NIPPON STEEL CORPORATION, Plaintiff-Cross Appellant, v. UNITED STATES, Defendant-Appellant, v. Bethlehem Steel Corporation and U.S. Steel Group, a Unit of USX Corporation, Defendants-Appellants, and Ispat Inland Inc., LTV Steel Company, Inc., Gallatin Steel, Ipsco Steel, Inc., Steel Dynamics, Inc., and Weirton Steel Corporation, Defendants