O1 vs 5160

[OldPhysics]

In my opinion the difference is so small you won't be able to tell them apart just by regular usage.

Although I'm no maker, this is what I would have thought.

I learned the difference between staring at spec sheets and phase diagrams ... and using materials in the laboratory/real world ... many decades ago.

 

[nullack]

I knew better than to start in on word definition

Mike the reason I provided those is that what you said makes no sense. You said "My opinion is most knives need to be of a steel and HT that fails by yield strength, not plastic/elastic."

By keeping under the yield strength, your actually using the elastic range of the material. You cant say "not plastic/elastic" in the context of claiming that designing to fail by yield strength.

 

[nullack]

Although I'm no maker, this is what I would have thought.

People say L6 is tough, well it has a v notched charpy toughness score of 2.8 ft lbs at HRC60 while S5 has the same v notched charpy test score of 8.4 ft lbs. Thats a difference of 300% greater notch toughness in S5 over L6.

Those that say the differences in mechanical properties dont make a difference to knives in use need to more testing. For example when I tested my micro melt maxamet allot knife it shattered the first time I did a toughness test on it in comparison to other knives lasting over 50 repeated tests without problems.

 

[AcridSaint]

Comparing just charpy figures is not enough when talking knives, even tough ones. There are a lot of tough materials out there, not all have desirable characteristics for knives. L6 is tough for knifemaking applications - the problem you're running into is that S5 is not a steel considered by most to be applicable to our needs.

 

[nullack]

Im happy to explore the other properties people consider to be important.

I have labelled three mechanical properties - toughness, strength and wear resistance. We know how to measure toughness and strength so thats easy.

The tribology of knife wear is not properly understood and I dont see any better method of testing it short of doing manual cutting tests which is what Im doing.

I know that the wear resistance of S grade tool steels is low, but for the purposes of hard use knife design I find it acceptable. Please note, that S7 knives are available from other knife makers as well. The difference between S7 and S5 is that S5 has more toughness at higher hardness than what is possible with S7. S7 can be heat treated using cheaper methods though.

 

[nullack]

Mate to give you an example of the issues with knife tribology, look at what latrobe specialty steel say about S5. They say S5 has better wear resistance than L6. We know this is true, because engineers for decades have developed ways to test things like:

Adhesive wear
Abrasive wear
Chemical wear

However because I dont, and it seems no one else fully understands the tribology of cutlery knives, I cant goto a materials expert with specific requirements and optimise material selection based on it.

 

[AcridSaint]

I don't think there's a person here who's going to tell you that S5 isn't OK for you to use on your knives, but I've yet to see a single bit of evidence that it will be of more use to the majority of knifemakers than any of the far more common and popular steels. Jackhammer toughness is only one factor that we consider for a knife steel - as are wear resistance, stain resistance, cost, availability, saleability and so many many more. Everyone has different criteria, but I don't know any other maker who is regularly willing to sacrifice all of the other considerations just to take one to the absolute extreme.

Show us some impressive results with S5 other than being able to hammer it through a car door without chipping. I've yet to see a datasheet that tells me that S5 is going to offer something to me that I need over my preferred steels (not L6, 5160 or ) O1, by the way) and I haven't seen anything convincing from you either. In other words, put up or shut up

 

[nullack]

Im not convinced that S5 is in fact at the expense of all other properties. S5 does indeed have a high strength and in no way can it be considered a compromise there. S5 does indeed have a high hardness, which can be HRC 62 but I choose to do it to HRC 60. No compromise there. I've shown you how at HRC 60, it is immensely tough in comparison to other materials, even L6 which is 300% less tough than S5 at the same hardness level.

The issue is wear resistance which is subjective to the tasks the knives will use and not properly understood in engineering terms. However, LaTrobe speciality steels according to their tests using standardised engineering wear tests says that S5 is more wear resistant than L6.

All things considered, for my *specific* needs S5 has proven to be the best material I've tested so far.

If you could expand on what makes you feel the material you use is best for your *specific* needs I could offer you my thoughts. You may find that there is other materials that will perform better for the *specific* use your intending.

 

[cotdt]

S5 seems very interesting, I want to try it. Where can we buy it?

 

[nullack]

Mate its not for everyone, as we know that for specific uses theres different qualities that are needed the most. What I can attest to is that for my hard use needs it is the best material Ive tried so far.

EDIT: Please note I have not tried CPM3V like what Acrid Saint suggested. I have however read the review cliff stamp did on some knives made in CPM3V that didnt go so well. This could indeed just be a manufacturing problem and not a true representation of the alloys qualities so until I test it for myself or find someone else with a known quality process that has been reviewed I dont have any conclusions about it.

EDIT: Forgot to say that Crucible also sell it but they call it Labelle Sicilon #2. Caprenter sell it as Carpenter No. 481.

Latrobe Speciality Steel sells it. For other quotes theres online metal suppliers where you can find sellers of it - google

Like most tool steels it will decarburize so unless your using a vacuum furnace with inert gas quenchant youll need to take steps to prevent hassles. Or you could post heat treat finish it and simply remove the bad layer of material. Be aware that all machine work after heat treating has to be water cooled otherwise you will damage the heat treat (or do it by hand). This is a proven by a German PHd (Dr Roman Landes) who did a heap of metallographic examinations. His book is in german I hope it gets translated.

