Steel plate fabrication is the process of cutting, shaping, welding, and finishing structural steel plates into finished components — plate girders, built-up sections, base plates, stiffener plates, gusset plates, equipment skids, and heavy structural frames. It is a core capability in heavy industrial fabrication, bridge construction, and structural steelwork across India. This guide covers the plate fabrication process, applications, IS standards, and thickness ranges used in Indian industrial projects.
What Is Steel Plate Fabrication?
Steel plate fabrication differs from section fabrication in that it starts with flat rolled steel plates — typically 6mm to 100mm thick — rather than hot-rolled structural sections. Plates are cut to shape, formed if required, and welded together to create components that either cannot be made from standard rolled sections or that require higher load capacity than any available rolled section can provide.
The most common applications of plate fabrication for industry in India include plate girders for bridges and crane runway beams, built-up columns and box sections for heavy structures, storage tank shells and heads, pressure vessel shells, base plates for steel columns, and heavy equipment skids and frames.
Steel Plate Fabrication Applications
- Plate girder fabrication: Built-up I-girders (top flange plate + web plate + bottom flange plate) for bridge spans, crane runway beams, and transfer girders in buildings — where spans or loads exceed what rolled sections can handle.
- Built-up columns and box sections: Four-plate welded box sections for heavily loaded columns in high-rise frames, industrial structures, and crane-served buildings.
- Base plates: Steel column base plates, machinery base frames, and equipment skids fabricated from 20–80mm thick plate.
- Gusset plates and connection plates: Connecting primary structural members at truss joints, bracing connections, and moment frame connections.
- Stiffener plates: Web stiffeners, bearing stiffeners, and transverse stiffeners welded to plate girder webs to prevent buckling.
- Storage tanks: Cylindrical or rectangular steel tanks for water, fuel, chemicals, and bulk materials — fabricated from 5–25mm plates with submerged arc welded (SAW) seams.
- Heavy equipment frames and skids: Structural frames for process equipment, pump skids, compressor bases, and reactor support structures in petrochemical and power plants.
- Hoppers and chutes: Material handling components in cement, mining, and bulk material handling plants.
Plate Girder Fabrication — Technical Details
A plate girder is a built-up I-beam fabricated by welding three plates together — a top flange plate, a web plate, and a bottom flange plate. Plate girders are used when the required section depth or flange width exceeds what is available in rolled Universal Beam (UB) sections, or when the load demands a heavier section than any standard rolled profile.
| Parameter | Typical Range — Indian Projects |
|---|---|
| Web depth | 500mm to 3,000mm |
| Web plate thickness | 8mm to 25mm |
| Flange plate width | 200mm to 600mm |
| Flange plate thickness | 16mm to 80mm |
| Girder length | 6m to 40m (in single piece or field-spliced) |
| Single piece weight | 2T to 150T+ |
| Steel grade | IS 2062 E250, E350, E410; IS 2002 for pressure parts |
| Weld process | SAW (submerged arc welding) for flange-to-web; SMAW/FCAW for stiffeners |
Steel Plate Fabrication Process
- Material receipt and inspection: Plates received with mill test certificates (MTC). Dimensions, surface condition, and heat numbers verified against the purchase order.
- Marking and cutting: Plates marked from shop drawings and cut by CNC plasma cutting, oxy-fuel cutting, or laser cutting depending on thickness and precision requirements. Plasma is standard for 6–50mm structural plates. Oxy-fuel for 50–150mm heavy plates.
- Edge preparation: Weld bevels machined or ground on plate edges for full-penetration welds at flange-to-web joints and butt splices.
- Fit-up and tack welding: Plates assembled in jigs to correct geometry. Tack welded to hold position before full welding.
- Welding — flange to web (SAW): Submerged arc welding used for the continuous fillet or partial-penetration weld joining flanges to web — high deposition rate, excellent quality, and consistent profile.
- Stiffener welding: Web stiffeners, bearing stiffeners, and transverse stiffeners fillet-welded to the web plate by SMAW or FCAW.
- Distortion control: Welding sequence planned to minimise distortion. Straightening by controlled heating or press if required after welding.
- NDT inspection: UT (ultrasonic testing) on full-penetration butt welds. Visual and DPT/MPI on fillet welds. RT (radiography) on critical joints where specified.
- Dimensional inspection: Final dimensions checked against shop drawings — straightness, camber, web squareness, hole locations.
- Surface treatment: Sa 2.5 blast cleaning, primer application, intermediate and finish coats. Intumescent fire protection where required.
MS Plate Fabrication — Steel Grades Used in India
MS plate fabrication (mild steel plate fabrication) in India uses plates conforming to the following IS standards:
- IS 2062:2011 — Hot-rolled structural steel plates, Grade E250 (Fe 410), E350, E410. Most common for structural plate girders, built-up sections, base plates, and gusset plates.
- IS 2002:2009 — Steel plates for pressure vessels. Used for storage tanks, pressure vessels, and process equipment shells.
- IS 1730 — Dimensions for steel plates, sheets, and strips. Governs standard mill plate sizes available in India.
- IS 3502 — Steel chequered plates (for floor plates, walkways, and equipment platforms).
Heavy Plate Fabrication — Thickness Ranges and Processes
| Plate Thickness | Cutting Method | Weld Process | Typical Application |
|---|---|---|---|
| 6–12mm | Plasma / laser | SMAW, GMAW, FCAW | Gusset plates, stiffeners, light hoppers |
| 12–25mm | Plasma / oxy-fuel | SMAW, FCAW, SAW | Plate girder webs, tank shells, equipment frames |
| 25–50mm | Oxy-fuel / plasma | SAW, SMAW (multi-pass) | Plate girder flanges, heavy base plates, box columns |
| 50–100mm | