TMT Bars,Thermo mechanically treated bars are high strength deformed steel bars used in reinforced cement concrete (RCC) work manufactured with the help of advancement of technology. TMT bars are latest production in MS steel bars and have superior properties such as strength, ductility, welding ability, bending ability and highest quality standards at international level.
What is thermo mechanically treatment process?
By adopting thermo mechanically treatment process higher strength of TMT bars is obtained. In this process, steel bars get intensive cooling immediately after rolling. When the temperature is suddenly reduced to make surface layer hard, the internal core is hot at the same time. Due to further cooling in atmosphere and heat from the core, the tempering takes place. This process is expected to improve properties such as yield strength, ductility and toughness of TMT bars. With above properties, TMT steel is highly economical and safe for use. TMT steel bars are more corrosion resistant than Tor steel.
How to get higher strength of TMT bars?
Generally, higher strength of TMT bars can be obtained by increasing carbon content, micro alloying, and thermo mechanically treatment or cold twisting.
So far in India, cold twisting of bars is extensively used for the production of high strength bars. The two main ribs become helical when cold twisting process is done whereas these ribs in hot rolled bars are straight. The excess of carbon content threatens its property of welding ability.
In TMT bars, this problem has been eliminated. In these bars, carbon content has also been brought down leading to improved ductility and can be restricted to 0.2% to attain welding ability and at the same time no strength is lost. The joints can be welded by ordinary electrodes without any extra precautions.
Features of TMT Bars
- Better ductility and malleability
- High yield strength and toughness
- More bonding strength
- Earthquake resistance
- Corrosion resistance
- High thermal resistance
- Economical and safe in use
- No loss in strength at welded joints
- Ordinary electrodes used for welding the joints
- While purchasing TMT bars, notice identification mark on these bars from manufacturing firm.
- For big projects it is advised to check that only one type/grade of bars is brought to the site and is used in the project after conducting test for each lot. Do not use mixed, 2 or 3 types/grades bars in RCC work at one work.