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Conjecture on abrasion resistance.

Discussion in 'Knife Reviews & Testing' started by Joseph Gardner, Oct 12, 2018.

  1. Joseph Gardner

    Joseph Gardner

    20
    Oct 12, 2018
    So this is intended to be a logical conjecture and not a "well i use this material so bark it up". Bear with me here.

    So two samples of .075" thickness steel, 1095 and cru forge v, both hardened to an estimated rhc 60 using a file ment for testing.

    A simple belt sander was used using fresh belts for both samples, it took 15 minutes to get the 1095 to the sharpness that it would preform a paper test, and an hour on the crv to preform the same the test, Using 120 grit.

    the edge dimensions were created using a Jig and half an inch indented both sides.

    Logically the crv has four times the abrasion resistance given that an abrasion medium was used for the test. please add your conjectures :)
     
    Last edited: Oct 12, 2018
  2. DocJD

    DocJD

    Jan 29, 2016
    https://www.alphaknifesupply.com/Pictures/Info/Steel/CruForgeV-DS.pdf It seems that cru forge v was specifically formulated to have improved abrasion resistance , so you're result shouldn't be too surprising .

    :) I wouldn't conjecture that you can count on 4X improvement ; because ,I assume you did the sanding by controlling the pressure applied by hand . Difficult to draw a scientifically quantified conclusion without a precise , repeatable method of sanding / grinding . :(

    Your reported experience is interesting and valuable as anecdotal evidence and may be totally accurate . :cool:
     
  3. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    So just for clarification's sake here.....you're not talking about a beveled blade. You are just taking .075" stock and putting an edge on that, correct? A beveled blade takes about a minute or two at the most to get a shaving sharp edge with a new 120 grit belt.

    One question....where did you get .075" Cru Forge V from? It had to have been forged down or surface ground, as it wasn't rolled at that thickness. The thinnest was ~.110" (undersized 1/8")

    As a maker who uses a belt sander, 120 grit ceramic blaze belts, it takes about the same amount of time to grind Cru Forge V as it does 1095, even at 63/64HRC. Ceramic belts just eat steel for lunch, because the ceramic is much much harder than the steel itself. When thinking of the harder carbides, the % of vanadium carbides in CFV is extremely small. It only has 0.75% vanadium by weight, and a total carbide volume once heat treated of ~5-7%. The noticeable difference of change in abrasion resistance with 1095 vs CFV comes during hand sanding, where we have a running joke about how hard it is to hand sand CFV, and CPM M4 is even worse. Is CFV 4X as hard as a simple carbon steel? I don't think so, maybe twice as difficult, but that is hard to judge.

    I just don't understand why it took you an hour to grind a bevel on Cru Forge V, even at a 0.075" thickness. What grinder and what belts were you using? The answer might help explain.
     
    DocJD likes this.
  4. Joseph Gardner

    Joseph Gardner

    20
    Oct 12, 2018
    I have a friend who has a shop set up for doing his own machinery work, I had him press a decent amount of various steels to those dimension for pattern welding.
    was a diablo belt, the belt for the crv was so worn at the end it was doing more polishing then stock removal, probally due to the vanadium wearing it down faster
     
  5. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    Ah yes, Diablo belts. Zirconia. In my experience, they don’t work that well on hardened steel compared to ceramic belts.

    But that said, even tho CFV has vanadium, again it is quite small (.75%), and the total carbide volume once heat treated is in that ~5% area. Quite small.

    It is very true, CFV is harder to hand sand. And thus it is has a higher abrasion resistance over 1095.

    I agree with the observation that it takes more effort to abrade over a simple steel. 4x is quite high tho.

    In another example....what you are saying by extrapolation is that if it takes 15 minutes to get a 120 grit polish on 1095, it would take an hour to get that same polish on CFV.

    As a maker who has used both alloys quite a bit, that is off. I would say it takes about twice the effort. So if it took 15 minutes to get a 120 grit finish with 1095 at a given 60hrc, it would take 30 minutes with Cfv.

    Still, you are on the right track.

