Heat Treating, general discussion

I should probably start a separate thread just on work hardening as that is a topic that does not seem to be well understood. There are at least two kinds of work hardening. The first is based on the idea that a crystal of metal can be deformed resulting in "misalignments" of the atoms within the crystal. These are called "dislocations" by metallurgists because the structure of the crystal has been dislocated relative to its most stable arrangement. Note that this is not the same as the change in structure we get via the transformation from austenite to martensite. This is simply taking the crystals we have at room temp and deforming them. The dislocations are happening …

Sorry if this has been talked to death, but I did a search but didn't find a lot. I'm getting ready to try to make a timber-framing 1-1/2" chisel from (I believe) 5160 from an old school bus leaf spring. My online searches lead me to believe oil is the best quenchant for this steel. I see "Parks 50 oil" recommended here, and here I see "Parks AAA, Mcmaster 11-second, Houghton G" recommended. Short of using free drain oil, I would like to buy something economical for my purposes. And since I have close to 100# of this leaf-spring material, I would like to find an oil that works well and stick with it. What oils are you folks using for quenching? And can…

Hi, Thought I would show my HT Oven made from a Toaster Oven... Opened the casing up and direct wired the Elements and added some K-Wool around the casing on 3 sides. Put in the Thermocouple and a firebrick to even the heat and she works pretty nice. Keeps a pretty even heat with no more than a 10 degree swing from what I can see. I also use this PID for my Cast Bullet Furnace and my Gun Kote Oven!

Hey, all, I want to get into antique bottle hunting by finding and digging old privy outhouses, and one of the tools used to locate them is a "T" shaped probe made of spring steel that you poke down into the ground and listen/feel for glass and different soil consistency. You can find them for sale online but a 3-footer will run close to $70 with shipping, so I was considering attempting to make one myself out of some 1095 rod. It looks like one popular one is about .270" diameter. My questions revolve around how to temper such a piece about .272" diameter x 36" long to "spring" hardness. I guess to harden 1095 steel, you would heat it to critical/non-magne…

Do I need to heat treat a newly forged hammer and if I do this is 1095. The next question is would i need to temper after heat treating? Thanks

Hello, I am a new guest a Dutchman living in Cape Verde. I want to experiment with some steel rings to harden it. It is intended for cylinder head bolts in an aluminum head. I want to heat the material on charcoal, but then the questions? How long, how warm, what color....etc. And is it actually possible because the steel I don't think has very much carbon. Best, caboverde.

Well, I am a blacksmith with 40 years experience and I still have a lot to learn. We had a shop fire 5 years ago. I was able to recover nearly all of my tools out of the ashes. One lingering problem was I was not able to successfully retemper my hammers. I retempered my chisels and could easily temper new hammers. The old ones would go through the process and still come out soft. I went on multiple forums and discussed this problem with friends to no avail. I described my process as follows: Heated them to bright red and let them cool slowly to normalize Heated them to above magnetic and quench in oil ( tried both Canola and Parks) They would not harde…

Hello fellow bladesmith, I've recently started a project of building a treadle hammer. I am conflicted on how to best secure my dies to the anvil and hammer. One thing I've seen online had been a mild steel base welded to a medium or high carbon die, then bolted to the top of the anvil and bottom of hammer. My real question is after preheating and post heating the welding of the mild and high carbon, do I need to heat treat my die to achieve the high hardness necessary in a die? I thought of doing a few thermal cycles with the entire base and die assembled, then heating it to non-magnetic and quenching in oil. Will this quenching destroy my welds? I hope my question …

So recently I was involved in a debate about steel, more precisely, modern carbon steels used in knife making. This may seem like a bladesmithing topic but I think it applies better to general forging of modern carbon steel. at any rate its a good study of material science. It started as I overheard some general conversation about forging a complicated knife shape vs stock removal to achieve the same shape. the argument was that in a "modern carbon steel" it dosnt matter whether you forge the shape or mill or grind it away, it would achieve the same strength once it was properly heat treated. this went against my general understanding of forging of parts, blades…

Hi, We do induction hardening of a part followed that induction tempering in same cycle. After induction tempering part is hot. Hence, we do 30 second air cooling then quench with polymer for safety handling purpose. Part temperature will be 80˚C before polymer quenching. We have checked part for any presence of crack after above activity. There was no crack observed. However, our customer objects that quenching shall not be done after induction tempering. We have explained them that part temperature will be lower during quenching and crack detection will be done. But customer is not accepting. We like to know technically that whether quenching af…

Distortion during normalizing of AISI316 a popular austenitic stainless steel used for good corrosion resistance. I am trying to normalize a sphere machined from a rod of 316. How do I control during distortion during the heat treatment.

