'Ironworkers' in the Bible

Then Nebuchadnezzar sent away into exile all of Jerusalem all the captains, all the valiant soldiers, 10,000 captives, and all of the craftsmen and ironworkers. Nobody remained except the poorest people of the land.

All 7,000 of the most valiant soldiers and 1,000 of the craftsmen and ironworkers all physically fit and trained for battle were brought by the king of Babylon into exile in Babylon.