You have greatly helped my understanding of material properties. I saw this in my material science classes, but had some horrible lecturers. I decided to watch this video because I was looking for some info on hardening steels for knife making, and I have seen your other videos in the past. I have to say, you always do a great job explaining very complicated subjects in a simple concise matter. Thank you for doing what you do! As for d mac, he shows two methods, the blow torch and the kiln. Watching material harden is like watching paint dry.
You most definitely did a great job explaining how these processes actually work and in which order they are to be completed in to obtain whatever properties are desired. Great video and thank you for breaking it down. Very informational.
Great video. I'll have to watch it again to get a better understanding of how to re-harden the pallet nails that come from my woodburner. Reheat to red heat and then cool quickly but not suddenly??
In the stress-strain plot, shouldn't stress be on the x-axis since it is the independent variable and strain should be on the y-axis since it is the outcome that is the dependent variable
Not quite sure what happened, but for some reason, I was actually able to keep up with everything you spoke of. My mind is weird. I have lots of interests and if I am in a drama free zone, I can learn very quickly. Like very very quickly. As you went through this video, I actually learned more than you spoke of simply out of curiosity and putting it through my sandbox brain. (When I tried to go to college, before the drama of my life took over, I was actually the favorite from every instructor on my campus because of that fact.)
NinjaOnANinja pepper669 Interesting, I guess there are three of us. I can almost always come up with something that ends up being right, simply by learning the basics. Some people I know think I am a genius, I know I am not, I just learn faster than the information gets to me. I can learn something once (EX: measuring what a circuit/component outputs), and know more than I was given (EX: The underlying process and internal workings) without testing further. Its odd, but it makes things REALLY easy for me when experienting with or repairing electronics for family/relatives/friends. I too have LOTS of interests besides just my main interest, electronics.I can also make the most believable lies imaginable, and add so much information that it seems like it couldnt be false. I can even remember it weeks later exactly as I said it. Its very hard for me to lnot lie in tough situations because of this ability, it comes naturally. Even scarier, after a few month I forget the truth and only remember the lie as if it was real. I can even lie to myself easily, I just keep "living the lie" and telling myself it is so until I believe it. I usually use this to help myself break bad habits by convincing myself that I do not normally do it and that it was someone else's idea. Works every time, and it takes only hours to program or remove a habit form my mind. I can literally treat my brain as a computer, programmable and automatic. Its very odd how the mind works, and I believe nobody will ever fully understand it. The brain is like a glorified analog computer, filled with all of its own quirks and advantages. It is self programming and has a free will. It can store close to 2,500,000GB of information and has a processing capacity greater than the most powerfull supercomputer. Just think of how many millions of measurements it makes and compares without you knowing. It stores EVERYTHING you have ever seen, heard or experienced in any way. You are not able to recall most of it, but everything is there forever, just like your search history (muahahahahha).
Yeah, you guys sum it up pretty well. But if that kinda stuff is your cup of tea, you should check out my channel. I do that kind of logical thinking but with video games. I was going to go for something more scholastic, but I became disabled. And I just know video games.
Metal atoms inherently have a crystal structure, namely face centered cubic (fcc) for steel (iron) in this case. The crystal structure you see in diamond is a unique configuration for carbon. Carbon can be added to steel to change material properties, but these carbon atoms appear in the steel as inclusions in the FCC structure. Did that answer your question? It was not very clear to me but answer me back if you need more help to understand :)
+graham kaveman I believe that is because when the carbon atoms become encased in the FCC crystal structure, any dislocation motion is inhibited, meaning, when atoms begin to slide past one another on a slip plane, the way is blocked by sequences of carbon atoms.
+graham kaveman I'm not sure about other atoms, but generally speaking, it is only feasible to add elements with similar electronegativity and size as the host element's. Also it is known that carbon has a very strong bonding with many elements.
Want a trippy superelastic steel? Austempering. A buddy in my guild quenches in a salt bath normally used for bluing (350-ish C, iirc) can bend a sword almost into a U, and it springs back, but still maintains 50+ R hardness. Google forth fellow science dude. Recipes abound. 😃
Ok, that is feaking awsome! I would love to see that. I looked up the process, it seems fascinating. I believe I will actually spend some time reading about it.
Well Thanks, that was very informative! My Dad was a Tool & Die Maker & I spent a lot of my early years in machine shops on Saturdays as he worked on side jobs. One thing I remember doing was hardening steel, as you've shown - heating to cherry-red & quenching. I remember Dad also adding Carbon to steel in an electric furnace by covering it (the steel work-piece) with coal and or charcoal and bringing the temperature up & holding it (temp) elevated for the carbon in the charcoal / coal to migrate into / penetrate the steel. He showed me how we could make a piece of coat-hanger wire into a tiny knife blade by flattening, carbonizing, hardening, annealing then sharpening. I was only 8 or 9 and didn't fully appreciate what I was being shown, not right away,
Hey Ben, Thanks for this excellent video too. While you would really need to pull the samples to get a more straight forward assessment of tensile strength, I appreciate the bending test, because it relates to the real world more readily. The difference in each radius resulting in the normalized vs your heat treated samples is a great indication of work hardening and gives some insight the stress concentration involved in the higher strength samples failing under far less load. . Also, it is interesting to note that it is possible to harden low carbon steel like a coat hanger with methods very similar to what you describe, thought the hardness will be more apparent in a file test than a bending test. . Carbon diffuses through steel at elevated temperature. This can cause a reduction in carbon in the outer layers of steel when it is at high temperature, so it is important to be aware of this and its possible ramifications. This phenomena is also useful for increasing the carbon levels in steel near the surface. This can be utilized to case harden many types of low carbon steel, providing a hard wear resistant surface, but still maintaining the ductility of low carbon steel for the whole piece. . A convenient low tech way to accomplish this for small pieces of steel from coat hangers or more usefully with things like knives,: - Use a lighter to apply a layer of soot to the piece by holding the piece in the lighter flame. - Use a more powerful torch to heat the entire piece up to a red glow and hold it there for a short time to allow the carbon to diffuse inward... a carburizing or neutral flame would be preferable to oxidizing. -Quench and temper. . Anyway, thanks again for this great video and the many others you have made.