[MOD NOTE: The following thread started out on the "It followed me home" thread, but is moved here to accommodate the discussion of testing and calibrating that started a few comments in.] Another mail call! Invested some of the money from my last commission in an infrared thermometer (goes up to 2,732°F/1,500°C) to take the guesswork out of heat treating.

I have a shaft to make for a mower gearbox. It has been unavailable for 30 years. I bought a piece of 0-1 water hardening drill rod and hardened it at around 1700° and tempered at 325° for an hour. The middle was file hard, ends came out soft. After more research another site said to harden at 1400° and I tried again, it is anealing right now and the ends seem hard now. Would the extra heat bozo the job? Double heat treat is good or bad? How hard is file hard at the minumum? This shaft has to roll on needle bearings and 58rC seems adequate, specs say I should be able to get 62-64rC. Doea all this sound right?

M2 steel 1190 C 1 hr and 620 C double tempering for 2 hrs. Etched using 5% Ni for 3 min. Around 100 um white region with big grains at the outside of the materials, the hardness is 200 HV. The brown region hardness is 750 HV. What could be this soft white region with big grains? How should I reharden it? Thanks!

I think I saw this in a video by John at BBF, where he was making tooling and annealed in vermiculite or wood ashes. I searched here as well and found the great comment by Glenn explaining Annealing, tempering etc in this IFI post: What did you do in the shop today? - Page 809 - Blacksmithing, General Discussion - I Forge Iron My Question is what ashes are good to use for Annealing? We burn all paper, wood cardboard etc. That is just part of farm life. All Plastics and rubber goes to the dump. And all metal gets saved for repairs or a scrap yard run. So would the ashes I create burning wood scrap, cardboard and paper pr…

Hi folks, I recently bought a Service Diamond Hardness Tester at an auction. Can't find any info on it and it doesn't seem to work. I was wondering if anyone has one of these it's a model 8blp, the problem is that the loading handle will only turn a few degrees then it comes up against very strong spring or possibly hydraulic resistance any help would be appreciated.

Hey guys. Seems like they same product is on multiple sites - like, Amazon, eBay etc - all described basically the same same way as large tomahawk & hammer/ mouse ax drift and made from ductile iron. My anvil is ductile iron and I love it but they’ll never be a time I’m quenching it lol - I did some reading on if you can quench when using as a drift and I seem to be getting varying answers….if I’m drifting with this and using it as a handle to work cheeks and all that can I quench them off? If not at a red heat then once it shows no color whatsoever?

Have an old Lindbergh furnace what is the reasoning that I am not getting case on my pieces

Just for the heck of it . . . I may build a very small power hammer . . . just to make a few things quicker and easier. I need two faces on it: one a "flat to flat" for making material extremely "flat" . . . the other "slightly rounded to slightly rounded" which would be for drawing out the material. I have an idea of how to make them so they would be easily removeable and changed . . . but will require me to use my little machine shop to work the steel. Therefore I need a steel I can work on with my little mill . . . then harden so it will do the desired work. I'm open to water harden / oil harden / whatever . . . have never done it . . . but will be…

First hammer head, didn't turn out too bad. I hardened it, and like an impatient boy, I bounced it, lightly, on the anvil a couple times. I have 2 cracks now. They run from the cheeks to the face. I just tempered it, cause who cares at this point. But is it weldable? I have mig and arc, would I have to grind a groove in the cracks? xxxxxxxxx Would I need to anneal first then reharden and temper?

Hi all, I’m building a large high temp salt pot kiln which is nearing completion. Despite my searching I haven’t been able to find answers to some questions I have about the salt itself and I hoping that the incredible knowledge base here may be able to help. I also hope that this information may be helpful to others in the future to safely maintain their systems. “Neutral” is a term often seen used to describe commercial salts. “Balanced” is another one. I haven’t found much information on what this means except some references to metallic oxides and other oxides building up in the pot which can be cleared by stirring with a graphite carbon ro…

Would it be a bad idea to anneal with crushed insulating firebrick from an old kiln? Also, is firebrick bad to breath in like ceramic wool is? I'm worried about firebrick degrading in the forge.

Went and picked this up today.

I made these hooks from a garage door spring, although far stronger than mild as is, I would to try heat treat them. my thoughts are veggie oil quench and temper in toaster oven. Any tips on hardening such thin stock? Thanks for looking

Hey guys. I want to build a guillotine tool. If I were to use fork lift tine for the dies do you think I should re heat treat entirely after grinding in the shapes I want? Or do you think as is they won’t be so hard as to chip and be dangerous? I have little to no heat treat knowledge by the way lol. Won’t they get tempered back a bit from the heat from grinding also? Making them a bit softer…