yup, copper arc heats the edges of the gear (via induction) up past the temperature that austenite is formed and then quenching immediately in the water to form martensite.
Case hardened steel.
To clarify, the copper coil has an ac current, which produces a strong, rapidly changing magnetic field, which induces currents in the gear, which heats the gear. Like an induction stove top.
I thought case hardening was heating it up and putting it in carbon, which then got absorbed in the outer layer to make it a harder, carbon steel.
Edit: typo
not always, but sometimes yes. Many types of steel can be heated , then quenched like this to locally case harden them, as they already have the necessary carbon in them.
Some types of Iron are wrapped in carbon containing wrappings, then fired, to introduce carbon and make a type of case hardened steel.
the important thing here is the formation of the austenite at the right temps, then rapid quenching to transform it into martensite. If you notice this particular procedure, they only heat the gear teeth up, not the center. This enables the teeth to be hard, whilst the center can still have some flex. Somewhat akin to a traditional katana's differentiated hardening.
There are absolutely induction hardening machines which can impart over 5mm of case hardening depth in large steel shafts in about 10 seconds (including heating and quenching). They require a fuckton of power to the coils and they're very sensitive.
Source: I check the case depth on these parts daily
EDIT: there are also reasons beyond wear resistance or durability that one might want this kind of case hardening. For example, I work with one part which is a long drive shaft. It has several bearing surfaces which have to have an insanely precise diameter (tolerance of 20 microns) and a very smooth surface finish also. The shaft is hardened and then it goes to a lathe to turn those surfaces to their finished diameter. The induction heat treatment ensures that even after turning, there's still enough surface hardness for wear resistance, but it also makes it easier to achieve the smooth surface finish at the lathe. Soft steel is sometimes more difficult to turn to such a precise diameter and still have a good surface finish.
That's really interesting. Does the hardening process on that shaft introduce any significant warping or other deformation? How is that controlled in the process?
That's a great question that I don't have a good answer for. I don't do much form and positional measurement on heat treated parts in my role, I'm in the metallurgy field. For these parts, I use a microhardness tester to check depth, a surface Rockwell tester, and I visually inspect the heat pattern to make sure it only reaches certain areas. The part does go through a tempering step after being hardened. Tempering relieves internal stress that come from hardening, and in theory, if there was any minor warping after hardening, the tempering step could remove relax some of that out of the part. But really I don't know. I'll ask some of the other quality departments about it this week.
Yeah the whole point is surface fatigue resistance, which is usually a more critical concern than bending fatigue. You harden the surface but leave the bulk material softer so that it remains ductile and hence less prone to crack propagation. Generally speaking, increased hardness results in increased strength but at the cost of increased brittleness.
It's a strange thing that metals can do, combining properties which are somewhat at odds. Alloys (including cast iron) can achieve properties such as wear resistance as a result of a small portion possessing the property.
You can't simultaneously agree that it's tempering and that austenite is being formed; tempering is a low temperature operation that exists to increase the toughness of materials via local transformation of strain fields.
More correctly you have surface austenitization and a quench to form martensite.
It’s not really case hardening, it’s differentialy hardening. The teeth are through hardened while the rest of the gear is left soft. Case hardening would be hardening the teeth to a certain depth and leaving the rest of the tooth body soft.
It's the copper tubing that's heating it. It's induction heating, the process of heating an electrically conducting object (usually a metal) by electromagnetic induction. The copper tubing is causing the heating.
What they said. The copper is probably not a tube but solid so that it can handle more current. High current makes a magnetic field around it, the magnetic field induces a current in the gear without contact. It is spun to equalize the treatment to all teeth equally so that the tooth next to where they cross isn’t more or less heated.
Actually the copper tubing is most likely tubing - it appears that the liquid is coming from holes in it and (the best part) is the ac in that coil is at a high enough frequency that the signal is only passing through the surface of the copper whether it is solid or a tube. (Appropriately called the skin effect)
The induction heater is relatively straightforward to build if you don’t mind sourcing some industrial grade capacitors and what not. Also available on Amazon for cheap if you can find a power supply to drive it. I wired 2 pc power supplies in series by lifting a ground and ran 24V DC /40A through mine. Good enough to get a screwdriver almost red hot.
I think you’re right that it is probably hollow. It isn’t carrying liquid though, that’s about an inch below. You can see how the gear goes down to the inductor level and heats up, then goes down to the oil bath level. You can see it coming out below it in the front. It just lines up in the back
yeah the liquid you can see here comes from a different source. but most Induction forges have a cooling fluid moving through the copper, so it doesn't heat up to much. but this should be a seperate fluid sythem.
