Comparing critical temerature with non magnetic for hardening steel.

[@johnjude2677]

Again you help me with steel problems Thanks.

[@TexasGodot]

I just wanted to thank you for being an amazing resource and inspiration for blacksmiths everywhere

[@workwithnature]

That was very interesting. Will give that a try with the lower temperatures and work my way up after the non magnetic.

[@gdwright65]

John, you are doing an excellent job of running your channel and providing information that works for us all. Thanks for the hard work and thought you put into it.

[@maxprophet2401]

This may explain a few of my most aggravating and repeated fails. Thanks John!

[@WinDancerX]

Great vid, John! Having made and sold hundreds of knives [and using a heat treat oven to heat treat and temper] I expected your theory about non-magnetic and cheery red and quench were correct. They aren't accurate. Often not even close. I use daylight bulbs in my shop and still don't trust 'color'. Now that I no longer have a heat treat oven I use temp sticks for knives. I watched a knifemaker fail his ABS journeyman test after heat treating blades one after another in the same gallon of oil. The oil got too warm to cool properly and the blades broke rather than bend, even after proper tempering. You have done a HUGE service to smiths and knifemakers everywhere who care about quality with this one. Thank you! Dave

[@BlackBearForge]

Thank you for the comment, I am glad it was useful.

[@mikafoxx2717]

For basic carbon steels, if you start out with normalized steel, it'll go nonmagnetic when it changes to austenite even before the curie temp, which is when you wanna quench it, not just the curie temp. If it's not normalized you definitely need to soak it a little first. I think you can get up to 52100 by the nonmagnetic thing, at least if you heat slow enough to not hit curie before it transforms fully. Anything fancier and curie will limit you.

[@patrickwoolery6000]

Your advice at the end, to just practice hardening steel to learn that skill, is so important! The skills come with repetition, not with trying to use every single piece of metal you ever touch. It is well worth making something that you know you will throw away just to learn something from doing it. Thanks for the video.

[@ChristCenteredIronworks]

Great video John! This one is going to be a hot one ;-)and will draw in quite a few people..

[@BlackBearForge]

boo! 😂

[@manga12]

ah yes it holds not always true, heaven forbid something always work, anything to make life harder huh. but i reckon that it needs to be told so someone out there dont screw up their metal if it needs to be brought to critical but the magnet could not be relied on due to its complexity but not too hot that they torch the steel and its properties.

[@bruceprosser8332]

This was a priceless test video. The brick is certainly acting as a heat sink and is important to realize this. For knife making my Evenheat has a stand for knife shaped blades so you can have the edge up so you make sure you get a good soak on the edge. Love the technical aspects of what you are doing, keep up this great work.

[@Jeffrose_]

Always a thumbs up. Thank you. Older video but still very helpful

[@bret354]

bin watching you for only a couple months, learned more from you in that time than I have in ALL the other channels combined! Thank you!

[@BlackBearForge]

I am glad it's helping

[@colinwinters2747]

Excellent video jhon ! I’m so glad you did this. It sheads some much need light on the often crude “I can just tell” mentality of heat treating. Thanks again.

[@brianfalls5038]

Many thanks for a very informative video John. As always I really enjoy viewing your videos. You area good teacher sir! Keep up the good work.

[@clydeulmer4484]

Well done, sir -- excellent video. And don't worry about dry and technical -- I'm betting that there are loads of geeks in your audience who will love it. I'm not going to give up my Evenheat oven, but as an alternative I have a shop built propane forge with burners that are stable over a wide range of temperatures. I use a K type thermocouple and digital display to get the forge to temp, then soak until I'm sure my piece is at forge temperature. Clyde

[@joehenry511]

I am really enjoying this heat treat series

[@mikechapple2363]

One of your best videos. I appreciate the scientific approach. Very useful.

[@krustysurfer]

Awesome observations Bear! Thank you blessings and aloha

[@Qrunch]

Clever test and very helpful to know. Thank you John!

[@BlackBearForge]

Glad you enjoyed it

[@bruceprosser8332]

I have found that what you said about color to be true too. Lighting like you said it very true. I do it at night now. Again thank you!

