A Silicon Valley firm sued the former U.S. Steel.

Sunnyvale’s USX Telecenter Corp. has filed a $50-million suit against what was formerly U.S. Steel Corp., claiming the Pittsburgh giant infringed on its trademark. The suit alleged that U.S. Steel knew of the existence of USX Telecenters, a telecommunications equipment distributor, and went ahead with its name-change to USX Corp. anyway. Dates for initial hearings in Santa Clara Superior Court have not been set.