I’ve made a lot of knives from mild steel and carburized them. I’ve found that grinding them to 90% finished before carburizing gives best results (hard edge with a tough spine) and that carburized anything’s structure benefits greatly from a soak at just above non magnetic temperature for as long as it was carburized for (I coat my blades to prevent scale from forming during this process.) Oh, and one more thing-no matter your carbirizing mixture, add kosher salt. The salt and the prussiate in it greatly aid carbon absorption to the steel, cutting down time needed for carburizing.
Charcoal has all kinds of impurities in it, and is never homogeneous. You might want to try sugar the next time. With sugar infusion (in Ti foil) I was able to harden even some relatively mild steel that remained soft even when quenched into brine. I didn't run any toughness tests though.
taking say structural steel bar and carburizing is a great idea but this 5160 is already so incredible it really didn't need that kind of treatment but it was a fun experiment to see
Clickspring made a fantastic video where he carburized his own steels for making files, its not a super in depth guide but it does give a very reasonable amount of information to follow. I believe its a part of his TOOLS TOOLS TOOLS! series.
In adding carbon you probably put the steel well over the eutectoid point and so quenching from 1525f put way more carbon in solution than was probably healthy for it. Even at 1475f there likely would have been more carbon in solution than the 5160 would normally have. That said 5160 is kind of finicky as Larrin shows in his article on it. Also, try doing a DET anneal instead of cycling, it saves a lot of time and arguably gives better results. 100f-500f cooling rate/hr in the oven from 1400f-1450f (depending on the steel) after normalizing.
I’ve missed you!! In my YouTubing experience the carburized knife does looks sharper, harder, faster and better…!!😂 Seriously, it does! This is why I love your channel..! You make science fun 😊😂😅
for the sake of your hand it seems like it might be worth while to make universal handle to hold your blades i used to make some quick and dirty ones out of the white cutting boards easy to cut and you can flame polish them quick as well a quick hit with a propane torch till they go ever so slightly translucent and you can bed the blade in (makes a great cheap chisel sheath as well ) this makes me want to get my but in gear and build a better gas forge i never got around to canister work but man do i love making kitchen knives for the family and wood turning tools
GB I'm a science nerd, I took AP classes in math and chemistry in HS, college classes as mechanic and metallurgist. I wanted to work in NASCAR and totally F'd that chance by graduating to Federal con college. You are on point with alot of your observations, keep trying with new methods, it's how we learn! I love your will to try something new, it's how humans grew to be dominate. While not all of us have the better interest in mind, I believe you do, keep up the good work!
Really interesting testing, Steve! Thanks! 😃 The sugar people suggested sounds interesting as well! Happy new year! Stay safe there with your family! 🖖😊
When making this practice blades id suggest making a hidden tang style knife and model it after a hand file tang and then you could slip a plastic file handle onto any of the knives you make quickly and easily and it'll give you a little something to hold onto and take a bit of the shock absorption and save your hand a bit. Just an idea. Anyways this was a fun video to watch and hope you make more along this line of fooling around and tinkering to see what might allow you to take another step up in your knife game.
I'm wondering if a graphite paste painted on (2-4 layers), then followed by a refractory coating with a 6 hour soak at 1550F would make a difference. Graphite is theoretically pure carbon with super small particle size, so it might migrate into the steel better, especially if it's painted on the surface in an even coat.
You created an amazing HRC63 on one of the toughest steels ever created. How about a follow up where you explore blade design to keep the HRC63? Seems a shame. HRC measures some form of hard, but how does toughness and durability get measured? It seems pretty amazing it took 3-4 cycles to drop HRC on such a thin blade. Great video! Looking forward to a future follow up!
Many years ago I carburized, hardened, and tempered towards the edge carbon steel woodworking chisels. In order keep the edge and the flat hard I heated from the top back and watched the color change, stopping it short when it came close to edge. Well, that's what I did in the 80's before information became pervasive. I know things have progressed since then, and differential tempering doesn't appear to be a thing now, but wouldn't that help with the brittleness?
