Description
IS 4923 Gr YST 210 YST 240 YST 310 Square Rectangular Circular Hollow Sections
IS 4923 is the Indian Standard specification that governs hollow steel sections for structural use. These are cold-formed welded steel tubes used extensively in construction, architectural applications, and infrastructure development. The standard ensures that structural steel pipes meet the required mechanical properties and dimensional tolerances for safety and durability in structural applications.
Key Features
Scope
Covers cold-formed rectangular, square, and circular hollow steel sections used in structural applications, including frames, trusses, bridges, towers, and industrial structures.
Material
Usually made from hot-rolled steel coils or sheets, which are cold-formed and electric resistance welded (ERW) into desired hollow profiles.
Shapes Covered
- Square Hollow Sections (SHS)
- Rectangular Hollow Sections (RHS)
- Circular Hollow Sections (CHS) (also known as structural pipe)
IS 4923 Chemical Composition
| Element | YST 210 | YST 240 | YST 310 |
|---|---|---|---|
| Carbon (C) | 0.20% | 0.20% | 0.22% |
| Manganese (Mn) | 1.30% | 1.30% | 1.50% |
| Sulphur (S) | 0.040% | 0.040% | 0.040% |
| Phosphorus (P) | 0.040% | 0.040% | 0.040% |
| Carbon Equivalent (CE)** | 0.45% max | 0.45% max | 0.50% max |
IS 4923 Mechanical Properties
| Property | YST 210 | YST 240 | YST 310 |
|---|---|---|---|
| Yield Strength (Min) | 210 MPa | 240 MPa | 310 MPa |
| Tensile Strength (Min) | 330 MPa | 410 MPa | 450 MPa |
| Elongation (Min, % on gauge length of 5.65 √S0) | 20% | 15% | 10% |
| Flattening / Bend Test | Required | Required | Required |
Available Grades Under IS 4923
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) |
|---|---|---|
| YST 210 | 210 MPa | 330 MPa min |
| YST 240 | 240 MPa | 410 MPa min |
| YST 310 | 310 MPa | 450 MPa min |
Advantages of IS 4923 Compliant Pipes
- Superior Dimensional Accuracy: Ensures tight tolerances, which makes fabrication and assembly easier.
- Higher Strength-to-Weight Ratio: Hollow sections are lighter yet strong — making building with structural pipe more efficient.
- Enhanced Aesthetics: Square and rectangular tubes provide clean edges and modern appeal.
- Economical: Cold-formed tubes are cost-effective and readily available.
Applications
- Architectural Frameworks: Aesthetic and strong square/rectangular profiles for facades and support structures.
- Industrial Structures: Used in conveyors, mezzanines, and steel structures due to high strength.
- Railings and Fencing: Especially with black structural pipe, offering clean finish and strength.
- Sign Boards and Lighting Poles: Circular sections are ideal for load and wind resistance.
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