WilliamMunny wrote: ↑Wed Sep 28, 2022 7:18 pm
weeping minora wrote: ↑Wed Sep 28, 2022 2:28 pm
WilliamMunny wrote: ↑Wed Sep 28, 2022 1:53 pm
I am bring back this thread with the upcoming release of the Manix 2 in 15v. This should have a lot of good info.
I have two questions, I have not read this whole thread yet so if it’s been answered already sorry.
1. How is 15v vs S90V? They have similar toughness and edge retention but S90V is stainless. Why wouldn’t you always go with S90V?
2. What kind of corrosion resistant can we expect from this? Rust spots, patina, will it just rust in the pocket, etc?
I don't think enough people have experience with 15V to even post a definitive comment to your requests. I don't want to sound like a rear-end, but you keep posting questions regarding minute differences on the same subject from thread-to-thread, seemingly dismissing any discussion or information specified in said threads as it is. It gets kind of muddied when you just keep posting, "what about A vs B?", "now what about A vs C?", "now what if A was treated like C vs B for people who think like D?". I understand the quest for knowledge and understanding is great, but there are vast resources on the subject that span far and wide. If you are into these super steels, you should do yourself a favor and start to research and decipher what alloying contents do what within a steel to form an idea on the overall performance of the matrix from the perspective of possibility given an ideal, or different heat-treatment.
S90V is to 15V, as apples are to oranges. The only comparable trait being low toughness, or in other words, they are both fruit. 15V will certainly rust in the pocket for most who perspire, or live in a humid environment, as has S90V for that matter, for a select few. 15V will have much higher attainable hardness and wear resistance. I assume the edge will yield much higher strength (due to hardness), be much more aggressive (due to Vanadium Carbide content) and will hold that aggression for a long time (again, high Vanadium Carbide distribution), given that you are cutting materials that are not very hard in their abrasiveness.
Why add REX 76 to the stable when REX 45 is marginally lesser alloyed? They should behave like the exact same steel, right? As always, Spyderco seems to ask the question of, "why not?", when offering a new steel to their line-up; which has pushed my understanding on what steel can do, beyond a mere "in-use" perspective. It bridges the "why", to the experiences in use.
I hope this doesn't come off too abrasive, it just seems there are too many of the exact same questions being asked all over this forum; sometimes literally post-after-post within the exact same thread, even if answers (experiences or opinions) have been submitted. Research is your best resource (and there are a whole lot of resources), following experience.
No it’s never too abrasive, thank you for the information. That is how I got to this old thread, trying to do research to learn more. With so many threads and topics things can get missed or mis-read. I do understand that the hardness of the steel effects edge retention but it’s not even across every type of steel.
When you speak to the edge as being aggressive does that mean having micro serrations when sharpened with a courser stone like CBN? Or aggressive mean that it will hold that razor edge before breaking down to a working edge?
Someone made the post stating finishing with a CBN stone gave them better results. I can’t remember the steel but maybe K390 or Maxamet.
I'd look at it as the
hardness affects edge characteristics more-so than retentive capability. The Carbide Type (which can be reflective in Hardness), Volume (Amount), Size and Distribution (Homogeneity) will affect edge retention and edge aggression, which is of course in turn further affected by the overall hardness, which in heat-treatment terms is essentially a manipulation of Alloying content to come into solution (with a goal of "entrapping" Alloyed clusters, or, causing the grain formation of Carbides [Carbon fused to an Element] into the matrix), or not. This will give a better understanding of how and why an edge behaves in the manner that it does (which many factors are involved). It dives deeper than simply "edge retention for edge retentions sake".
As a side note, CarboNitrides will form when Carbon and Nitrogen are present and Nitrides will form when Nitrogen is used as replacement for Carbon. For the sake of my limitations of understanding (and longevity), I will only discuss Carbon based steels.
Without delving too deeply, Carbon content will allow higher hardness to be achieved. Chromium is complex in that it can form Carbides within the matrix, affect stain-resistance (if the content is in the 11/12%+ range freely-roaming to reduce surface oxidation and not soaked into the solution as Carbide), or it can act as a secondary hardening element when used in lower concentration and in conjunction with Harder Carbide Formers (which will assist in the hardness needed to form Harder Carbides in place of softer Cr Carbides, given a heat-treating process that favors such; typically in applications where stainlessness may not be a goal). Too much Chromium, needed for stain-resistance, places limitations on the addition, or formation of, aforementioned Harder Carbide Formers (for example; Vanadium Carbide); inhibiting heat-treating capabilities.