When I was in high school, quite a while back now, we used a powder called Hardite. Heat whatever you were making up to red/orange, dip it in the Hardite. It worked well. You had to make sure the exhaust fan was on cause that stuff was really toxic. But a little cyanide never hurt nobody. Later while doing an apprenticeship we had to harden a shaft that we'd machined. There was a big machine with a crucible inside it. In the crucible there was mineral salts of some kind. The whole lot would melt into a kind of bath that you chuck, well place your work into. It also worked quite well, and was also toxic as F. Going back to the Hardite, I later became a teacher and found a tin of hardite in the stores at the school I worked at. A couple of decades after it was banned outright. But we learned to be resilient you know.....
Charcoal doesn't vaporise, I think it has to physically be in contact with the steel then atoms diffuse into then though the steel. Probably need more finely ground charcoal to speed things up and get better consistency.
Maybe he can try using activated charcoal powder, or just regular charcoal powder. I bought some on Amazon earlier this month and it comes ground finer than flour.
Cela parrait difficile de cémenter de l'acier en phase solide uniquement par contact avec du carbone. La cinétique doit être très lente. Mais ici, il me semble que le mélange contient aussi du bicarbonate de sodium. Peut être que cette carburation se fait en plusieurs étapes, telles que: 1) Décarbonatation du bicarbonate de sodium: 2 NaHCO3 = Na2O + 2CO2 + H2O. 2) Équilibre de Boudoire entre le CO2 formé et le charbon: CO2 + C = 2CO 3) Cémentation de l'acier en phase gazeuse par le CO: 3Fe + 2 CO = Fe3C + CO2. Peut être qu'il se produit d'autres phénomènes, tels que: 4) Formation de CO supplémentaire par l'équilibre du "Gaz à l'eau" : H2O + C = CO + H2. Mais je ne suis pas sûr. Tout dépend de la température, et aussi de la pression: sur ce point, je n'ai pas réussi à savoir si la cartouche était scellée, mais si c'était le cas, je pense que cela pourrait être dangereux!
Great to see you again,, Brother I think I worked out why you don’t post as much as you use to,, is it to give your arm hair time to grow back before you post again?? Thanks for sharing and informing us (teaching) us
Question is if all that work is worth getting like that slight improvement in blade hardness? Also I wonder if we would cut it using cooled saw blade(or break it clean...) before grinding, and put under microscope would we see that carbonized layer on the surface?
The problem is the addition of carbon isn't uniform. The tradeoff isn't worth it. That's why case hardening is usually not a good idea for knives but useful to increase wear resistance in other applications like some roller bearings.
but if you tempered it down to 62 pr 63 the edge retention could be better plus it could take a finer edge? i feel tempering it down misses the point of case hardening.
I did have a pretty good laugh at the nail test, one of those things I'll do once in a blue moon for bushcraft and cleavers just to make sure they hold up. Which in the era of super-tough, high alloy tool steels is actually not beyond most of them to be completely fine apart from some very minute rolls once in a while, still rattles the brain which is telling you 'this is wrong, stop it!' 5160 is an alloyed steel, not a huge amount but it is what it is with that chromium. So that might have have some bearing on adding more carbon into the mix in a post-ingot stage of its cycle and there's definitely a reason for the grain size being like that. Just extreme temperatures for extended periods of time will blow out those boundaries and it'd maybe need 3 or so reduction cycles to get it back to something more sensible. I wonder if using maybe 1084 or something with much less alloying in it would yield more noticeable results bumping it up from a say 0.8% to the 1.25% carbon contents- the main thing I notice when using say 1084 to 125SC is that the latter takes a lot more care, a 'near' water quench and some extent the result is getting those very high HRC's which increase the geometric stability and let it take very acute final cutting edges. So while the end result there is that the different between a 1084 and 125SC is really just that one is tougher, the edge holding is pretty much the same and the other can take a finer ultimate sharpness
