TMT bars of the same grade usually have more than one type, while it is uncommon to hear about Fe 415D or Fe 415S. One must surely be heard of Fe 500 and Fe 500D, here Fe stands for iron, 500 stands for the tensile strength and D stands for ductility. Other than the names they also have a different chemical composition as well. When talking about carbon content Fe 415 has a maximum per cent 0.30 carbon while Fe 415 D and Fe415 S has a maximum carbon per cent of 0.25.
While the standard Fe 415 TMT bar has a maximum per cent of 0.060 Sulphur, the TMT bars of Fe 415 S and Fe 415 D has a maximum Sulphur content of 0.045. It is a similar story when it comes to Phosphorus as well, while the standard Fe 415 has a maximum Phosphorus content of 0.060%, the specialist Fe 415D has a maximum Phosphorus content of 0.045% and Fe 415S also a maximum Phosphorus content of 0.045%. When taking the combined Phosphorus and Sulphur content, the standard TMT bars have a maximum of 0.110% and the specialists Fe 415S and Fe 415D have Sulphur and Phosphorus content of 0.085%.
These specialists TMT bars are manufactured for projects which require a high degree of elongation or for a project where a higher grade of tensile strength is needed. These bars have allowed engineers to balance the needs, demands of the clients with their budgets as well. These specialist TMT bars have allowed the common man to build their dream home without pinching their pockets too much. These bars also developed with keeping specific geographical areas as well, for example, Fe 415 S is very resistant earthquakes when compared with its standard sibling.