Dalhausser and Rogers won eight of the first nine points in the first set and eight of the first 10 in the second to dismantle Renato Gomes and Jorge Terceiro in the semifinals 21-11, 21-13.
Gomes and Terceiro represented Georgia in the Olympics although they also have citizenship in Brazil.
The Americans, defending world champions, lost their first match in pool play to a Latvian team and then in the round of 16 found themselves down 6-0 in the third set against a duo from Switzerland.
There was no such drama Wednesday in a match that lasted 42 minutes.
Dalhausser and Rogers will face Marcio Araujo and Fabio Magalhaes, who won an all-Brazilian semifinal over Ricardo Santos and Emanuel Rego 22-20, 21-18.
The first gold medal in beach volleyball will be decided Thursday when the United States team of Kelli Walsh and Misty May-Treanor will face China's Wang Jie and Tian Jie.
The Americans will be trying for their 108th consecutive victory.
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