PEEKAY ROLLING MILLS (P) LTD
THE TEMPCORE PROCESS
The re-bar leaving the last stand of hot rolling passes through a special
water cooling section. The cooling is such that a surface layer of the bar is
quenched into martensite, the core remaining austenitic. The quenching treatment
is stopped when a determined thickness of martensite has been formed under the
skin. The re-bar leaves the drastic cooling section, the temperature gradient
established in its cross section causes heat to flow from the centre to the
surface. This results in self tempering of martensite. Finally, during the slow
cooling of the re-bar on the cooling bed, austentic core transforms into ferrite
and pearlite.
Peekay TMT is produced by the
world's most advanced technology licensed from Centre de Recherches
Metallurgiques (CRM), Belguim, inventors of this process.
Tempcore bars are being successfully used in most parts of the developed world.
TMT are produced in two grades: TMT 415 and
TMT 500. The numbers indicate the proof stress. Because of the unique manufacturing
process, TMT bars exhibit an excellent combination of strength and ductility
that far exceeds the minimum limits specified by IS:1786.
Typical values for yield strength are as high as 465 N/mm2 for TMT
(as against IS standards, 415 N/mm2). Ductility as
measured by elongation is 21% min (as against standards 14.5% min). Thus, you
get product which offers you higher safety
margins.
