Case Hardening
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- เผยแพร่เมื่อ 1 มิ.ย. 2024
- Brought to you by the Machine Tech Video Blog!
In this video, Adam and Todd show you how to case harden low carbon steel. They cover:
+ Pack carburizing steel
+ Using a furnace
+ Basic heat treatment
+ Basic steel metallurgy
+ Hardness testing
Follow along and case harden your own parts!
Music by Andrew Applepie:
"Festivities", "Spirits", "Klicks", "Take Some Time Off"
andrewapplepie.com
Special thanks to Todd M., Sam O. and Laney College in Oakland, CA.
For more about Laney College, check out the website: laney.edu/machine_technology/
AND BE SURE TO SMASH THAT "LIKE" BUTTON! - วิทยาศาสตร์และเทคโนโลยี
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I learned a similar technique from Machinery's Handbook. The carbon material was combined with rock salt. The salt when it liquefies allows freer movement of the carbon, and creates a reducing atmosphere minimizing oxidation. Hold temp at 1800* 6-8 hours, reduce temp to 1400* for 2 hours. Remove from furnace and quench parts in water. Follow up with a draw temper at 400* for 1-2 hours. It's best if you can suspend your parts in the salt/carbon solution. I was making specialty hammers for metal smithing which needed case hardening. These already had eyes for attaching handles and I was able to suspend using baling wire. Heavier parts could be suspended using slings of several strands of baling wire. This whole process allows for more even, deeper penetration throughout the parts being treated. I never did a Rockwell test, I do know that once treated, then mirror polished my hammer faces never marred or deformed.
Seems like it would give you a very nice, thick case (100 thou or more). Not that common in industry. I do many "shallow case" jobs requiring only 1 hour at 1700 to meet the spec. I've only seen a few very deep case jobs. Thanks for sharing that old recipe.
The song in the beginning gave me inner peace and taught me how to find calmness. I have been emotionally healed and cannot express my gratitude enough for this gift. I come here just for it atleast a few times a week. Thank you.
I kinda got irritated by the music !
When you just pass material science course without knowing anything at all such as pearlite and its brothers and you suddenly find a video in which you learn a whole topic in just 8 minutes.
I’m being in love with this channel!
No shit. I should have watched this video in school! So information dense.
So true... education expects you to be interrested enough to find out more on your own i guess... but it lacks the part where it teaches you to do just that, available, free and fun ways to quickly go deeper and uncover much more interesting things full of other more interesting things...
Congratulations gentlemen,
As an “old” retired toolmaker, I have machined quite a lot of tool steels, that were “sent out”, and did some in house O-1. I have never done any case hardening. Your presentation is very informative, and presented in a clear and concise manner.
I learned this method in trade school in the mid-70's. It is quite effective, and a good way for apprentices to gain an understanding of metallurgy and heat treating, Very appropriate for making one's own tools without the expense of commercial tool steels. We were also using, along with the powdered charcoal, barium carbonate as a catalyst to speed up the process (As I remember, 10-20% CaCO3). Basically, what is happening is that carbon monoxide is generated to fill the sealed box, which gives the carbon to dissolve into the steel. More time gives deeper penetration. The early Mauser bolt action receivers and bolts were treated this way, as well as other makes of firearms. Even cast iron can be pack hardened.
I hardened my blocks by telling them their mama never loved them and life is a big fight!
@@emptychristbuddha but they hard af bro
Don’t you be sayin’ bout they Mama! Hmm huh!
I sprinkled viagra on my blocks
Aaaaaaahahahahhahahahahah
Yeah that should do it. That's pretty much my story and I dont even have real emotions anymore .
I've been using tools treated in this manner for forty years and just learned what it actually is. Thank you
can you case harden 300 series stainless?
Incredibly informative. You clearly explained the pearlite --> austenite --> martinsite process -- far better than any material science book I've ever looked at.
You need to make more of these videos! They're incredible!
Excellent video. Thank you for taking the time to make it interesting, factual, and succinct. I have subscribed because I like the efficient way you put these videos together. Great work all-around. Much appreciated. I like your sense of humor as well.
Holy cow guys, excellent presentation.
A newcomer to your channel. I appreciate the clarity in which you explain your subject matter, bravo and keep up the good work.
