Induction melting of steel - melting time calculation

James H. · 2005-12-18T06:18:06+00:00

Hi,We're trying to size a small induction melting furnace (similar to those used in the jewelry making industry) for our application and I was wondering if anyone with some experience in this subject can help answer the following question:How long would it take to melt 3.5 lbs of 4140 Steel (2"Dia. x 4"L bar at 1500 deg. C, 7.8 g/cc) with a 10 KW medium frequency (10-30Khz) water-cooled induction melting machine using the proper crucible (350 cc capacity)? Are there any other factors missed here that would influence this calculation?Thanks in advance,James

Dec 18, 2005 20 Replies

Rate this thread:

Hi James, sorry for the late reply I don't hang out on the group these days.

I just did a ball park calculation using heat capacity of steel roughly

500J/kg/K ie. 500* 1500 * (3.5/2.2) = 1.2MJ; the 0.1 error is because I did it the calc in my head.

I (knowingly) didn't include the latent heat of fusion for the ballpark calculation. In retrospect I probably should have because it is significant. I think for iron/steel Lf = 250kJ/Kg which comes out to

250k*(3.5/2/2) = 0.4MJ. That should be added onto the 1.2MJ giving a total of 1.6MJ (45% higher than my rough estimate).

James H. wrote: