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THE NEW GENERATION TATA TISCON

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 properties.

TEMPCORE (TMT) TECHNOLOGY

TATA TISCON is produced using the world’s 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 this stage.

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.

SUPERIOR PRODUCT QUALITY

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 predictable.

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).

 

PRODUCT SUPERIORITY
  
High Ductility No cold twisting Higher and uniform strength
Elongation 18-25%* No residual stress Yield strength 460 N/mm2 (min)*
Uniform properties all through due to TMT process.
*(Typical values for 90% of cases)

  

CHEMICAL COMPOSITION

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.

Chemistry Unit IS:1786 TATA TISCON*
   Fe 415
Carbon % 0.03**max 0.17-0.24
Carbon equivalent % 0.38 max
(C + Mn/6)      
Sulphur % 0.060 max 0.050 max
Phosphorous % 0.060 max 0.045 max
S & P % 0.110 max 0.090 max
Nitrogen ppm - 100 max
*(Typical Values for 90% of heats)
*(In case of weldable bars the carbon content should be 0.25% max)

 

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