|THE NEW GENERATION
TATA TISCON, the new generation high
strength ribbed reinforcement bar, is a product from Tata Steel. It is different from
traditional bars in its method of manufacture and consequently, in its combination of
TATA TISCON is produced using the
worlds most advanced technology - the Tempcore Process, introduced in
India for the first time by Tata Steel under licence from Centre de Rechaerche
Metallurgiques (CRM), Belgium - inventors of the process. Tempcore bars are being
successfully used in most parts of the developed world.
The Tempcore Process imparts high
strength to the bar using thelatest technique of thermomechanical treatment (TMT) as
against cold twisting, wh ich is used to manufacture traditional reinforcing bars.
Steel billets are heated in a reheating
furnace and rolled through a sequence of rolling stands which progressively reduce the
billet to the final size and shape of the reinforcing bar. The Tempcore Process takes over
and the bar is subjected to heat treatment in three successive stages. The first stage of
Quenching begins when the hot rolled bar leaves the final mill stand and is
rapidly quenched by a special water spray system. This converts the surface layer of the
bar to a hardened structure called Martensite while the core remains
austenitic. The second stage of Self Tempering begins when the bar leaves the
quenching box with a temperature gradient through its cross section, the temperature of
the core being higher than that of the surface.
This allows heat to flow from the core to
the surface, resulting in tempering of the surface, giving a structure called
Tempered Martensite which is strong and tough. The core is still austenitic at
The third stage of Atmospheric
cooling takes place on the cooling bed, where the austenitic core is transformed to
a ductile ferrite-pearlite core. Thus, the final structure consists of a combination of
strong outer layer of tempered martensite and a ductile core of ferrite-pearlite. This is
what gives TATA TISCON its unique combination of strength and ductility.
Why is TATA TISCON superior to
traditional rebars in the market ? The answer lies in Tempcore Technology, superior steel
quality and the hi-tech Wire Rod Mill and Merchant Mill where this process has been
installed.The steel used to produce TATA TISCON is of superior quality. Tata Steel owns
its captive raw material sources, and has the perfect combination of facilities like blast
furnace, L.D.and continuous billet casting. The resultant steel is of superior quality
containing no harmful residuals. As a result, properties of TATA TISCON are consistent and
TATA TISCON (12 mm dia and below) is
produced in a high speed Wire Rod Mill which is the most technologically advanced mill of
its kind in India.This mill has a walking hearth furnace, where the unique method of
uniform heating, leads to uniform properties in the product. The mill proper has a modern
sophisticated No Twist-Block with 10 stands arranged at right angles to one another. This
arrangement ensures excellent dimensional tolerance and surface quality free from
scratches and other rolling defects.
In addition, a fully modernized merchant
mill processes billets into TATA TISCON bars of larger sizes (16 mm and above).
||No cold twisting
||Higher and uniform
||No residual stress
||Yield strength 460 N/mm2 (min)*
Uniform properties all through due to TMT process.
|*(Typical values for 90% of
TATA TISCON bars are produced in Fe 415,
IS:1786 grade. However, carbon levels are restricted to much lower than the specification,
which results in excellent ductility, high bendability and superior weldability.
|(C + Mn/6)
|S & P
|*(Typical Values for 90% of heats)
|*(In case of weldable bars the carbon
content should be 0.25% max)