Excellent video. Thanks for taking the time to film and edit it and of course for positing it for our benefit. Keep up the good work! -Migs
Adam, your channel is straight quality!
What a great video! I am trying to learn more about steel hardness and its relation to carbon and this video was full of information and was very educational! Thank you and keep up the good work!
Love the Lindberg furnace. Chicago. Vacuum heat treat changed all that warping and carbon. Well presented video. Tool Maker of 40 years. Father knew ALL the heat treat methods. Good luck and make some big money with your knowledge.
Thanks - excellent informational video. I especially apprecieated the concise but complete presentation of the process along with the science!
excellent video! just subscribed ..love the thorough explanation of the process from start to finish..well done.
EXCELLENT explanation and covering diverse topics
Very much appreciate your videos and hope you will continue to publish. Thank you.
Great video. The animations helped me learn about the grain structures. All this time I thought it was called "Case Hardening" because the metal was put in a case. Now I know better.
Great video. I needed to learn about this for my manufacturing job. Thank you!
One of the issues with pack carburizing is the problem of getting the steel to pick up the carbon that the charcoal lets off. Commercial carburizing compound, like what you might buy at McMaster Carr, has additives to promote carbon absorption. I think one of those additives is calcium carbonate, but I am not sure. The advantage here is to absorb more carbon, therefore add more carbon per unit of time, giving you a deeper (thicker) effective case depth, a topic which you do not cover. With commercial carburizing compound, you get a harder, deeper case that responds better to quenching, ensuring maximum hardness and a thicker case. The minor disadvantage is the tendency to produce a "white" outer case layer, which is commercially too brittle, requiring a "diffusion" temperature cycle slightly below 1700F for a few hours before slow cooling. Also, you should be quenching in a fast oil (possibly a used motor oil for the poor man) instead of water to minimize the chance of cracking, which will ruin your part, requiring you to start all over machining another piece of steel. The reason why you are quenching in water is because the carbon from the charcoal briquettes was not being absorbed as fast as it could, requiring a more severe (water) quench to achieve a high hardness, at the risk of a higher probability of cracking the steel. Also, keep in mind to temper the steel immediately after quenching because some quench cracks are time-delayed, and will not occur if the steel is already tempered.
This is absolutely the first time i've subbed to a channel off of the the first 30 seconds of a video... Damn.
I did! I have heard that case hardening can also be done by quenching in oil after taking the parts out of the first furnace treatment. This is for a decorative finish on the steel.
YOU GUYS IS THE INTELLIGENT OF THE CHEMISTRY AND THE MACHINE
Great video. One of the best explanations of the metallurgy that I've seen. Thanks for the effort put into the comment responses.
I'm a subscriber.
This is GREAT for new people in machining, whether machinists or inspectors. The right amounts of practical knowledge and science.
I worked in commercial heat treat for 30 years, cool video 👍🏼
Excellent explanation, and showing. Thanks
We did this in High School. I was lucky. Forever grateful to Mr.Earl
Hammerston.
Great stuff! Very interesting processes.
Thank you for the very informative video. I just finished a couple of small forming dies that are subjected to fairly heavy loads. They turned out very well and solved a problem for me. The only variation to your procedure was to add 10% by weight of sodium carbonate to act as catalyst while carburizing.
I was most impressed with your choice of carbon and it worked. We used Kasenit in high school and I understand it is no longer available. There is another product available but i will be using Kingsford charcoal in the future.
Thanks again and keep up the good work.
I just joined your site because i think your presentation is great
Friends, I make these Carbon Granules for carburizing and tempering process. My contact is ventasduraco@hotmail.com, the product name is Duro Carbon 310
Wish there were videos like this when I did my machinist apprenticeship
Thanks! My friend works at a place that makes transmissions for airplanes and helicopters and he brought me some scrap pieces of 9310. Pretty sweet steel if I can case-harden it properly.
That was awesome! Great use of my time.
I did the same project in college but sadly got poor results as the carbon powder we had to use was too well used already and the carbon was leached out. Your crushed briquets are a better idea. Almost 60 Rockwell to 1/16"? Amazing! Well done.
this video really helped me to understand this process, thank you very much.
