steel vs steel

LOL, I read the post, scratch my head, and said to myself, "What?" Good to know I'm not crazy, or if I am, there are others out there!
 
Thanks guys!

Does a crazy/I knows oneself is crazy? :cool:

Maybe for some crazy reasons, you read my post carefully and between the lines, then perhaps my statement may not be vapid/retarded and actually be insightful.

Going forth, I will refrain from posting about super quench and other info that don't agree with the established KM world.

For those new makers/readers were confused by my posts :barf:- my apology. Just to be clear, madness & thick-skin still am...
 
No one is asking you to refrain from posting about topics - we simply don't understand what you're attempting to accomplish. This has nothing to do with you being mad or thick-skinned, and it has nothing to do with the "established KM world".

Nothing in your posts could be construed as insightful. If you're trying to discuss factual information, don't require your audience to "read your post carefully and between the lines".

Can you explain what your end goals are, and what your methodology seeks to prove?
 
Element mass % translate to atom count gives insight into carbide/alloying count - useful, no?

If you can control % Carbon in hardening, setup high & ultra high carbon as low carbon, resulting in high toughness mart matrix - useful, no? I share to BF it's possible get high [hardness + toughness + wear resistant]. True or not, your call. Understand or don't get or don't agree up to you.

I use tests to assess experiment results - very subjective/bias perhaps but I've control over the process. I am not here on BF to prove anything, just sharing/rambling ideas and facts (unproven to anyone by myself). I've learned a lot from many generous contributors here, seem that my way to pitch-in is counter productive. Hence my previous post...

Best regards,

Matthew Gregory said:
No one is asking you to refrain from posting about topics - we simply don't understand what you're attempting to accomplish. This has nothing to do with you being mad or thick-skinned, and it has nothing to do with the "established KM world".

Nothing in your posts could be construed as insightful. If you're trying to discuss factual information, don't require your audience to "read your post carefully and between the lines".

Can you explain what your end goals are, and what your methodology seeks to prove?
Click to expand...
 
John Nash whaaaa????


I'm interested in your trial and error testing, so long as it's actual tests, not abstract communication of ideas going down the proverbial rabbit hole... It would be easier to digest if your intentions were followed through with a legitimate experiment, utilizing the scientific method. Lay it out for everyone else in those simple terms, as I will second the notion that your posting is "out there" (which, if I'm saying that means you're "really-really OuT ThEre")...

I'm interested in learning, my mind is an open parachute.


Oh, and I love that avatar... One of the best fruits I've ever had the privilege of eating... filipino ba?
 
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I don't know anything about element mass % as it relates to carbide count. My chemistry teacher was not very good, and I had a hard time understanding her. I sure would love to know how to figure all that out. Can you help explain that to me? That has been one of the nagging things that i don't know how to sort in my head. How to figure what carbides, in what amounts, are present in a steel with a given carbon content. What does changing x, or y, or z in a heat treat regimen do to the amount of vanadium carbide vs tungsten carbide....or is that even a variable? And also, you said, "Set up high and ultra high carbon as low carbon" what does that mean? Are you saying that you are trying to make a hypereutectoid a hypoeutectoid for some reason? I have a hard time following you, especially with the "get it or don't" "understand or don't" "agree or not".
 
e.g

M4: 1.42%C, 4%V, 5%W, 5.25%Mo, 4%Cr.

Take a chunk of M4 with 100,000 atomic mass. So Carbon 1.42% in M4 composition translate to (100000 * 0.0142)/12.011 = 118.2 Carbon atoms. 4%V translate (100000 * 0.04)/50.94 = 78.5. 5%W translate (100000 * 0.05)/183.84 = 29.9.

As you can see 4%V has over 2x atoms than very heavy 5% Tungsten.

0.6%C (50 atoms) taken by the matrix leaving 68 carbon for alloying with V+W+Mo+Cr. Well, that just not enough Carbon for simple alloy with those carbide forming elements. So other alloying (non-carbide) may occurs.

D2 has more Carbon% (atoms) than M4.
 
