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AUS8 vs. ATS-34
- Thread starter Warthog
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Folks,
I think a great deal of simplification is clearly visible in this thread, somewhat in taste of George Orwells two legs are bad, four legs are good!
Which steel is better? Depends on for what, as usually at least. Cliff is completely right, ATS-34 (or 154CM) holds the edge significantly longer than AUS-8 assuming that both are hardened to their optimal performance. This is clearly visible on pure slicing, especially on not too hard but abrasive materials like hemp, cardboard or gritty carpet. I have received confirmation numerous times testing different blades on different materials.
On the other hand AUS-8 is tougher what means less brittle and prone to chipping than ATS-34 or 154CM. Conclusion I would prefer ATS-34 over AUS-8 (or especially AUS-6) for typical hunting knife because it would hold up much better when skinning, especially when opening the game. The skin on wild boar belly is not just pretty thick and covered with hard bristle. Quite usually it also very gritty and you probably could get your knife dull even before starting the work when you should have it really sharp. However I would prefer AUS-8 over ATS-34 in somewhat bigger, say 5-inched general use outdoors blade because it can take more accidental abuse without chipping. The blade can always be resharpened as long as it stays in one piece and is not badly damaged.
Yes, it is truth that AUS-8 is somewhat easier to sharpen because it is softer and less abrasion resistant. However it is not truth that ATS-34 is difficult to sharpen to shaving sharp edge. All depends on edge thickness and sharpeners skills. My SPYDERCO Ti-Salsa with ATS-34 blade cuts forearm hair even without touching the skin, so it is really (not metaphorical) hair-popping sharp. The cost of such sharpness is very thin edge what in combination with ATS-34 steel would chip easily on relatively low lateral load. This way sharpened AUS-8 edge would roll even easier and even on normal cutting, without noticeable lateral load losing its cutting ability. The steel with lower carbon contents shouldnt be sharpened to so thin edge at all unless they are razor blades.
I think a great deal of simplification is clearly visible in this thread, somewhat in taste of George Orwells two legs are bad, four legs are good!
Which steel is better? Depends on for what, as usually at least. Cliff is completely right, ATS-34 (or 154CM) holds the edge significantly longer than AUS-8 assuming that both are hardened to their optimal performance. This is clearly visible on pure slicing, especially on not too hard but abrasive materials like hemp, cardboard or gritty carpet. I have received confirmation numerous times testing different blades on different materials.
On the other hand AUS-8 is tougher what means less brittle and prone to chipping than ATS-34 or 154CM. Conclusion I would prefer ATS-34 over AUS-8 (or especially AUS-6) for typical hunting knife because it would hold up much better when skinning, especially when opening the game. The skin on wild boar belly is not just pretty thick and covered with hard bristle. Quite usually it also very gritty and you probably could get your knife dull even before starting the work when you should have it really sharp. However I would prefer AUS-8 over ATS-34 in somewhat bigger, say 5-inched general use outdoors blade because it can take more accidental abuse without chipping. The blade can always be resharpened as long as it stays in one piece and is not badly damaged.
Yes, it is truth that AUS-8 is somewhat easier to sharpen because it is softer and less abrasion resistant. However it is not truth that ATS-34 is difficult to sharpen to shaving sharp edge. All depends on edge thickness and sharpeners skills. My SPYDERCO Ti-Salsa with ATS-34 blade cuts forearm hair even without touching the skin, so it is really (not metaphorical) hair-popping sharp. The cost of such sharpness is very thin edge what in combination with ATS-34 steel would chip easily on relatively low lateral load. This way sharpened AUS-8 edge would roll even easier and even on normal cutting, without noticeable lateral load losing its cutting ability. The steel with lower carbon contents shouldnt be sharpened to so thin edge at all unless they are razor blades.
- Joined
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Because of lower hardness,person feels that toughness of AUS-8 is superior to ATS-34.But if he can compare these toughness at
same hardness level,he will understands toughness of ATS-34 is superior to AUS-8.He will understand why expensive Moly content of ATS-34 is much amount.But grindablity of AUS-8 is somewhat superior to ATS-34 because of low carbon content.because of same reason,wear resistance of AUS-8 is inferiot to ATS-34.So if he want to cut softer things than average level,it is recommended AUS-8.Material choice depends upon usage.
same hardness level,he will understands toughness of ATS-34 is superior to AUS-8.He will understand why expensive Moly content of ATS-34 is much amount.But grindablity of AUS-8 is somewhat superior to ATS-34 because of low carbon content.because of same reason,wear resistance of AUS-8 is inferiot to ATS-34.So if he want to cut softer things than average level,it is recommended AUS-8.Material choice depends upon usage.
Cliff Stamp
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japansteel :
It doesn't work this way with most steels. If you drop the hardness of A2 down for example, you don't get a higher toughness than for A6. Do you have any charpy data for AUS-8A and ATS-34 at lower RCs?
-Cliff
It doesn't work this way with most steels. If you drop the hardness of A2 down for example, you don't get a higher toughness than for A6. Do you have any charpy data for AUS-8A and ATS-34 at lower RCs?
-Cliff
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CharpyHit sounds like amature thinking.
