| 摘要 |
<p>The present invention provides a high-strength thick steel plate capable of ensuring a tensile strength to be more than 570MPa and realizing an excellent HAZ (Heat Affect Zone) toughness. The high-strength thick steel plate consists of specified chemical compositions, KV obtained by the following formula (1) is lower than 0.060, more than 90% of the area of a steel structure is bainite, in addition, an Nb atom or C atom having other Nb atoms or other C atoms within a distance of 1.7nm combines with the other Nb atoms or the other C atoms to form an aggregate having more than 5 atoms, by using a 3D atom probe field ion microscope to measure, the aggregate has a number density of more than 1.0*10<22> per cubic meter. KV = [V] + [Nb] ... (1) (wherein, [V] and [Nb] respectively represent V content and Nb content (mass%)).</p> |
