MS Angles & Channels — Complete Guide
Mild Steel (MS) Angles and Channels are hot-rolled structural steel sections widely used in construction, fabrication, and engineering. They form the backbone of structural steel frameworks — trusses, columns, beams, brackets, supports, and frames — thanks to their high strength-to-weight ratio and economy.
In India, these sections are governed by IS 2062 — Hot Rolled Medium and High Tensile Structural Steel, with their dimensions standardised under IS 808 (Dimensions for Hot Rolled Steel Beam, Column, Channel and Angle Sections).
What are MS Angles & Channels?
MS Angles are L-shaped structural steel sections with two perpendicular legs. MS Channels are U-shaped sections with a vertical web and two horizontal flanges. Both are produced by hot-rolling mild steel billets.
Common designations: ISA (Indian Standard Angle), ISMC (Indian Standard Medium Channel), ISLC (Indian Standard Light Channel), ISJC (Indian Standard Junior Channel).
Types of Angles
1. Equal Angles (ISA)
Both legs of equal length. Most common type used in trusses, frames, brackets.
2. Unequal Angles (ISA)
Legs of different lengths. Used where load is unequal in two directions.
| Designation | Size (mm) | Thickness (mm) | Weight (kg/m) |
|---|
| ISA 25x25x3 | 25 x 25 | 3 | 1.1 |
| ISA 35x35x5 | 35 x 35 | 5 | 2.6 |
| ISA 40x40x5 | 40 x 40 | 5 | 3.0 |
| ISA 50x50x5 | 50 x 50 | 5 | 3.8 |
| ISA 50x50x6 | 50 x 50 | 6 | 4.5 |
| ISA 60x60x6 | 60 x 60 | 6 | 5.4 |
| ISA 65x65x6 | 65 x 65 | 6 | 5.8 |
| ISA 75x75x6 | 75 x 75 | 6 | 6.8 |
| ISA 75x75x8 | 75 x 75 | 8 | 8.9 |
| ISA 90x90x8 | 90 x 90 | 8 | 10.8 |
| ISA 100x100x10 | 100 x 100 | 10 | 14.9 |
| ISA 130x130x12 | 130 x 130 | 12 | 23.6 |
| ISA 150x150x12 | 150 x 150 | 12 | 27.3 |
| ISA 200x200x16 | 200 x 200 | 16 | 48.2 |
Types of Channels
Indian Standard Medium Channels (ISMC) — Most Common
| Designation | Depth (mm) | Flange Width (mm) | Web Thickness (mm) | Weight (kg/m) |
|---|
| ISMC 75 | 75 | 40 | 4.4 | 7.14 |
| ISMC 100 | 100 | 50 | 4.7 | 9.56 |
| ISMC 125 | 125 | 65 | 5.0 | 13.10 |
| ISMC 150 | 150 | 75 | 5.4 | 16.40 |
| ISMC 175 | 175 | 75 | 5.7 | 19.10 |
| ISMC 200 | 200 | 75 | 6.1 | 22.10 |
| ISMC 225 | 225 | 80 | 6.4 | 25.90 |
| ISMC 250 | 250 | 80 | 7.1 | 30.40 |
| ISMC 300 | 300 | 90 | 7.6 | 36.30 |
| ISMC 400 | 400 | 100 | 8.6 | 49.40 |
Other Channel Types
- ISLC (Indian Standard Light Channels) — lighter weight
- ISJC (Indian Standard Junior Channels) — smallest, for light work
- ISPC / Parallel Flange Channels — modern variant with parallel flanges
Chemical Composition (IS 2062, E250 Grade)
| Element | Maximum % |
|---|
| Carbon (C) | 0.23 |
| Manganese (Mn) | 1.50 |
| Sulphur (S) | 0.045 |
| Phosphorus (P) | 0.045 |
| Silicon (Si) | 0.40 |
| Carbon Equivalent (CE) | 0.42 |
Mechanical Properties (IS 2062 E250)
| Property | Value |
|---|
| Yield Strength (Min.) | 250 MPa |
| Ultimate Tensile Strength (Min.) | 410 MPa |
| Elongation (Min.) | 23% |
| Impact Test (Charpy V-Notch at 0°C) | 27 J (min) |
| Bend Test | 180° bend without cracks |
Steel Grades Under IS 2062
- E165 (Fe 290) — min yield 165 MPa
- E250 (Fe 410W) — min yield 250 MPa (most common)
- E300 (Fe 440) — min yield 300 MPa
- E350 (Fe 490) — min yield 350 MPa
- E410 (Fe 540) — min yield 410 MPa
- E450 (Fe 570) — min yield 450 MPa
Standard Lengths
- Standard length: 11 metres / 12 metres
- Custom lengths available on order