Pure iron (alpha ferrite phase) is very ductile and malleable, it has low yield. As carbon content increases harder phases can form, especially iron carbide phases once the ferrite is saturated with carbon at around 2%. Around 1/3 to 1/2 a percent carbon is where steel peaks in "toughness", beyond that it keeps getting harder but more brittle until cast irons which are more dominated by intermetallic iron carbide phases (eventually graphite too). The iron/carbon system is very complex.
Excellent point. If I understand you, the carbon inclusions no longer reside as part of the cubic array and become inclusions that disrupt the continuum of the crystal structure? And you're saying that this occurs at or about the 2% carbon point? I hope I've worded it right. That seems to be critically important in adjusting the properties of the steel
I've been watching videos about forging and have been wondering about the actual differences between tempering, normalizing, hardening and annealing. You're video was very good at explaining it, especially with the examples you demonstrated.
carbon is not impurity, you want to keep as much carbon as you can, because even with the old methods you dont end up with enough carbon (thats why they choose only few pieces of the produced steel while making katana sword, the parts with highest carbon content only), all you need to do is to distribute that carbon evenly into the steel and make a homogenous mixture of iron and carbon (by forging). look at some photos of steel under microscope.
With all your scientific graph and load holding test all you mentioned when it's hardened is when the the steel becomes cherry-red hot. I'm disappointed that you mentioned nothing about losing its magnetic properties. Using magnet is so much easier and accurate than just observing the colour of the heated steel.
The upper-case Greek letter delta is often used to represent the relative change in some quantity. So, "delta L" is the change in length for a given beginning and ending condition. Lower-case delta can indicate the deflection of a mechanical system under load.
I was pretty tempted to use imperial because yield strengths are often quoted in ksi, but I figured that I would use the opportunity to help push people toward SI. I think concepts are better taught without getting too bogged down in units anyway.
You said that hardening does not change material stiffness. However, metal sample resonating frequency is determined by its geometry and its stiffness and if you harden a metal sample, it's pitch rises significantly. I mean, if you hit a metal sample with something and let it ring, hardened steel rings with higher pitch than normal steel which means it has greater stiffness.
I was the only one in my shop that can run the induction others could not see the color temperature of heat the way I can plus when I change the polarity own the batteries I'm talking big battery the type that electrocute you if you do not ground them out probably I had the honor of doing all the military parts I could also maintenance all the machinery the vacuum furnaces chromoly lined man I hate having severe arthritis I miss work in 24 7 my walking is limited im partially in a wheelchair :(
Hi Ben, I study Mechatronics Engineering here in Brazil and this is a big part of one of my classes. We did absolutely everything as you did, testing heating and breaking points, crystalline structures, etc. Very good video as always. Thank you very much!
Wrap your coathanger in leather,insert into a metal tube, seal the ends, heat to RED, hold for 4 hours, and check your "yield" point now.? edit:- forgot, after the 4 hours, quench the whole shebang in water.
Nice refresher course Ben - for an old fella :) Be interested later if you cover this again - to get your take on using silver steel to make, say, a small cutter insert for a boring bar - degree of temper you'd apply to back off from too hard. Other thing is oil vs water quench and your approach to that. Oh and - one other thing - making a spring!!! To some more of an art than a science! Thx for another great video.
The hammering you refer to is probably making wrought iron from bloom? Prior to blast furnaces (which make pig iron - high in carbon 4-5% - brittle as hell), bloomeries avoided getting too much carbon into the iron (
Very Nice Video, I really liked it. Seems you know what your talking about. (+1 : 1,273) So if I buy 1095 Blue Tempered Spring Steel from McMaster Carr, which I'm going to be doing Friday 05.02.2014, Will it be very strong? I want to make lock picks, and I want very nice steel, because I'm making the shank of the picks 2mm to 1mm. They say that the Hardness is C44-C51, which according to there chart is between hard & very hard, where Tungsten is like a C79, but they don't have any Tungsten in the thickness that I want, 0.025" I would like to ask you, how would I go about cutting the 1095 Full Hard Tempured Shims (Item No. 9014K67) ? Would I just use an Abrasive Cutting Disk for a Dremel or Right angle grinder?
This is very helpful, feels like I'm in school or uni. Thanks for the upload!!! That file trick is pretty handy, I noticed when trying to file a hard steel, It felt like there was no progress, it was smooth. I did learn annealing in work experience at a jewellery shop where you heat the silver up then let it cool down slowly, then you can work on it like draw silver wire through different size holes to make the wire thinner. Pretty cool stuff.
Thanks for the video! I've a question: what if you were trying to soften the steel, but maintain elasticity? ie to make it deform elastically at lower loads? would longer cooling times help?
Hey ben. I love this video, and I love the array of videos that I see on your channel. You say you're a big hobbyist, and I feel sort of similarly. I'm wondering how big of a shop you have. I'm also wondering how big of a shop you'd dream of having, and what kind of electrical feed you'd want...and all sorts of stuff! I haven't bought a home yet that I'd like to settle down in...and heck..I might build mine...but I'd like to future-proof my shop plans so that I can build it once and call it good...if I ever make it to that point in life.
Thank you so much for helping me understand tempering and hardening steel in an easy and practical way, although i'm not clear 100% because i'm not familiar with some of the terms that you use. But it is very good actually.
Im 15 and i just learned more information in 17 minutes 29 seconds than i was taught all day at school today GREAT JOB ben keep up the amazingly educational and intriguing videos:)
Hey Ben, I was just contemplating making my own compression coil spring for a mountain bike and came across this old video -- great explanation! Also, a good resource describing various alloys and their hardening properties is Machinery's Handbook. Now if I can only find an annealing kiln...
And then there is work hardening that also needs to be annealed so it doesn't break, like working copper, where if you form it enough without annealing, it will fracture from hardness.
