Glenn Posted February 1, 2017 Share Posted February 1, 2017 Does metal care how it gets hot? The blacksmith uses the fuel that is available to get metal up to forging temperature so it moved easier under the hammer. Wood, charcoal, coal, coke, peat, lignite, liquid fuels, induction (electric) heating and other heat sources or fuels are used. The fuel of choice is usually chosen in relation to what is cheap and available in your area. My question is, does the metal really care what is used to produce the BTUs in order to get it hot? Link to comment Share on other sites More sharing options...
JHCC Posted February 1, 2017 Share Posted February 1, 2017 Simple answer: no. Without the neural network to perceive different states (let alone to develop a preference for one over the other), metal simply can't care. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 1, 2017 Share Posted February 1, 2017 Metal cares more about the atmosphere it is heated in: Reducing, Oxidizing, Sulfur containing, etc...In the best of all possible worlds we would probably be working in a vacuum! Link to comment Share on other sites More sharing options...
Tubalcain2 Posted February 1, 2017 Share Posted February 1, 2017 12 minutes ago, ThomasPowers said: In the best of all possible worlds we would probably be working in a vacuum! Hmmmm. Astrosmiths.... Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 1, 2017 Share Posted February 1, 2017 No scale, slower cooling times,... Link to comment Share on other sites More sharing options...
Kozzy Posted February 1, 2017 Share Posted February 1, 2017 To add to Thomas Powers, yes the atmosphere is critical. I do parts for some high temperature industrial systems for brazing, heat treating, sintering, and sometimes pre-forged part blanks. One common atmosphere to protect parts is disassociated ammonia, so the atmosphere basically becomes nitrogen and hydrogen to exclude oxygen from the parts being heated. You need to make sure any gasses from the chosen fuel don't introduce nasties in the burning process which overpower the NH3 or add unwanted herbs and spices which the atmospheric ions can't scrub, making burner adjustments and quality of fuel used critical to the metal being heated. The latest industrial job I'm working on is heating aluminum doughnuts to annealing temps which are then ring rolled to be machined into fancy wheels. Because temps are only about 1000 f, things aren't as critical as one would see in hump furnaces for steel or sintered parts. One other aspect of fuel that can be critical is the exposure temperature: It takes time for heat to penetrate the part so hot fuels or burners which provide too much high temperature exposure to parts can easily over-heat the surface while the core is still a bit cool. This can introduce stresses into some shapes which will distort PRIOR to any work being done and obviously cause surface damage if not controlled. For example purposes, that's why using an arc or plasma as your "fuel" to heat is likely a bad idea because the metal WOULD care about those ultra-high temperature sources in relation to most processes other than liquifying. Although both of those issues are a bit of a side-route with regards to the original question, they are effectively ways the metal being heated does care about the nature of the fuel and how that fuel and atmosphere is managed to heat the product. Link to comment Share on other sites More sharing options...
SmoothBore Posted February 1, 2017 Share Posted February 1, 2017 From a much simpler perspective, ... I'd say yes. In solid fuel forges, the material is immersed in a virtually "non-directional" heat. While gas burners always have hot and cold regions. Yes, there are ways to overcome those issues, ... but there is no doubt they exist. . Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 1, 2017 Share Posted February 1, 2017 back to the old: Conduction, Convection and Radiation! Link to comment Share on other sites More sharing options...
rockstar.esq Posted February 2, 2017 Share Posted February 2, 2017 Taking a different approach to this question, it occurs to me that chemical reactions, friction, pressure, and resonance can agitate molecules to very high temperatures without resorting to combustion. Getting metal up to forging temperature with any of those approaches would potentially change the properties of the stock beyond physical dimensions. I don't recall which IFI member posted the video, but they took a bit of room temperature round stock to hot enough to light a cigarette using nothing more than their hand hammer and anvil. That was impressive to watch on many levels. Link to comment Share on other sites More sharing options...
Marc1 Posted February 2, 2017 Share Posted February 2, 2017 No need for the video, you can do it yourself with a 4mm wire and a hammer on the round horn, just keep on pounding fast Link to comment Share on other sites More sharing options...
Glenn Posted February 2, 2017 Author Share Posted February 2, 2017 It was a video by Glenn Moon of OZ. Link to comment Share on other sites More sharing options...
Frosty Posted February 3, 2017 Share Posted February 3, 2017 On 2/1/2017 at 2:25 PM, ThomasPowers said: back to the old: Conduction, Convection and Radiation! Induction is none of the above. Frosty The Lucky. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 3, 2017 Share Posted February 3, 2017 Correct as that is not a method of heat transfer; otherwise we would also have to add in resistance and we know that is futile! Link to comment Share on other sites More sharing options...
JHCC Posted February 3, 2017 Share Posted February 3, 2017 38 minutes ago, ThomasPowers said: Correct as that is not a method of heat transfer; otherwise we would also have to add in resistance and we know that is futile! Besides, it only works in your ohm forge. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 3, 2017 Share Posted February 3, 2017 Now you have me thinking of my Grandfather: Moultie Amster Powers Link to comment Share on other sites More sharing options...
rockstar.esq Posted February 3, 2017 Share Posted February 3, 2017 15 hours ago, Frosty said: Induction is none of the above. Frosty The Lucky. I believe that's incorrect. Radiation is the emission of electromagnetic waves or subatomic particles. For example, an inductive cooktop generates an alternating radio frequency waves (radiation) that induces eddy currents in iron bearing materials that generate heat as the currents flow through the resistance of the material. Link to comment Share on other sites More sharing options...