Probrem is probability of thin edge of cutlery.
Egde og cutlery isnt structural part like conventional steel.
If you want to know toughness of thiner cutlery edge,
you must understand distribution of fracture defect.
Charpy is not sensitive evaluation for this problem.
Probrem is probability of thin edge of cutlery.
Egde og cutlery isnt structural part like conventional steel.
If you want to know toughness of thiner cutlery edge,
you must understand distribution of fracture defect.
Charpy is not sensitive evaluation for this problem.
Cliff Stamp
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japansteel :
I would not argue that charpy impact toughness statistics provide a complete perspective on edge durability, however I don't think they are irrelevant either. I have seen many edges take damage, and higher toughness statistics correlate very strongly to lower damage.
More details would help here. Are you arguing that ATS-34 is as likely or more likely to take fracture than AUS-8A, but the spread of the cracks is less, or that the frequency of crack initiation is directly lower even though the impact toughness and ductility are lower? How are either of these explained from the internal actions of the steels?
-Cliff
I would not argue that charpy impact toughness statistics provide a complete perspective on edge durability, however I don't think they are irrelevant either. I have seen many edges take damage, and higher toughness statistics correlate very strongly to lower damage.
More details would help here. Are you arguing that ATS-34 is as likely or more likely to take fracture than AUS-8A, but the spread of the cracks is less, or that the frequency of crack initiation is directly lower even though the impact toughness and ductility are lower? How are either of these explained from the internal actions of the steels?
-Cliff
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i think what japansteel is trying to say is that for specialised applications like cutlery, the conventional tests for metal strength are not very applicable
i get the feeling his emphasis is more on blade geometry, heat treat, etc, instead of WHAT the metal is made out of
but that might just be me
i get the feeling his emphasis is more on blade geometry, heat treat, etc, instead of WHAT the metal is made out of
but that might just be me
Cliff Stamp
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DEA :
This is a frequent claim, but isn't factual. Properties like hardness, strength, ductility, corrosion resistance, etc., have direct consequences on edge behavior. Heat treatment (and steel selection) works by promoting the optimal levels of these properties. The choice of geometry is one which based on these properties crafts the maximal cutting ability with the required durability. Better steels (which mean better materials properties) means that you can directly create better blades by further optomizing the geometry.
-Cliff
This is a frequent claim, but isn't factual. Properties like hardness, strength, ductility, corrosion resistance, etc., have direct consequences on edge behavior. Heat treatment (and steel selection) works by promoting the optimal levels of these properties. The choice of geometry is one which based on these properties crafts the maximal cutting ability with the required durability. Better steels (which mean better materials properties) means that you can directly create better blades by further optomizing the geometry.
-Cliff
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DEA
Thank you for your good notes.
Cliff
Even if differences can be mentioned,actually ATS-34 is superior to
AUS-8 in case of fracture especially.Because M7C3 carbide of AUS-8
is more stable than ATS-34.In other words, AUS-8 have few expensive amounts of addition of Moly.M7C3 carbide is easy to become bigger
and is easy to cause breakage.If you watch both microstructures,
you understand my words without statistical mechanical testing.
japansteel
Thank you for your good notes.
Cliff
Even if differences can be mentioned,actually ATS-34 is superior to
AUS-8 in case of fracture especially.Because M7C3 carbide of AUS-8
is more stable than ATS-34.In other words, AUS-8 have few expensive amounts of addition of Moly.M7C3 carbide is easy to become bigger
and is easy to cause breakage.If you watch both microstructures,
you understand my words without statistical mechanical testing.
japansteel
Cliff Stamp
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japansteel, If the moly in ATS-34 enhances the toughness so that it exceeds AUS-8A at its optimal hardness (usually 58 RC), why does this only happen in very thin structures? How comes it doesn't show up in a Charpy test? In general charpy tests do correlate very well to edge durability.
These are not aesthetic aspects we are talking about, but well defined materials properties. If there is an enhanced toughness it has to be measured to be meaningful.
-Cliff
These are not aesthetic aspects we are talking about, but well defined materials properties. If there is an enhanced toughness it has to be measured to be meaningful.
-Cliff
- Joined
- Oct 28, 2002
- Messages
- 74
Cliff,You must study metallurgical effects like this more.
AUS is not good status less Moly and not optimum condition of
steel makin process.AUS is almost stable at the side of
M7C3 carbide.But ATS-34 is stable at the side of M23C6
carbide thermodynamically.M7C3 is easy to be huge at solidification process.Even if ATS,huge M7C3 exists after casting.But after that,M7C3 is broken up to smaller M23C6.
Our disccusion needs comprehension that both chemical composition and steel makin condition are important.
japansteel
AUS is not good status less Moly and not optimum condition of
steel makin process.AUS is almost stable at the side of
M7C3 carbide.But ATS-34 is stable at the side of M23C6
carbide thermodynamically.M7C3 is easy to be huge at solidification process.Even if ATS,huge M7C3 exists after casting.But after that,M7C3 is broken up to smaller M23C6.
Our disccusion needs comprehension that both chemical composition and steel makin condition are important.
japansteel