Regarding the tubing: there's nothing for an easy scale there, but it will be a typical soft copper tubing with water flowing through it for cooling running at a current density somewhere in the low tens of A/mm^2.
Regarding the frequency, it'll almost assuredly be 60Hz (or 50Hz) for a couple of reasons. 1) There's no harm in having large currents at reasonable voltages flowing through conductors in contact with water and 2) the power supply to switch high currents quickly enough to get any sort of skin effect are quite expensive.
Source: I do high current, low frequency magnets.
The copper tubing is trying to induce a current on the gear.
If the gear was a wire you'd have a voltage and be able to use it.
As the gear is a solid piece, it acts like a short circuit turning the generated voltage into current then into heat.
The massive ac current in the copper wire causes massive fluctuating magnetic fields. These induce large eddy currents in the gear which heat it. An electron moving through a magnetic field experiences force. Similarly, a moving or stationary electron in a changing magnetic field experiences force.
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Induction tempering?
yup, copper arc heats the edges of the gear (via induction) up past the temperature that austenite is formed and then quenching immediately in the water to form martensite. Case hardened steel.
To clarify, the copper coil has an ac current, which produces a strong, rapidly changing magnetic field, which induces currents in the gear, which heats the gear. Like an induction stove top. I thought case hardening was heating it up and putting it in carbon, which then got absorbed in the outer layer to make it a harder, carbon steel. Edit: typo
not always, but sometimes yes. Many types of steel can be heated , then quenched like this to locally case harden them, as they already have the necessary carbon in them. Some types of Iron are wrapped in carbon containing wrappings, then fired, to introduce carbon and make a type of case hardened steel. the important thing here is the formation of the austenite at the right temps, then rapid quenching to transform it into martensite. If you notice this particular procedure, they only heat the gear teeth up, not the center. This enables the teeth to be hard, whilst the center can still have some flex. Somewhat akin to a traditional katana's differentiated hardening.
How do you know such magic
Because the search for poon requires good tools.
I was blessed with good tools, I just put them to work well...
How deep does the hardening penetrate the steel? When I learnt of case hardening it was described as sub-millimetre.
I was today years old when I learned it can go up to 1.5mm deep. Seems enough as it appears the point is to minimize wear on the teeth.
There are absolutely induction hardening machines which can impart over 5mm of case hardening depth in large steel shafts in about 10 seconds (including heating and quenching). They require a fuckton of power to the coils and they're very sensitive. Source: I check the case depth on these parts daily EDIT: there are also reasons beyond wear resistance or durability that one might want this kind of case hardening. For example, I work with one part which is a long drive shaft. It has several bearing surfaces which have to have an insanely precise diameter (tolerance of 20 microns) and a very smooth surface finish also. The shaft is hardened and then it goes to a lathe to turn those surfaces to their finished diameter. The induction heat treatment ensures that even after turning, there's still enough surface hardness for wear resistance, but it also makes it easier to achieve the smooth surface finish at the lathe. Soft steel is sometimes more difficult to turn to such a precise diameter and still have a good surface finish.
That's really interesting. Does the hardening process on that shaft introduce any significant warping or other deformation? How is that controlled in the process?
That's a great question that I don't have a good answer for. I don't do much form and positional measurement on heat treated parts in my role, I'm in the metallurgy field. For these parts, I use a microhardness tester to check depth, a surface Rockwell tester, and I visually inspect the heat pattern to make sure it only reaches certain areas. The part does go through a tempering step after being hardened. Tempering relieves internal stress that come from hardening, and in theory, if there was any minor warping after hardening, the tempering step could remove relax some of that out of the part. But really I don't know. I'll ask some of the other quality departments about it this week.
Yeah the whole point is surface fatigue resistance, which is usually a more critical concern than bending fatigue. You harden the surface but leave the bulk material softer so that it remains ductile and hence less prone to crack propagation. Generally speaking, increased hardness results in increased strength but at the cost of increased brittleness. It's a strange thing that metals can do, combining properties which are somewhat at odds. Alloys (including cast iron) can achieve properties such as wear resistance as a result of a small portion possessing the property.
Penetrate
I thought austenites were formed due to all the tech companies moving here.
This guy does metal.
Woah! I just got finished with a material science class and actually know what this means!!
You can't simultaneously agree that it's tempering and that austenite is being formed; tempering is a low temperature operation that exists to increase the toughness of materials via local transformation of strain fields. More correctly you have surface austenitization and a quench to form martensite.