[@egghead992]

John I am a beginner blacksmith and have only taken a few classes. One of our teachers tricks to gauging critical temperatures is to use salt. We sprinkle salt on our project and heat it in a low forge until the salt begins to melt and at that point we seem to be at critical temp then we quench. With 3 different applications it has worked just fine. Just passing this on. Maybe put some salt on a piece and place in your new oven and heat till it melts the salt to find what the temp. is. I think around 1400 - 1450 . Not sure about that. Bill Pettit

[@stantilton3339]

An interesting and complex subject for a video. I learned a few things. Thanks John, I'll be digging out my reading materials again. Great topic and video.

[@normandbujold6677]

Good video as always Jonh. Non magnetic will happen when ferrite is converted to austenite. The quenching temperature will be dictated by getting the carbides in solution. For carbon it is around 1475F. For chromium, vanadium, tungsten and others it will be at higher temperatures

[@anvilflyforge2965]

Thanks for all your great knowledge

[@3870TheDad]

John, another great teaching video!! Thanks again for all your work.

[@bentoombs]

Oh yeah.very good explanation on the temperatures on different Steel. And some possible consequences

[@williamcunha9136]

Awesome Video John, very interesting.

[@philipdunn7538]

Thank you Sir for all the great videos.

[@mattwyeth3156]

Thanks for you're reply

[@jeffbarkett366]

Awesome video John! You've addressed a subject that I haven't seen on any other channel. It's time to start experimenting!

[@joelkoonce8559]

Thanks again John, YOU DA MAN !!! For us beginners, this hitech stuff is above Our pay scale 🤣

[@baddogforge5181]

I love this series I've learned so much

[@rafaellastracom6411]

The old tricks using magnets to see if it has entered into the austenitic range is OK for carbon steels and very low alloy steels, like O1. The higher the alloy content the higher the austenitizing temperature. Thankfully with that new HT oven you don´t have to worry about that. For those that do not own one and have to HT the ´old-fashioned´ way help yourself out by sticking with steels that are more forgiving. O1, S7, 4340 among others have broad hardening ranges that yield good results, i.e. avoiding cracking and maintaining grain growth to a minimum.

[@dbissdude]

Excellent video. It has convinced me to use the kiln my mother has for glasswork, even though I have to travel to it, instead of using my forge. I've had luck in the past with O1 in the forge but I think it truly was luck so far

[@adampablodayc]

Excellent as usual,thanks again.I am thinking i need a pdf download of all your videos.

[@tryptaminezen3528]

Ferrite is magnetic below lower transformation temp. Loses magnetism at upper transformation temp as ferrite turns austenitic . There is a progressive magnetic loss from lower to upper transformation temps as the cubics are closer to face center cubics in the austenitic region.

[@loul7239]

So jealous about that oven. This was a very informative video and a great simple experiment. I’ve been using leaf spring (treating it as 5160) to make daggers for a friend. I practiced with some pieces using a magnet just as a guide knowing I had to be at least 100 degrees higher than nonmagenetic for decent hardness. Now I know that I was probably off. I got decent hardness in the quench and I feel confident I wasn’t too hot. Still.....my kingdom for an oven!

[@BlackBearForge]

They are nice. But it is also true that blacksmiths were making quality tools long before precision equipment.

[@loul7239]

Black Bear Forge I agree and will continue to try to perfect my heat treatment skills the old fashioned way. Still, I imagine Blacksmiths have suffered from tool envy ever since Gorgo found that perfectly shaped stone for shaping hot metal. I think my envy over that oven is in line with blacksmithing culture and history :)

[@beni2094]

Very interesting! As usual great video. Cant wait to see your next project. Would love to see you make do some more decorative gift ideas. Like your twisted ornament.

[@mikeywatts322]

great series of videos John, and impeccable timing too. this may be a fairly dry subject and all that, but i can see by the amount of comments and discussion that everyone is as keen as mustard and as interested as i am. i have a coal forge and did my first heat yreat that mattered today on a set of joinery marking knives and a scribe. they hardened a beauty and i tempered after a basic polish- when i noticed some small cracks had appeared on one of them! bugger. I'm thinking i should've tempered in the oven instead of a flame cos i reckon it cracked when i arrested yhe temper. either that or the water was too cold. i think im just ruminating now, btw.. yeah mate its a true science, and i tell you- being colour blind doesn't help! keeps it interesting though. thanks again mate for all the work you're doing for us

[@papymike6291]

good information John! Thanks for sharing.

[@Solemngolem]

I would really like to see a video where you use different methods like temp sticks, or a pyrometer to test hardening temperature and see how accurate these methods are.

