Ranking of Steels in Categories based on Edge Retention cutting 5/8" rope

[Vicv]

Exactly. Steels like o1, 1084, 5160, 52100 are all much easier to grind and heat treat. Anyone can get a decent heat treat with rudimentary tools. They will not get the best they can from that particular grade but it'll be decent. With the super steels you're guaranteed to make a bad knife unless you have precise equipment

You mean a super steel without the skills will be worse than a normal steel without the skills?

 

[daberti]

You mean a super steel without the skills will be worse than a normal steel without the skills?

No.I was clearly making reference to the fact (FACT) that I've never seen a single shooter smashing his/her nose with a 45ACP...out of examples, getting BD1N @60 it is very easy and straightforward for lets say even production knives, but they prefer (even the semi-custom mentioned above) to put out poorly HTd supersteels equipped knives that are noticeably punished by the first ones.
What we are talking about here is Sebbie with same TBE scores 31% less. Now, ok they don't want any claim from customers so lets privilege toughness, ok they want customers to be allowed an easy smooth and delicious sharpening experience.....and now potential customers know that an "underhardened" (skilled and gifted Phil forgive me, just meaning to say 58 against possible 63) ordinary steel in a test knife performs 31% more, as far as edge holding in a (mainly) abrasive cutting test where -once again- MC type V based carbides of Sebbie should indeed tell their own story.

Sebbie is just an example, though.
I think this is plain agreed by everyone here

 

[daberti]

Exactly. Steels like o1, 1084, 5160, 52100 are all much easier to grind and heat treat. Anyone can get a decent heat treat with rudimentary tools. They will not get the best they can from that particular grade but it'll be decent. With the super steels you're guaranteed to make a bad knife unless you have precise equipment

Ie.: get M390, fail the proper HT, nufoil wrapping, quenching media and CCT timings, you get a piece of s***

 

[daberti]

For the record, I have read every post in this thread, but with nearly 2800 of them, my memory isn't near what it needs to be in order to remember everything that you have said. No matter, if you recant the statement that I was commenting on or are modifying it then it helps to clarify your position for everyone. I doubt that I am the only reader who took your statements in post 2756 literally. So thank you for the clarification.

Now let's get back to our regularly scheduled program...

Oh mate, I was NOT upset, my emoticons were all

 

[dazzleaj]

This is fascinating stuff.

I know vastly more about steels and knives than anyone around me or for that matter anyone that I have ever met. But I know almost nothing compared to most of the "guys" here. (Guys is used as a general non gender reference).

I have designed and built equipment most of my life and have chosen steels to be hardened and even specified heating procedure, final temperature, time at temp, quenching medium, Nitriding depth, case hardening, inductive hardening etc etc etc. Reading these posts, I feel like a child. You "guys" really do impress me. I always check here before I buy anything knife.

Thanks for taking the time to share the fruits of so much work.

 

[daberti]

As a matter of facts Jim has built so much useful info to help me doing the right purchase that I should readily suggest him founding a new religion with his own name and I'll be his very first devoted follower [emoji106]🏻

 

[SBaker34]

Something to keep in mind. I found BD1N somewhat fragile compared to s30v. It is more corrosion resistant and seemingly at least has a bit more wear resistance. But I would put it next to s90v. But honestly more chippy it think.

 

[skwurll]

I like CRK's S35VN even though the HT may not be maxed out and it's not No1 in Jim's testing.

 

[daberti]

Did you HT it yourself ? If so with which parameters? Just asking.
In any case a toughness like s90 would not be that shabby for a non PM steel.

All in all S30V/35VN/S90V have more lateral toughness than lets say 440C at comparable hardness, yet the same vertical toughness.
FWIW my own general purpose trekking knife is an 7.5" N690@60 (deep cryo) blade, which never chipped and happily held an edge noticeably longer than its S3xx counterparts I put it against. No oil quenching, just vacuum+gas overpressure quenching+temper and cryo.

The point with S3xx and above is that nowadays you don't need to go the guru way. Of course oil or molten salt bath quenching would be best, but vacuum+ 5bar overpressure quenching+ three tempers with deep cryo in between can be done in nearly any HTing facility and it is well within reaching.
This way S3xx could reach 61-62 and a = or > 600 cuts per Jim tests.

As Prof. Verhoeven says so clearly in his publications, when you start dealing with good amounts of V and W (or Niobium) you have to understand that the austenitizing temperatures needed to obtain the optimal diffusion of these elements into the Matrix it is in excess of 1150°C, also because this way you'll minimize the amount of Cr and Moly carbides and use these two for stain resistance.
Not only in SS.
A clear example is the knives Phil made for a mate here which albeit not being SS (CPM-M4) had a more than decent performance in heavily salted environment.

Then I would like to talk about the common practice of underhardening steels like S3xx or alike and toughness.
You will get a softer martensitic Matrix which could mistakenly lead us into thinking that it could be an advantage toughness wise. However this is only a part of the Whole picture, the most important being the fact that at these aust. temperatures you'll get the greatest amount possible of carbides most of these bigger Cr carbides (and noticeably less stain resistance, obviously enough) for the given steel but NOT a Matrix strong enough to support them. Not so nice afterall.