Frosty Posted February 3, 2017 Share Posted February 3, 2017 21 minutes ago, rockstar.esq said: I believe that's incorrect. Radiation is the emission of electromagnetic waves or subatomic particles. For example, an inductive cooktop generates an alternating radio frequency waves (radiation) that induces eddy currents in iron bearing materials that generate heat as the currents flow through the resistance of the material. You're right and I didn't even put a qualifier in the sentence. Boy am I slipping. How about friction? Frosty The Lucky. Link to comment Share on other sites More sharing options...
Farmall Posted February 3, 2017 Share Posted February 3, 2017 Well, I think both of you are correct, it's just a matter of perspective. Inductive heating is a function of both the electrical resistance of the material being heated to generate heat as explained by rockstar.esq, but is also a function of the magnetism of the material as the waves are "electromagnetic" - the electro part heats by resistance and the magnetic part heats through hysteris losses - as the alternating current flips the magnetic poles back and forth, these losses generate heat as a by product. That's why you need magnetic pans for an induction cooktop whereas you can use any type of pan including glass for radiant cooktops. I would assume (but have no empirical data to back it up) that it is called inductive heating because the heat is induced in the object itself, rather than transferred directly through contact. So, it really depends on how we interpret the term radiation as in the earlier "conduction, convection, and radiation" Since induction "radiates" electromagnetic waves, radiation is involved. However, I think that we are using the term for "radiant energy" which is a different type of heating than induction. Look up Inductive versus radiant cooktops for an explanation of the difference. So, if "radiation" is referring to "radiant energy", Frosty is right. If "radiation" is the emission of waves, then rockstar.esq is right. Just my two cents worth and worth every bit of what you paid! Simply put, Friction creates heat through the elastic collisions of the surfaces and the release of the kinetic enrgy from those collisions. So, the greater the number of collisions and the faster they occur, the more heat. Rub a piece of steel with 60 grit sandpaper as fast as you can and feel how much it heats, versus touching it to a grinder with 60 grit sandpaper or disc. Heating is all about getting something more excited than it is - ever notice how hot you get when in an argument? The faster the atoms move, the warmer something gets. That's why all motion stops at Absolute zero - no energy is being transferred, created, or stored. The atoms simply stop. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 3, 2017 Share Posted February 3, 2017 Well I was mentioning the methods of heat transference from my old Thermodynamics days: Conduction, Convection and Radiation I can't recall a material that transfers heat by emitting radio waves or magnetic waves. Heating a material with such waves or by straight resistance was a different area than what I was describing. Link to comment Share on other sites More sharing options...
Farmall Posted February 3, 2017 Share Posted February 3, 2017 Thomas, you and I shared the same Thermo teacher apparently. Using induction or microwaves to heat something was all new science to me that I had to learn after college. My heat and mass transfer class didn't really go into all that - but, at the end of the day, doesn't matter how it gets there, but Hot is Hot! I think you had the best answer to Glenn's original question - the metal doesn't care how it got hot, but it does care about the atmosphere it got hot in! Look at welding processes after all - it's all about the atmosphere created by the fluxes or gases etc. whether it's Mig, SMAW, DSMAW, or even explosive welding (which is really neat and how they make metal for the planchets that our coins are made from like quarters and dimes -here's a neat link that describes it => Explosive Weldiing Presentation ) Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 3, 2017 Share Posted February 3, 2017 Farmall; I live within hearing distance of the explosive pads at EMRTC (Energetic Materials Research and Training Center) at NM Tech university. We have explosive repousse and explosive welding art all over the campus---I attended a lecture given by one of the "early" artists to use explosives and remember her complain how the cost of plastique has quadrupled lately... As far as "practical" uses I'm impressed by the Steel/Aluminum pieces allowing you to weld up ships using both materials Link to comment Share on other sites More sharing options...
rockstar.esq Posted February 3, 2017 Share Posted February 3, 2017 Farmall, I think your explanation was very good. It's called "inductive" heating because the heat is a function of electromagnetically induced eddy currents. It's generating electricity within the iron-bearing metal. As these currents encounter the resistance of the metal, the electrical energy is converted into heat. One of the "aha" moments for me in physics/science was when I realized the first law of thermodynamics applies to a heck of a lot more than just "hot or cold". I sorta knew that if you shake the xxxxxxxx out of something and it will eventually make noise, magnetic fields, light, or heat. It was semi-amazing to realize that energy can move in any direction. The physical properties of the material might make the losses greater in one direction than another, but that doesn't change the energy involved. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 3, 2017 Share Posted February 3, 2017 "You can't win"; You can't break even"; "you gotta play the game"! Link to comment Share on other sites More sharing options...
Farmall Posted February 4, 2017 Share Posted February 4, 2017 Thomas, thank you for the discussion on the explosive artwork. I did not know about it, but after you mentioned, I used my googlefu to find out more. Great stuff to say the least! One of my senior thesises was on the use and types of explosives in construction, so I have always had an interest. Hopefully I can get out that way someday to see it done! Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 4, 2017 Share Posted February 4, 2017 Check with EMRTC about when they host an open house, (rare but good BOOMY fun)! The were also experimenting on making industrial diamonds using explosives once had an inversion bounce the boom back into town so they had to tell folks what was going on... And if you are in the area....look me up! Link to comment Share on other sites More sharing options...
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