I'm trying to get an estimation of the temperature that a Kanthal (A1) wire would get, when applied an amount of electrical power.
The wire is 30cm long. The diameter is 0.3mm (or there about).
The electrical resistance from the specifications sheet says "1.45 Ω mm2/m" (I'm not sure how to read this). I'll actually leave you the spec sheet link:
https://www.kanthal.com/en/products/material-datasheets/wire/resistance-heating-wire-and-resistance-wire/kanthal-a-1
In the specifications sheet they provide a temperature table, from which I kind of understood that the temperature is not going to be a linear function, but a rough linear estimation would be just fine.
My ultimate goal is to calculate the minimum and maximum electrical power that I need to supply to the wire, in order to control it between 50°C and 100°C 100°C and 200°C.
Edit, as requested by @Transistor
I am unsure where to find a more appropriate spec sheet, in that page you can expand the sections to reveal the data. Anyway, I have also found these 2 pages:
https://temcocontent.com/attachments/kanthal_wire_data_sheet.pdf
https://www.hi-tempproducts.com/pdf/the-kanthal-furnace-mini-handbook.pdf
Maybe they provide more useful information.
The "element" will be used for a foam wire cutter (thus, not really an element, just a bare wire). As far as I could find, foam can be cut at 200°C, but that may be too aggressive so I'd like to keep it a good amount below that temperature. I am going to make tests later, but right now I only need to "convert" W to T(°C) in order to calibrate an initial electrical circuit…
Best Answer
Basically, it turns out there is no simple way of finding an answer. However, I was wondering if I could find a function whoose curve passes through, or near, most of the temperature points from the spec sheet table... turns out, yes, there is such a function! I have actually found 2 functions of interest. The first is a logarithmic function (base 10):
This function is the one I found gets nearest to all thermal points of the table, but definitely deviates a lot at the 20W and 27W marks.
The second is a linear function:
This function is simpler, not involving a Log. However, it also deviates the most compared to the Log one, noticeable at the 22W, 27W and 35W marks. This is the one that I ended up using. I could then calculate that: 11.8W = 100°C; 13.5W = 200°C. A quick math gives that my project needs a minimum of 3 Li-Ion cells in series, capable of 1.1A continous discharge current (max needed for 200°C).
I guess that, if the thermal expansion table would've been taken into account, a better estimation would've resulted. For some estimations however, it's not worth the trouble.
Hopefully this will be useful for someone else. And thanks to anyone here who tried to help me.
Graph plotting provided by Desmos.com