Hi, first of all congratulations for doing what I would do lol... "where there's a will, there's a way"... man, I'm going to make my second knife from recycled 5160 and I've learned a lot from your experiences (thanks for showing it) I also have a small channel in Spanish (where I test knives in my style) I got tired of buying expensive knives and had problems with the Esee 4 and a controversy with Jeff Randall over his 1095 treatment (which I think is awful, almost a rip-off) I say that for the Esee 4 that treatment is not correct, for the Esee 6 it could be because of the length of the blade that needs more flexibility, but in 4" or 5" blades, why do you want more flexibility? ...man I want maximum strength and edge retention, don't give me a castrated 1095 (that's what I told Jeff) he just replied that that's how they do it... so I come here and see your great experiments with the same steel that I'm starting to use... please give me your magic treatment recipe so I can get to the point. (I would greatly appreciate it) ...and in your project, this one of adding carbon, I also thought about it with charcoal, I think you should make the steel liquid to incorporate the Carbon (any Steel I mean) ...So maybe you can do it with a Stainless as well like 420 or 410 to get to 440C (who knows?) ...keep going like this, trial and error... until you find out. Greetings from Chile
From what i know the iron gets fully saturated with carbon around the .80-.85 range, and after that the remaining carbon forms iron carbide pockets at the grain boundries. Since 5160 has less then .85% carbon maybe there is some direct knife and tool performance to be gained when adding carbon up to that point? After though idk, theres no right answer to wether or not you want the toughness reducing effects of having excess carbon and forming a bunch of iron carbide. Consider that 1084 is significantly tougher than 1095 and the carbon difference is very low (and other than this theyre basicly the same). Toughness is an often overlooked aspect of cutting performance by bladesmiths bc theyre all obsessed with rockwell hardness, but the effect of high toughness is edge stability at lower edge angles, which has a better than linear realationship (i dont wanna say its exponential, but its very significant) with edge retention while hardness has only a linear relationship. And as a bonus, higher toughness steels can have a thinner behind the edge thickness for heavier tasks like batoning, reducing force required to make the cut without getting macroscopic rolls an bevel deformation. tldr: adding carbon probably wont imporve an already good blade / tool steel in an overall sense.
Right you are. Alloying moves the eutectoid point back and forth a bit but 1095 , w1, w2, white paper, 26c3, 52100, etc and all 'supersteels' are hypereutectoid. There are many hypereutectoid knife steels.
Normally when the steel manufacturers are adding Carbon, (Coke), this is done while the steel is molten. I do not think just heating the steel to red, or welding temperatures in a home built forge is hot enough to get the results you are looking for. I could be incorrect, but I think that is the process.
You are incorrect, pack carburization, flame carburization etc are real techniques which can be performed in home shop conditions. They have historical evidence and are widely used in industry. No liquidization required.
@murmenaattori6 I stand corrected, and newly educated. I knew different types of steel could be hardened or softened through Quench processes and Anieling, but though through those processes the steel would only achieve a certain harness before becoming too brittle and useless. Thank you for the info.
Carbon is not everyting... If you take a 1084 sn carburize it frpm .85 to 1 pe4cent carbon the steel gets a little harder, the edge retention is slighteley better , but the toughness drops to the hslf amount. The ideal carbon cobtent for a not aloyed steel is 0.84 percent. For a steel with sone chromium around 0,6 percent oor so. Depending on the content. More carbon forms chromium carbides. And these are particles in the steel matrix. They can ruin your edge while grindind and make the steel briddle. Metallurgy is a complex thing...m
You can temper too much and cause embrittlement, i would have gave them the same temper. That said what a great video i absolutely love tests like this
@GreenBeetle indeed, it's a fairly new concept to me too but the term to research is "tempered martensite embrittlement". You can find graphs to compare temperature to v-notch impact resistance for many steels. Often 450 to 800f is more brittle than a lower temper
I was thinking the same thing while watching. You are super smart and much better at math and the engineer here. However, having researched a bit of case hardening- thru antiquity, there is a logic that seems missing. If you add the carbon it should improve the stock, right? The evidence of improvement was shown in the need to temper multiple rounds to reduce hardness. Where is the valuing of removing something you added? If you ever revisit this, complete the same process. Could the video be about how to harness the value you created? What is the value in having a steel that needs THREE reduction cycles?! You've done something amazing. That is so cool. Perhaps the thickeness and profile of the blade isn't best to utilize the great hardness you created?
