. so in your opinion is s30v better than say 1095, o1,thanks again for the info.
 
I'm of the opinion that carbon steels and at that precisely controlled heat treated carbon steels like 1095, W1, W2, O1 etc will always hold an edge longer than it's stainless cousin's. to me the only thing stainless is better at is not rusting., or rusting slower than carbon steels.

Jason
 
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soft edges are mushy... they will need to be thicker to keep from rolling

I would put S30V @ rc 60 way ahead of O1 at rc 60 for edge-holding... O1 is great steel but S30v stays sharp longer
 
wnease said:
soft edges are mushy... they will need to be thicker to keep from rolling

I would put S30V @ rc 60 way ahead of O1 at rc 60 for edge-holding... O1 is great steel but S30v stays sharp longer
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I've had the same experience. At least for cutting soft and medium objects, S30V cuts for quite a bit longer than carbon steels.
 
cptncavman said:
sorry havent been on for awhile, so how does this compare to brittleness, the harder the knife the more brittle right. thats why the japanese sword uses hard and soft steel. the 55-57 rockwell is going to allow more flex in the blade before it snaps, than the 63 rockwell will allow. so in your opinion is s30v better than say 1095, o1,thanks again for the info.
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With many simple steels there's a pretty direct correlation between hardness & brittleness, but with more complex alloys it's not so straight forward. Some steels, such as A2, will actually get much more brittle by tempering them softer, until you get really soft & then it comes back. Also, this varies greaty by alloy due to their inherent toughness. Some steels can be much tougher at 61 Rc than others are at 55.

When it comes to "flexing", let's make sure we're on the same page. This is a concept I've struggled with myself so I hope I'm not leading you astray here... Flexing means the steel can be strained and then will return true. When you go too far, it takes a bend or set (plastic deformation). Harder steel is stronger, meaning it can flex further before bending. But if you take them to their breaking point, the harder steel will break before taking as much of a permanent bend. HOWEVER, it will take much greater force to get there.

So, you can choose between a soft blade that will get bent after applying 40 pounds of torque, but will continue to bend into a pretzel, or a harder blade that will take 150 pounds of torque before taking a set, but then breaks once you've bent it just a little more. (for example)

Please note that this bending toughness does not necessarily correlate to impact toughness. It's possible to have a steel that's soft and bendy, that will still break if you whack it on something hard.

To compare specific alloys, check out the comparison tools from Latrobe- http://www.latrobesteel.com/technical_alloycomparison.cfm?View=Results&CatID=1 (also see the tabs for Hot Work and Shock steels)

Crucible also has similar features for many of their steels-
http://www.crucibleservice.com/datash/ds3Vv5b.pdf
 
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