BAINITE STEEL MATERIAL OF LITTLE SCATTER OF QUALITY AND METHOD OF MANUFACTURING THE SAME

摘要

This invention provides a bainite steel material, such as a steel plate of a large thickness, a steel strip, a shape or a steel bar which have little scatter of quality in the direction of the thickness thereof and among different types of steel materials, wherein the bainite steel material comprises a composition containing not less than 0.001 wt.% and less than 0.030 wt.% of C, not more than 0.60 wt.% of Si, 1.00-3.00 wt.% of Mn, 0.005-0.20 wt.% of Nb, 0.0003-0.0050 wt.% of B, not more than 0.100 wt.% of Al and not less than 90 wt.% of bainite structure.