Vanadium will form Vanadium Carbides, which are extremely hard and offer great wear resistance and aggression. This capability in hardness also lowers toughness (the ability of the Carbide clusters bound within the matrix to resist fracture). The higher attainable hardness and the hardness of VC formed during heat-treat increases the amount of force needed to cause that deformation to begin to occur (Yield Strength), when in comparison to "tougher" steels with a lower yield strength (when relating to a lack of Hardness). Tougher steel will therefore resist permanent deformation better, though that deformation will start to be noticeable (much) sooner. Please note that the larger and the harder the Carbides are, the less toughness will be present. The volume of the Carbide (and Type) will describe just how brittle the steel will be; the higher the volume being more brittle. This is why S110V seems much chippier than its S90V counterpart.
The Powder Metallurgy process mitigates this lack of toughness within Highly Alloyed steel by creating very homogeneous, finely grained Carbide boundaries within the matrix, which will allow the harder Carbide Types to keep a reduction in size in hardening, thus increasing their toughness when relative to Ingot Metallurgy. The drawback being that Harder Carbide Types (as with Vanadium Carbide) are not necessarily tough to begin with. The increase in Carbon within the PM process allows a greater distribution of these smaller, harder Carbides to form in solution over higher temperatures (which many Hard Carbide Types require for formation). Carbide formation is essentially a "dog-eat-dog" atmosphere, where certain (harder) Carbides will form in place of other potential (softer) Carbide, given specific treatment in hardening, regardless of the steel composition. This is where differential heat-treatments are most critical. There are also interactions that can occur between Alloying Elements, binding to form Complex Cardbides, which obviously further change the behavior beyond singular Carbide Types.
Please note that I am not the most knowledged resource when it comes to the subject of steel (
within the context of cutlery, or otherwise) and this is not an in-depth comprehensive understanding on the whole process, but a collective potential overview on what possibilities there are amongst Elements and how they interact and play roles in the formation of steels used for knives. I chose to place hard emphasis on Vanadium (Vanadium Carbide) as an example so frequently, because VC makes up the bulk of Carbide volume formed within CPM 15V. This is my layman understanding (and terms) and I am sharing what of the process I have come to know to the best of my understanding, whilst trying to remain understandable in relaying that info. Shawn, or anyone else can freely address and correct any miffed information at will.
IME, the edge aggressiveness is most noticeable in experience on softer abrasive materials (flesh, fruits or vegetables, cardboard, etc.). I'd describe it as such: following the "three-finger" Murray Carter sharpness testing method; the aggression at the edge is sort of like you're frozen upon contact, feeling the imminent cut if you were to apply pressure, or slide your fingers along that apex... Almost as if you were a bug that landed in a spyder's web, still, out of fear of the "bite" that will incur
. Kind of reminds me honestly of how a very sharp saw will catch your finger with its teeth, however in this instance the cutting character is clean, calculated and sadistic in intent, instead of barbaric, shredding, or tearing. The bite itself is not toothy (as-in regarding actual "teeth", or extreme unrefined coarseness at the edge), but it grips you in a way that when you know, you know not to push your bounds, or you will be cut (quickly and aggressively). It has a feel all its own and I think Shawn summed it up nicely with the description being unquantifiable "sharpening geek speak".
As vivi had stated, this edge characteristic can be achieved from both coarse, or medium-grit finishes. I prefer a bit more refinement in my edges, as I find the longevity to increase quite noticeably, IME. You just have to pick-and-play with an array of gear to find what combination you prefer. Not all sharpening abrasives are created equal, even amongst the same abrasive materials themselves.
Regarding a "working edge"; any edge will fall into a working edge after use, though the details behind just what behavior that entails can be quite different from steel to steel. Some steel will act very similar, though, too. This is again, where the overall characteristics of the steel will tell the tale of how and why a steel degrades in the manner that it does. This is also where you will
experience what that heat-treatment has done to the Carbide Type drawn out in hardening and will relay the information of Carbide Volume (increasing aggression, in higher Volume, IMO). In sharpening; the abrasive used to restore the Carbides (
*which must be hard enough to cut the Carbide Type within the matrix), along with the abrasiveness of the abrasive itself, will contribute to how that working edge develops, in-and-of-itself.
I would recommend at the very least Silicon Carbide abrasives for sharpening K390, or Maxamet. I've had good results with CBN and my last sharpening of K390 was finished at a coarse 400 grit SiC stone, followed by a strop on leather with 4 and 1 micron diamond suspension. Edge is aggressive with a touch of refinement (not quite to the level of sticky, as Shawn has described it), which was to my surprise after such a huge grit jump from stone to strop. As stated, I typically prefer more refinement to my edge, though I am really seeming to like this lower grit finish so far, so I may have to eat my words regarding that preference (at least on these Higher Carbide Volume steels).
Make Knife Grinds Thin Again.