 

[AcridSaint]

Sorry, I wasn't asking for suggestions about my knife steels, I'm happy with them I'm asking that you show some actual results that offer real evidence that S5 is suitable for a knife steel and what steels it competes with. Obviously, S5 isn't going to compete with M2 or M4 for edge retention, for example. But maybe you have some steel that S5 will give a run for its money in knife applications - once again, you just have to prove it. Simply stating "latrobe says..." isn't going to cut it around here - neither is quoting anything from Cliff Stamp.

 

[69_knives]

If you make medium to larger blades will there be much difference if o1 steel or 5160 steel is used?
(Assuming the blades are made correctly)

Your better off using a tool steel designed for shock applications than 5160. Say, S5,

S5 seems very interesting, I want to try it. Where can we buy it?

Mate its not for everyone,

Sorry, everybody, statements retracted. I should think before I type.

 

[nullack]

Sorry, everybody, statements retracted. I should think before I type.

69_Knives, the bloke is using 5160. The performance reason why 5160 is liked for blades is due to toughness and hardness. Some shock resisting tool steels *have been specifically designed* to provide maximum toughness and hardness like S5. The properties have been objectively measured and they are btter than 5160. This is why I said to the bloke hes better off with these materials not 5160 if performance is his objective.

 

[nullack]

I'm asking that you show some actual results that offer real evidence that S5 is suitable for a knife steel and what steels it competes with. Obviously, S5 isn't going to compete with M2 or M4 for edge retention, for example. But maybe you have some steel that S5 will give a run for its money in knife applications - once again, you just have to prove it. Simply stating "latrobe says..." isn't going to cut it around here - neither is quoting anything from Cliff Stamp.

What do you mean exactly by edge retention? How do you measure it objectively?

With wear resistance, are you saying that the ASTM G65 abrasive wear tests by LaTrobe are meaningless?

If you want to have a fair dinkum discussion, you should stop ignoring facts Ive presented to you. e.g. You claim that S5 is all a sacrifice to everything but toughness when Ive shown you thats not the case at all.

 

[cotdt]

Sorry, I wasn't asking for suggestions about my knife steels, I'm happy with them I'm asking that you show some actual results that offer real evidence that S5 is suitable for a knife steel and what steels it competes with. Obviously, S5 isn't going to compete with M2 or M4 for edge retention, for example. But maybe you have some steel that S5 will give a run for its money in knife applications - once again, you just have to prove it. Simply stating "latrobe says..." isn't going to cut it around here - neither is quoting anything from Cliff Stamp.

I don't think he needs to show any evidence in favor of S5. It can get to 62 hrc and is tough, and so far almost all tool steels that can get 60+ hrc have been used in knives. I'm going to order some from Crucible and make a thin knife out of it, to see how it holds up.

 

[nullack]

neither is quoting anything from Cliff Stamp.

Here you are misrepresenting what I said. Youve suggested I look at cpm3v. I acknowledged to codt that I have not as of yet trialled it myself. The bit about cliff was that I saw his reviews of knives in these materials. Again you seem to ignore things I have said, where I specifically said I had no conclusions about that material and I placed some doubts on cliffs conclusions.

 

[69_knives]

I'm going to order some from Crucible and make a thin knife out of it, to see how it holds up.

Awesome! we'll finally get some real world test results from a knifemaker regarding this steel. Be sure to keep us posted.

 

[nullack]

Awesome! we'll finally get some real world test results from a knifemaker regarding this steel. Be sure to keep us posted.

I previously said "Yes, I have made blades out of S5 as well as other materials including S7, 52100, 5160, micro melt maxamet, aermet for tooling, 1095, others Ive probably forgotten. The S5 knife is so far the best blade Ive made for my use."

cotd I start with annealled stock. Following shaping, my blanks are triple normalised to refine the grain to give me the mechanical benefit of smaller grains. Its then sent for vacumm furnance quenching, which doesnt have carb problems but with other heat treat methods you can combat carb problems. I use a high pressure gas quenchant. I specifically dont keep any soak time when the austenizing temp is reached to not allow grain growth to occur and our blades dont have large section sizes anyway. Then it is deep cyrod at -300F to recover retained austenite but you could do multiple quenches to do the same thing. I triple normalise for a target HRC of 60 as going further there is a distinct toughless loss for next to very little hardness gain. Dont dry machine it after heat treating - either cooled or hand tools only.

 

[hardheart]

I'm confused, Acrid says not to listen to Latrobe, but to listen to Crucible. Why is one so much more superior to the other? What did Crucible use to determine suitability for cutlery outside of measured performance in actual testing, like the Rockwell testing, wear resistance testing, or toughness testing?

Is a steel suitable for knives just because someone says it is? Why do they use it? Is it the best steel? Or was it cheap, easier to heat treat, available in flat stock that didn't need to be forged down, or what? Is the steel great, or is it just good enough? And what makes one good enough and another not so much?

Why are knives made from D2? That's a die steel, who makes knives from something like that? Why use 5160, that's for springs! How about that crap about using ATS-34, what was Loveless thinking? What does a turbine have to do with skinning or chopping?

 

[69_knives]

The S5 knife is so far the best blade Ive made for my use.

Well, anecdotes are really interesting but could you provide some form of real world test results, charts or graphs that you have personally performed that support that statement and other blanket generalized statements like "Your better off using a tool steel designed for shock applications than 5160. Say, S5".