Current Carrying Capacity

[EMachine]

I am trying to calculate the ampacity through a piece of .01"(.254e-003m) metal. The metal is stainless steel 304, it has a
resistivity of 7.2e-007 ohm-m, a length of .012m, and an area of .836e-006m^2. There are tons of references to ampacity ratings of
copper and aluminum wires, but no resources I could find that explain
how they calculate the current carrying capacity of a particular
material. I just want to know the amount of current this piece of metal
can carry and what temperature rises are experienced. The melting point of this particular type of metal is 1400-1455 degrees celcius. Any help or references would be appreciated.

Thanks in advance,

P.S.
This is not a school problem. This piece of metal is going to be welded to the base of a 1500W lamp, which experience high currents during startup. The transient current is the most important factor, but being able to find steady state current is also necessary.

-Erik

 

[Bob NH]

Resistance = Resistivity x Length / Area

Where:
Resistivity is in units of ohm*meter
Length is in meters
Area is in meters squared

You will have to calculate the integral of (current squared)dt and use the specific heat and mass of the stainless, probably neglecting the conduction losses to the parts to which the piece is welded.

You will have to convert everything to get consistent units. How many watt-seconds does it take to raise the temperature of 1 gram of stainless steel by 1 degree C if the specific heat is 0.11 kcal per kg per C deg?