toughest steel in a folder

1095? I trust it to have more impact resistance than any of the ultra- hard stainless steels that are in vogue. I had S30V develop tiny chips in the edge but I've never had CV or 1095 chip on me. A sodbuster isn't as sexy as a ZDP Leek but I bet it's a lot tougher.

Frank
 
knarfeng said:
In your original post you said you were not talking about edge retention, but rather a steel that is hard to break. For that you want a lower carbon content and will need to give up some on edge retention. Toughness and edge retention are opposites. The rule of thumb is that to get more of one, you have to give up some of the other.

D2 is one of the best for edge retention. But not good for el destructo work. 440A would be much tougher. Won't hold an edge real well, but it would be tougher.

If I wanted a combination of pretty good edge retention and pretty good toughness, I'd look at AUS8. If I wanted to go tougher than that and get less edge retention, I'd look at AUS6 maybe even AUS4. CRKT has some of their blades in these steels. Maybe one of the M16's.

Remember that blade shape is also going to play a part in the perceived toughness. A thinner blade is going to be damaged more easily than a thicker one. I just got a KaBar Large Dozier in AUS8. The blade is 0.155" thick. That'll take quite a lot of hard work. Think the CRKT M21 also has a very thick blade in AUS8 also.

Anyway, you're looking at the wrong steels in D2 and S30V if you are looking for pure toughness.
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Interesting...I have an M16 in AUS4 in my pocket right now. I have also thought about something very thick, do you think that a 154 blade like that on the H&K 14255 (.15 thick) would be tougher than say the .115 D2 blade on the BM 710 or Cabelas griptilian? I don't care too much for the AUS4 steel (I care even less for CRKT's edge profile) and I think I could break it...I just haven't had the oportunity yet (not that I'm looking for it...gosh). Also, I've got some blade play that I really don't like as well, I want something much more high end. I just don't want to break it and be all pissed cuz I broke an expensive knife.

I may have to try AUS 8. Is there an AUS8 blade that has a tough lock and g10 handles out there? (american made preferred)
 
Should be, but I can't name one right away. Got a couple of other suggestions though.

Some of the web stores still have the Ontario Knives RAT-1. It's been discontinued but some places still have stock. Has FRN handle but also has steel liners. So the end effect should be the same as G10. Read some really good reviews about it. Add: seen it for $60-$80

There's been a couple of reviews about the KaBar Mule. Everyone says it's bloody indestructible. Big knife though. Might not fit in your pocket. Add: Runs about $45.

ADD:
not enough experience to comment on the 154 vs. the D2.
 
therulebookman said:
I may have to try AUS 8. Is there an AUS8 blade that has a tough lock and g10 handles out there? (american made preferred)
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You'd have to check on the country of manufacture, as I'm not sure, but SOG makes the Spec Elite and Pentagon Elite w/ the Arc Lock, similar to BM's Axis Lock. They come in 4" and 5" blade versions. Handles arent G10, but it has steel liners inside Fiber Reinforced Nylon (FRN).
 
Well, it's a CUSTOM and an AUTOMATIC but I believe the Severtech folder has A2 tool steel for it's blade.
 
typically, when we think of toughness....we think of steels that can withstand heavy impacts with little or no deformation.

Chromium typically decreases toughness...which is why stainless steels can have great edge-retention...nice polish...etc...but not toughness.

Add to that the fact that most high carbon steels are not "folder ready"....except for maybe A2. That would be one of my top choices.


There are certainly better steels for different applications...


Personally, S30V is the steel of choice for me on my EDC folders...hard working stainless steel...but certainly not the "toughest".
 
therulebookman said:
I'm interested to see what people think is the toughest steel in a folder. When I say toughest I mean the technical definition: highest SHEAR YEILD. In other words: hardest to break. Edge retention aside what knife do you own that you just can't break no matter how hard you try?

If you want to give your thoughts on fixed blades thats cool too, but IMO INFI pretty much has to win since over in the busse forum they say only 2 have broken.

I also think that fixed blades are just designed to be stronger from a materials standpoint and that alot of makers don't try to put tougher materials in a folder because they don't think they can be made strong just based on principle.
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It pretty much depends on the dimensions. You will breake any steel edge, because it is so thin and you will have much more trouble with a thick stock of about .25" no matter the steel.
 
knarfeng said:
Anyway, you're looking at the wrong steels in D2 and S30V if you are looking for pure toughness.
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Do you have figures to show concerning toughness comparison in stainless steels?

For the time being I'm going to stick with the S30V being number one choice. It seems to be the best choice in tough stainless steels since...well...because Bill Harsey says so and Striders prove it :) S30V edge retention ain't that bad either...
 
PatriotDan said:
Do you have figures to show concerning toughness comparison in stainless steels?