    Now try to do the same comparison of 1095 vs CPMM4! I would say CPMM4 is 3x harder to sand than 1095 at the same hardness.

    If you’re inclined, try doing your experiment by hand, with samples that are harder. Say 62-63HRC.

    Have your samples at a true base finish of, say, 120 grit. Then, by alternating the scratch pattern, time how long it takes to hand sand to a true 220 grit finish. 1095 vs CFV at 62-63.

    What grinder did you use? I also have a delta 4x36 which you really can’t use to grind hardened steel. It bogs down with even mild pressure.
     
    DocJD likes this.
  6. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    The finer in grit you go, the more accurate your results will be. And the more difficult to get that finish. At coarse grits, you’re plowing away the steel matrix, and the carbides go with it. The finer the grit, the less steel martensite matrix gets plowed away, and the more the carbide type and % becomes a factor.

    It’s relatively easy to get a 120 grit finish on cfv. But try to get a clean 800 grit finish. It is MUCH MUCH more difficult.
     
    DocJD likes this.
  7. Joseph Gardner

    Joseph Gardner

    20
    Oct 12, 2018
    I still think the abrasion resistance measure might be off due to wearing of the medium faster. the vanadium even wears down stones faster.

    well I didnt polish just went to paper test sharpness, one thing about the carbides you are not accounting for is that cpm steel isnt like any other melted steel as far as where the carbides and elements are, they arnt clustered or in long chains like conventional steel but spread out evenly, so there is more carbides evenly along the surface and even on the blade edge then in conventional steel. not to mention having a higher carbide formation because of the eletron bonding that happens during the powderization (its not a word but fuck it) thats where the improved toughness and the ability to pump so much elements that would make normal liquidized steel shatter instantly. Lengthy I know. more carbides on the surface means more "resistances" at the cost of being spineless because they arnt in chains that spring steel boasts. the steel tends to just bend or deform given enough pressure instead of springing back into place. the designers even stated that was what they intended. for crv, the other cpm steels with higher alloying content seem to retain their spring quite well but crv just doesnt seem to have enough alloy in the dots.

    another off property iv noticed is that shock seems to pass through crv quickly wheras spring steels tend to retain it and vibrate because... thats what a spring needs.

    Doing some odd testing on how w2 and crv works when mixed impulse wise. My theory is that the bonded element chains act as highways for energy, and that the cru forge v doesnt have enough chained elements so it can still behave like iron, but get the hardness due to content, mixing the two for those properties.

    I might just have an off batch of crv, I ordered more to try and get confirmation on my tests, I can see grain lines on the base steel.
     
    Last edited: Oct 15, 2018 at 9:19 AM
  8. Joseph Gardner

    Joseph Gardner

    20
    Oct 12, 2018
    recommended heat treats for rhc 60 and baked in an oven at 450 for an hour and temper quenched in water afterwards.

    I normally do my blades forged to as close as I can comfortably heat treat; then stock removed to rough shape and then use cheap stones 1000/2000 to surface and sharpen, 7 angles on the 1000 and then 3 angles on the 2000, followed by sand paper from 1000 to 1500 to 2000 I cheat and use a cordless drill and wrap the sand paper on round stock with a slit in it. I just cut off the sand paper when it gets worn. followed by an end honing on a 5000 stone.

    its not a mirror finish or buffed polish but it definately shows off the grain content and sparkles.

    these two samples are for edge against edge testing.
     
    Last edited: Oct 15, 2018 at 9:14 AM
  9. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    I’m not sure I understand a thing you said. What is CRV? Do you mean CFV? Shock passing thru CFV faster than a spring steel? How/why did you come up with that? I don’t think your comments about the CPM process make much sense.

    You do realize cru forge V is NOT a particle metallurgy steel, right? You
    Mentioned something about me not accounting for the CPM process. CFV is a regular ingot steel.
     
  10. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    “Higher carbide formation?” You were describing the CPM process. How does the CPM process give a “higher carbide formation”? It doesn’t. That isn’t even a term conducive to the CPM process. Exactly the opposite. The CPM process prevents “carbide formation”, as you call it. It prevents carbide networks.

