Most scrap metal yards are closed on Sunday so they can have a day off.
Some scrap metal yards are also closed on both Saturday and Sunday and are only open from Monday through Friday.
Some of the larger scrap metal yards may be open on Saturday and Sunday but if they are open on Sunday they likely will be only open for a few hours on the Sunday.
We'd really have to know your location to tell you if there's a scrap metal yard open on Sunday in your area because we don't know what scrap metal yards are in your area.