Kaiser Aluminum Corp., the second-largest U.S. aluminum maker, will cut at least 540 jobs, or 19%, of the hourly work force at five plants in Ohio, Louisiana and Washington, after settling a two-year strike. A federal arbitrator reached a settlement Monday between the company and members of the United Steelworkers of America. Under the five-year contract, workers will get wage and benefit increases that average 2.6% a year, Kaiser said. The company will take a third-quarter pretax charge of $30 million to $40 million for the costs of the labor settlement. The plants employed about 2,800 workers before the strike began in September 1998. Kaiser shares were unchanged at $5 on the NYSE.