I miss the days when green beetle made knives. When he experimented hammered out different style knives, some were successes some were failures but it was all blacksmithing. Lately it seems like it's just endorsements for knife sharpening products and whatever this is
I’ve made a lot of knives from mild steel and carburized them. I’ve found that grinding them to 90% finished before carburizing gives best results (hard edge with a tough spine) and that carburized anything’s structure benefits greatly from a soak at just above non magnetic temperature for as long as it was carburized for (I coat my blades to prevent scale from forming during this process.) Oh, and one more thing-no matter your carbirizing mixture, add kosher salt. The salt and the prussiate in it greatly aid carbon absorption to the steel, cutting down time needed for carburizing.
Charcoal has all kinds of impurities in it, and is never homogeneous. You might want to try sugar the next time. With sugar infusion (in Ti foil) I was able to harden even some relatively mild steel that remained soft even when quenched into brine. I didn't run any toughness tests though.
Carbon black and certain forms of soot are better more pure as well. Can be produced in situ via a rich acetylene flame.
taking say structural steel bar and carburizing is a great idea but this 5160 is already so incredible it really didn't need that kind of treatment but it was a fun experiment to see
Clickspring made a fantastic video where he carburized his own steels for making files, its not a super in depth guide but it does give a very reasonable amount of information to follow. I believe its a part of his TOOLS TOOLS TOOLS! series.
I did read that case hardening can take multiple days to get good penetration.
In adding carbon you probably put the steel well over the eutectoid point and so quenching from 1525f put way more carbon in solution than was probably healthy for it. Even at 1475f there likely would have been more carbon in solution than the 5160 would normally have. That said 5160 is kind of finicky as Larrin shows in his article on it. Also, try doing a DET anneal instead of cycling, it saves a lot of time and arguably gives better results. 100f-500f cooling rate/hr in the oven from 1400f-1450f (depending on the steel) after normalizing.
I’ve missed you!!
In my YouTubing experience the carburized knife does looks sharper, harder, faster and better…!!😂
Seriously, it does! This is why I love your channel..!
You make science fun 😊😂😅
I love these videos. Im a steel nerd and really enjoy watching your tests.
I used carburization on a railroad spike knife. It tested fairly well, but I didn't do any controlled comparison. This is good..
It's about time to see a new knife video Not what I expected ❔but I'll take it and give you a thumbs up 👍 for it
that was a great video! very interesting in deed. thank you for taking the time and document these experiments.
I've actually been meaning to try this exact same experiment for quite a while myself. Thanks!
for the sake of your hand it seems like it might be worth while to make universal handle to hold your blades i used to make some quick and dirty ones out of the white cutting boards easy to cut and you can flame polish them quick as well a quick hit with a propane torch till they go ever so slightly translucent and you can bed the blade in (makes a great cheap chisel sheath as well ) this makes me want to get my but in gear and build a better gas forge i never got around to canister work but man do i love making kitchen knives for the family and wood turning tools
GB I'm a science nerd, I took AP classes in math and chemistry in HS, college classes as mechanic and metallurgist. I wanted to work in NASCAR and totally F'd that chance by graduating to Federal con college. You are on point with alot of your observations, keep trying with new methods, it's how we learn! I love your will to try something new, it's how humans grew to be dominate. While not all of us have the better interest in mind, I believe you do, keep up the good work!
Im banned from Nascar for life. Sadge.
Really interesting testing, Steve! Thanks! 😃
The sugar people suggested sounds interesting as well!
Happy new year!
Stay safe there with your family! 🖖😊
Same to you!
I have recently decided to invest in braided rope futures.
Love the metallurgy experiments!