Might want to write Closed/Captioning yourself (or not).. Auto-generated said about the steel color changes (@ 12:05 ) "..it's actually quite - *_ineffective_* - and decent means.."
i have heard about diffrent condition of heat treated low carbon steel such as "817M40 PD 970 CONDITION 'V'",can you provide me heat treatment cylce to reach condition V
I want to harden some 3/8" wide copper strips to make a leaf spring for a 32" long model of a a 1929 Miller race car. I will have approx 5 layers of copper for the leaf springs of approx. 7" in length. I want some spring action, this piece will be a static display, but would like a bit of spring back should the suspension be pushed down. Help is welcome, Dale in Indy
Wow! I'm new to knife making and was having trouble understanding exactly why the heat treating and tempering are done. Your video made it super easy to understand. Great job!
what do you think about the 80CrV2 Steel blade knife ?? for Survival - Bushcraft/Outdoor knife use ?? do you think is it durable or not ?? whats the best stone to sharpening the blade ?? 80CrV2 Steel knife blade is it weak or is it strong ?? thanks
w1 tool steel from mcmaster is b95 medium hardness. low carbon steel is b70 medium hardness. apples to oranges but a rough comparison of as delivered hardness. both have very similar yield strengths of 55,000 psi for w1 and 54,000 psi for low carbon steel
Just when I thought I knew everything... I have a question I think you may have the answer to, or point me in the right direction. I need to find a metal (preferably 1/2 rod) that can be bent and welded to a vehicles exhaust system to prevent certain expensive parts from growing legs and walking away. Thefts of this nature seem to be a huge issue right now. It would need to be so hard that a Sawzall blade or grinder would have a very hard time getting through. What would you recommend for this situation? Great video.
1. Heat steel to white hot, then quench in liquid nitrogen. Steel will shatter with the slightest touch. 2. Bet someone $100 you can break steel with your bare hands. 3. Repeat until Jeff Bezos.
You mentioned your very strong piece was tempered at 300C in your kiln, was that for 1 hour and was that after heating it to 800C and quenching it? What of the speed of the heating process, is it important to pre-heat the kiln for temper so it is brought up to the right temperature as quickly as possible? If it takes as long as 10 seconds of cooling to ruin the hardening, why is it that any steel is rated for water cooling when oil cooling is plenty capable of cooling it faster than 10 seconds? Does cooling it faster make it stronger aswell? What happens above the 800C hardening target? Is getting further below ~150C more beneficial?
Yes It was very helpful in deed ! See if you can have a video about tempering steel individually ,because I think lots of people want to know that, and the reason is that tempered steel has less impact on tools' and sandpapers and blades' ,,etc . I'm a beginner in metal work and knife making (epidemic illness these days') and this kind of information specially is helpful for me and people like me with limitations in tools and space for work. The more we know the easier we can deal with limitations' !!! Thank you
Here's where I display my naivete. Why is low-carbon steel cheap? I assume it has more to do with the process of attaining the level of carbon necessary, rather than... you know, finding some carbon to put in there.
PMMA is used in our lab for conductive flexible thin films. Coat a glass substrate with it, deposit the material and coat it again. Then you can get it off, provided you have a sacrificial layer beneif the first PMMA layer.
Beautifully done overview of an apparently touchy subject. Lots of misinformation out there. I feel like I get fine performance using my normal kitchen oven, but always verify the temperature with the oxide color the steel shows. I also recenrly learned about a phenomenon that I have seen many times while quenching -apparently shadow passing through steel as it approaches an orange color is actually the carbon going into solution. It seems to happen at the right temperature - I'm just wondering if you could confirm or deny this.
Any chance of you doing a video on sharpness? Asked my father recently about sharpening, and he says there are 2 schools of thought on how to do it. One school says "only sharpen one side" the other party says "sharpen both sides". The single side party says "sharpen one side, then remove the bur on the other side" The double party says "sharpen both sides, it will leave a small bur but it doesn't matter." I'm curious what both methods look like under a scanning electron microscope.
Very informative and explained in the simplest manner. Would you be able to advise me on a heat treatment related subject ? I want to manufacture a steel tube that would have flexible expanding feet at the end and axial splits across diameter for the reason of radial expansion. I am working on a project to design a temporary single sided fastener for aerospace assembly. My question is that how to manufacture such flexible clamping fingers in a collapsed position which can expand through a driving mechanism and collapse back too again.
You can show use of that much better that my professor lol! How suggestion for you, could you do a movie using the tension deformation using temperature too, to generate a tension, deformation and temperature graphic. Sorry if a can't be clear, my English is not very good, yet lol!
I have a ratcheting lopper.. The bad part is the tempering of the blade. Overall the blade is good except for the teeth, gears or cogs.. They break off but the blade maintains an edge.. I'm guessing by your statement, the heat treating of the blade, makes the gears brittle, but it benefits the edge.. It would be nice if the product was heat treated individually between the edge and gears instead of buying a new blade once a year due to broken teeth.
That very last bit seemed confusing to me. You are saying that a very very low, almost negligible carbon percentage is 'cheap low quality' steel, around 1-2% is 'good steel' but as you get higher quantity carbon in your iron... it's just cast iron? What if the absolutely no carbon, even just pure Iron? Apart from that, amazing video, really informative and well presented. Thanks!
Ben, I made the wire you are using from mc master-carr! At Universal Wire Works, we make wire primarily for welding. Drawing and straightening. I have done many similar experiments. Most annealing only requires reaching the "annealing temperature" upon which a "solution anneal" occurs and then it doesn't really matter how quickly you quench the material from my experience. I would really enjoy discussing my research further with you.
What's the application you need the wire for? You might not need a high carbon. McMaster has some 1065, 1075, 1080 which all harden up nicely. 65+ hrc out of quench. (the 65,75,80 is the amount of carbon. so .65%-.8%) They are not 1% but you don't need that. These are commonly used for swords and knives. If your using a torch I would go with the 1080. It's eutectoid, meaning its pretty friendly to a torch. Where as most steels will give a poor HT without using a temp controlled oven.
Nope. Only thing you can do is case harden (does not involve hammering), which involves soaking steel at around 1800*f for anywhere from 30 minutes to 6 or so hours in a carbon rich environment (IE charcoal, bones work really well). Even then you will only get a few thou thick of material with carbon and even then it will be a low amount. Getting a high carbon content and a uniform alloy requires you to re-smelt.
