Who belonged to the steel curtain? I only remember 3 out of 4 members.
Because the term "Steel Curtain" was used to describe the Pittsburgh Steelers defensive unit for almost a decade, beginning in the mid 1970s, it's somewhat misleading to suggest there were just four members. However, there are four players from those Steelers' defenses in the Pro Football Hall of Fame: "Mean" Joe Greene (#75), Jack Ham (#59), Jack Lambert (#58) and Mel Blount (#47).
Other players most associated with the "Steel Curtain" were L.C. Greenwood (#68), Dwight White (#78), and Ernie Holmes (#63).