Reinforced concrete is a widely used construction material due to its durability and strength. Steel reinforcement is added to concrete to enhance its strength, ductility, and toughness. The selection of steel grade is a critical decision that can impact the performance and cost of the structure. In this article, we will compare the two most commonly used steel grades for reinforced concrete – FE500 and FE550 – and help you decide which one is better for your construction project.

 

What are Fe 500 and Fe 550?

Definition of Fe 500

Fe 500 is a grade of TMT steel bar that is commonly used in construction projects. “Fe” denotes iron, and “500” indicates the minimum yield stress of the bar in megapascals. Fe 500 TMT bars are ductile and have high tensile strength, making them ideal for reinforced concrete structures.

Definition of Fe 550

Fe 550 is another grade of TMT steel bar that is used in construction projects. It has a minimum yield stress of 550 megapascals, which is higher than that of Fe 500. Fe 550 TMT bars are also ductile and have high tensile strength.

 

 

Understanding the Differences between FE500 and FE550 Steel Grades

FE500 and FE550 are both high strength deformed steel bars that comply with the Indian Standard IS 1786. The “FE” in FE500 and FE550 stands for “High Yield Strength” (FY), which means that the steel has a minimum yield strength of 500 N/mm² and 550 N/mm², respectively. The higher the yield strength, the better the steel’s ability to withstand bending and deformation.

FE500 and FE550 steel grades differ mainly in their carbon content, which affects their strength properties. FE550 steel has a higher carbon content than FE500, making it stronger and more suitable for high load-bearing structures.

 

Strength Properties of FE500 and FE550 Steel Grades

Tensile strength comparison

FE500 has a minimum tensile strength of 545 N/mm², while FE550 has a minimum tensile strength of 585 N/mm². This means that FE550 steel can withstand more stress than FE500 steel before breaking.

Yield strength comparison

FE500 has a minimum yield strength of 500 N/mm², while FE550 has a minimum yield strength of 550 N/mm². This means that FE550 steel can withstand more stress than FE500 steel before it starts to deform permanently.

Ductility comparison

Ductility is the ability of a material to undergo plastic deformation before failure. FE500 and FE550 steel grades have similar ductility properties, with elongation values of at least 12% and 8%, respectively.

Effect of temperature on strength

Both FE500 and FE550 steel grades exhibit a reduction in strength at high temperatures. However, FE550 has a higher resistance to thermal degradation due to its higher carbon content.

 

Durability Properties of FE500 and FE550 Steel Grades

Corrosion resistance comparison

Corrosion is a major concern in reinforced concrete structures, as it can weaken the steel reinforcement and affect the overall structural integrity. FE500 and FE550 steel grades have similar corrosion resistance properties, but FE550 has slightly better resistance due to its higher carbon content.

Fatigue resistance comparison

Fatigue is a phenomenon where repeated loading and unloading cycles can lead to structural failure. FE550 steel has better fatigue resistance than FE500 steel, making it more suitable for structures that are subjected to cyclic loading, such as bridges and high-rise buildings.

Creep resistance comparison

Creep is a time-dependent deformation that occurs under sustained load. FE550 steel has better creep resistance than FE500 steel, making it more suitable for structures that are subjected to sustained loads over a long period of time.

 

Cost Comparison of FE500 and FE550 Steel Grades

Manufacturing cost comparison

FE550 steel is more expensive to manufacture than FE500 steel due to its higher carbon content and additional processing steps required to achieve the desired strength properties.

Market price comparison

FE550 steel is more expensive than FE500 steel in the market due to its higher strength properties and better durability performance.

Life cycle cost comparison

The selection of steel grade can impact the overall cost of the structure over its life cycle. While FE550 steel may have a higher initial cost, its better durability properties can lead to reduced maintenance and repair costs over the life of the structure, making it a more cost-effective choice in the long run.

 

Applications of FE500 and FE550 Steel Grades

FE500 applications

FE500 steel is suitable for most reinforced concrete structures, including buildings, bridges, and dams. It is commonly used in low-rise buildings, where the load-bearing requirements are not very high.

FE550 applications

FE550 steel is suitable for high-rise buildings, long-span structures, and structures subjected to high loads, such as bridges, industrial plants, and power plants. It is also suitable for seismic zones, where the structures are subjected to earthquake forces.

