Comparative
features of the
three main processes for production of High Strength Deformed Bars viz
(i) Cold
Twisting , (ii) Microalloying & (iii) so called TMT process are
tabulated
below:
S.No.
Production
process
Treatment
Production
Costs
Mechanical
Properties
Ductility
Weld-ability
1
Cold
Twisting
Cold
work hardening by means of: ¶Stretching
¶ Twisting
High
(Due to Manpower and Equipment)
Poor
Good
(deteriorating due to heat generated by welding)
2
Micro-
Alloying
Addition
of alloying elements as: C, Mn, V, Nb etc.
High
(Due to alloying elements and equipment)
Good
Poor
(Due to high carbon equivalent)
3
TMT
Process
Rapid
cooling and controlled cooling from rolling heat
Low
Excellent
Excellent
(Due to low carbon equivalent)
The
TMT bars have virtually
replaced the conventional cold twisted
deformed bars as
reinforcement material all over the world. With the increasing
availability of
TMT bars here, India
is also set to change over to the use of TMT bars.
References: “Latest developments on
steel front” by Jagvir
Goyal “Thermex Quenching and
Tempering Technology” by R.K. Markan, the
Chairman and Managing Director
of H&K India Websites
of SAIL,
Rajuri
steel & Evcon
virtually
replaced the conventional cold twisted
deformed bars as
reinforcement material all over the world. With the increasing
availability of
TMT bars here, 
