[TheForge] A36 vs 1018

[Bob Rackers]

This will show my ignorance, but I have to ask anyhow.
I called a local steel supply searching for some 3/4" round 1018 hot-rolled.
The sales rep told me the closest I could get was 1020, which would have been
fine.
I got the price and passed on the info to the girl at work in charge of
purchasing. She assumed I wanted cold-rolled, and when I told her I wanted
hot-rolled, she then said "Oh, then you want A36."

I told her I DIDN'T want A36, I wanted 1018 or 1020.
She had just told me that she used to sell steel for six years, and the only
thing she knew as hot-rolled was A36.

The sales rep told me I could get 1020 hot-rolled, but when our girl called and
spoke to another sales rep, she was told they only had A36.

So one question is does 1018 and/or 1020 come in hot-rolled?
And can someone tell me the exact difference between A36 and 1020?
I think I know, but I figure I might as well just ask anyhow.

Thanks.

Bob