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Bluntcut, I think you are misunderstanding some of the simpler principles while focusing on the more complex ones. This is common with out of the box thinkers (I'm one too, and have to remind myself this all the time.) You cannot take the composition and calculate what you will get in the end, as the matrix can get complicated and compromised. The industrial heat treat recipes have been tested to get the best percentages of the elements where they are needed. Straying will either not get the elements into solution, or inversely get them to move to places where you don't want them, such as in grain boundaries, or in overly large carbides. Quenching at rates outside of recommendations, will stress the matrix, and cause microfractures throughout the steel. None of this is good for the properties we look for in blades. You are focused on carbon, but vanadium and tungsten are valuable carbides as well. They help with wear resistance, which you are looking for. Getting them into solution properly, and distributed evenly in small carbides will be your best bet. Reading your posts, I think a steel like 15N20 would be your ideal if it came with 1% carbon. The nickel would give you some toughness, and you could push the Rc# higher than typical. Would there be an advantage over W2? Probably not.
 
Mang Cuc is the name of this fruit in Vietnamese.

Imagine a 'what' with a little bit on 'why', let ppl figure out the 'how' are my way of trying to engage discussion on ideas. 'Out there' concepts without evidences in hand requires more faith than scientifically wishful/imagination. In person or if one can trust video ;), I can probably show a 52100 harden temp at 1480F 5 minutes soak, super quench, cryo dip, 5 minutes temper at 300F, grind, sharpen, then cut tests against a production or custom 52100/m4/s110v. So far, we stuck on the 'what'. It would be a great deal of fun & informative once we get going with the 'how' back-up by 'why'. however we are OT a bit here on this thread. So I will try just to stay with steel vs steel topic.

SinePari said:
John Nash whaaaa????


I'm interested in your trial and error testing, so long as it's actual tests, not abstract communication of ideas going down the proverbial rabbit hole... It would be easier to digest if your intentions were followed through with a legitimate experiment, utilizing the scientific method. Lay it out for everyone else in those simple terms, as I will second the notion that your posting is "out there" (which, if I'm saying that means you're "really-really OuT ThEre")...

I'm interested in learning, my mind is an open parachute.


Oh, and I love that avatar... One of the best fruits I've ever had the privilege of eating... filipino ba?
Click to expand...
 
e.g. Super quench A36 or even 1018 or RRS, will result in good hardness and high toughness. Of course, wear resistant is low due to absent of carbide.

Now for example, take Aldo 52100 shipped condition - 95% spherodized carbides - heat to around 1475-1500F hold for 5 minutes, quench in oil. hrc# will depend on oil/quenchant speed. Super quench probably will produce maximum hardness and assumed it didn't crack from terribly large annealed spherodized carbides. Resulting steel (albeit large grain + large carbide) will be hard & tough and has good wear resistant. So instead of large carbide, a proper 'setup' of fine carbide+fine grain+fine microstructure will produce high [ hardness + toughness + wear ]. Aahhh figuring 'how' should be fun for those read this far (too late, you took both red & blue pills).

samuraistuart said:
And also, you said, "Set up high and ultra high carbon as low carbon" what does that mean? Are you saying that you are trying to make a hypereutectoid a hypoeutectoid for some reason?
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Excellent rational points & concerns Warren! Usually most flaws will quickly manifest during performance test: dry shave, push cut newsprint, whittle dry hardwood, cut cardboard/rope/more-wood, cut & twist. Edge durability (per good thin geometry) will reveal grain+microstructure+wear levels. If my test blades perform poorly, for sure I would abandon ht variables contributed to poor performance.

I don't really know what excess/free V & W & Mo & Cr play & interact during cold & hot (high-speed) operations. Once Carbon is all taken up by matrix + carbides, excess V&W&Mo&Cr possibly alloying (non-carbide) in more complex structure/bond+aggregation. Nitrogen can be introduce for getting nitride + other benefits however add variables will reduce set size of useful structure/configurations.

A hypothetical 15N20 with 1%C sounds promising. If I have a choice, Cobalt be my pick over Nickel for increase toughness. I had no problem super quench std 15n20 (.75%C) but wear resistant was sub-par.

I started inside the box, made & fine tuned quite a few 52100 knives. Didn't take long to hit grain+carbide+structure size (and carbide volume) ceiling with current std ht recipes from BF,Kevin,Ed,Darrin... Well Warren, what would be a good next advancement step if all you confine to just 52100 steel? I attacked the grain boundary first, then carbide size&distribution and then squeezed extra volume. Microstructure followed. Take all 3 advancements before a successful super quench can taken place.

