| 摘要 |
<p>The objective of the present invention is to provide a thick steel plate having little change in toughness, before and after a strain aging. The thick steel plate satisfies a predetermined chemical composition, at the same time satisfyingΔG/[Si]>0.4, and [Ti]×[N]>=4.0×10-5. Moreover, the thick steel plate has a mixed weave wherein the partial component of the ferrite is 40-90% by surface, and the partial component of the bainite is 5-60% by surface. The combined partial component of ferrite and bainite is above 90% by surface, at the same time containing above 1% by surface of a hard phase material. A valid crystal grain diameter is 3-25μm, and an engaged carbon, included in the entire weave, takes up below 0.035% by weight.</p> |
