| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a thick steel plate for ultra-low temperature, which has excellent arrest properties, at a low cost. <P>SOLUTION: There are provided the thick steel plate for ultra-low temperature and a method for producing the thick steel plate which has excellent arrest properties, and has a composition comprising, by mass%, 0.01 to 0.12% C, 0.01 to 0.3% Si, 0.4 to 2.0% Mn, ≤0.05% P, ≤0.008% S, >5.0 to <10.0% Ni, 0.002 to 0.05% Al and ≤0.005% N, and the balance Fe with impurities, and in which the amount of residual γ at the position of (1/4)t of the plate thickness is ≥3.0 vol.%, and also, the average value of the equivalent circle diameters in a structural unit surrounded by high angle grain boundaries of ≥15° observed by an EBSP method at the magnification of 2,000 times is ≤5.5 μm at the position of (1/4)t of the plate thickness. The thick steel plate may further include one or more kinds among Cu, Cr, Mo, V, B, Nb, Ti, Ca, Mg and REM. <P>COPYRIGHT: (C)2012,JPO&INPIT |
