Heavy plate and thermomechanical treatment method for a starting material for the production of the heavy plate

A thermomechanical treatment method for a starting material for the production of a heavy plate consisting of a steel alloy, containing the following, each in wt %:

• 0.01 to 0.20 carbon (C),
• 0.5 to 2.50 manganese (Mn),
• 0.05 to 0.80 silicon (Si),
• 0.01 to 0.20 aluminum (Al),
• <0.05 phosphorus (P),
• <0.01 sulfur (S),
• and optionally individual elements from the following group or combinations thereof:
• 0 to 1.5 chromium (Cr)
• 0 to 1.0 molybdenum (Mo)
• 0 to 1.0 copper (Cu)
• 0 to 5.0 nickel (Ni)
• 0 to 0.30 vanadium (V)
• 0 to 0.20 titanium (Ti)
• 0 to 0.20 niobium (Nb)
• 0 to 0.005 boron (B)
• 0 to 0.015 nitrogen (N)
• 0 to 0.01 calcium (Ca)
• and residual iron (Fe) and inevitable production-related impurities, which treatment method comprises the following steps:
• heating the starting material to above the Ac3 temperature and partial forming the starting material using a first rolling procedure,
• accelerated cooling of the starting material after the first rolling procedure from a first final rolling temperature to below the Ar3 temperature,
• heating the starting material after the accelerated cooling to a second initial rolling temperature for a second rolling procedure above the Ac3 temperature and final forming of the starting material by the second rolling procedure to a thickness of the heavy plate and
• multi-stage cooling optionally with at least one straightening procedure after the final forming in that
• a cooling from a second final rolling temperature of the second rolling procedure to a first temperature between Ar3 and Ar1 is carried out at a first cooling rate in a first stage after the second rolling procedure and
• a cooling from the first temperature to a second temperature <Ar1 is carried out at a second cooling rate in a subsequent second stage, where the first cooling rate is < the second cooling rate.