TMT Rebar is the backbone of every type of construction in Nepal. Only the highest grade TMT Rebar can endure natural disasters such as earthquakes, floods, or fires. Hence, the quality cannot be compromised during manufacturing or selecting the best rebar. In the present scenario, Fe 500 and Fe 500D TMT Rebars are the most popular TMT rebars used in construction.
While the naming, Fe 500 and Fe 500D may seem a little confusing and a little too ‘sciencey’, they are categories that help to determine the grade of the steel. To be more exact, the letters ‘Fe’ stands for a chemical symbol of Iron in the periodic table, and the numbers such as Fe 500, Fe 600, and Fe 550 denote the quality and strengths of the bars (minimum stress yield in N/m²). Last but not least, ‘D’ in 500D and others represent the ductility of the bar.
As mentioned earlier, Fe 500 and Fe 500D are one of the most trusted and popular steels when it comes to construction. Although both of these steels are great for construction, a few differences set them apart, including chemical properties, durability, ductility, and of course the price. Detailed below are the differences between Fe 500 and Fe 500D and the properties that set them unique from each other.
What are the Differences between Fe 500 & Fe 500D TMT Rebar?
TMT steel bars are those steel bars that have been manufactured with a distinctive metallurgical process known as “Thermo Mechanical Treatment”. According to NS: 191 and BIS (IS: 1786:2008) Certification Standards, both Fe 500 and Fe 500D are varieties of TMT steel bars.
The letter ‘Fe,’ as in Fe 500, stands for iron, from which the TMT bars are manufactured. The number ‘500’ represents the minimum yield stress in N\m². Likewise, the letter “D” in Fe 500 D and other types denotes ductility, implying that the higher the number greater the percentage of elongation.
When it comes to the proof stress/yield stress (Min), it is the same for both Fe 500 and Fe 500D. However, the tensile strength of Fe 500D is enhanced by 2% as the minimum tensile strength for Fe 500 is 545 MPa and 565 MPa for Fe 500D.
While Fe 500 has a value of 12%, Fe 500D has an increased mandated minimum percentage elongation of 16%. When compared to Fe 500, Fe 500D has a maximum carbon content of 0.25%, while Fe 500 has a maximum carbon content of 0.30%. Additionally, the maximum concentrations of phosphorus and sulfur are lower in Fe 500D. The low quantities of chemicals such as carbon, sulfur, and phosphorous in Fe 500D contribute to the steel’s preservation and its ability to withstand future seismic shocks.
The D type of rods has a greater TMT bar elongation and tensile strength under tension or force. Because of their improved mechanical qualities, D-grade TMT bars are more resilient to natural disasters and stress.
| Property | Fe 500 | Fe 500D |
| 0.2 % proof stress/ Yield stress N/m2 | 500 | 500 |
| Elongation percentage | 12% | 16% |
| Tensile Strength | Fe 500 has a proof stress/yield stress 8 %higher than actual values of 0.2 percent, but not lower than 545.0 N/m2. | Fe 500 D has a proof stress and yields stress 10% higher than the actual 0.2 percent proof stress but not lower than 565.0 N/m2. |
Table 1: Differences in Physical Properties of Fe 500 and Fe 500D
Although the yield and tensile ratio are the same for both, the elongation percentage differs; the higher the elongation percentage, the better the TMT steel will perform under difficult circumstances.
| Chemicals | Fe 500 | Fe 500D |
| Carbon (%max) | 0.30 | 0.25 |
| Sulphur (%max) | 0.055 | 0.040 |
| Phosphorus (%max) | 0.055 | 0.040 |
| S+P (%max) | 0.105 | 0.075 |
A lower carbon concentration enhances the steel’s ability to be welded, while a lower impure phosphorus and sulfur content results in TMT rods that are tougher and more ductile.
Which grade TMT is best for house construction?
TMT bars are manufactured through a process known as Thermal Mechanical Treatment. Thus the bars have high strength reinforcement making them the best grade bars for construction purposes including the construction of houses.
Currently, three distinct grades of TMT steel bars, Fe- 415, Fe- 500, and Fe- 500D are available in the market. However, it is crucial to remember that these grades determine the steel bar’s strength; the greater the steel grade, the stronger the steel will be. Further, TMT bars have higher elongation compared to other steel bars. Due to the hard outer layer and soft inner core of TMT bars, the building structure can elongate, providing increased strength and flexibility, and protecting it from natural disasters such as earthquakes. Currently, FE 500D has a higher percentage of elongation than any other Grade of TMT Rebar.
- Fe 500 is ideal for all common building projects, including houses, apartments, stores, and more.
- Fe 500D is more suitable for the construction of high-end structures such as Skyscrapers, factories, dams, and others.
- Particularly in seismic zones, Fe 500D should be used above other materials for buildings in earthquake-prone locations.
What are the Special Features of TMT Steel Bar?
When it comes to the construction of houses or any other buildings the demand for TMT steel bars is considered the best option. Low levels of phosphorus and sulfur, which are detrimental to steel specimens intended for use in construction, are present in TMT steel bars. Higher phosphorus levels can result in “Cold Shortness,” which renders steel brittle at extremely cold temperatures and can cause cracking. Higher sulfur concentration can cause “Hot Shortness,” which lowers the steel’s melting point and eventually causes failure under extremely hot temperatures. These bars also maintain a low total carbon content in order to increase the steel’s ductility and weldability. Other special features of TMT steel bars are:
Best Paired with Concrete – TMT rebars are a perfect material to employ with concrete to strengthen constructions because of their great strength. The TMT rebars’ distinctive ribbed design gives them greater strength by tying them more closely to concrete.
Corrosion Resistant – The TMT rebars get anti-rust qualities as a result of the Thermal Mechanical Treatment production process. TMT rebars are corrosion-free and moisture-resistant, making them suitable for building projects near sewage drains and other wet environments.
Earthquake Resistant – TMT rebars are entirely earthquake resistant because of their elongation feature. It may elonggate longer than its initial length without cutting dimensions, eventually being cost effective during construction. Additionally, the soft core of TMT rebars imparts a high amount of flexibility, providing TMT constructions additional freedom in dealing with dynamic and seismic loads.
Cost Effective – TMT rebars offer higher tensile strength and elongation value, which implies less steel is required for the same quantity of construction. This saves money on shipping and storage in addition to lowering the cost of raw materials. TMT steel bars are also easier to control on-site, resulting in additional cost savings owing to shorter construction and fabrication times. Higher tensile strength and better elongation value TMT (Thermo-Mechanically Treated) rebars can help in cost saving in several ways:
- Reduced steel consumption: TMT rebars with higher tensile strength can withstand higher stress and strain before yielding, which means that less steel is needed to achieve the same level of strength as conventional rebars. This can lead to a reduction in the amount of steel required for construction, which can result in cost savings.
- Increased durability: TMT rebars with better elongation values can withstand greater deformation before breaking, which can increase the durability and longevity of structures. This means that structures built with TMT rebars may require less maintenance and repair over time, resulting in cost savings.
- Improved construction speed: TMT rebars with higher tensile strength and better elongation values can be bent and shaped more easily than conventional rebars, making them easier to work with during construction. This can lead to faster construction times, which can result in cost savings.
- Reduced waste: Because TMT rebars with higher tensile strength and better elongation values are stronger and more durable, they are less likely to break during handling and installation. This can reduce the amount of waste generated during construction, which can result in cost savings.
Overall, the use of TMT rebars with higher tensile strength and better elongation values can help in cost saving by reducing steel consumption, increasing durability, improving construction speed, and reducing waste.
Why Fe 500D is the most preferred TMT Bar?
When selecting the correct TMT bars, it is critical to consider their strength depending on their grade. The greater the grade, the higher the quality of the TMT bars. Fe 500D Grade TMT Rebars rate exceptionally well in this category, delivering the optimal combination of strength and flexibility in accordance with IS Standards. Furthermore, because of their extraordinary flexibility in accordance with the same standards, they are perfect for all sorts of construction projects.
When it comes to steel bars for construction in Nepal, Jagadamba Steel has been the backbone of every construction in Nepal including those considered nation’s pride for more than two decades. Maintaining their high standard of quality service, Jagdamba Steel has been providing steel of the highest quality like FE 500D Rebar.
The combined restriction of impurities like sulfur and phosphorous to a maximum of 0.075 percent in Rhino Steel Rebar in grade Fe 500D assures improved strength and ductility in the rebar. Sizes 8 mm and up to 32 mm of Rhino 500D Rebar are offered at retail locations all throughout Nepal. According to the needs of the customer or project, it is also offered in 36 mm and 40 mm diameters. To assure consistent processing and reduce fabrication waste, each rebar is delivered at a predetermined length of 12 meters.