The Temp core 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 center 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 processes 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.
The specially designed deformation pattern of Peekay TMT ensures excellent bond strength between the bars and the surrounding concrete. Typical values of the strength are 200% to 800% more than mild steel plain re-bars as against conventional cold twisted bars that have 86% to 627% more strength than MS plain bars. (Specifications require 40% more bond strength than MS plain bars)
It often happens that for reasons inherent in building techniques, re-inforcing steel has to be bent and re strengthened. The tough outer surface and ductile core of TMT bars result in a rebar of excellent strength and bendability. The bar can be bent and re bent around very small mandrels of 2d and 4d respectively. The advantage at construction sites is obvious. The table below shows that these figures are much superior to IS 1786.
Nowadays, pre-fabricated re-inforcements are increasingly used in all fields of construction. For reasons of profitability these requirements are assembled by welding. User requirements of weldability of re-bars are, therefore, increasing. The low carbon content ensures excellent weldability superior to conventional cold twisted bars.
All main welding process can be used. Bars can be buttwelded or lap-welded using ordinary rutile coated electrodes of matching strength. No pre-heating or post heating treatment is necessary in case of manual arc welding.
The TMT process, unlike cold twisting, leaves no torsional stresses in the bar. This result in better corrosion resistant characteristics in TMT compared to conventional cold twised bars.
Peekay TMT bars are certified to IS:1786-1985 dimensional tolerance.
Peekay TMT is the perfect re-inforcing bar for all structures-dams, powerplants, bridges, flyovers, factories, hotels, skyscrapers, plus all commercial and residential structures. .