U.S. tariffs on imported steel are delivering higher profits for steel companies but haven’t changed the country’s dependence on foreign-made steel.

Foreign steelmakers have been subjected since March to 25% tariffs in the U.S. Instead of isolating imported steel as the most expensive in the market, domestic steel producers have raised their prices by as much or more, moves that have generated higher profits for those steelmakers and driven up costs for U.S. manufacturers. Foreign steel’s share of the steel market remains...