 

[SBaker34]

Did you HT it yourself ? If so with which parameters? Just asking.
In any case a toughness like s90 would not be that shabby for a non PM steel.

Same test knife [emoji14], it was a weird steel honestly. Did decent at 20dps though. Just didn't like lateral stress at all

 

[daberti]

Same test knife [emoji14], it was a weird steel honestly. Did decent at 20dps though. Just didn't like lateral stress at all

Just edited my post. Please read.
My opinion is that is due to a relatively high Cr carbide content (possibly with some to be avoided M23C6 type of them). Raising the aust. temp to >1055°C and doing deep cryo should increase real (see my post above) toughness by means of getting a more stable Mart. Matrix with lesser and finer Cr carbides.

Edit: yes, I'm quite sure there are a good deal of M23C6 Cr based carbides. It mentions 15-17%Cr and 0.85-0.95C.
Would it be 17%, by aust. @1000°C we'd have all Cr carbides of M23C6 kind or in the y+M23C6+M7C3 region which explains all in either case.
(Source: http://www.calphad.com)
y+M23C6+M7C3 would almost certainly be the case until 1040°C (raise by 20°C if doing vacuum).

 

[chiral.grolim]

Then I would like to talk about the common practice of underhardening steels like S3xx or alike and toughness.
You will get a softer martensitic Matrix which could mistakenly lead us into thinking that it could be an advantage toughness wise. However this is only a part of the Whole picture, the most important being the fact that at these aust. temperatures you'll get the greatest amount possible of carbides most of these bigger Cr carbides (and noticeably less stain resistance, obviously enough) for the given steel but NOT a Matrix strong enough to support them. Not so nice afterall.

This is some key info here for folks :thumbup:, and it holds true with cemented carbide hard-metals as well. As the % soft binder increases, "toughness" increases but strength drops, and if the carbide-grains are overly large then "tear-out" quickly becomes an issue as the soft binder deforms too much to hold them in place, resulting in excessive chipping. For knife use, strength dominates and informs on apparent toughness.

 

[daberti]

This is some key info here for folks :thumbup:, and it holds true with cemented carbide hard-metals as well. As the % soft binder increases, "toughness" increases but strength drops, and if the carbide-grains are overly large then "tear-out" quickly becomes an issue as the soft binder deforms too much to hold them in place, resulting in excessive chipping. For knife use, strength dominates and informs on apparent toughness.

Holy God, one follower at last
One WELL KNOWN example? D2 (not CPM-D2) austenitized at 1020°C

 

[Surfingringo]

Same test knife [emoji14], it was a weird steel honestly. Did decent at 20dps though. Just didn't like lateral stress at all

That same BD1n test knife made it through my hands too. I tested it extensively for weeks in very harsh saltwater environments and it performed quite well. I was testing s90v at the same time and they both performed admirably considering what I subjected them to. Similar corrosion resistance on the two and both performed significantly better than s30v.

 

[daberti]

That same BD1n test knife made it through my hands too. I tested it extensively for weeks in very harsh saltwater environments and it performed quite well. I was testing s90v at the same time and they both performed admirably considering what I subjected them to. Similar corrosion resistance on the two and both performed significantly better than s30v.

Very useful news as I do know your testing environment, mate.
Also S90V has 0.1N in its chemistry

 

[nccole]

Very useful news as I do know your testing environment, mate.
Also S90V has 0.1N in its chemistry

For corrosion resistance? I realize it's not a typical nitrogen replacing carbon like H1, so are there other reasons to have it in the mix?

 

[daberti]

For corrosion resistance? I realize it's not a typical nitrogen replacing carbon like H1, so are there other reasons to have it in the mix?

Other reason already been explained
http://www.bladeforums.com/forums/s...cutting-5-8-quot-rope?p=15334109#post15334109
Notably.... http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=kts&NM=202

Nitrogen and pitting resistance:
http://www.bladeforums.com/forums/s...cutting-5-8-quot-rope?p=14714197#post14714197
"....This would make for a theoretical PRE ...."

 

[skwurll]

Holy God, one follower at last
One WELL KNOWN example? D2 (not CPM-D2) austenitized at 1020°C

Not at all daberti, you bring a lot of insight and knowledge to the table. I just think there are a lot of non-tangibles that get lost when talking metallurgics alone. I see Jim's testing as moving through that and offering something tangible and direct people can process. I know a lot of this info is over my head.

 

[daberti]

Not at all daberti, you bring a lot of insight and knowledge to the table. I just think there are a lot of non-tangibles that get lost when talking metallurgics alone. I see Jim's testing as moving through that and offering something tangible and direct people can process. I know a lot of this info is over my head.

Thanks buddy
Jim feeds us with comparative edge holding results, I'm trying to give results a metallurgical explaination.
A lot of this info WAS ACTUALLY over my head too lets say up to five years ago...until I met "Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel" by Prof. Emeritus John D. Verhoeven.
I invite everyone here getting a hold of this book.

 

[calc]

"Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel" by Prof. Emeritus John D. Verhoeven.
I invite everyone here getting a hold of this book.

I actually just started this, it's been very informative.