| 摘要 |
PROBLEM TO BE SOLVED: To provide an H-shaped steel for low temperature in which Nb obstructing productivity is not added, the addition of expensive alloy elements is suppressed, and toughness at -40°C is excellent as air-cooled, and a method for producing the same.SOLUTION: Provided is an H-shaped steel for low temperature having a composition comprising, by mass, 0.06 to 0.12% C, 0.80 to 2.00% Mn, 0.010 to below 0.040% V, 0.005 to 0.025% Ti, 0.01 to 0.60% Cu, 0.01 to 0.50% Ni and 0.0020 to 0.0120% N, in which V/N is 1.0 to 11.0, CE(=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15) is 0.42 or lower, the sheet thickness of a flange is 12 to 40 mm, the area ratio of ferrite at the 1/4 position from the outside of the sheet thickness of the flange and also at the 1/6 position from the outside of the flange width is 75% or higher, and the ferrite grain size is 14 μm or lower. Also provided is a production method where hot rolling is performed at the final draft pass temperature≤66.43log(V×N)+1,081, and air-cooling is performed.SELECTED DRAWING: Figure 1 |