Suitability for different structural elements

The selection of steel grade should also consider the suitability of the steel for different structural elements, such as beams, columns, and slabs. FE550 steel is more suitable for beams and columns, while FE500 steel may be sufficient for slabs.

 

Which grade of TMT bar is ideal for construction?

Fe 500 TMT bars

Fe 500 TMT bars are the most commonly used TMT bars in construction projects in India. They are ideal for small and medium-sized construction projects.

Fe 550 TMT bars

Fe 550 TMT bars are ideal for larger construction projects such as high-rise buildings, bridges, and dams, which require higher tensile strength and ductility.

Fe 500D and Fe 550D grade TMT bars

Fe 500D and Fe 550D grade TMT bars have higher ductility than Fe 500 and Fe 550 TMT bars. They are ideal for areas prone to seismic activity, where they can better withstand the effects of earthquakes.

 

How do the grades affect the properties of steel bars?

Tensile strength of Fe 500 and Fe 550 TMT bars

As discussed earlier, Fe 550 has a higher tensile strength than Fe 500. The ultimate tensile strength of Fe 550 is around 20% higher than Fe 500’s ultimate tensile strength.

Elongation of Fe 500 and Fe 550 TMT bars

Elongation refers to the ability of a TMT bar to deform before breaking. Fe 550 has a higher elongation than Fe 500, making it more ductile and able to withstand more deformation.

Ductility of Fe 500 and Fe 550 TMT bars

Both Fe 500 and Fe 550 TMT bars are ductile, but Fe 550 is more ductile than Fe 500. This means that Fe 550 TMT bars can better withstand deformation under stress.

 

What are the major differences between Fe 500 and Fe 550 TMT bars?

Corrosion resistance differences between Fe 500 and Fe 550 TMT bars

Fe 550 TMT bars have higher corrosion resistance than Fe 500 TMT bars, making them ideal for construction projects in areas with high humidity and rainfall.

Seismic resistance differences between Fe 500 and Fe 550 TMT bars

Fe 550 TMT bars have better seismic resistance than Fe 500 TMT bars. They can better withstand the effects of earthquakes, making them ideal for construction projects in areas prone to earthquakes.

Phosphorus content differences between Fe 500 and Fe 550 TMT bars

Fe 550 TMT bars have a lower phosphorus content than Fe 500 TMT bars. The higher the phosphorus content, the greater the risk of embrittlement of the steel bar during welding. Therefore, Fe 550 TMT bars are more suitable for welding. In conclusion, both Fe 500 and Fe 550 TMT bars are ideal for construction projects. Fe 500 TMT bars are suitable for small and medium-sized construction projects, while Fe 550 TMT bars are suitable for larger construction projects that require higher tensile strength and ductility. The choice of TMT bar grades depends on the nature and scale of the construction project.

 

FAQs

What is the meaning of FE in FE500 and FE550?

FE stands for “High Yield Strength” (FY) in these steel grades, which means that the steel has a minimum yield strength of 500 N/mm² and 550 N/mm², respectively.

Which steel grade is better for earthquake-prone areas?

FE550 steel is more suitable for seismic zones, where the structures are subjected to earthquake forces.

What is the difference between Fe500D and Fe550D?

The “D” in these steel grades stands for “Ductility,” which means that the steel has a minimum elongation of 14.5% and 10%, respectively. The main difference between Fe500D and Fe550D is their yield strength, which is 500 N/mm² and 550 N/mm², respectively.

Is FE550 steel always a better choice than FE500 steel?

Not necessarily. The selection of steel grade should consider various factors, such as the load-bearing requirements, the durability requirements, and the cost. FE550 steel is a better choice for structures that are subjected to high loads, cyclic loading, and sustained loads over a long period of time. However, FE500 steel may be sufficient for low-rise structures with less demanding load-bearing requirements.

Can FE500 and FE550 steel grades be used interchangeably?

No, FE500 and FE550 steel grades cannot be used interchangeably, as they have different mechanical and physical properties. The selection of steel grade should be based on the specific project requirements and constraints.

 

Conclusion

The selection of steel grade for reinforced concrete structures is an important decision that should consider various factors, such as the load-bearing requirements, the durability requirements, and the cost. FE500 and FE550 steel grades have different mechanical and physical properties, and the selection should be based on a comprehensive analysis of the specific project requirements and constraints. While FE550 steel may have a higher initial cost, its better durability properties can lead to reduced maintenance and repair costs over the life of the structure, making it a more cost-effective choice in the long run.