- Random lengths (RL): 4 – 8 metres (for small jobs)
Uses of MS Angles
- Roof trusses (especially residential and industrial)
- Frames for shutters, gates, grills
- Brackets and supports
- Door and window frames in industrial buildings
- Tower structures (transmission, telecom)
- Furniture, racks, shelving
- Reinforcement of edges
- Cable trays and ladders
- Industrial machine frames
- Cross-bracing of columns
- Stairs and railings
- Cleat angles for connections
Uses of MS Channels
- Columns of light steel structures
- Purlins for industrial roofing
- Frames for sheds and warehouses
- Cross beams in light steel buildings
- Lintels (in steel-framed buildings)
- Bridges and walkway supports
- Vehicle chassis and trailers
- Door and window frames (heavier)
- Cable trays
- Mezzanine floor beams
- Conveyor structures
- Industrial machine bases
Connection Methods
1. Welded Connections
Continuous fillet welds or butt welds. Strong, permanent, but require skilled welders. Welding procedure conforms to IS 9595.
2. Bolted Connections
Using HSFG (High-Strength Friction Grip) bolts or black bolts. Allow disassembly. Bolt grades per IS 1367.
3. Riveted Connections
Older method, largely replaced by welds/bolts. Used in heritage structures and railway works.
Weight Calculation Formulas
Weight of Angle = (2 × Leg Length - Thickness) × Thickness × 7.85 (kg/m, with mm dimensions in dm)
Weight of Channel ≈ (Web + 2 × Flange) × Thickness × 7.85 (kg/m approximation)
Refer to IS 808 or manufacturer tables for exact weights.
Surface Treatment
- Mill Finish: Standard supply, with mill scale on surface
- Red Oxide Primer: Anti-rust paint after fabrication
- Galvanised (Hot-Dip): Zinc coating for outdoor / corrosive use
- Powder Coating: Decorative finish for indoor use
- Epoxy Coating: Chemical-resistant industrial finish
Field & Laboratory Tests
- Tensile Test (yield, ultimate, elongation) — IS 1608
- Bend Test — IS 1599
- Charpy V-Notch Impact Test — IS 1757
- Dimensional Verification (depth, width, thickness)
- Weight per metre verification
- Chemical Composition Analysis (mill test certificate)
- Visual inspection for surface defects, twists, bends
- Ultrasonic test (for critical applications)
Storage
- Store under cover, off the ground on wooden sleepers
- Stack flat with separators between layers
- Protect from rain to minimize surface rust
- Apply red oxide primer before long-term storage
- Tag bundles with size, grade, mill, lot number
- Allow ventilation between stacks
Cost (Approximate, Indian Market)
| Item | Price per kg (Rs) | Price per Tonne (Rs) |
|---|
| MS Angles (ISA) | 60 – 80 | 60,000 – 80,000 |
| MS Channels (ISMC) | 62 – 85 | 62,000 – 85,000 |
| GI Galvanised Angles | 85 – 110 | 85,000 – 110,000 |
Popular Manufacturers in India
- SAIL (Steel Authority of India)
- Tata Steel
- JSW Steel
- Jindal Steel
- Vizag Steel (Rashtriya Ispat)
- Essar Steel / ArcelorMittal Nippon Steel India
- Bhushan Power & Steel
- Local re-rolling mills (regional)
Conclusion
MS Angles and Channels are the building blocks of steel-framed construction. The right size selection (ISA for L-sections, ISMC for U-sections) depends on the load, span, and connection details. Always procure IS 2062-certified sections with a valid Mill Test Certificate.
For roof trusses and light fabrication, MS angles like ISA 50x50x6 or 75x75x6 are popular. For columns and beams of small steel structures, ISMC 100 to ISMC 200 are commonly used.