When making this practice blades id suggest making a hidden tang style knife and model it after a hand file tang and then you could slip a plastic file handle onto any of the knives you make quickly and easily and it'll give you a little something to hold onto and take a bit of the shock absorption and save your hand a bit. Just an idea. Anyways this was a fun video to watch and hope you make more along this line of fooling around and tinkering to see what might allow you to take another step up in your knife game.
I'm wondering if a graphite paste painted on (2-4 layers), then followed by a refractory coating with a 6 hour soak at 1550F would make a difference. Graphite is theoretically pure carbon with super small particle size, so it might migrate into the steel better, especially if it's painted on the surface in an even coat.
oh wow thats an interesting idea
For pure carbon I would try carbon black or soot such as produced by a rich acetylene flame or bought as a colorant.
@@GreenBeetle An acid etch might also help show any hardness inconsistencies, at least on simple carbon steels.
You created an amazing HRC63 on one of the toughest steels ever created.
How about a follow up where you explore blade design to keep the HRC63?
Seems a shame. HRC measures some form of hard, but how does toughness and durability get measured? It seems pretty amazing it took 3-4 cycles to drop HRC on such a thin blade. Great video! Looking forward to a future follow up!
Geometry always wins! Great video 👍✌️
yeah i think the steel and hrc put you in a wide range and geometry pinpoints the performance
Much rope was harmed in the making of this video
Many years ago I carburized, hardened, and tempered towards the edge carbon steel woodworking chisels. In order keep the edge and the flat hard I heated from the top back and watched the color change, stopping it short when it came close to edge.
Well, that's what I did in the 80's before information became pervasive. I know things have progressed since then, and differential tempering doesn't appear to be a thing now, but wouldn't that help with the brittleness?
It would but it would also drop the hrc and I was trying to keep the hrc the same between the two knives.
Hope that you and yours are well. I dig the idea of improving 5160. Its great but greater is better right. ? Great video Steve
Hey thanks, James
When I was in high school, quite a while back now, we used a powder called Hardite. Heat whatever you were making up to red/orange, dip it in the Hardite. It worked well. You had to make sure the exhaust fan was on cause that stuff was really toxic. But a little cyanide never hurt nobody.
Later while doing an apprenticeship we had to harden a shaft that we'd machined. There was a big machine with a crucible inside it. In the crucible there was mineral salts of some kind. The whole lot would melt into a kind of bath that you chuck, well place your work into. It also worked quite well, and was also toxic as F.
Going back to the Hardite, I later became a teacher and found a tin of hardite in the stores at the school I worked at. A couple of decades after it was banned outright.
But we learned to be resilient you know.....
we drank from rubber hoses dammit
@@GreenBeetle lol!
Charcoal doesn't vaporise, I think it has to physically be in contact with the steel then atoms diffuse into then though the steel. Probably need more finely ground charcoal to speed things up and get better consistency.
Maybe he can try using activated charcoal powder, or just regular charcoal powder. I bought some on Amazon earlier this month and it comes ground finer than flour.
carbon monoxide dude.
Cela parrait difficile de cémenter de l'acier en phase solide uniquement par contact avec du carbone. La cinétique doit être très lente. Mais ici, il me semble que le mélange contient aussi du bicarbonate de sodium.
Peut être que cette carburation se fait en plusieurs étapes, telles que:
1) Décarbonatation du bicarbonate de sodium:
2 NaHCO3 = Na2O + 2CO2 + H2O.
2) Équilibre de Boudoire entre le CO2 formé et le charbon:
CO2 + C = 2CO
3) Cémentation de l'acier en phase gazeuse par le CO:
3Fe + 2 CO = Fe3C + CO2.
Peut être qu'il se produit d'autres phénomènes, tels que:
4) Formation de CO supplémentaire par l'équilibre du "Gaz à l'eau" :
H2O + C = CO + H2.
Mais je ne suis pas sûr. Tout dépend de la température, et aussi de la pression: sur ce point, je n'ai pas réussi à savoir si la cartouche était scellée, mais si c'était le cas, je pense que cela pourrait être dangereux!
How hard is this canister now?!
