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,

"Ok I hope that was helpful" You know damn well that it was helpful! Thanks a lot.

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.

This goes in my "Best lectures" hall of fame. I'd like to see a follow up that shows detail about deformation over time.

Wish I'd had this to reference during my materials science classes!

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!

A truly excellent tutorial, has summarised most things I 'know' in a wonderful, concise, clear video. You have my respect sir!

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.

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.

Your "bridge" got me to the point that I realized how much more I'd like to learn. Thank you!

for more than 20 years i am a engineer and this is the best way i ever see how hardening works good job interested inthe rest of you videos

Practice becomes chancy & theory becomes ivory-tower-boring when isolated. It is the hallmark of a very, very, good teacher to provide the missing link. Like you just did, and words fail me in praising you adequately. Anyway, cheers !

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:)

I went to a mechanical engineering university and none explained this stuff enough like you did in this video ben, they didnt show us any experiment too. another great and highly educational video.

Best explanation of the hardening proces I've seen so far. Easy to understand even for a noob :)

You are awesome. You probably hear that every day but you have so much knowledge. The greatest part about this is that you use this for useful applications. Your you tube channel name is 100% fitting. I wish I I had the "in" to just hang with you. I am a mental sponge and just like to learn how things work and you just put things into perspective. Thank you most people would PAY for this info for a instructor to fly through lectures leaving you confused. Thank you for what you do.

Extremely helpful to have the science behind the method

Perfect mixture of practical and info about physics involved... Was very helpful, thank you

I've been watching your videos for a long time and recently got interested in heat treating steel, it was nice to discover that you had this excellent explanation of it.

I'm an engineer long since removed from college. It's been quite a while since I've seen a stress/strain graph and you sir did a fine job of explaining it...better than I remember learning it the first time. The applied tests are superb and really help illustrate the theory. Well done!

Like many others I impressed with and grateful for this video in equal quantities. Thank you very much for posting it, you’ve filled many gaps.

this is likely the best and most informative video I've seen on youtube. Extremely concise and easy to follow. And super informative.

I had a bucket of confusing myths and random facts about this topic and your video was a great way to sort things out. Thanks for sharing your nerdiness

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!

This is great. It makes so much sense when you think about materials like glass in a Prince Rupert's drop. Thanks for the time you put into this Ben.

Yes. Thank you for this video. I was never quite to sure on all that, and it's nice to see it approached like this, with examples. It would make for a great in depth analysis review. Keep up the fantastic work!

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.

Great video, you cleared up load of things my father tried explaining to me as a child. Now all the pieces fit together.

Best I'v ever seen on the subject ! Thanks, professor.

Thank you for teaching. To my mind, teaching is among the most noble of professions.

This is probably the best explanation of the stress/strain curve...Well done!!!!

Great information ! ! ! You are an effective teacher, Thank You. I've looked at a bunch of videos, and you covered all the basics.

I just took a metallics class at Texas A&M and I approve of this video :D Very helpful, I'm glad you didn't throw crazy vocabulary around as that would have confused many people that don't know about this subject.

Excellent video. I had quite a lot of this in patchy background knowledge and this tied it together nicely. Thank you!

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.

You have a wonderful method of explaining complex issues. There is useful content in all your videos, regardless of topic, you are a fabulous teacher. I especially enjoyed / learned from this one. Thanks. Ross

Fantastic explanation of how hardening and tempering is accomplished. Thank you!

This has been a really useful bit of info. You explained something that has always confused me, and you did a good job.

Outstanding presentation. Clear, concise and extremely informative. Thank you for this.

Great work! The testing method and examples really helped explain this in a simple way. thanks

Thanks for showing us this Ben, superb presentation as always. I'm going to reference back to this one a time or two for sure!

Great explanation. I wish I had seen your video tutorial a few years ago. It would have saved me from a lot of hassle.

great explanation. thanks for the time to help others to understand the process.. all the best Patricio

Very well explained and concise, thank you for taking the time to explain this, specially with the didactic material. Cheers

i watched this to learn one thing and wound up learning so much more. Terrific presentation!!! Thank You

God damnit I love Ben Krasnow (in a professional way). Best explanation of hardening and strength of steel I have seen. Didn't spot any errors even. AND he uses SI units! Hurray!

