Oct 18 (Reuters) - Gold prices were steady on Tuesday as the dollar faltered, although risks from looming aggressive interest hikes by the U.S. Federal Reserve limited gains in zero-yielding bullion. * A fourth straight 75-basis-point Fed interest rate hike is expected next month after data last week showed inflation increasing strongly in September. * The German government is aiming to cushion an expected recession with its investment programmes, but without fuelling inflation, Economy Minister Robert Habeck said on Monday.