Steel Workers and USX Corp. Agree on New Contract : Labor: The three-year deal averts a walkout by about 18,000 employees in six states. Both sides had reasons to avoid a strike.

USX Corp. and the United Steelworkers of America reached a tentative agreement early today on a new three-year contract, averting a strike by about 18,000 union members in six states.

The settlement came about 30 minutes after a midnight strike deadline and followed phone negotiations between USX Chairman Charles Corry and Lynn Williams, union president.

In a statement, USX said the agreement followed “considerable give and take on both sides” and that a strike would have been “costly and competitively damaging.”

The settlement came after three days of nearly non-stop bargaining in Pittsburgh, Pa. The union, citing progress in the talks, had twice agreed to 24-hour contract extensions from the original deadline of midnight last Thursday.

Mired in a recession and still hurting from a brutal six-month walkout during contract negotiations in 1986, neither side appeared to have much appetite for a strike. But elaborate strike preparations had been made, and USX was said to have stockpiled a month’s worth of steel.

Details of the tentative agreement were not immediately available. The pact must be ratified by members of union locals at mining and steel-making operations in Pennsylvania, Ohio, Indiana, Illinois, Minnesota and Alabama.

The 900 union members at the only California steel plant now operated by USX, a recently modernized mill in Pittsburg owned jointly with Korea’s Pohang Iron & Steel Co., are covered by a separate agreement.

Although the talks proceeded under a news blackout, the main issue apparently was the union’s demand that USX workers catch up with the rest of the industry after widespread concessions were made by labor in the early 1980s.

Union spokesmen said they wanted a raise of $2.30 an hour from the current average wage of $10.84 an hour. About $1.30 of that would restore wages given up in the past, the union said.

Charles A. Bradford, a steel industry analyst at Union Bank of Switzerland, said the labor-cost advantage had served USX well in competing against other major steel companies.

Also hanging over the negotiations was the ongoing uncertainty about the future of the steel division of USX, which is now chiefly an oil and gas company that earns most of its profits from the energy side.

USX, formerly U.S. Steel Corp., signaled last summer that it might sell its steel assets. It was being pressured by corporate raider Carl C. Icahn, who owns 13% of its common shares, to separate the steel and energy units in some fashion.

Hours before last Thursday’s strike deadline, Corry announced that the company would do just that by creating separate categories of stock for steel and energy. Uncertainty over the implications of that move for steel workers was thought to be one reason the union extended the deadline.