Ameron International Corp. said it will close its concrete pipe plant in Portland, Ore., in March and move the work to a California plant to improve efficiency and reduce costs. The Pasadena-based maker of steel, concrete and fiberglass pipes will move the work to a larger plant in Tracy. Chief Financial Officer Gary Wagner said some of the 40 to 50 workers at the Oregon plant will be offered transfers. "This move will improve our operating efficiencies and further reduce the overhead associated with many of our primary concrete and steel pressure-pipe products," said Ameron Chief Executive James Marlen in a prepared statement. Ameron said the Portland factory is its smallest pressure-pipe plant. In an earlier cost-cutting move, the company closed a fiberglass pipe plant in Spartanburg, S.C., in June and transferred its equipment to a factory in Texas. Ameron, meanwhile, said its fourth-quarter net income rose 33%, to a record $6.11 million, or $1.48 a share, from $4.61 million, or $1.16, in the year-earlier period. Ameron shares were unchanged at $60 on the NYSE.