Essential steel plates for
bridge use of JFE Steel are reviewed together
with relevant key-technologies. Owing to Super-OLAC
featured with an ultimate theoretical cooling
rate, high performance steels such as a TS
570 N/mm2 class ones and weathering
steels with a low PCM value are materialized
by effi cient on-line process, which offers
a short delivery time and saving in welding
fabrication. As for weathering steel, two
kinds of advanced ones of Ni type are lined-up
for various airborne salt environments. Also
presented herein are new surface treatment
technologies to promote protective rust formation
for a better appearance of a bridge. Furthermore,
longitudinally profi led (LP) steel plates
are lined-up for welding labor and dead weight
reductions and low transformation-temperature
welding consumables are developed for remarkable
fatigue strength of welded joints.