I've made a few high alloy (s110v, rex121 - soon, s90v,k390) knives heat treated according to mfg specs or well known recommendation. My out-of-box ht knives head-head test against these high alloy knives. There is an intersection point between carbide volume vs size, where size become more important than volume from performance perspective.

Willie71 said:
Bluntcut, I think you are misunderstanding some of the simpler principles while focusing on the more complex ones. This is common with out of the box thinkers (I'm one too, and have to remind myself this all the time.) You cannot take the composition and calculate what you will get in the end, as the matrix can get complicated and compromised. The industrial heat treat recipes have been tested to get the best percentages of the elements where they are needed. Straying will either not get the elements into solution, or inversely get them to move to places where you don't want them, such as in grain boundaries, or in overly large carbides. Quenching at rates outside of recommendations, will stress the matrix, and cause microfractures throughout the steel. None of this is good for the properties we look for in blades. You are focused on carbon, but vanadium and tungsten are valuable carbides as well. They help with wear resistance, which you are looking for. Getting them into solution properly, and distributed evenly in small carbides will be your best bet. Reading your posts, I think a steel like 15N20 would be your ideal if it came with 1% carbon. The nickel would give you some toughness, and you could push the Rc# higher than typical. Would there be an advantage over W2? Probably not.
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I don't think you can get a "good hardness" out of a "superquenched" A36 or 1018...infact the level of hardness derive from the carbon % in solution at the moment of the quench, which by the way, doesn't have to be "super", it is enough if it allows to rapidly bring the temperature of the austenite under the "nose" of pearlite without allowing diffusion of the carbon in that range. Faster than that you are only increasing avoidable stresses and temperature difference in the shell/core during the martensite transformation possibly resulting in micro or macro fracture of the piece.
I also don't believe you would get maximum hardness with that temperature/soak time of a 95% spheroidized 52100 steel... that carbon would be not in the right place to start that recepit with much success.
Point is there is a lot to learn in metallurgy before reinventing the wheel. If you have fun doing experiment try smelting your own steel and make up your favorite composition, i would be interested in your result if you had the basic instrument (science) to communicate it, because a video of a knife wouldn't help at least with me. You see eggehead's science it's all about it...sharing knowledge beetween people in order to progress toghether without reinventing things. ;)
Now i put out MY question "out of the box": why do you need all this wear resistence? are we talking about knive's keen edges or industrial sandpaper slitting blades? In my limited experience the edge stability is the primal concern, and when wearing comes into play the edge is long time rolled or chipped unless we are talking about edge degrees i wouldn't see on a knife, maybe an axe. :)
 
".....why do you need all this wear resistence? are we talking about knive's keen edges or industrial sandpaper slitting blades? In my limited experience the edge stability is the primal concern, and when wearing comes into play the edge is long time rolled or chipped unless we are talking about edge degrees i wouldn't see on a knife, maybe an axe.."

Exactly!!!!!!
People spend too much time and effort thinking which steel has this or that element and forget that most good quality knife steels will make a blade beyond normal use requirements. Edge geometry and construction are probably far more important.
 
From what I understand, yeah, taking Aldos 52100 and bringing it to 1475 for 10 minutes and quench (be it oil, brine, superquench, whatever) is not going to give you an optimum performing blade at all. The carbides need to be taken care of first, put into solution, and then distributed. Then grain refinement needs to be done, because putting the carbides into solution and distributing them evenly takes heat and time that blow up the grain. Not good for edge! So we thermal cycle. Some guys do the step down, others do 3 right around aust temp or just under, with additional variable being air cool vs quench during cycling. There is also the variable of spher anneal before hardening step. Once the carbides are in solution, evenly dispersed, and now grain size taken care of, only then should we go to aust temp, short soak, and quench. This should produce a blade that is way better than a blade, same steel, with only a hardening step.
 
Right on Stacy and stezann. Edge stability - not just very high hardness - and edge geometry are what's really key.

The geometry is really quite simple. The thinner it is and the more acutely it's ground, the better it will cut. The thicker and less acute, the more durable it will be. That's true regardless of alloy or even if it's heat-treated at all.

