Heating Elements and Forges

[jackal]

Has anyone ever seen an induction heating forge?

I've seen induction coils get a 2cm dia steel bar to white hot literally in a few seconds.

They're not that hard to make either.

EDIT: oops didn't rouges post on induction heating! Silly me...

[imagedude]

Can't you make a simple nichrome heater exactly the same shape as the blade you wish to forge? if you could insulate it well enough it may be powerful enough.

[Rogue]

Ahh, interesting. There'll be a PM on the way soon

Jackal, based on the topic, what current/gauge would you recommend for getting to the 1400F range? Or higher still, maybe?

Imagedude, the idea about the shaped nichrome is interesting though it may limit the utility. As far as I remember, once the wire has been heated up then it should not really be restretched or changed, so it may not be reusable unless you are only making one shape. On the other hand, I would still be very interested if it would be capable of working.

[imagedude]

Make 2 heaters and place 1 on each side of the blade. Move them according to the size of the blade.

[jackal]

Ahh, interesting. There'll be a PM on the way soon

Jackal, based on the topic, what current/gauge would you recommend for getting to the 1400F range? Or higher still, maybe?

Imagedude, the idea about the shaped nichrome is interesting though it may limit the utility. As far as I remember, once the wire has been heated up then it should not really be restretched or changed, so it may not be reusable unless you are only making one shape. On the other hand, I would still be very interested if it would be capable of working.

To get a wire to 1000 C (1832 F) in static air:

wire diameter (mm)________________current (amps)
4.0__________________________________144
2.0__________________________________57
1.0__________________________________22
.75__________________________________13.9
.5___________________________________9.5
.25__________________________________4.3
.20__________________________________2.64
.19__________________________________2.48
.15__________________________________1.19
.14__________________________________1.78
.13__________________________________1.63
.12__________________________________1.51
.11__________________________________1.39
.10__________________________________1.30

This is for VIACROM 80/20 (80% nickel 20% chromium).

You should be aware that if your using nickel-chrome resistance wire, you need to make sure it isn't exposed to any sulphur which can make it brittle or even burn out (unlikly it'll burnout to be fair).

Also it melts at 1400 C.

If you want to work out the resistance at various temperatures the specific resistance at room temp is: 109 ohms/cm

And the temp. resistance coefficient is 6*10^-5, per degree C.

Bare in mind though this curve passes an inflection at 500 C, so for high temperatures you probably want to look up what happens. I don't know off the top of my head.

Hope thats useful.