(Reuters) - United States Steel Corp (>> United States Steel Corporation) has named President Mario Longhi to succeed John Surma as chief executive, effective September 1.

Longhi, 59, who is also the steelmaker's chief operating officer, was given the title of president in June, and put in charge of a major cost-cutting initiative, prompting speculation that he was in line for the top job.

Surma, 59, touted U.S. Steel's "well-established succession planning process" in the release.

Longhi takes the helm as there is a massive oversupply in the global steel market.

He worked at aluminum producer Alcoa Inc (>> Alcoa Inc) for 23 years before jumping to the steel sector, and served as chief executive of Gerdau Ameristeel from 2006 to 2011.

The company, a unit of Brazilian steelmaker Gerdau SA (>> Gerdau SA), was taken private by its parent in 2010. Longhi joined U.S. steel as COO in July 2012.

Surma, who is also U.S. Steel's executive chairman, will retire from the board at the end of 2013, and Longhi has been elected to the board.

Separately, U.S. Steel said Chief Financial Officer Gretchen Haggerty would retire, and be replaced by David Burritt, who was chief financial officer of Caterpillar Inc (>> Caterpillar Inc.) from 2004 to 2010.

(Reporting by Allison Martell in Toronto; Editing by Bernard Orr and Leslie Gevirtz)