TMT steel bars are steel bars that are manufactured with a unique metallurgical process known as “Thermo Mechanical Treatment”. This is the reason they are also known as Thermo Mechanically Treated steel.
TMT bars are a high-strength variety produced from low carbon steel by the quenching of the surface layer of the bar. The resulting pressure changes the crystal structure of the surface layer of the bar turning it into martensite and hence shrinks it. Martensite is a very hard crystal structure of steel and is highly durable.
Features of TMT bars
- Grade of the TMT Bar: TMT bars have multiple grades. Higher the grade number, the higher the strength and quality of the TMT bars. Currently, there are many different grades available of which Fe-415, Fe-500, Fe-550, & Fe-550D are the most common ones used in building structures. Since the TMT bars are used in the core of the construction structure like beams and columns, it is advisable to go in for a higher-grade TMT steel bar owing to better mechanical and chemical properties. While selecting a TMT bar from any TMT manufacturer, always select one with higher grades. In case, in an earthquake-prone zone like the north-east, higher grade TMT bars are a must.
- Brand and Certification: This is an important aspect to consider while selecting a TMT Bar. Before purchasing TMT Bars, always check the Brand profile and the ISO Certification of the brand. It is always advisable to go for brands that have BIS and ISO certification though they may cost you more. Reputed brands always comply with international safety standards.
- Bending ability: Construction materials should be easy to use as it will make the construction process better and swifter. Towards this end, it is advisable to go for TMT bars with excellent bendability capabilities which will allow the TMT bars to be molded into varied shapes and stretched to suit constructional measurements, and bent to suit building designs. This way, they will be able to withstand more structure loads and will be easy to use in different construction works.
- Corrosion Resistant: It is essential to check whether the TMT bars are corrosion-proof or not. Corrosion and rusting can create serious problems and ultimately hamper the quality of the construction. TMT bars are often exposed to moist conditions and hence, TMT bars need to be corrosion resistant.
- ISO Certification: Before buying TMT Bar you need to check the certification as well. ISO (International Standards Organization) certified TMT Bars are the must one you should choose. It ensures the quality TMT Bar.
- Seismic Resistance: Seismic resistant structure is dependent on its reinforcement strength. Buildings that are compliant with the recent seismic building code and standards are obviously more capable of withstanding the earthquake damages. TMT bars along with a good concrete bond, fortify the tensile strength of a structure. However, grades of the TMT bar differ at different seismic zones. Higher UTS/YS ratio and percentage determine the seismic property of a TMT bar. Uniform energy dissipation in every cycle is significant of the higher ductile strength and superior seismic resistance in a good quality TMT Bar, which is crucial to reduce structural damage and human casualties.
These were some of the factors that you should look for to choose TMT bars that are best for you. Additionally, market experts believe that buyers need to go by the NAKED TEST philosophy before choosing TMT bars. Under the NAKED TEST process, the TMT steel bars meet the following essentials:
- Contain manufacturer’s seal/logo on it.
- Look less rusty or worn-out.
- Have ends of each bundle of TMT rods in equal length.