Heating steel constantly doesn't really lower its carbon content. The temperatures you need for this to happen are at the melting point. Well past critical. Before that can happen you will run into issues with irreversible grain growth that will destroy the steel anyways. --- Also color is a poor judge for HTing anything, A difference off 100*f can produce poor results but the color difference can't easily be seen. When tempering colors can get thrown off by contaminants on the steels surface.
in that case yeah - i assumed you had soem premade object/item you didnt want to change. The thinner the metal when you heat it in a chamber with a carbon source would allow it to penetrate deeper - or through the whole metal. Blacksmiths dont actually add carbon - they still smelt it to mix with carbon or use pre carbonized steel. Constantly heating the metal will lower its carbon content over time.
impurities in steel always make it brittle but in the same time are lowering the strength, similar to what ben draw at 6:56 but without the plasticity. most of the impurities are clumps of carbon, silicon minerals, dirt... i am talking about the old methods as shown here: watch?v=mprtHmEzXjI by forging (hammering, folding, forge wielding...) your removing most of those impurities, and by mixing different steels and forging them together you get amazing properties, like the damascus steel.
He could have made a do-it-yourself stress tester. Then each test would have produced its own graph of strain as a function of applied stress (or stress as a function of imposed strain), for a very powerful visualization. He could have annealed a piece of that steel, just to show the effect of annealing, and the different plot it would produce. He could have tested an actual aluminum sample, to show its different curve for real.
When I sharpen lawn mower blades, I use a file rather than motorized grinder to avoid hardening the edge too much. Seems like a shrapnel risk. I certainly have seen grinders take an edge to a blue color. Also I have read that a bucket of wood ashes is useful for tempering a piece - slows cooling.
taking me back to school days I seem to remember, if you take the coat hanger steel say, heat it up then dip into carbon, you can case harden it, repeat this by working the steel and the harder it will get. used for knifes, swords etc in days of old.
My cousin was talking to me about how he was trying to harden some steel with his fireplace by heating it red hot and quenching, but he couldn't get it to work. The thing about some steels not being hardenable might explain why he couldn't do it.
Your statement about "what we mean when we say a material is hard its actually very strong" is sadly inaccurate. strength and hardness are two very different contrasting things. 14:22 Strength and Hardness are an equal trade off when dealing with a single material's variations without adding elements. Otherwise this was a great video. Very informative.
The reason the ductile rod held more weight was because it allowed a fully plastic deformation in bending. The ductility allows the stresses to move inward where the entire cross section is plastic instead of just the outermost edges. On the other hand when the outermost section of the hardened steel reaches yield, the outer section fractures. The cross section is reduced, stresses are higher. The result is a quick failure of the entire rod. The strongest rod will allow for full plastic deformation of the cross section while "using" the extra ductility as strength in the hardening process. It's also an interesting look into why we want some ductility.
ALUMINUM IN FREE SPACE CAN NOT FULLY PENETRATE STRUCTURAL STEEL AT SUBSONIC SPEED, PERIOD I have had extensive training in metallurgy, and viewed this to review or add to. Still managed to learn a few details though.
this. this the most important part. the relation between theory and practice. there are a zillion things i know in theory, but when actually trying to apply them, all hell breaks loose and nothing works as intended
because the duration of the heat exchange has also an effect on the final properties of the material. Quenching in oil gives you a slower transfer thus resulting in a less strong steel but also less brittle.
I heat treated for years I enjoy running the Epson furnaces the most I was the best at probing the baskets of metals whenever they slipped on the elevator going to a oil quince I can take it 8 foot stainless steel hook probe around the sides of 0.1 stainless steel baskets and hang them without seeing what I was doing once the steels removed we had to load it into a draw furniture. Dixie barons had to go into deep freeze than into a draw furnace best of all induction heat treating :)
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You have greatly helped my understanding of material properties. I saw this in my material science classes, but had some horrible lecturers. I decided to watch this video because I was looking for some info on hardening steels for knife making, and I have seen your other videos in the past. I have to say, you always do a great job explaining very complicated subjects in a simple concise matter.
Thank you for doing what you do!
As for d mac, he shows two methods, the blow torch and the kiln. Watching material harden is like watching paint dry.
luvmyTM1911 Thanks! Let me know if you ever have a suggestion for a video topic.
+Applied Science Great video, thought about maybe using this to make primitive drillbits. Think it'll work?
Have you seen Alec Steele's channel? He's a mad blacksmith
Yes but can you stab, bludgeon, lacerate, or simply make a al47 receiver with dried paint??
I want to know how to make steel flexible?
You most definitely did a great job explaining how these processes actually work and in which order they are to be completed in to obtain whatever properties are desired. Great video and thank you for breaking it down. Very informational.
Your "bridge" got me to the point that I realized how much more I'd like to learn. Thank you!
Just learning about heat treating and tempting. This video was great for this beginner. Thanks for such an informative video.
"Ok I hope that was helpful"
You know damn well that it was helpful! Thanks a lot.
TwiztidShet -----You should never give up hope.
You replied to a 3 year old post??!? I *HOPE* he gets a laugh out of it :)
DrKnow65
@@DrKnow65 I HOPE you find this funny too
@@DrKnow65 who cares !
Great video. I'll have to watch it again to get a better understanding of how to re-harden the pallet nails that come from my woodburner. Reheat to red heat and then cool quickly but not suddenly??
Thank you very much for a very informative video, I learned many things.
Thank you so much...Very helpful
In the stress-strain plot, shouldn't stress be on the x-axis since it is the independent variable and strain should be on the y-axis since it is the outcome that is the dependent variable
Not quite sure what happened, but for some reason, I was actually able to keep up with everything you spoke of.
My mind is weird. I have lots of interests and if I am in a drama free zone, I can learn very quickly. Like very very quickly.
As you went through this video, I actually learned more than you spoke of simply out of curiosity and putting it through my sandbox brain.
(When I tried to go to college, before the drama of my life took over, I was actually the favorite from every instructor on my campus because of that fact.)
Strange, but I've got the same mind :).