Edge stability is a good deal more complicated and starts with developing the right structures within the steel matrix itself. Tempered martensite is good. Untempered martensite, retained austenite, pearlite etc... not so much. Nathan the Machinist is just one maker who has done some really interesting experiments on this topic and written about them here. Kevin Cashen is another member whose threads on steel structure are well-worth reading through.

I think this is why people are strongly questioning some of bluntcut's quenching methods and are confused about what exactly he's trying to accomplish with these short soaks and super-fast quenches. It just doesn't seem to "add up" with what we know about these structures.

Of course factors like tempering, final general Rc hardness, carbide content and size/distribution play an important role as well...
 
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Somewhere along the way, I am falling into this knife making rabbit hole. Edge stability hinges on material & geometry, this thread could be the seed for this journey http://www.bladeforums.com/forums/showthread.php/992879-Apex-Bevel-Geometry-cross-sectional. And then http://www.bladeforums.com/forums/s...-Wear-resistance-test-for-12-different-steels. So yeah, through sharpening POV, I am a big believer in edge stability. So much more to learn...

Carbides are teeth/cutter and shield the matrix from abrasion. However trade of at cost of carbide hardness liable for fracture (due to reduce toughness).

Out of time ... more later.
 
Carbides can also be pulled out of the matrix, especially if the matrix is messed up from improper heat treat/quench. Small, evenly distributed carbides in a relatively stress free matrix are what we try to get. In other applications, such as bearings, larger carbides can be an advantage, which is why there is a range of HT for 52100. Higher austentizing gives larger carbides and results in retained austentite, which is easily dealt with in industrial applications. These traits are not advantageous for a knife. I suppose if we were rolling steel balls over our knives packed in grease it would be good, but that's not what I intend my knives to do.

I find even my lowly 15n20 kitchen knives get stropped every week or so, and re-sharpened every 2-3 months, with daily use. This is the low end of my wear resistance. What more do I need?
 
Willie71 said:
Carbides can also be pulled out of the matrix, especially if the matrix is messed up from improper heat treat/quench. Small, evenly distributed carbides in a relatively stress free matrix are what we try to get. In other applications, such as bearings, larger carbides can be an advantage, which is why there is a range of HT for 52100. Higher austentizing gives larger carbides and results in retained austentite, which is easily dealt with in industrial applications. These traits are not advantageous for a knife. I suppose if we were rolling steel balls over our knives packed in grease it would be good, but that's not what I intend my knives to do.

I find even my lowly 15n20 kitchen knives get stropped every week or so, and re-sharpened every 2-3 months, with daily use. This is the low end of my wear resistance. What more do I need?
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Based on some admittedly old (40 yr+) research, finer carbides are better even for bearings of 52100. Higher austenization results in smaller carbides, or none at all. This is one of the issues with knife maker terms vs. industrial terms. One of the reasons for normalizing is to get rid of all the carbides, at least in low alloy steels. All the carbides are dissolved and reform smaller later if treated properly. Knifemaking normalization is just a heat to 1420 to 1500 and air cool. That may or may not dissolve all the carbides, depending on steel.
 
Finer "grain" in any steel is tougher and more durable than big lumpy sloppy "grain"... and it also happens to cut better, longer.

That is not my opinion, that's a fact.
 
me2 said:
Based on some admittedly old (40 yr+) research, finer carbides are better even for bearings of 52100. Higher austenization results in smaller carbides, or none at all. This is one of the issues with knife maker terms vs. industrial terms. One of the reasons for normalizing is to get rid of all the carbides, at least in low alloy steels. All the carbides are dissolved and reform smaller later if treated properly. Knifemaking normalization is just a heat to 1420 to 1500 and air cool. That may or may not dissolve all the carbides, depending on steel.
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Interesting. I was basing my information on a discussion with a well known heat treat expert. I may have misunderstood what he was saying, but I was pretty sure he noted industry preferred the 1550 austentizing with 52100 as the larger carbides wear better. Like I said, I could have misunderstood. No one disagrees that fine carbides are good for knives though. :thumbup:
 
The 1550 F austenizing temperature is used for bearings because it leaves a higher amount of retained austenite, which is advantageous for some reason. The higher heat will certainly result in smaller carbides. Even higher, and they will be completely dissolved.
 
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