Great videos dudes! Keep it up!
Watching this on the day of my engineering A level helped a lot thanks
Real good stuff. Actually understood the practical application instead of just mugging it up from books
Your voice and cadence is perfect for spoken word songs
Awesome video guys.
Nicely done gentlemen.
hi adam, please do upload more videos on different types of hardening,grinding etc and more of bearings
That was an excellent video guys! God job!
Thanks for the info & demo. Was interesting. Good video.
Nice presentation. Subbed. More please😀
Best treatment of the topic I have seen to date. Now maybe do a Shop built Heat heat treat oven? Compete with controls thermocouples and wiring?
GREAT video.. I learned a lot.. You have a great vlog personality.. Thanks!
Great Job guys! Keep it up...
This was really well done 👍🏻
Good presentation!
Thank you very much. I now i understand and see case harden works.
Thank you, I've learned a lot from you than my school...
Almost as hard to finishing watching as an adult film. Amazing work gents. Really wanna fix up the C on an old J Stevens 12 GA Pap used as a "tractor gun, idk where to start, I can cold blue the rest.
So awesome content man! Please keep it up!))
nicely done i was a general machinist for 35 years and never run across this process
This is an excellent video! Subbed...
Now that's old school!!! Haven't seen that in years!!! 😊
I did this with a machine shop class in 1973, we all made a pair of parallels. I remember as if it where last week. I still use mine weekly. We dumped the whole lot still red hot into a tank of water.
Fantastic content 👍
Fascinating! This is some incredible editing and the explanations are very thorough and concise. Thank you so much for making this video, it's very helpful!
Amazing video guys keep it up
U people are doing great
Subbed! I’m definitely trying this process on some mild steel and try to make a knife out of it!
Very cool channel.
I'm in! 🤙
Hi Adam, thanks for the video, I think this is the most comprehensive video about case hardening in youtube. I want to ask a question about this process, will the process alter the dimension of the part? I'm going to make a precision part using mild steel, with tight dimension tolerance, the part will be about 60mm in diameter and tolerance of 0.5um.
Mr. Todd
Mr. Adam
Wow! So glad to see this vid. You peeps seem to know what your talking about. Thank you for clearing up some old misconceptions.
One question I havn't found the answer to yet, - inline with your process - quenching in water in fig 8 vs. quenching in warm used motor oil? Im thinking the carbon in the used oil would help out but maybe the idea is out of place here. Can someone help expand this thought please.
one more thing, thank you again for explaining the time, temp, carbon prep and hardness testing. All very important info. 1/16" Thank you.
I agree with Terry Davis.Best explanation of the metallurgy involved that I have yet seen.Well done and thanks for sharing.
Thank you Adam.
You have demystified case hardening for me.
I seem to remember a much more toxic process I did Once at tech decades ago.
Never to revisit...
Not with crushed BBQ brickets!
1018 is Soo much cheaper than tool steels!
And I like the idea of tough core with a hard case.
Now for a pair of electronic controlled ovens....
In order to color case harden and get really pretty colors gunsmiths would use a recipe based on cyanide salts. Really toxic stuff, and probably what you're referring to.
Might be fun to relate what you did the iron-carbon phase diagram and TTT diagram.
great...
please do more videos on surface treatments and heat treatments, threads, machining processes, material science......thnx
A good and informative video.
thank you for sharing, I learn't something today
1018 if hardened will run about 40RC, throughout. any tempering at all will, obviously, make it quite soft (250f draw is around 25RC, if memory serves). the "as hardened" condition isn't file hard on the surface like the case part would be, but would still produce quite serviceable blocks for all but the most abusive of alloys. don't do "mild steel" the disservice of dismissal from heat treatment unless carburized. it just won't get too hard to deform without fracturing. it also is limited in depth of hardness to about 1 inch wall thickness to produce uniform hardness. without the manganese content, it would be half that for wall thickness, and an "as hardened" condition of 30RC or so. the manganese encourages the carbon to remain in solution, so the cooling has a chance to "freeze" thicker parts before carbides drop out. but, within those limits, you can get 50 ksi working parts out of 1018, and single cycle heat treat to boot, lol
What quench temp and quench medium? I have heard of people hardening mild steel with the proper quench medium.
