Analysis of information sources in references of the Wikipedia article "United Airlines Flight 232" in English language version.
All the fan disks manufactured after January 1972 were made in accordance with the new triple-melt material requirements
TITANIUM CLEANLINESS: ... (Sioux City crash) As a consequence, triple melt VAR was adopted by the industry asa premium (rotor) grade requirement
TITANIUM CLEANLINESS: ... (Sioux City crash) As a consequence, triple melt VAR was adopted by the industry asa premium (rotor) grade requirement
All the fan disks manufactured after January 1972 were made in accordance with the new triple-melt material requirements