What a helpful video. Your explanation of these processes will help me on a up coming project, thank you.

Hi Ben, I really appreciate that you made this video. Its a great introduction to the hardening processes, without being too overwhelming. Thank you very much! :) Michel

Just learning about heat treating and tempting. This video was great for this beginner. Thanks for such an informative video.

That was extremley helpful in demonstrating what you can find in textbooks. My sincere thanks as a current student.

Concise succinct and completely kick-ass! Good work.

This is my favorite video of yours! You should do more like it!

It is pretty rare to have the instructor who not only understands the material and can apply it, but can also actually teach or convey it to other people. If for some reason the students don't understand, repeating the same words again just doesn't work, other words need to be chosen to get the point across. I can only think of a handful instructors from high school and college who had this talent. I believe Ben has this gift.

This is awesome, thanks for showing me this! I was trying to find information in this and you just helped me hugely!

One of your most-excellent videos! Thanks

I went to the top engineering school in Canada and this was 10x better than my first year materials science class.

exactly what I was looking for. Thank you for the explanation.

Round of applause and a like..... Bravo! Perfect execution of explaining how the hardening and tempering process works. Now I can skip a class, thanks man I appreciate the effort good luck.

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.

Train wheel heat treating is pretty neat. They will only quench the outer rim of the wheel that makes contact with the tracks.

This sort of explanation was why I subscribed in the first place, great stuff to learn about and presented very well!

He explained it so well of what took me 3 weeks to study. Life.

Wow...best explanation I've ever heard! Thank you!

Explained very well. Great Job

Beautiful and informative video. Thanks!

Brilliantly explained, Thanks a lot Sir.

Wow, that was really interesting. I had seen a bit about it during my chemistry undergrad, but not as in-depth. Thanks!

Well. I must say, this is an excellent presentation of a somewhat complex and confusing topic. Well done indeed.

A very clear explanation of a complex topic. Many thanks.

Such a clear and understandable explanation. Thank you very much.

Thank you. Wonderful teacher. You made it very easy to understand, much appreciated

Thank you very much for making this video.. very easy to understand and very useful

Never knew Gabe from the office had this kind of knowledge. Jokes aside - perfect video.

best video on heat treatment. well done for sharing knowledge

Very nicely explained the basic idea. You could go into more depth, but that wouldn't be for the general public, that'll be for scientists and engineers. Keep it coming. Amazing content you've got there boss.

This was an excellent video. I very much hope you put out more videos of this sort.

Thank you for a clear explanation, the file test is most useful and I have used it after hardening a small hole saw bit.

Excellent!!! I hope you make a video explaining the TTT curve and explain things like austempering, marquenching etc. from the curve..

Very informative! Helped me to better understand the process and reason behind it. Thanks!

Did you make that kiln yourself and do you have (or could you make) a video about making it?

Very well done. Simple and to the point.

very nice experiment. really enjoyed your channel. thanks for sharing.

Excellent explaination of hardening. Thank you.

I love your videos, you always pick the coolest obscure projects man. I'm pretty sure you're some sort of wizard, though.

Thank you! Your work is greatly appreciated!

Always cool and informative! Thanks for another awesome video.

EXCELLENT!......highly useful and well delivered information, Thanks Much!

that was highly informative.. both theoretically and practicaly.. thanks

Great Knowledge sharing... keep it up

an exceptional piece of instruction. Thanks.

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.

Superb logical presentation ~ Thanks!

Excellent video. Thanks for making it.

I really appreciate your making this video! It brings to life the things my dad explained when I was a kid :P

Another informative video! Thanks! Everything I ever wanted to know and much more!!!

Quite enjoyable, thank you. I think that was well layed out and explained nicely.

Great video 👍 very clear and simple explanation thank you 🙏

REALLY GOOD EXPLANATION ,EVEN MY ENGLISH IS NOT VERY GOOD I'VE UNDERSTOOD 100 %,. YOU REALLY CAN TEACH. THANKS

This was a very helpful and informational video.

This was an awesome explanation. I appreciate this