Thanks
I'm
I thought case hardening was a very thin layer. I didn't realise you could get really useful thicknesses of case using just charcoal.
Not something I need to do now but I'm definitely going to file it away in the mental locker.
Thanks very much!
Very informative video. Thanks for sharing.
What would be its HRC after carburizing (before quenching)?
Also, will you lose the high-carbon property of a case hardened steel when you anneal it repeatedly?
Patrick Tan it would be dead soft without quenching. Yes each anneal process would diffuse the carbon in the surface case
Great video. Do you do anything to burn off the oxygen in the box with anything wood chips etc? Or have you tried using foil? I have a few jobs to carburize and could use a few pointers. It it 8" Ø by 1" thick. Your thoughts please? Cheers from Canada.
Looks like you are using a nitriding furnace for your temper furnace. For this type of tempering, I use a toaster oven from WalMart. Plugs into a standard wall socket.
Good video guys!!
Great video! what does the treatment time depend on?
Can you link the next video about, "finishing on the surface grinder" in the description?
I learned a lot. Thank you.
This video has excellent production values. You deserve more views.
Great stuff
thanks for the video.. it helped me for interview
Hey guys, I have a quick question, if you carburize a mild steel knife blade fro a couple of hours, in order to succesfully finish the process does it need to be enmediatly quenched or air cooling it works just fine??
After the carburization I intend to clay quench it to make a hamon that's why I don't want to quench it after carburizing it and before apliying the clay.
Awesome video! What would happen if you didn't hinder air flow with the cement and alow oxygen in during the carborizing process.
If oxygen was allowed in the box the carbon (charcoal) would ignite and burn off thus creating a hell of a lot of smoke and depriving the steel of the carbon it needs to create the case hardening.
I've been making knives for years and this is the best explanation of grain structure and how hardening works that I've ever heard.
Excellent. Thank you.
Great stuff here Subbed.
For once I am impressed by a TH-cam presentation ! Very impressed, your tutorial is spot on with both the process, and the reason for case hardening, it is not always a requirement to give a second heating and quench ,but it does give a better grain structure, as does you tempering process, many thanks for a sensible and factual video, unfortunately most viewers of TH-cam will not appreciate the knowledge that you are imparting on them. Subscribing!
Excellent!
Two questions. Could you form mild steel into a raw billet so it sucks carbon all the way through? And can it be case hardened multiple times to get a good blade worthy steel like 1095?
hi ! thank you very much for the video, I would like ask, do you know what is the phase of the midde of the of the steel which wasn't cabunized? thanks
If you don't want to case harden this type of block, you can machine the blocks out of tool steel, which will still require a quench and temper to approach the hardness of the blocks in the video. From a practical standpoint, machining the blocks out of 4130, 4140, 4340 alloy steels will also work (after a quench and temper, without carburizing) (water quench 4130, oil quench 4140, 4340). They will be a lower hardness, but you will rarely, if ever be machining anything harder. By avoiding carburizing, you will bypass the problems a newbie will encounter. However, avoid stamping them to avoid a starting point for quench cracks.
Cool video
Might be a silly question, but if you're machining, rather than forging, the case hardened steel, how do you get the hardened metal to stay on the outside of the part? What's the point of hardening the surface if you're cutting off parts of the surface to make a tool?
Emil Sorensen: The only finishing these blocks will receive is from a very light surface grinding, to get the surface true, this will leave .030" of hard surface, you cannot machine the blocks when they have been quenched, the whole point of case hardening, as explained in the video, is to achieve a glass hard wear proof surface, with a strong malleable core, this is just perfect for things like gears, or parts subjected to impact stress that need to be wear resistant.
The material removal is just enough to true the part since it may not be flat and square after the quench. Carehardening, as used in firearms for example, seldom exceeds .005" depth since if deeper than this any thin sections may through harden and become brittle. Its possible to do deeper levels on blocks and other parts without thin sections and thus more can be taken off to true the parts and still retain the very hard slick surface. HOWEVER. The part must be intentionally made over size to allow grinding to proper dimension.
Cool vid! watch inhaling carbon dust though. This is how 6 guys at Crosman made hardened parts for 1920-50's pellet guns.
Thanks that was excellent!