TS590 MPa Class Extremely-low Carbon Bainitic Heavy Gauge H-Shapes Having Excellent Weldability*

TS590 MPa class heavy gauge H-shapes having an excellent weldability have been successfully developed by applying an extremely-low carbon bainitic steel. The developed H-shapes have high strength and high toughness, whichsatisfies the SA440 specification without any heat treatment. Because the steel has excellent cold cracking resistance and low hardenability in heat affected zone, no pre-heating is required at welding. Column to column and column to beam welded joints, in which the developed steel was used as a column material, showed sufficient strength and toughness in terms of SA440 specification. The developed heavy gauge H-shapes under a brand name of "RIVER TOUGH 440" were applied to the highrise buildings as column materials at the HARUMI urban renewal project.