[@hosiercraft9675]

This is a wonderful informative video. I have been looking on and off for years for some sort of temperature reader that will tell me the temperature in my forges and or if my hot steel. So far no luck. I do pretty well by eye, but some steel, like crome vanidium has a very narrow range between welding heat and burning. Thanks for all the teaching.

[@BlackBearForge]

There are some heat sensors out there, they are expensive and can be delicate. Check a ceramics kiln supplier. However they wouldn't work well in a coal forge.

[@hosiercraft9675]

Black Bear Forge I have both solid fuel forge and gas. I've only been using the gas forge 4 or 5 years, but I used it more because I can use it inside with ventilation. But thanks for the info.

[@leperejoe1536]

Good info to know.

[@johnnygeorge8385]

It’s interesting that steels lose magnetism around 1420ish but don’t regain magnetism again until around 500f. Maybe it has something to do with the percentage of ferromagnetic material but I would think the iron or fero part would always lose magnetism at around the same temperature regardless of the whole of the content of the metal / alloy. Thanks for the video.

[@manfoodchannel]

Hey this was good I havent understood this trick with the magnets I work on induction furnaces for 10 years so working with gray and white iron I always found it's magnet was always lost at low tems

[@nofunclub]

Thanxalot 5160 (leafspring) could do with some soaking time in the fire like o1 toolsteel Got a new batch of springs and my first o1 As well as a usb microscope Need to do some break tests with variations of heat and soak. Gonna be a learning session

[@BlackBearForge]

Feel free to share your results. I agree on soak time. I generally soak everything 20 minutes at 1200, then soak for 10 muinutes at critical temp unless the specs call for more.

[@BrianDaleNeeley]

I would like to see if your over thermostat is accurate. One way to check (more of a spot-check) would be to see at what point aluminium melts (1220 F) according to the temperature readout. I would probably place an aluminium can, a well-folded piece of aluminium foil, or a small block of aluminium in a terracotta flowerpot base (to keep liquid aluminium from going everywhere). Copper (1983 F) would be another easy to check metal. I would make checks slightly below the melting point (say 1150 - 1200 F for aluminium) to see that the sample hadn't become liquid, another check right at temperature, and maybe slightly above the melting point. It would also be interesting to check if a sample hardens AT ALL below its critical temperature, but still non-magnetic. I am not being critical of this video or this series. On the contrary, I have found it to be very enlightening already, and look forward to future installments of the series. Keep up the great work.

[@stanervin6108]

While that method sounds viable in theory, it may not be a good idea to do it in a heat treat oven dedicated to high carbon and/or alloy steels, as even a small bit of copper contamination can adversely affect the steel (I'm talking less than .05%). Wish I could remember the source of this information, think it was a Carpenter Steel heat treating book from the late '80's. The copper molecules will basically vaporize and condense into the refractory upon cooling, only to revaporize at the next heat cycle. Copper is very detrimental to tool steels causing brittleness if I remember correctly. Any real metallurgist please jump in and correct me if I'm wrong. 🐾🔥⚒ Edit >> I think I found the info: ispatguru.com/copper-in-steel/ it's a long, technical article,, but informative on the matter

[@newinventions9175]

If I do some bending on a tempered spring steel. Do have to heat up to it's critical temperature the part that I bended and tempered again or can I go and just tempered to the spring level. Thanks for answering my question

[@johntompkins147]

Great findings reveal, So is the brick heat sinking the wider piece? Should the metal be in a rack of some type to heat the metal properly? Thanks John for the work on this.

[@jeffreyquinn3820]

If it's a refractory brick, it would be insulating part of the metal instead of heat sinking, but the effect on the metal (if any) would be the same.

[@BlackBearForge]

Given a little more preheat and soak time the brick would reach the same temperature as the rest of the oven and it wouldn't matter. In use you just have to ensure that the working portion of the tool is not in contact as it heats. If the body of the tool doesn't fully harden it is not a big deal and is usually desirable.

[@lenblacksmith8559]

This is very good, and also a bit complex and hard maybe to try and determine these temps by eye.

[@BlackBearForge]

That is part of the problem we face as blacksmiths

[@lenblacksmith8559]

Yeah sure is mate.

