Iron Man, Vol. 1 #70 (1974)

Confrontation, Part 2: Who Shall Stop Ultimo?
Iron Man and Sunfire team up to defeat Ultimo, and that success leads to Sunfire's realization that he may have misjudged America. Meanwhile, the Mandarin fights his way into his own stronghold, now run by Yellow Claw. Also meanwhile, Marty March reveals to Roxi Gilbert that he doesn't want to return to America because he's discovered an underground city. Also also meanwhile, Happy Hogan decides that the best way to avoid the marital problems he and Pepper have had from working apart is to not work apart, and he applies to work for S.I.'s security division.
Release Date: 1974