NinjaOnANinja pepper669
Interesting, I guess there are three of us. I can almost always come up
with something that ends up being right, simply by learning the basics.
Some people I know think I am a genius, I know I am not, I just learn
faster than the information gets to me. I can learn something once (EX:
measuring what a circuit/component outputs), and know more than I was
given (EX: The underlying process and internal workings) without testing
further. Its odd, but it makes things REALLY easy for me when
experienting with or repairing electronics for family/relatives/friends.
I too have LOTS of interests besides just my main interest, electronics.I can also make the most believable lies imaginable, and add so much information that it seems like it couldnt be false. I can even remember it weeks later exactly as I said it. Its very hard for me to lnot lie in tough situations because of this ability, it comes naturally. Even scarier, after a few month I forget the truth and only remember the lie as if it was real. I can even lie to myself easily, I just keep "living the lie" and telling myself it is so until I believe it. I usually use this to help myself break bad habits by convincing myself that I do not normally do it and that it was someone else's idea. Works every time, and it takes only hours to program or remove a habit form my mind. I can literally treat my brain as a computer, programmable and automatic.
Its very odd how the mind works, and I believe nobody will ever fully understand it. The brain is like a glorified analog computer, filled with all of its own quirks and advantages. It is self programming and has a free will. It can store close to 2,500,000GB of information and has a processing capacity greater than the most powerfull supercomputer. Just think of how many millions of measurements it makes and compares without you knowing. It stores EVERYTHING you have ever seen, heard or experienced in any way. You are not able to recall most of it, but everything is there forever, just like your search history (muahahahahha).
Yeah, you guys sum it up pretty well.
But if that kinda stuff is your cup of tea, you should check out my channel. I do that kind of logical thinking but with video games.
I was going to go for something more scholastic, but I became disabled. And I just know video games.
Great work . So are the Carbon Atoms the reason the crystalline structure occurs ( as in Diamonds ) ?
Metal atoms inherently have a crystal structure, namely face centered cubic (fcc) for steel (iron) in this case. The crystal structure you see in diamond is a unique configuration for carbon.
Carbon can be added to steel to change material properties, but these carbon atoms appear in the steel as inclusions in the FCC structure. Did that answer your question? It was not very clear to me but answer me back if you need more help to understand :)
+Sam yes I would . im trying to understand that if steel has a crystaline structure how does carbon add to its hardness
+graham kaveman I believe that is because when the carbon atoms become encased in the FCC crystal structure, any dislocation motion is inhibited, meaning, when atoms begin to slide past one another on a slip plane, the way is blocked by sequences of carbon atoms.
+Sam oh so adding different atoms other than carbon isn't as effective ?
+graham kaveman I'm not sure about other atoms, but generally speaking, it is only feasible to add elements with similar electronegativity and size as the host element's. Also it is known that carbon has a very strong bonding with many elements.
It's like if Mister Rogers taught heat treating!
Wish I'd had this to reference during my materials science classes!
Want a trippy superelastic steel? Austempering. A buddy in my guild quenches in a salt bath normally used for bluing (350-ish C, iirc) can bend a sword almost into a U, and it springs back, but still maintains 50+ R hardness. Google forth fellow science dude. Recipes abound. 😃
Ok, that is feaking awsome! I would love to see that.
I looked up the process, it seems fascinating. I believe I will actually spend some time reading about it.
Rion Motley does he do them for cutting buhurt or Hema? I'm genuinely interested.
What thickness was the material, the amount of elastic deflection a peice can have goes up with thinner peices.
This goes in my "Best lectures" hall of fame. I'd like to see a follow up that shows detail about deformation over time.
Well Thanks, that was very informative! My Dad was a Tool & Die Maker & I spent a lot of my early years in machine shops on Saturdays as he worked on side jobs. One thing I remember doing was hardening steel, as you've shown - heating to cherry-red & quenching. I remember Dad also adding Carbon to steel in an electric furnace by covering it (the steel work-piece) with coal and or charcoal and bringing the temperature up & holding it (temp) elevated for the carbon in the charcoal / coal to migrate into / penetrate the steel. He showed me how we could make a piece of coat-hanger wire into a tiny knife blade by flattening, carbonizing, hardening, annealing then sharpening. I was only 8 or 9 and didn't fully appreciate what I was being shown, not right away,
By this time You must be a highly skilled person. Long live thanks.
Did you make that kiln yourself and do you have (or could you make) a video about making it?
Excellent!!! I hope you make a video explaining the TTT curve and explain things like austempering, marquenching etc. from the curve..
Agreed, excellent overview. Good food for an engineering brain.
Hey Ben,
Thanks for this excellent video too.
While you would really need to pull the samples to get a more straight forward assessment of tensile strength, I appreciate the bending test, because it relates to the real world more readily.
The difference in each radius resulting in the normalized vs your heat treated samples is a great indication of work hardening and gives some insight the stress concentration involved in the higher strength samples failing under far less load.
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Also, it is interesting to note that it is possible to harden low carbon steel like a coat hanger with methods very similar to what you describe, thought the hardness will be more apparent in a file test than a bending test.
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Carbon diffuses through steel at elevated temperature. This can cause a reduction in carbon in the outer layers of steel when it is at high temperature, so it is important to be aware of this and its possible ramifications. This phenomena is also useful for increasing the carbon levels in steel near the surface. This can be utilized to case harden many types of low carbon steel, providing a hard wear resistant surface, but still maintaining the ductility of low carbon steel for the whole piece.
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A convenient low tech way to accomplish this for small pieces of steel from coat hangers or more usefully with things like knives,:
- Use a lighter to apply a layer of soot to the piece by holding the piece in the lighter flame.
- Use a more powerful torch to heat the entire piece up to a red glow and hold it there for a short time to allow the carbon to diffuse inward... a carburizing or neutral flame would be preferable to oxidizing.
-Quench and temper.
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Anyway, thanks again for this great video and the many others you have made.
