United States Steel Corp. said today it lost money for a third straight quarter as the global economic downturn continued to dampen demand for the metal.

But the company said its steel production and shipments rose significantly, and that it expects improved results in the fourth quarter. Still, it forecast another loss for the October-December period.

The loss highlights an industrywide slump in demand that began when the world economy faltered late last year. That undermined key customers in the construction, auto and industrial equipment industries. Steel makers like U.S. Steel, based in Pittsburgh, responded by winding down production and laying off thousands of workers.

The company operates three facilities in northwest Indiana, including Gary Works, U.S. Steel’s largest manufacturing plant on the south shore of Lake Michigan.

Although prices and production rose during the quarter as steel distributors scrambled to fill orders after depleting their stockpiles, the market for the metal remained far weaker than it had been a year earlier, when U.S. Steel notched record profits.

In April, U.S. Steel posted its first quarterly loss in more than five years. After reporting a second quarterly loss in July, the company said it expected all of its businesses to post operating losses for the July-September period.

The largest U.S. steel maker said it lost $303 million, or $2.11 per share, for the three months ended Sept. 30. That compares with a profit of $919 million, or $7.79 per share, in year-earlier period.

Revenue tumbled 61 percent to $2.82 billion from $7.31 billion.

Analysts expected a loss of $2.87 per share on revenue of $2.72 billion. Wall Street estimates typically exclude one-time items.