When it comes to construction, TMT Steel Bar is an unavoidable construction material as it offers better strength to the structure. Today, there are numerous construction materials, and we have many options, even in TMT Steel Bars like Fe 500, Fe 500D, and whatnot.
Fe 550 and Fe 550D are other variants of TMT Steel Bars that have become a go-to choice of many builders, contractors, and constructors. Are you wondering why the hype for them?
Well, this blog is tailored for you.
Here, we explain what Fe 550 and Fe 550D TMT Steel Bars are, the advantages they offer and their properties. So, let’s dive in.
What Is Fe 550 TMT Steel Bar?
The Fe 550 TMT bar is a high-strength variant designed for structures that must bear heavy loads.
Here, ‘Fe’ stands for iron, while ‘550’ denotes the minimum yield strength of 550 N/mm².
With superior tensile strength and load-bearing capacity, Fe 550 bars are ideal for:
- High-rise buildings
- Industrial complexes
- Bridges and heavy foundations
In short, Fe 550 bars combine strength and economy, allowing you to use fewer bars while maintaining structural integrity.
What Is Fe 550D TMT Steel Bar?
The Fe 550D TMT bar offers all the benefits of Fe 550 — with an added advantage: higher ductility.
The “D” stands for ductility, meaning it can bend and stretch slightly without cracking, making it perfect for areas prone to earthquakes or heavy vibrations.
It features improved chemical composition and mechanical strength, ensuring better weldability, flexibility, and corrosion resistance — ideal for critical infrastructure like flyovers, dams, and towers.
Advantages of Fe 550 and Fe 550D TMT Steel Bar?
Advantages of Fe 550 TMT Steel Bar
- High yield strength suitable for large and high-rise structures
- Superior tensile strength compared to Fe 500 grade
- Reduced steel consumption — fewer bars needed for the same strength
- Enhanced corrosion resistance, ideal for humid or coastal conditions
- Cost-effective due to lower material requirement
Advantages of Fe 550D TMT Steel Bar
- Even higher yield and tensile strength than Fe 550
- Excellent ductility for seismic resistance
- Lower carbon, sulphur, and phosphorus content ensures better durability
- Requires fewer bars and reduces overall labour costs
- Superior weldability and bendability
- Enhanced corrosion resistance and temperature stability
The Difference Between Fe 550 and Fe 550D TMT Steel Bar?
Both Fe 550 and Fe 550D offer great yield strength, tensile strength, and elongation properties. However, the specifications of Fe 550 and Fe 550D slightly differ. For instance, the Mechanical & Chemical properties of Fe 550D are a step higher than that of Fe 550.
Let’s take a look.
Fe 550 & Fe 550D – Difference in Mechanical Properties
| Parameter | Fe 550 | Fe 550D |
| Yield Strength (N/mm2) | 560 | 565 |
| Ultimate Tensile Strength (N/mm2) | 600 | 610 |
| Elongation (%) | 15% | 16% |
Fe 550 & Fe 550D – Difference in Chemical Properties
| Constituent | Fe 550 | Fe 550D |
| Carbon | 0.25 | 0.23 |
| Sulphur | 0.045 | 0.035 |
| Phosphorous | 0.04 | 0.035 |
| Manganese | >=0.60 | >=0.60 |
| Sulphur + Phosphorous | 0.08 | 0.07 |
The Manufacturing Process of Fe 550 and Fe 550D TMT Steel Bar
At Kairali TMT, both Fe 550 and Fe 550 go through a comprehensive 5-step manufacturing process at our automated rolling mill. Let’s see how the process works.
1. Processing Iron Ore
The process kickstarts with the processing of raw materials in the furnace. The impurities of iron are tackled through beneficiation. Next, steel conversion takes place through pre-treatment and ladle heating.
2. Producing & Moulding Billets
The molten steel is poured into the casting machine and heated at 1200°C. Now, the billet is moulded into rebars in the rolling mill stand.
3. Quenching
Thermo-mechanical treatment starts in this step. The rebars go through Quenching – a process where water is sprayed onto the hot bars. Ultimately, this process enables toughening of the outer material of the bar, while the core remains smooth.
4. Self-Tempering
Here, the heat of the core is transferred to the outer surface. This gives the bars extra toughness.
5. Atmospheric Cooling
Finally, the bars are left to cool down on an automatic cooling bed. This balances the temperature of the core and the outer part of the bars, making it a complete product.
Fe 550XD: An Even Stronger Grade of TMT Steel Bars
If you think you need a stronger version of Best TMT Bars, Kairali TMT’s latest addition Fe 550XD would be a great choice.
Everything from the yield strength and tensile strength to the elongation is better when compared with Fe 550. Furthermore, its cost-saving is higher.
Kairali TMT Fe 550 XD TMT bars are ideal for construction projects based in marine, coastal or underground environments.
In a Nutshell
Long story short, both variants offer better yield strength, tensile strength and elongation. We also provide tips on how to reduce construction cost using these materials. However, the 550D variant fares better when we compare both. Selecting one depends on your building project. If your project is marine-based or underground projects, the best bet would be to go for Fe 550 XD.
No matter which steel you use using it according to bar bending schedule is very important.Especially when it comes to beam you have to follow bar bending to schedule for beam.
Are you still unsure about which one to select for your project? Don’t worry. We will help you. Feel free to contact us.