"Andy Dingley" wrote in message
...
On Mon, 1 Mar 2004 17:39:53 -0000, "Ed Rear"
wrote:

Why don't manhole covers, drain grids, etc, rust away?

Because they're cast iron not steel.

[snip]

Wrought iron is almost unheard of these days, but like cast iron it
carries its non-iron parts separated out into slag grains, and again
it's resistant to serious rusting. If you find an old anchor or chain
of it, you'll see a pronounced "wood grain" effect developing after
some decades.

That was a great explanation. Thank you.

Now a question on why it is that we don't see Wrought Iron these days? I
will hazard a guess something to do with cost, but it would be good to know.

Thanks
Rob