Steel material for seismic damper having superior impact toughness, and manufacturing method for same
AssigneePosco
InventorsJae-Young CHO, Sang-Deok KANG
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Abstract
The present invention provides a steel material for a seismic damper, and a manufacturing method for same. The steel material comprises, in wt %, at most 0.006% of C, at most 0.05% of Si, at most 0.3% of Mn, at most 0.02% of P, at most 0.01% of S, 0.005 to 0.05% of Al, at most 0.005% of N, 48/14×[N] to 0.05% of Ti (here, [N] is the nitrogen content in wt %), 0.04 to 0.15% of Nb, and the remainder in Fe and other unavoidable impurities, and has a ferrite single structure, and has a ferrite grain average particle size of 150 to 500 μm in a region of a surface layer part, corresponding to 30% of the total thickness from the surface thereof.
Claims11
A steel material for a seismic damper, comprising by weight:
- 0.006% or less of C, 0.05% or less of Si, 0.3% or less of Mn, 0.02% or less of P, 0.01% or less of S, 0.005 to 0.05% of Al, 0.005% or less of N, 48/14×[N] to 0.05% of Ti, where, [N] refers to a weight of nitrogen (weight %), and 0.04 to 0.15% of Nb, with a balance of Fe and other unavoidable impurities, having a ferrite single structure,
- wherein an average ferrite grain size in a surface layer portion from a surface thereof to a region corresponding to 30% of the total thickness is 150 to 500 μm.
A manufacturing method for a steel material for a seismic damper, comprising:
- heating a steel slab including by weight:
- 0.006% or less of C, 0.05% or less of Si, 0.3% or less of Mn, 0.02% or less of P, 0.01% or less of S, 0.005 to 0.05% of Al, 0.005% or less of N, 48/14×[N] to 0.05% of Ti, where, [N] refers to a content of nitrogen (weight %), and 0.04 to 0.15% of Nb, with a balance of Fe and other unavoidable impurities, to a temperature within a range of 1050 to 1250° C.;
- subjecting the heated steel slab to finish rolling in a temperature range of Ar3-80° C. or higher and Ar3 or lower;
- and
- performing a shot blasting treatment operation on a surface of the finish-rolled steel material,
- wherein the shot blasting treatment operation is performed so that a metallic ball or a non-metallic ball is rotated at a rate of 1500 to 2500 rpm and sprayed on a surface of the plate material at a rate of 60 to 100 m/s.
Dependencies are inferred from the claim text.