    Electron bonding? You’re right, not part of anything. No need to cuss because you don’t know what words you’re trying to find.

    The improved toughness over the same steel ingot steel is because the carbides are much smaller and more well distributed


    What is “liquidized steel”? How does it shatter?

    How does the CPM process put “more carbides on the surface”? And what in the world do you mean by “more carbides on the surface means more resistances at the cost of being spineless?”

    “Because they aren’t in chains like spring steel boasts”. Spring steels don’t really have much in the way of carbide formation. 1095 does to some extent, it has proeutectoid cementite, but the others (1084,1080,1075,1060,5160,1050) don’t have hardly any carbides, much less strings of them.

    How do “higher alloy CPM steels” “retain their spring quite well”?

    What do you even mean by “crv....” (I assume you mean CFV) “....doesn’t seem to have enough alloy in the dots”????


    Look, Joseph, I applaud your effort to try and understand some things about metallurgy. You are correct, CFV is more abrasion resistant than 1095. Anyone with a basic understanding of steel chemistry can come to that conclusion. Just stop at that. Leave it there. You’ve gone off the deep end now, and make absolutely no sense in what you have to say in your replies. I see you are very very new here. Before posting off the cuff again, I suggest you do more research, learn a bit more of what it is you are trying to talk about, be a bit more humble about it, and try again. Later. Much later.
     
    Eli Chaps likes this.
  11. Joseph Gardner

    Joseph Gardner

    20
    Oct 12, 2018
    CFV is a CPM steel, its not advertised as one but it is, this is largely evident in its soft state, during forging, heating, and cooling off. Which leads to ask the question are you even a smith or just a cut away guy?

    It has chrome vanadium and 1.05 carbon but is almost as soft and malleable as 1018, anyone who has forged O1 will tell you its tough shit in stock form to work, CFV doesnt have enough alloy to brag about as far as CPM though, but being a cpm steel is the only explanation for the soft working at 1.05 carbon because if it wasnt it would be a bear to forge.

    Since I suck at communication as you so.. daftly put it ile leave this here but if you can really grasp it im not wrong, crucible and other PM steels advertise pictures taken of the grain structure in comparison to other steels, if you look one up it will show you there are more carbides on the edge of the picture, ergo more carbides presenting themselves on any surface. Cru Forge V also boasts the same picture set up of isolated clusters of elements as the rest of the CPM series.

    also carbides form from just carbon (carbon carbon carbide) as well as forming in conjunction to manganese and ESPECIALLY chromium which is in two steels you listed, especially in those two steels; you seem unaware of this. a carbon dissolution treatment can fix some of the carbon chains, I said chains and not carbides. carbides don't like to move at all once formed. (crucible heat treats for the cast iron variants recommend it on their datasheets and that is WHY they recommend it).

    From Crucible:
    The proprietary Crucible Particle Metallurgy (CPM®) process has been used for the commercial production of high speed steels and other high alloy tool steels since 1970. The process lends itself not only to the production of superior quality tool steels, but to the production of higher alloyed grades which cannot be produced by conventional steelmaking. For most applications the CPM process offers many benefits over conventionally ingot-cast tool steels.

    Conventional Steelmaking vs.Particle Metallurgy Processing

    Conventional steelmaking begins by melting the steel in a large electric arc furnace. It is usually followed by a secondary refining process such as Argon Oxygen Decarburization (AOD). After refining, the molten metal is poured from the furnace into a ladle, and then teemed into ingot molds.

    Although the steel is very homogeneous in the molten state, as it slowly solidifies in the molds, the alloying elements segregate resulting in a non-uniform as-cast microstructure. In high speed steels and high carbon tool steels, carbides precipitate from the melt and grow to form a coarse intergranular network. Subsequent mill processing is required to break up and refine the microstructure, but the segregation effects are never fully eliminated. The higher the alloy content and the higher the carbon content, the more detrimental are the effects of the segregation on the resultant mechanical properties of the finished steel product.

