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?

Fe 550 is one of the variants of TMT Steel Bars, which is ideal for high-rise buildings and other structures that require bearing a lot of weight. Here, ‘Fe’ refers to the iron content present in the bar, and 550 refers to the minimum yield strength of the bar. Fe 550 TMT bars also have better tensile strength when compared with their predecessors. 

What Is Fe 550D TMT Steel Bar?

Fe 550D is another grade of TMT Steel Bar that provides better minimum yield strength and tensile strength than the 550 variant. The ‘D’ denotes the flexible property of Fe 550D TMT Steel Bars, making it the right option for earthquake-prone areas. Moreover, the minimum yield strength of this grade is higher than Fe 550 bars. 

Advantages of Fe 550 and Fe 550D TMT Steel Bar?

Fe 550 TMT Steel Bar Advantages

  • It has high yield strength, making it ideal for large buildings. 
  • It offers better tensile strength when compared with Fe 500 variant, giving structures better elongation. 
  • Stronger than Fe 500 means you need to buy fewer bars, helping you save cost. 
  • It’s good for supporting large buildings and high-rise projects. 
  • Fe 550 is corrosion-resistant 

Fe 550D TMT Steel Bar Advantages

  • The Fe 550D grade bar boasts better yield and tensile strength than the 550 variant. Hence, it’s the best for heavy structures like dams, towers, flyovers, and more.
  • It has high flexibility, which helps in withstanding seismic activity. 
  • Cost saving is better than 550 grade since you need less number of bars, thanks to its strength.  
  • Since you require fewer bars, you could cut down the labour costs as well. 
  • It also offers high weldability. 
  • The comparatively low carbon, sulphur, and phosphorous enable it to stay unaffected during temperature variations. This also gives it better durability.  
  • It has the ability to resist corrosion

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

ParameterFe 550Fe 550D
Yield Strength (N/mm2)560565
Ultimate Tensile Strength (N/mm2)600610
Elongation (%)15%16%

Fe 550 & Fe 550D – Difference in Chemical Properties

ConstituentFe 550Fe 550D
Carbon0.250.23
Sulphur0.0450.035
Phosphorous0.040.035
Manganese>=0.60>=0.60
Sulphur + Phosphorous0.080.07

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

Click here to learn more

In a Nutshell

Long story short, both variants offer better yield strength, tensile strength, and elongation. 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

Are you still unsure about which one to select for your project? Don’t worry. We will help you. Feel free to contact us.