[@desertdanblacksmith1394]

Hey John! always good stuff......What do you think about Infrared or Laser Temperature handhelds? for measuring how hot it is? I have really only found one that would go to 2700 degrees......It seems that maybe these "new fangled" devices could be helpful? Maybe a demonstration of these "thingys" if you can get some to compare? Maybe you could get one from Amazon and compare it to your oven? I dont have an oven with those precise high temps.....then you could return it if it didnt measure up? (DEFECTIVE ?) lol

[@BlackBearForge]

I have one that reads hot enough. But it doesn’t have the pin point aim to know wether you are checking the material, the forge or the flame.

[@tjjohnson310]

Awesome video im going to try and use my laser thermometer that i have for my grill to see how high it will read thank you for the idea

[@pascualvasquezjr.6285]

Great tutorial and analysis. What is your "must have" books on blacksmithing?

[@BlackBearForge]

Here are some thoughts on books kzbin.info/www/bejne/apa4eomlbKqFiNk

[@johnwinchell1029]

Thanks for the information. Is there a type of stick that melts at different temperatures when placed in contact with the steel piece of interest?

[@BlackBearForge]

They call them Tempel sticks I believe

[@mrsensable]

Interesting

[@dustinroberts6771]

Have you ever used 80crV2 for anything. That’s the steel I’m using but I’m new to all of this.

[@alanbuban9020]

so that seems to suggest that if you were wanting to anneal then just reaching a temperature where one looses magnetism does not mean it will be hot enough to properly anneal..or normalize.

[@BlackBearForge]

That is correct. You must reach the correct temperature. Magnetism is only an indicator in the steels that have a lower critical temp.

[@josephroberts7597]

I have found a pyrometer to be my friend when it comes to hardening without an oven...

[@drewhoward2975]

What about using decalescence as an indicator of critical temperature? My understanding is that this is a very accurate method. Thanks for the video!

[@BlackBearForge]

I have heard of that term, but never tried it

[@Rob337_aka_CancelProof]

4:01 wouldn't it be great to have a research lab with the ability to control barometric pressure atmosphere content and create a tunable electromagnetic field to do all of these experiments in?

[@ke6bnl]

very interesting video, I have an unrelated question? I was playing with my pneumatic rivet gun and put in a planishing bit for flattening sheetmetal and began to wonder if anyone has used this device to flatten and forge metal instead of the hammering technique???

[@BlackBearForge]

I have seen air guns used for decorative forging with chasing tools. But I haven't seen anyone move any significant amounts of material. Roy over at Christ Centered Iron works has been doing a series of videos on his rivet gun

[@ke6bnl]

I kinda lost interest in his videos. But will give it a try and see what happens, I do have a serious rivet gun, and even the smaller guns are used in machines to take the waviness out of hammered on sheet metal for auto body work, thanks for the response

[@Rob337_aka_CancelProof]

What kind of magnet are you using 5:25

[@jessehannah2989]

You should.make a video showing how to forge, grind and handle a wood slick chisel

[@BlackBearForge]

I suspect I will at some point.

[@alifetomake]

Interesting... I wonder if it's possible to test what differences it makes when it's non magnetic and hardened under, on, and above the proper temperature.

[@BlackBearForge]

Those types of questions could become a long term research project.

[@alifetomake]

Indeed! I would watch it, for sure. Even just a test on one or two steels could reveal interesting things, though...

[@kmccolly]

Would an IR thermometer be useful for determining critical temp?

[@markmyword1742]

At the risk of repeating a previous comment would it be safe to say when heating to critical to reach the proper hardning temp for basic steels would be to heat for a few moments past magnetic for a more optimal hardness? BTW great videos I've been learning a lot from them

[@BlackBearForge]

That pretty well describes the process. My point in the video is that it isn't very exact and becomnes less reliable as you move toward more complex steels that require higher temps.

[@Loan--Wolf]

so how about a laser temp gauge should work i haven't used a modern one but my friend has a 20 ish year old one that bottoms out at 2k

[@BlackBearForge]

I find that they lack the ability to pinpoint in on the material being heated

[@Loan--Wolf]

i just thought might be a better indcater than the eye or a magnate but i am not the blacksmith and thats why i asked thanks for the reply

[@BlackBearForge]

Loan Wolf It does seem like the ideal solution. I bought a real nice one for that purpose and was disappointed it didn’t work that well.