    The CPM process also begins with a homogeneous molten bath similar to conventional melting. Instead of being teemed into ingot molds, the molten metal is poured through a small nozzle where high pressure gas bursts the liquid stream into a spray of tiny spherical droplets. These rapidly solidify and collect as powder particles in the bottom of the atomization tower. The powder is relatively spherical in shape and uniform in composition as each particle is essentially a micro-ingot which has solidified so rapidly that segregation has been suppressed. The carbides which precipitate during solidification are extremely fine due to the rapid cooling and the small size of the powder particles. The fine carbide size of CPM steel endures throughout mill processing and remains fine in the finished bar.

    The powder is screened and loaded into steel containers which are then evacuated and sealed. The sealed containers are hot isostatically pressed (HIP) at temperatures approximately the same as those used for forging. The extremely high pressure used in HIP consolidates the powder by bonding the individual particles into a fully dense compact. The resultant microstructure is homogeneous and fine grained and, in the high carbon grades, exhibits a uniform distribution of tiny carbides. Although CPM steels can be used in the as-HIP condition, the compacts normally undergo the same standard mill processing used for conventionally melted ingots, resulting in improved toughness.

    CPM Eliminates Segregation

    Conventionally produced high alloy steels are prone to alloy segregation during solidification. Regardless of the amount of subsequent mill processing, non-uniform clusters of carbides persist as remnants of the as-cast microstructure. This alloy segregation can detrimentally affect tool fabrication and performance.

    CPM steels are HIP consolidated from tiny powder particles, each having uniform composition and a uniform distribution of fine carbides. Because there is no alloy segregation in the powder particles themselves, there is no alloy segregation in the resultant compact. The uniform distribution of fine carbides also prevents grain growth, so that the resultant microstructure is fine grained. Advantages of CPM

    For the End User:

    • Higher Alloy Grades Available
    • Improved Wear Resistance
    • Improved Toughness (less chipping)
    • Consistent Tool Performance
    • Good Grindability (on resharpening)
      For the Tool Manufacturer:

    • Consistent Heat Treat Response
    • Predictable Size Change on Heat Treat
    • Excellent, Stable Substrate for Coatings
    • Excellent Grindability
    • Improved Machinability (w/sulfur enhancement)
    • Efficient Wire EDM Cutting
     
    Last edited: Oct 18, 2018 at 8:51 AM
  12. Joseph Gardner

    Joseph Gardner

    20
    Oct 12, 2018
    The sections of steel I cut away? I use them for hardened edge on edge testing at 24 inch length of leverage.
     
  13. Pilsner

    Pilsner Gold Member Gold Member

    Oct 28, 2017
    :rolleyes:
     
  14. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment Knifemaker / Craftsman / Service Provider

    Jan 12, 2005
    No.

    It isn’t.

    Only two heats of CruForgeV were made, totaling approximately 80,000 pounds, and both of them were conventional ingot steels. It is EXTREMELY unlikely that it will ever be made again.

    I know because I had the opportunity to work with it before it was even available to the public. It was a steel developed in conjunction with one of my mentor’s in knifemaking, Dan Farr, and the PhD metallurgists at Crucible. The melts were done at Crucible’s facility in Syracuse, NY, and rolled to final dimension at Niagara Specialty Metals in Akron, NY.

    Consider contacting Crucible and asking them.



     
  15. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    You clearly have no clue as to what you are talking about.

    There is a saying you need to take heed to.

    “ it’s better to keep your mouth shut and have people think you’re an idiot, than to open it and remove all doubt”.

    You clearly have crossed the point that everyone on the planet now knows you are an idiot.

    Good luck in the future, Joseph. You don’t have much of one here.

    And you just reposted a bunch of stuff about CPM steel that has ABSOLUTELY NOTHING TO DO WITH CRU FORGE V!!!!


    Bwahahahahaha! Best post of the year! What a joke you are! Let this go down in history as the most arrogant and stupid post EVER! How old are you? Let me guess. Betweeen 15 and 22. Dude. Grow up. Not here. Somewhere else.
     

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