6.1.1 Where reference is made in this chapter
to A, B, D, E, AH, DH, EH and FH hull structural steels, these steel
grades are hull structural steels according to recognized standards.
6.1.2
A piece is the rolled product
from a single slab or billet or from a single ingot, if this is rolled
directly into plates, strips, sections or bars.
6.1.3
A batch is the number of items
or pieces to be accepted or rejected together, on the basis of the
tests to be carried out on a sampling basis. The size of a batch is
given in the recognized standards.
6.1.4
Controlled rolling (CR) is
a rolling procedure in which the final deformation is carried out
in the normalizing temperature range, resulting in a material condition
generally equivalent to that obtained by normalizing.
6.1.5
Thermo-mechanical controlled processing
(TMCP) is a procedure that involves strict control of both
the steel temperature and the rolling reduction. Unlike CR, the properties
conferred by TMCP cannot be reproduced by subsequent normalizing or
other heat treatment. The use of accelerated cooling on completion
of TMCP may also be accepted, subject to approval by the Administration.
The same applies for the use of tempering after completion of TMCP.
6.1.6
Accelerated cooling (AcC) is
a process that aims to improve mechanical properties by controlled
cooling with rates higher than air cooling, immediately after the
final TMCP operation. Direct quenching is excluded from accelerated
cooling. The material properties conferred by TMCP and AcC cannot
be reproduced by subsequent normalizing or other heat treatment.