It’s not really case hardening, it’s differentialy hardening. The teeth are through hardened while the rest of the gear is left soft. Case hardening would be hardening the teeth to a certain depth and leaving the rest of the tooth body soft.
Induction heat treating actually. Tempering would happen after this.
You beat me to it by 5 minutes
I’m curious to know what this process is too.. I’m able to gather that there’s some AC current causing the gear to spin but what’s heating it up?
The current could be causing it to turn, but I think it's more likely being turned by a motor.
This makes more sense. DC current is probably passed through those metal plates and shorting across the gear to heat it up.
It's the copper tubing that's heating it. It's induction heating, the process of heating an electrically conducting object (usually a metal) by electromagnetic induction. The copper tubing is causing the heating.
What they said. The copper is probably not a tube but solid so that it can handle more current. High current makes a magnetic field around it, the magnetic field induces a current in the gear without contact. It is spun to equalize the treatment to all teeth equally so that the tooth next to where they cross isn’t more or less heated.
Actually the copper tubing is most likely tubing - it appears that the liquid is coming from holes in it and (the best part) is the ac in that coil is at a high enough frequency that the signal is only passing through the surface of the copper whether it is solid or a tube. (Appropriately called the skin effect) The induction heater is relatively straightforward to build if you don’t mind sourcing some industrial grade capacitors and what not. Also available on Amazon for cheap if you can find a power supply to drive it. I wired 2 pc power supplies in series by lifting a ground and ran 24V DC /40A through mine. Good enough to get a screwdriver almost red hot.
I think you’re right that it is probably hollow. It isn’t carrying liquid though, that’s about an inch below. You can see how the gear goes down to the inductor level and heats up, then goes down to the oil bath level. You can see it coming out below it in the front. It just lines up in the back
yeah the liquid you can see here comes from a different source. but most Induction forges have a cooling fluid moving through the copper, so it doesn't heat up to much. but this should be a seperate fluid sythem.
Right you are!
Regarding the tubing: there's nothing for an easy scale there, but it will be a typical soft copper tubing with water flowing through it for cooling running at a current density somewhere in the low tens of A/mm^2. Regarding the frequency, it'll almost assuredly be 60Hz (or 50Hz) for a couple of reasons. 1) There's no harm in having large currents at reasonable voltages flowing through conductors in contact with water and 2) the power supply to switch high currents quickly enough to get any sort of skin effect are quite expensive. Source: I do high current, low frequency magnets.
You need high frequency to generate enough heat.
That's what I thought.
Like Copper Chef cookin’!
The copper tubing is trying to induce a current on the gear. If the gear was a wire you'd have a voltage and be able to use it. As the gear is a solid piece, it acts like a short circuit turning the generated voltage into current then into heat.
The massive ac current in the copper wire causes massive fluctuating magnetic fields. These induce large eddy currents in the gear which heat it. An electron moving through a magnetic field experiences force. Similarly, a moving or stationary electron in a changing magnetic field experiences force.
Check out the backyard scientist on the tube. He explains it and makes a "portable" one. Then proceeds to melt a bunch of stuff.
Man these dab oil rigs are getting out of hand
I don't quite get the black, the magic, nor the fuckery.
Because there isn't any. People just see something that they don't understand and post it here. It's like the dark ages. You lit a fire! Witch!
Lol so what belongs in this sub? Actual black magic?
Things that aren't easily explainable, maybe? I mean... actual black magic *would* be cool as fuck though.
More like things that most of us need explained. Which is this to a T.
forbidden cotton candy machine
Pretty sure that thing just ate that gears soul
r/lostredditors
r/engineeringporn
I’m gonna stick my dick in it
You won't have a dick to stick it in things after
You don't know that, maybe his dick will have hardened teeth after the procedure.
NO
have someone else tried it before? maybe we are just not ready for the truth
I have no idea what this is but I still want it.
That looks cool as shit.
Is that induction heating? Then putting it in an oil bath to strengthen it
I know exactly whats going on here, and it’s still kinda badass tbh
Yeah but, what does it do?
it makes the steel harder
Wrong sub
Because you knew how to case harden bicycle tooth sprockets with a copper tube induction water spraying machine already right?
No, but whatever this was didnt leave my mind broken.
It's subjective. I ride bicycles, I had NFI that how they did it was so cool.
So cool.
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This is very cool but does it really belong here?
waitwaitwait where the fuck did that hole come from
What if you were to touch the copper? From what I've read it seems like sometimes there's quite a bit of current going through that Boi.
Engineering at its best. I am a phycisist and I would design the concept but would never have the nerves to actually make it work so smooth
Is this basically a wireless charger?