Heheh
you can make a nice epoxy handle from the ropecutoffs! like your doghair handle. great video
Very interesting. Great job
Would the harder tip where it meets the 60 hardness be the most likely fail point ? Meaning would it break
Great to see you again,,
Brother I think I worked out why you don’t post as much as you use to,, is it to give your arm hair time to grow back before you post again??
Thanks for sharing and informing us (teaching) us
😂 I wish I had more time
Question is if all that work is worth getting like that slight improvement in blade hardness?
Also I wonder if we would cut it using cooled saw blade(or break it clean...) before grinding, and put under microscope would we see that carbonized layer on the surface?
No, not at the expense of toughness in this case. Would be easier and better to just use 52100 but I can’t be reasoned with. 😃
What benefits are there to surface harness other than scratch resistance?
Carbon dissolves pretty quickly, it would have penetrated fairly deep
Edge retention and resistance to deformation
The problem is the addition of carbon isn't uniform. The tradeoff isn't worth it. That's why case hardening is usually not a good idea for knives but useful to increase wear resistance in other applications like some roller bearings.
Great point
but if you tempered it down to 62 pr 63 the edge retention could be better plus it could take a finer edge?
i feel tempering it down misses the point of case hardening.
Good point. I was mainly interested to see what extra carbon carbides would do.
The true sign of a knife maker! No hair on one arm lol
Interesting experiment; not sure if the results justify replication!
I did have a pretty good laugh at the nail test, one of those things I'll do once in a blue moon for bushcraft and cleavers just to make sure they hold up. Which in the era of super-tough, high alloy tool steels is actually not beyond most of them to be completely fine apart from some very minute rolls once in a while, still rattles the brain which is telling you 'this is wrong, stop it!'
5160 is an alloyed steel, not a huge amount but it is what it is with that chromium. So that might have have some bearing on adding more carbon into the mix in a post-ingot stage of its cycle and there's definitely a reason for the grain size being like that. Just extreme temperatures for extended periods of time will blow out those boundaries and it'd maybe need 3 or so reduction cycles to get it back to something more sensible. I wonder if using maybe 1084 or something with much less alloying in it would yield more noticeable results bumping it up from a say 0.8% to the 1.25% carbon contents- the main thing I notice when using say 1084 to 125SC is that the latter takes a lot more care, a 'near' water quench and some extent the result is getting those very high HRC's which increase the geometric stability and let it take very acute final cutting edges.
So while the end result there is that the different between a 1084 and 125SC is really just that one is tougher, the edge holding is pretty much the same and the other can take a finer ultimate sharpness
Is that a 2 barrel or 4 barrel carburetor you put on that 5160?
3 barrel
@@GreenBeetle That's why it broke.
Hi, first of all congratulations for doing what I would do lol... "where there's a will, there's a way"... man, I'm going to make my second knife from recycled 5160 and I've learned a lot from your experiences (thanks for showing it) I also have a small channel in Spanish (where I test knives in my style) I got tired of buying expensive knives and had problems with the Esee 4 and a controversy with Jeff Randall over his 1095 treatment (which I think is awful, almost a rip-off) I say that for the Esee 4 that treatment is not correct, for the Esee 6 it could be because of the length of the blade that needs more flexibility, but in 4" or 5" blades, why do you want more flexibility? ...man I want maximum strength and edge retention, don't give me a castrated 1095 (that's what I told Jeff) he just replied that that's how they do it... so I come here and see your great experiments with the same steel that I'm starting to use... please give me your magic treatment recipe so I can get to the point. (I would greatly appreciate it) ...and in your project, this one of adding carbon, I also thought about it with charcoal, I think you should make the steel liquid to incorporate the Carbon (any Steel I mean) ...So maybe you can do it with a Stainless as well like 420 or 410 to get to 440C (who knows?) ...keep going like this, trial and error... until you find out. Greetings from Chile
Peanut butter and chocolate... perhaps the greatest achievement mankind has produced in centuries. 😂
LOL
From what i know the iron gets fully saturated with carbon around the .80-.85 range, and after that the remaining carbon forms iron carbide pockets at the grain boundries. Since 5160 has less then .85% carbon maybe there is some direct knife and tool performance to be gained when adding carbon up to that point?
