[hmale]

Metals corrode when they release their ions within the fluid medium they exist.

When a metal goes into solution e.g. in water, it is due to the loss of at least one electron. The rate of discharge is specific and unique to each metal.

The wetted metals now exist between a specific range of voltages. This voltage differential is the result of the balance of the anodic and cathodic reactions...and while the voltage differentials are unique for each metal, they are indeed measureable.

The balance of the voltages for different metals within a fluid medium (water in this case) is commonly referred to as a galvanic series.

Any time metals with different voltages are electrically connected in a fluid, a current will want to flow between them until they have the same voltage.

There is another consideration that must be taken into account when considering using different metals in water, and that is their mass relative to each other. The rate of galvanic corrosion is directly impacted by these values. A small amount of copper will not cause a great deal of corrosion when it coexists with a large amount of steel within a fluid medium, whereas a large amount of copper will very quickly cause extensive damage relative to a small amount of steel.

My recommendation would be not to use the steel radiators.

I hope this helps.

Cheers!