The Ultimate Guide to Sheet Metal Fabrication in India: Gauges, Materials, Laser Cutting, and Bending Specs
Whether you are designing custom enclosures, industrial machinery components, or architectural metalwork, understanding the fundamentals of sheet metal fabrication is key to optimizing both cost and quality.
In this guide, we break down the most common metal grades used in India, sheet metal gauge-to-millimeter conversions, laser cutting power requirements, and bending tolerance standards.
1. Popular Metal Types Used in Indian Fabrication
Selecting the right material depends on your project’s structural requirements, environmental exposure, and finishing needs:
- Mild Steel (MS): The primary workhorse of Indian industrial fabrication. Highly weldable, cost-effective, and easy to form. Requires surface finishing such as powder coating or zinc plating to prevent oxidation.
- Galvanized Iron / Steel (GI / GP): Mild steel coated with a layer of zinc to provide corrosion resistance. Widely used for HVAC ducting, outdoor enclosures, and roofing.
- Stainless Steel (SS 304 / SS 316): Highly resistant to corrosion and heat. SS 304 is the default choice for general industrial panels and food-grade equipment, while SS 316 is ideal for marine and chemical environments.
- Aluminum (AL 5052 / AL 6061): Lightweight, non-magnetic, and inherently corrosion-resistant. Preferred for aerospace, automotive, and outdoor electronics enclosures.
2. Sheet Metal Gauge (SWG) to Thickness Reference
In India, sheet thickness is commonly designated using the Standard Wire Gauge (SWG) system or direct millimeter (mm) measurements.
Pro Tip: Remember that as the gauge number goes down, the metal thickness goes up.
| Gauge (SWG) | Carbon / Mild Steel (mm) | Stainless Steel (mm) | Galvanized Steel (mm) | Aluminum (mm) | Typical Applications |
| 10 Gauge | 3.42 | 3.42 | 3.51 | 2.59 | Heavy chassis, structural brackets, base plates |
| 12 Gauge | 2.66 | 2.66 | 2.75 | 2.05 | Heavy control panels, machine guards |
| 14 Gauge | 1.99 | 1.99 | 2.00 | 1.63 | Server racks, heavy-duty frames |
| 16 Gauge | 1.52 | 1.59 | 1.61 | 1.29 | Control cabinets, metal wall decor, bodies |
| 18 Gauge | 1.21 | 1.27 | 1.31 | 1.02 | Appliance bodies, auto panels, light covers |
| 20 Gauge | 0.91 | 0.95 | 1.00 | 0.81 | HVAC covers, light enclosures |
3. Top Sheet Metal Manufacturers in India
When sourcing raw sheets in India, look for mill-certified stock from leading manufacturers:
- Mild Steel & GI: Tata Steel (Tata Astrum, Tata Shaktee), JSW Steel (JSW Pragati), AM/NS India, and SAIL.
- Stainless Steel: Jindal Stainless Limited (JSL) is the primary market leader.
- Aluminum: Hindalco Industries and NALCO.
4. Fiber Laser Cutting Power Requirements
Fiber lasers are the industry standard for precision sheet metal cutting. The laser wattage required depends on the material thickness and your desired production speed:
| Gauge | Thickness (Mild Steel) | Min. Laser Power (Slow Cut) | Recommended Power (Production) | Assist Gas Used |
| 18 SWG | ~1.2 mm | 1.0 kW | 1.5 kW – 2.0 kW | Oxygen (MS) / Nitrogen or Air (SS/AL) |
| 16 SWG | ~1.5 mm | 1.0 kW | 1.5 kW – 2.0 kW | Oxygen (MS) / Nitrogen or Air (SS/AL) |
| 14 SWG | ~2.0 mm | 1.5 kW | 2.0 kW – 3.0 kW | Oxygen (MS) / Nitrogen (SS/AL) |
| 12 SWG | ~2.6 mm | 1.5 kW | 3.0 kW | Oxygen (MS) / Nitrogen (SS/AL) |
| 10 SWG | ~3.4 mm | 2.0 kW | 3.0 kW – 4.0 kW | Oxygen (MS) / Nitrogen (SS/AL) |
5. Bending Radii & V-Die Specifications
Precision CNC press brake air bending requires choosing the correct V-die opening to avoid cracking or material failure along the bend lines.
Standard V-Die Selection (The 8x Rule)
For standard mild steel bending, choose a bottom V-die opening (V) roughly 8 times the sheet thickness (T).
- Minimum Inside Bend Radius (Rmin): Keep the inside radius equal to or greater than 1×T to prevent material cracking.
- Springback: Mild steel requires around 1° – 2° over-bending, whereas Stainless Steel and Aluminum typically require 3° – 5° to achieve an exact 90° angle.
| Gauge | Sheet Thickness (T) | Min. Inside Radius (Rmin) | Recommended Radius (R) | Recommended V-Die Opening (V) |
| 18 SWG | ~1.2 mm | 1.2 mm | 1.2 mm – 1.5 mm | 8 mm – 10 mm |
| 16 SWG | ~1.5 mm | 1.5 mm | 1.5 mm – 2.0 mm | 12 mm |
| 14 SWG | ~2.0 mm | 2.0 mm | 2.0 mm – 2.5 mm | 16 mm |
| 12 SWG | ~2.6 mm | 2.6 mm | 2.6 mm – 3.0 mm | 20 mm |
| 10 SWG | ~3.4 mm | 3.4 mm | 3.5 mm – 4.0 mm | 25 mm – 32 mm |
Key Takeaway for Designers
Designing for sheet metal fabrication requires balancing aesthetics, structural integrity, and manufacturing efficiency. Keeping standard SWG dimensions, laser power limits, and bend radii top-of-mind during CAD layout will eliminate rework and lower unit costs.