Steel plate with excellent hydrogen induced cracking resistance, and manufacturing method of the same

A steel plate comprising:

• C:
• 0.02 to 0.20% (in percentage by mass, also for the following chemical components),
• Si:
• 0.02 to 0.50%,
• Mn:
• 0.6 to 2.0%,
• P:
• 0.030% or less,
• S:
• 0.004% or less,
• Al:
• 0.010 to 0.08%,
• N:
• 0.001 to 0.01%,
• Nb:
• 0.002 to 0.06%,
• Ca:
• 0.0003 to 0.0060%,
• O:
• 0.0040% or less,
• REM:
• 0.0002 to 0.05%,
• Zr:
• 0.0003 to 0.020%, and
• the remainder being iron and inevitable impurities,
• wherein, in a composition of an inclusion contained in the steel and having a width of 1 μm or more, a ratio (RES/CaS) of a mass of a REM sulfide (RES) to that of a Ca sulfide (CaS) is equal to or more than 0.05,
• wherein a Zr content of the inclusion is in a range of 5 to 60%, and
• wherein a Nb content of the inclusion is 5% or less.