Extremely helpful to have the science behind the method
Pure iron (alpha ferrite phase) is very ductile and malleable, it has low yield. As carbon content increases harder phases can form, especially iron carbide phases once the ferrite is saturated with carbon at around 2%. Around 1/3 to 1/2 a percent carbon is where steel peaks in "toughness", beyond that it keeps getting harder but more brittle until cast irons which are more dominated by intermetallic iron carbide phases (eventually graphite too). The iron/carbon system is very complex.
Excellent point. If I understand you, the carbon inclusions no longer reside as part of the cubic array and become inclusions that disrupt the continuum of the crystal structure? And you're saying that this occurs at or about the 2% carbon point? I hope I've worded it right. That seems to be critically important in adjusting the properties of the steel
I've been watching videos about forging and have been wondering about the actual differences between tempering, normalizing, hardening and annealing. You're video was very good at explaining it, especially with the examples you demonstrated.
carbon is not impurity, you want to keep as much carbon as you can, because even with the old methods you dont end up with enough carbon (thats why they choose only few pieces of the produced steel while making katana sword, the parts with highest carbon content only), all you need to do is to distribute that carbon evenly into the steel and make a homogenous mixture of iron and carbon (by forging). look at some photos of steel under microscope.
With all your scientific graph and load holding test all you mentioned when it's hardened is when the the steel becomes cherry-red hot. I'm disappointed that you mentioned nothing about losing its magnetic properties. Using magnet is so much easier and accurate than just observing the colour of the heated steel.
Maybe disappointment is a bit of an over reaction ... :D But that's a good tip.
Train wheel heat treating is pretty neat. They will only quench the outer rim of the wheel that makes contact with the tracks.
Perfect mixture of practical and info about physics involved... Was very helpful, thank you
Thanks for using real units :)
whos watching this in 2021 🥺🥺🤪😱😱🥶🥵🥵
The upper-case Greek letter delta is often used to represent the relative change in some quantity. So, "delta L" is the change in length for a given beginning and ending condition. Lower-case delta can indicate the deflection of a mechanical system under load.
I was pretty tempted to use imperial because yield strengths are often quoted in ksi, but I figured that I would use the opportunity to help push people toward SI. I think concepts are better taught without getting too bogged down in units anyway.
Best I'v ever seen on the subject ! Thanks, professor.
You said that hardening does not change material stiffness. However, metal sample resonating frequency is determined by its geometry and its stiffness and if you harden a metal sample, it's pitch rises significantly. I mean, if you hit a metal sample with something and let it ring, hardened steel rings with higher pitch than normal steel which means it has greater stiffness.
I was the only one in my shop that can run the induction others could not see the color temperature of heat the way I can plus when I change the polarity own the batteries I'm talking big battery the type that electrocute you if you do not ground them out probably I had the honor of doing all the military parts I could also maintenance all the machinery the vacuum furnaces chromoly lined man I hate having severe arthritis I miss work in 24 7 my walking is limited im partially in a wheelchair :(
Hi Ben, I study Mechatronics Engineering here in Brazil and this is a big part of one of my classes. We did absolutely everything as you did, testing heating and breaking points, crystalline structures, etc. Very good video as always. Thank you very much!
I want to know how to make steel flexible?
As a welder, I like to keep a separate file for this...you can damage/ruin a good file by using it for unknown hardness testing...
Good suggestion, but I don't think it matters a lot for normal users ...
+Paul Hendrix ...You're probably right...but a good file can cost $10-15 or more....
Wrap your coathanger in leather,insert into a metal tube, seal the ends, heat to RED, hold for 4 hours, and check your "yield" point now.? edit:- forgot, after the 4 hours, quench the whole shebang in water.
Nice refresher course Ben - for an old fella :) Be interested later if you cover this again - to get your take on using silver steel to make, say, a small cutter insert for a boring bar - degree of temper you'd apply to back off from too hard. Other thing is oil vs water quench and your approach to that. Oh and - one other thing - making a spring!!! To some more of an art than a science! Thx for another great video.
The hammering you refer to is probably making wrought iron from bloom? Prior to blast furnaces (which make pig iron - high in carbon 4-5% - brittle as hell), bloomeries avoided getting too much carbon into the iron (
A truly excellent tutorial, has summarised most things I 'know' in a wonderful, concise, clear video. You have my respect sir!
Very Nice Video, I really liked it. Seems you know what your talking about. (+1 : 1,273)
So if I buy 1095 Blue Tempered Spring Steel from McMaster Carr, which I'm going to be doing Friday 05.02.2014, Will it be very strong? I want to make lock picks, and I want very nice steel, because I'm making the shank of the picks 2mm to 1mm. They say that the Hardness is C44-C51, which according to there chart is between hard & very hard, where Tungsten is like a C79, but they don't have any Tungsten in the thickness that I want, 0.025" I would like to ask you, how would I go about cutting the 1095 Full Hard Tempured Shims (Item No. 9014K67) ? Would I just use an Abrasive Cutting Disk for a Dremel or Right angle grinder?
This is very helpful, feels like I'm in school or uni. Thanks for the upload!!!
That file trick is pretty handy, I noticed when trying to file a hard steel, It felt like there was no progress, it was smooth.
I did learn annealing in work experience at a jewellery shop where you heat the silver up then let it cool down slowly, then you can work on it like draw silver wire through different size holes to make the wire thinner. Pretty cool stuff.
exactly what I was looking for. Thank you for the explanation.
Thank you for a clear explanation, the file test is most useful and I have used it after hardening a small hole saw bit.
Thanks for the video!
I've a question: what if you were trying to soften the steel, but maintain elasticity?
ie to make it deform elastically at lower loads?
would longer cooling times help?
Hey ben. I love this video, and I love the array of videos that I see on your channel. You say you're a big hobbyist, and I feel sort of similarly. I'm wondering how big of a shop you have. I'm also wondering how big of a shop you'd dream of having, and what kind of electrical feed you'd want...and all sorts of stuff!
I haven't bought a home yet that I'd like to settle down in...and heck..I might build mine...but I'd like to future-proof my shop plans so that I can build it once and call it good...if I ever make it to that point in life.
This is awesome, thanks for showing me this! I was trying to find information in this and you just helped me hugely!
Great work!
