I am trying to make a heating element using a 304 stainless steel flat bar for simplicity. I'm choosing stainless steel instead of nichrome since it will be more durable.
If I know its electrical resistance is 0.72 x 10-6 Ω.m and I figure out the object's mass, how can I calculate the wattage required to bring that stainless steel bar to a specific temperature?
All I have been able to find so far are formulas for heating wire.
It seems like there should be a very simple formula to calculate this but in all of my searching online I can't seem to find it. If your answer is simply lookup the "so and so" formula that would be all the help I need.
What I've learned from your responses:
First, thanks everyone for your answers! From what many of you have said I now understand that this is a multifaceted problem that is quite complicated to solve in it's entirety. It seems that the best way to go about this is to do some testing and construct a temperature control circuit.
My initial approach will be to supply the element with excessively more amperage then I expect it will require. Then, as it heats up I will monitor amp draw and temperature to get an estimate of amps required to reach desired temp. Then, based on that information I can find a power supply that is a good match. I'll also make a circuit that measure's temp and turns power on or off to maintain that temperature.
What is this for?
Some of you asked for more context about the purpose of this element. To many of you serious engineers this will seem silly but it's for a custom sword. The Cyberpunk 2077 Thermal Katana to be exact. One of my hobbies is to try and make real prototypes of technology found in science fiction. What makes this sword unique is that the edge is super heated. Why? No idea, it's a terrible design. Any metal that has reached a high enough temp to turn red will be useless. The blades design itself is terrible as well but I want to try and replicate it anyway. I have since changed my original element design to achieve this but the process will be the same. I want to make this sword still able to cut and yet have the super heated capability. So what I'll be doing now is using NiChrome flat ribbon wire on the flat of each side of the blade (ceramic barrier between 1095 blade and Nichrome element). This way I have a high carbon edge that begins the cut and the sides that apply the heat. There are many more details involved in the entire build that I have figured out but the element was the primary obstacle.
Just an FYI to anyone wondering, yes I am trying to make a functional-ish weapon, no I do not ever plan to use it for anything more than a display piece and the challenge of making it work. I am aware of the dangers of the voltage required for this and the intense heat output. There are a lot of technical and mechanical challenges as well but that is exactly the reason I want to do it. As safely as possible of course.