Types of Structural Steel as per IS Codes
Structural steel is one of the most important construction materials used in buildings, bridges, industrial structures, transmission towers, and infrastructure projects. Steel structures are generally built using hot-rolled steel sections manufactured according to Indian Standard specifications.
IS 800:2007 is the primary code of practice for the use of structural steel in general building construction in India. Different grades of steel are specified for different applications depending on strength, weldability, ductility, and corrosion resistance.
Steel Structures Built Using Hot-Rolled Steel Sections
- Hot-rolled sections are manufactured using structural steel.
- Structural steel sections are widely used in buildings, bridges, industrial sheds, towers, and offshore structures.
- IS 800:2007 provides guidelines for design, fabrication, and erection of steel structures.
Types of Structural Steel
| IS Code | Steel Type | Main Characteristics |
|---|---|---|
| IS 226 | Standard Quality Steel | General structural steel for buildings and bridges |
| IS 2062 | Fusion Welding Quality Steel | Suitable for welded structures |
| IS 961 | High Tensile Steel | Higher strength and corrosion resistance |
| IS 1977 | Ordinary Quality Steel | Used for general engineering applications |
| IS 8500 | Medium and High Strength Steel | Micro-alloyed high strength structural steel |
1. IS 226 – Standard Quality Structural Steel
IS 226 steel is one of the most commonly used structural steels for buildings, bridges, industrial structures, and transmission towers.
Main Features
- Suitable for riveted and bolted connections.
- Welding permitted for thickness up to 20 mm.
- Carbon content ranges from 0.23% to 0.25%.
- Elongation approximately 23%.
- Designated as Fe 410-S.
Applications of IS 226 Steel
- Residential and commercial buildings
- Industrial sheds
- Bridge structures
- Transmission towers
- General structural fabrication
2. IS 2062 – Fusion Welding Quality Steel
IS 2062 steel is specially developed for structures where welding is extensively used. It is widely used in structures subjected to dynamic loading and impact forces.
Main Features
- Suitable for welded construction in all thicknesses.
- Used for crane girders, bridge girders, and dynamic structures.
- Better weldability compared to ordinary structural steel.
- Carbon content approximately 0.20% to 0.25%.
- Elongation approximately 23%.
Common Grades
- Fe 410 WA
- Fe 410 WB
- Fe 410 WC
Applications of IS 2062 Steel
- Bridge decking
- Crane girders
- Industrial structures
- Heavy welded structures
- Dynamic load carrying structures
3. IS 961 – High Tensile Structural Steel
IS 961 high tensile steel provides greater strength and better atmospheric corrosion resistance compared to ordinary structural steel.
Main Features
- High strength-to-weight ratio.
- Improved atmospheric corrosion resistance.
- Suitable for heavily loaded structures.
- Reduced structural dead weight.
Types of High Tensile Steel
- Fe 570-HT: Used for structures fabricated without fusion welding.
- Fe 540-W-HT: Used for structures involving fusion welding.
Typical elongation for high tensile steel is approximately 20%.
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Mechanical Properties of Structural Steel
| Type of Steel | Grade / Classification | UTS (MPa) | Yield Strength (MPa) | Elongation (%) | ||
|---|---|---|---|---|---|---|
| < 20 mm | 20 – 40 mm | > 40 mm | ||||
| Standard Structure Steel (IS 226 & IS 2062) | E250 (Fe 410A) | 410 | 250 | 240 | 230 | 23 |
| E250 (Fe 410B) | 410 | 250 | 240 | 230 | 23 | |
| E250 (Fe 410C) | 410 | 250 | 240 | 230 | 23 | |
| Micro Alloyed High Strength Steel (IS 8500) | Fe 440 | 440 | 300 | 290 | 280 | 22 |
| Fe 540 | 540 | 410 | 390 | 380 | 20 | |
| Fe 590 | 590 | 450 | 430 | 420 | 20 | |
Understanding Important Terms
Ultimate Tensile Strength (UTS)
Ultimate tensile strength is the maximum stress that steel can withstand before failure.
Yield Strength
Yield strength is the stress at which steel begins to deform permanently.
Elongation
Elongation indicates ductility and the ability of steel to deform before fracture.
Advantages of High Strength Structural Steel
- Reduced self-weight of structures
- Higher load carrying capacity
- Better corrosion resistance
- Suitable for long-span structures
- Economical steel usage
- Improved structural efficiency
Applications of Structural Steel Grades
| Steel Grade | Applications |
|---|---|
| Fe 250 / E250 | General buildings and industrial structures |
| Fe 410 | Bridges and heavy structural work |
| Fe 540 | Heavy load carrying structures |
| Fe 590 | Long-span and high-rise structures |
Conclusion
Structural steel is available in different grades and specifications to satisfy various engineering requirements. The proper selection of steel grade depends on structural loading, fabrication method, welding requirements, durability, and economy. Understanding IS codes and steel properties is essential for safe and efficient structural design.
References
- IS 800:2007 – General Construction in Steel
- IS 2062 – Hot Rolled Medium and High Tensile Structural Steel
- IS 8500 – Structural Steel Micro Alloyed
- Design of Steel Structures by N. Subramanian
- Limit State Design of Steel Structures by S.K. Duggal
Disclaimer
This article is intended for educational and informational purposes only. Engineers should always refer to the latest IS codes, project specifications, and professional engineering judgment before final design and construction.
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