The testing method and examples really helped explain this in a simple way.
thanks
Thank you so much for helping me understand tempering and hardening steel in an easy and practical way, although i'm not clear 100% because i'm not familiar with some of the terms that you use. But it is very good actually.
Great video, very useful for a blade I am making.
Im 15 and i just learned more information in 17 minutes 29 seconds than i was taught all day at school today GREAT JOB ben keep up the amazingly educational and intriguing videos:)
Hey Ben, I was just contemplating making my own compression coil spring for a mountain bike and came across this old video -- great explanation! Also, a good resource describing various alloys and their hardening properties is Machinery's Handbook. Now if I can only find an annealing kiln...
awesome !!! ....... I am from mechanical branch ...so I expect more technical terms relaed to CCT and TTT ... however your explanation was fantastic
Wow, that was really interesting. I had seen a bit about it during my chemistry undergrad, but not as in-depth.
Thanks!
Excellent video. Explained very well. Thank you.
And then there is work hardening that also needs to be annealed so it doesn't break, like working copper, where if you form it enough without annealing, it will fracture from hardness.
EXCELLENT!......highly useful and well delivered information, Thanks Much!
Might want to write Closed/Captioning yourself (or not).. Auto-generated said about the steel color changes (@ 12:05 ) "..it's actually quite - *_ineffective_* - and decent means.."
i have heard about diffrent condition of heat treated low carbon steel such as "817M40 PD 970 CONDITION 'V'",can you provide me heat treatment cylce to reach condition V
I want to harden some 3/8" wide copper strips to make a leaf spring for a 32" long model of a a 1929 Miller race car. I will have approx 5 layers of copper for the leaf springs of approx. 7" in length.
I want some spring action, this piece will be a static display, but would like a bit of spring back should the suspension be pushed down.
Help is welcome,
Dale in Indy
Best explanation of the hardening proces I've seen so far. Easy to understand even for a noob :)
Hi could you do a video on Cryo Hardening? I love the subject and think others will too.
Wow! I'm new to knife making and was having trouble understanding exactly why the heat treating and tempering are done. Your video made it super easy to understand. Great job!
Been confounded on heat treating and annealing steel and glass for a while before this.
Than thanks.
what do you think about the 80CrV2 Steel blade knife ?? for Survival - Bushcraft/Outdoor knife use ?? do you think is it durable or not ?? whats the best stone to sharpening the blade ?? 80CrV2 Steel knife blade is it weak or is it strong ?? thanks
w1 tool steel from mcmaster is b95 medium hardness. low carbon steel is b70 medium hardness. apples to oranges but a rough comparison of as delivered hardness. both have very similar yield strengths of 55,000 psi for w1 and 54,000 psi for low carbon steel
Excellent video! Next time your bucket overflows, replace with piece of Uranium or Plutonium - should be heavy enough!
Thank you very much for making this video.. very easy to understand and very useful
Just when I thought I knew everything...
I have a question I think you may have the answer to, or point me in the right direction. I need to find a metal (preferably 1/2 rod) that can be bent and welded to a vehicles exhaust system to prevent certain expensive parts from growing legs and walking away. Thefts of this nature seem to be a huge issue right now. It would need to be so hard that a Sawzall blade or grinder would have a very hard time getting through. What would you recommend for this situation?
Great video.
1. Heat steel to white hot, then quench in liquid nitrogen. Steel will shatter with the slightest touch.
2. Bet someone $100 you can break steel with your bare hands.
3. Repeat until Jeff Bezos.
You mentioned your very strong piece was tempered at 300C in your kiln, was that for 1 hour and was that after heating it to 800C and quenching it? What of the speed of the heating process, is it important to pre-heat the kiln for temper so it is brought up to the right temperature as quickly as possible? If it takes as long as 10 seconds of cooling to ruin the hardening, why is it that any steel is rated for water cooling when oil cooling is plenty capable of cooling it faster than 10 seconds? Does cooling it faster make it stronger aswell? What happens above the 800C hardening target? Is getting further below ~150C more beneficial?
Yes It was very helpful in deed !
See if you can have a video about tempering steel individually ,because I think lots of people want to know that, and the reason is that tempered steel has less impact on tools' and sandpapers and blades' ,,etc .
I'm a beginner in metal work and knife making (epidemic illness these days') and this kind of information specially is helpful for me and people like me with limitations in tools and space for work.
The more we know the easier we can deal with limitations' !!!
Thank you
Thanks I'm an amateur knife maker currently making a blade out of a leaf spring, so this will help a lot. I thought you did a great job explaining.
Usually, the x axis is the strain for a tensile testing graph
I thought the same thing. I've seen this done before and it always throws me. I don't know why they do this.
Here's where I display my naivete. Why is low-carbon steel cheap? I assume it has more to do with the process of attaining the level of carbon necessary, rather than... you know, finding some carbon to put in there.
PMMA is used in our lab for conductive flexible thin films. Coat a glass substrate with it, deposit the material and coat it again. Then you can get it off, provided you have a sacrificial layer beneif the first PMMA layer.
Beautifully done overview of an apparently touchy subject. Lots of misinformation out there. I feel like I get fine performance using my normal kitchen oven, but always verify the temperature with the oxide color the steel shows. I also recenrly learned about a phenomenon that I have seen many times while quenching -apparently shadow passing through steel as it approaches an orange color is actually the carbon going into solution. It seems to happen at the right temperature - I'm just wondering if you could confirm or deny this.
Any chance of you doing a video on sharpness? Asked my father recently about sharpening, and he says there are 2 schools of thought on how to do it. One school says "only sharpen one side" the other party says "sharpen both sides". The single side party says "sharpen one side, then remove the bur on the other side" The double party says "sharpen both sides, it will leave a small bur but it doesn't matter." I'm curious what both methods look like under a scanning electron microscope.
Such a clear and understandable explanation. Thank you very much.
Very informative and explained in the simplest manner. Would you be able to advise me on a heat treatment related subject ? I want to manufacture a steel tube that would have flexible expanding feet at the end and axial splits across diameter for the reason of radial expansion. I am working on a project to design a temporary single sided fastener for aerospace assembly. My question is that how to manufacture such flexible clamping fingers in a collapsed position which can expand through a driving mechanism and collapse back too again.
