Energy Used Smelting and Rolling Steel

It is specific heat capacity of that element aluminium/ steel/ or any other which decides Energy input to Solid phase of aluminium/ steel.

Though specific heat capacity changes with the temperature of the charge, you can calculate starting from defination of Specific Heat Capacity at ambient temperature x difference of extruding or forging temperaure x mass; in proper units gives the energy required.

If you are melting aluminium/ steel, the latent heat of fusion for that material is added to the above calculation; giving good approximation of what you want.

Hello Tonymech,

Your question is about smelting and rolling steel, for a comparison with aluminum extrusion? Aluminum ore is converted with a massive use of electricity, the billets are usually transported cold remelted and alloyed before extrusion. It seems that you are not considering the processes on an equal basis. The iron ore is often converted in a Bessimer furnace where oxygen is used to burn coke and carbon releasing heat to melt and reduce the iron oxides before it is poured into ingots that can be rolled into sheets often at the same foundry without significant reheating. You should clarify the mass you quoted is spelled tonne. Is that a 2000 pound ton requiring 15 Mega Watt Hours to produce? It doesn't seem equivalent to consider aluminum extrusions compared to rolled steel. You would have to specify a sheet thickness for the steel and a cross section for the aluminum extrusion.

Regards,

Luther M

Hi All

I am afraid I'm guilty of posting this twice(very bad, sorry). I hadn't intended too, the other answers are at:

http://cr4.globalspec.com/thread/53507/Energy-Used-Smelting-and-Rolling-Steel

A Tonne is 1000kg or 2200lbs.

I have been told that the general rule of thumb used by the "green groups" is that Aluminium uses 6 times the power to make an extrusion against a rolled Steel sheet. Since posting the above I've got some new numbers 63mWh/Tonne for extruded Aluminium and 9.7mWh/Tonne for Steel sheet, a ratio of about 6.5.

How these numbers are derived, I'm not sure and whether rolling the steel straight from a just solidifed billet or reheating to roll is not specified.

Thanks for your answers, Tony