POSCO Holdings Inc.
High-strength steel having superior brittle crack arrestability, and production method therefor

Abstract:

Provided are high-strength steel having superior brittle crack arrestability and a production method therefor. The structural ultra-thick steel comprises 0.05-0.1 wt % of C, 0.9-1.5 wt % of Mn, 0.8-1.5 wt % of Ni, 0.005-0.1 wt % of Nb, 0.005-0.1 wt % of Ti, 0.1-0.6 wt % of Cu, 0.1-0.4 wt % of Si, at most 100 ppm of P, and at most 40 ppm of S with the remainder being Fe and other inevitable impurities, has microstructures including one structure selected from the group consisting of a single-phase structure of ferrite, a single-phase structure of bainite, a complex-phase structure of ferrite and bainite, a complex-phase structure of ferrite and pearlite, and a complex-phase structure of ferrite, bainite, and pearlite, and has a thickness of at least 50 mm. The high-strength steel has high yield strength and superior brittle crack arrestability.