After though idk, theres no right answer to wether or not you want the toughness reducing effects of having excess carbon and forming a bunch of iron carbide. Consider that 1084 is significantly tougher than 1095 and the carbon difference is very low (and other than this theyre basicly the same).
Toughness is an often overlooked aspect of cutting performance by bladesmiths bc theyre all obsessed with rockwell hardness, but the effect of high toughness is edge stability at lower edge angles, which has a better than linear realationship (i dont wanna say its exponential, but its very significant) with edge retention while hardness has only a linear relationship. And as a bonus, higher toughness steels can have a thinner behind the edge thickness for heavier tasks like batoning, reducing force required to make the cut without getting macroscopic rolls an bevel deformation.
tldr: adding carbon probably wont imporve an already good blade / tool steel in an overall sense.
Right you are. Alloying moves the eutectoid point back and forth a bit but 1095 , w1, w2, white paper, 26c3, 52100, etc and all 'supersteels' are hypereutectoid. There are many hypereutectoid knife steels.
old timers used leather scraps
Normally when the steel manufacturers are adding Carbon, (Coke), this is done while the steel is molten. I do not think just heating the steel to red, or welding temperatures in a home built forge is hot enough to get the results you are looking for. I could be incorrect, but I think that is the process.
this is case hardening. another method doesn't require casting would be cementation.
You are incorrect, pack carburization, flame carburization etc are real techniques which can be performed in home shop conditions. They have historical evidence and are widely used in industry. No liquidization required.
@murmenaattori6 I stand corrected, and newly educated. I knew different types of steel could be hardened or softened through Quench processes and Anieling, but though through those processes the steel would only achieve a certain harness before becoming too brittle and useless. Thank you for the info.
Is pronouncing “sisal” as seesal a regional thing? I’ve only ever heard it pronounced like that by one other person.
Carbon is not everyting...
If you take a 1084 sn carburize it frpm .85 to 1 pe4cent carbon the steel gets a little harder, the edge retention is slighteley better , but the toughness drops to the hslf amount.
The ideal carbon cobtent for a not aloyed steel is 0.84 percent.
For a steel with sone chromium around 0,6 percent oor so.
Depending on the content.
More carbon forms chromium carbides.
And these are particles in the steel matrix. They can ruin your edge while grindind and make the steel briddle.
Metallurgy is a complex thing...m
Good point. Isn’t 52100 over 1% carbon?
@GreenBeetle you have to look to the alloy elements
Some need carbon, some lower the eutectic point
You can temper too much and cause embrittlement, i would have gave them the same temper. That said what a great video i absolutely love tests like this
I haven’t heard that before are you sure that’s correct
@GreenBeetle indeed, it's a fairly new concept to me too but the term to research is "tempered martensite embrittlement". You can find graphs to compare temperature to v-notch impact resistance for many steels. Often 450 to 800f is more brittle than a lower temper
@@GreenBeetle above 200 - 250°c retained martensite decomposes into cementite and ferrite
I was thinking the same thing while watching. You are super smart and much better at math and the engineer here. However, having researched a bit of case hardening- thru antiquity, there is a logic that seems missing. If you add the carbon it should improve the stock, right? The evidence of improvement was shown in the need to temper multiple rounds to reduce hardness. Where is the valuing of removing something you added?
If you ever revisit this, complete the same process. Could the video be about how to harness the value you created?
What is the value in having a steel that needs THREE reduction cycles?! You've done something amazing. That is so cool. Perhaps the thickeness and profile of the blade isn't best to utilize the great hardness you created?
Damn you have about as much hair on your arms as me i test blade sharpness myself like that.
😂
have to wait a week to make your knife by arm hair should have grown back by then
I use minoxidil on my arms no problem
I miss the days when green beetle made knives. When he experimented hammered out different style knives, some were successes some were failures but it was all blacksmithing. Lately it seems like it's just endorsements for knife sharpening products and whatever this is