[@mattwyeth3156]

Great video would these tests very by a very larger amount in Cole or gas

[@BlackBearForge]

As long as the temperature can be maintained it would be the same. The trouble is coal forges and most gas forges cannot be controlled accurately enough to hold a specific temperature.

[@skininktattoobekasi3763]

Mr . Im from indonesia. Can you tell me . How to making knife . Specialy in ht . Can be cut nails n the edge still in good conditions . .

[@gregorygraham8810]

Where you lose magnetism , is called the curry point of the steel . Great info .

[@donstephenson9474]

That's the Curie point, named after Pierre Curie, Madame Curie's husband. Using additional data (the critical temp. info) available for modern steels it allows a "seat of the pants" approximation of temperature so we smiths without a fancy heat treating oven can get by. :-)

[@hankatmaggies8819]

curry 😋

[@bobrees4363]

This may be a silly question, but do the various steels have the same color at the same temperature? I have never really liked the old adage "Heat it to cherry red then quench." As you stated, differing light conditions make for different apparent colors.

[@BlackBearForge]

AT 1475 all of my samples had the same color

[@dbissdude]

If they're all in the same lighting, they should all appear the same. But they don't all heat treat at the same temp, so the same color won't be right for them all

[@donoday8101]

Good video Unfortunately I am colorblind. So I have alot ro learn on the colors as I see them. Worst case scenario would be get the oven or send out work to a vendor . Thanks for the good info.

[@BlackBearForge]

A heat treat furnace would be a real benefit.

[@donoday8101]

@@BlackBearForge John that is on my wish list. But as a novice I will wait until I have the basics down and the proper skill set to justify the expense. Thank you for responding, I have learned so much from you already words can not describe my gratitude for what you so freely give to others. Bless you and your family.

[@neilyeag]

Interesting. I only work with O1, and harden in the forge. Some one told me, take it to non magnetic and then back in the fire for a "little" longer. That is pretty much my method. Seems to work OK, but I sure wished I had an oven to be more specific. I am curious John, you said the O1 lost at 1400, but could it have been even less than that? Did you check at 1200 , 1300 ect? Thanks for the good video on this topic.

[@BlackBearForge]

I did not check at lower temps and was surprised it had already lost magnetism as soon as it did. I was hoping it would be OK at 1400 and then I would work up from there

[@neilyeag]

Then theoretically it could be non magnetic at even a lower temp. I have hardness files, the best I can do. I try to see if I am at Rc65 or close after hardening. Wish I had a dandy oven like yours. The only thing about your oven I see is that the door swings down. I would be afraid that I would brush my arm against that!

[@BlackBearForge]

Most of them seem to be built that way, I'm not sure why.

[@davidsattler7810]

Do those metals regain magnetic ability once cooled

[@BlackBearForge]

Yes they are

[@WinDancerX]

John, where do you buy your french files?

[@BlackBearForge]

I bought these from Lie Nielsen tool works

[@garyd7217]

does your test hold true with altitude change

[@BlackBearForge]

Altitude may effect your forge but doesn’t effect magnetism or critical temperature.

[@jasonvolkert1938]

I use table salt. Once it melts on the steel I know I am about 1474°f.

[@BlackBearForge]

That is something I hadn't heard of before. Thanks for the information

[@jasonvolkert1938]

No problem. Thanks for all your great informative videos!!!!

[@christopherconkright1317]

Need a thermometer 🌡 that does 2500 degrees

[@milonguerobill]

Wouldn't a heat gun be a viable option for the guy without a fancy oven?

[@milonguerobill]

www.zoro.com/reed-instruments-thermometer-infrared-dual-laser-50-1-r2007/i/G0644572/ Sorry for posting the link but I read down after commenting.

[@BlackBearForge]

The link is fine. The problem I have had is that these read an overall forge temp well. But not the piece being heated and since it is very difficult to get a gas forge to run low enough it doen't really tell you when the piece being heated is at the right temp. It is even harder to get a coal forge to idle at just the right temp.

[@milonguerobill]

I was thinking of checking the piece on taking it out of the forge to see if it is at the right temperature , but I see what you are saying. I was a code welder for years and have used heat guns to check preheats and heat correction temperature ranges for years, mostly to make sure we didn't exceed temperatures that would change the properties of the steels we were fabricating things out of, mostly bridge work..

[@duesing6]

You should refrain from the closeups, your scaring my kids!