Patent ID: 9023158
Filing Date: 2015-05-05
Classification: C21D,C22C

Abstract:
1. A steel material comprising, by mass %, C: 0.005% to 0.03%, Si: 0.05% to 0.40%, Mn: 0.40% to 1.70%, Nb: 0.02% to 0.10%, Ti: 0.005% to 0.025%, N: 0.0008% to 0.0045%, and B: 0.0003% to 0.0030%, restricting P: 0.030% or less, S: 0.020% or less, and Al: 0.02% or less, and having a balance of Fe and unavoidable impurities, where the contents of C and Nb satisfy and Ti-based oxides of a grain size of 0.05 to 10 μm are present in a density of 30 to 300/mm wherein the steel material is produced by a method comprising adjusting solute oxygen to within a range of from 0.003 to 0.015 mass % before the addition of Ti.