You can show use of that much better that my professor lol!
How suggestion for you, could you do a movie using the tension deformation using temperature too, to generate a tension, deformation and temperature graphic.
Sorry if a can't be clear, my English is not very good, yet lol!
I have a ratcheting lopper..
The bad part is the tempering of the blade.
Overall the blade is good except for the teeth, gears or cogs..
They break off but the blade maintains an edge..
I'm guessing by your statement, the heat treating of the blade, makes the gears brittle, but it benefits the edge..
It would be nice if the product was heat treated individually between the edge and gears instead of buying a new blade once a year due to broken teeth.
That very last bit seemed confusing to me. You are saying that a very very low, almost negligible carbon percentage is 'cheap low quality' steel, around 1-2% is 'good steel' but as you get higher quantity carbon in your iron... it's just cast iron? What if the absolutely no carbon, even just pure Iron? Apart from that, amazing video, really informative and well presented. Thanks!
Ben, I made the wire you are using from mc master-carr!
At Universal Wire Works, we make wire primarily for welding. Drawing and straightening.
I have done many similar experiments. Most annealing only requires reaching the "annealing temperature" upon which a "solution anneal" occurs and then it doesn't really matter how quickly you quench the material from my experience. I would really enjoy discussing my research further with you.
What's the application you need the wire for? You might not need a high carbon.
McMaster has some 1065, 1075, 1080 which all harden up nicely. 65+ hrc out of quench. (the 65,75,80 is the amount of carbon. so .65%-.8%) They are not 1% but you don't need that. These are commonly used for swords and knives.
If your using a torch I would go with the 1080. It's eutectoid, meaning its pretty friendly to a torch. Where as most steels will give a poor HT without using a temp controlled oven.
Nope.
Only thing you can do is case harden (does not involve hammering), which involves soaking steel at around 1800*f for anywhere from 30 minutes to 6 or so hours in a carbon rich environment (IE charcoal, bones work really well). Even then you will only get a few thou thick of material with carbon and even then it will be a low amount.
Getting a high carbon content and a uniform alloy requires you to re-smelt.
Heating steel constantly doesn't really lower its carbon content. The temperatures you need for this to happen are at the melting point. Well past critical. Before that can happen you will run into issues with irreversible grain growth that will destroy the steel anyways.
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Also color is a poor judge for HTing anything, A difference off 100*f can produce poor results but the color difference can't easily be seen.
When tempering colors can get thrown off by contaminants on the steels surface.
in that case yeah - i assumed you had soem premade object/item you didnt want to change.
The thinner the metal when you heat it in a chamber with a carbon source would allow it to penetrate deeper - or through the whole metal.
Blacksmiths dont actually add carbon - they still smelt it to mix with carbon or use pre carbonized steel.
Constantly heating the metal will lower its carbon content over time.
impurities in steel always make it brittle but in the same time are lowering the strength, similar to what ben draw at 6:56 but without the plasticity. most of the impurities are clumps of carbon, silicon minerals, dirt... i am talking about the old methods as shown here: watch?v=mprtHmEzXjI
by forging (hammering, folding, forge wielding...) your removing most of those impurities, and by mixing different steels and forging them together you get amazing properties, like the damascus steel.
The Colonial Williamsburg channel also has some good information about the production and craftsmanship of iron in the early US.
He could have made a do-it-yourself stress tester. Then each test would have produced its own graph of strain as a function of applied stress (or stress as a function of imposed strain), for a very powerful visualization.
He could have annealed a piece of that steel, just to show the effect of annealing, and the different plot it would produce.
He could have tested an actual aluminum sample, to show its different curve for real.
When I sharpen lawn mower blades, I use a file rather than motorized grinder to avoid hardening the edge too much. Seems like a shrapnel risk. I certainly have seen grinders take an edge to a blue color.
Also I have read that a bucket of wood ashes is useful for tempering a piece - slows cooling.
taking me back to school days I seem to remember, if you take the coat hanger steel say, heat it up then dip into carbon, you can case harden it, repeat this by working the steel and the harder it will get. used for knifes, swords etc in days of old.
My cousin was talking to me about how he was trying to harden some steel with his fireplace by heating it red hot and quenching, but he couldn't get it to work. The thing about some steels not being hardenable might explain why he couldn't do it.
Your statement about "what we mean when we say a material is hard its actually very strong" is sadly inaccurate. strength and hardness are two very different contrasting things. 14:22 Strength and Hardness are an equal trade off when dealing with a single material's variations without adding elements. Otherwise this was a great video. Very informative.
Has anyone told you that you sound like Android 17’s voice actor from Dragon Ball? 😂
The reason the ductile rod held more weight was because it allowed a fully plastic deformation in bending. The ductility allows the stresses to move inward where the entire cross section is plastic instead of just the outermost edges. On the other hand when the outermost section of the hardened steel reaches yield, the outer section fractures. The cross section is reduced, stresses are higher. The result is a quick failure of the entire rod. The strongest rod will allow for full plastic deformation of the cross section while "using" the extra ductility as strength in the hardening process.
It's also an interesting look into why we want some ductility.
ALUMINUM IN FREE SPACE CAN NOT FULLY PENETRATE STRUCTURAL STEEL AT SUBSONIC SPEED, PERIOD
I have had extensive training in metallurgy, and viewed this to review or add to. Still managed to learn a few details though.
this. this the most important part. the relation between theory and practice. there are a zillion things i know in theory, but when actually trying to apply them, all hell breaks loose and nothing works as intended
because the duration of the heat exchange has also an effect on the final properties of the material. Quenching in oil gives you a slower transfer thus resulting in a less strong steel but also less brittle.
I heat treated for years I enjoy running the Epson furnaces the most I was the best at probing the baskets of metals whenever they slipped on the elevator going to a oil quince I can take it 8 foot stainless steel hook probe around the sides of 0.1 stainless steel baskets and hang them without seeing what I was doing once the steels removed we had to load it into a draw furniture. Dixie barons had to go into deep freeze than into a draw furnace best of all induction heat treating :)