Ameron International Corp on Wednesday said that it has agreed to sell its 50 percent stake in steelmaker Tamco for $82.5 million in cash.

Tamco is a Rancho Cucamonga facility that manufactures steel rebar primarily for construction markets in California, Arizona and Nevada. It has struggled in the last few years due to the weak construction markets in the Western United States.

The buyer, Brazilian steelmaker Gerdau, will own 100 percent of the mill after it pays Ameron’s Japanese partners in the venture – Tokyo Steel and trading house Mitsui & Co – $82.5 million for their ownership share. The total sale price is $165 million.

Ameron, a Pasadena maker of water transmission lines, pipes and fabricated steel, said it began evaluating the strategic alternatives for Tamco in late 2008. “We concluded that the potential of Tamco would be more fully realized under the ownership of a full-line, vertically-integrated steel company such as Gerdau,” said Chief Executive James S. Marlen in a statement.

Ameron did not say how it plans to use net proceeds, but may consider acquisitions within its core business units or in closely-related businesses.

Ameron shares were up $2.19, or 3.6 percent, to $62.17 in midday trading on the New York Stock Exchange.