For the time being I'm going to stick with the S30V number one choice. It seems the best choice in tough stainless steels since...well...because Bill Harsey says so and Striders prove it :) S30V edge retention ain't that bad either...
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Don't have figures. Have the comments of Joe Talmadge from his sticky on the Toolshed forum:

"Toughness: The ability to take an impact without damage, by which we
mean, chipping, cracking, etc. Toughness is obviously important in
jobs such as chopping, but it's also important any time the blade hits
harder impurities in a material being cut (e.g., cardboard, which
often has embedded impurities).

The knifemaker will be making a tradeoff of strength versus toughness.
Generally speaking, within the hardness range that the steel performs
well at, as hardness increases, strength also increases, but toughness
decreases. This is not always strictly true, but as a rule of thumb
is generally accurate. In addition, it is possible for different heat
treat formulas to leave the steel at the same hardness, but with
properties such as toughness, wear resistance, and stain resistance
significantly differing."

440A is tougher than S30V or D2. That's why big stainless chopping knives are made from it. The original question was, "what is the toughest steel?"

That being said, my EDC is not 440A. Like you, I value edge retention over pure toughness. So I carry a blade made from VG10 or ATS-34. But the original question was "what is the toughest steel?" I answered the question, staying focused on stainless steels because the guy was talking folders.
 
a lot of dead links on crucible pages, but here's a few I could dig up on charpy C-notch testing

D2 @ 60 21 lbs
A2 @ 60 40 lbs
3V @ 60 70 lbs
M2 @ 62 20 lbs
M4 @ 62 32 lbs
10V @ 63 14 lbs
S7 @ 57 125 lbs
440C @ 58 16 lbs
S90V @ 58 19 lbs

for S30V, the pdf only showed that the transverse testing was 10 lbs (compared to 2.5 for 154CM & 440C), and a cryptic 25-28 lbs longitudinal for all three steels, hardness not stated. Yes, one Crucible document said 16 lbs for 440C, and another said 25-28 lbs, I don't know why.
 
Daniel Koster said:
typically, when we think of toughness....we think of steels that can withstand heavy impacts with little or no deformation.

Chromium typically decreases toughness...which is why stainless steels can have great edge-retention...nice polish...etc...but not toughness.

Add to that the fact that most high carbon steels are not "folder ready"....except for maybe A2. That would be one of my top choices.


There are certainly better steels for different applications...


Personally, S30V is the steel of choice for me on my EDC folders...hard working stainless steel...but certainly not the "toughest".
Click to expand...

What do you mean by "folder ready?" As a knife maker, why do you think that most (if not all) manufacturers wont put really tough steel in a folder (besides the pure fact its not stainless)?

If I got a folder, no matter what the edge retention and I broke the lock/pivot/handle before I broke the blade, I'd be really happy, because I cant see that happening, but there are at least a few people here who seem to think it possible.

Hardheart - those are some great numbers (assuming that the Charpy test is a good test of toughness). According to your analysis of those numbers which would you say is the toughest of D2, 154, and S30V as those are the main steels found in higher end folders? I didn't look at the raw data so I dont know what to make of those 154 and S30V numbers.
 
hardheart said:
a lot of dead links on crucible pages, but here's a few I could dig up on charpy C-notch testing

D2 @ 60 21 lbs
A2 @ 60 40 lbs
3V @ 60 70 lbs
M2 @ 62 20 lbs
M4 @ 62 32 lbs
10V @ 63 14 lbs
S7 @ 57 125 lbs
440C @ 58 16 lbs
S90V @ 58 19 lbs

for S30V, the pdf only showed that the transverse testing was 10 lbs (compared to 2.5 for 154CM & 440C), and a cryptic 25-28 lbs longitudinal for all three steels, hardness not stated. Yes, one Crucible document said 16 lbs for 440C, and another said 25-28 lbs, I don't know why.
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Not to throw rocks, just to clarify.

Toughness values are in ft-lbs (or lb-ft), not lbs. They measure energy, not force.

Toughness is a measure of resistance to fracture, not resistance to bending.

Yield strength is a measure of resistance to bending. Blade bending strength is a function of both blade geometry (thicker has more strength) and yield strength.

For any given steel, the harder it is, the higher the yield strength. And if you're just hardening/tempering, the higher the yield strength, the lower the toughness.

Carl
 
A point to consider. If the blade is tougher than the handle,the handle will break (or snap shut on your hands) before the blade breaks. Ouuuch!!!! If the blade breaks first, the failure is away from your hand.

What is the intended purpose of this knife?
 
cds4byu said:
Not to throw rocks, just to clarify.

Toughness values are in ft-lbs (or lb-ft), not lbs. They measure energy, not force.
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is there a diff in ft/lb & lb/ft, I remember Car & Driver having an absolute hissy fit over the way the other mags reported torque. little lazy of me to leave off the ft. either way; mass times acceleration, force over distance, ability to do work, I'll get it straight some day :D
 
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