Process for manufacturing of thick armour plates

摘要

The invention relates to a process for the manufacture of armour plates having a high hardness from steel ingots, in which the ingots are hot-rolled to a final thickness of more than 50 mm and then hardened and, if appropriate, annealed. The invention is characterised in that a continuously cast ingot is produced from a steel with 0.25 to 0.32 % of C 0.05 to 0.75 % of Si 0.10 to 1.50 % of Mn 0.90 to 2.00 % of Cr 0.10 to 0.70 % of Mo 1.20 to 4.50 % of Ni 0.01 to 0.08 % of Al at most 0.015 % of P at most 0.005 % of S at most 0.012 % of N the remainder being iron including usual impurities, heated to a temperature of 1150 DEG C or higher and heated right through and, after cooling in air and by spraying the two long sides with pressurised water, is hot-rolled to the final thickness at a surface temperature in the range from 1050 to 900 DEG C with forming passes, which have an individual change of shape of epsilon h > 0.1, and with a shape factor SF of > 0.40.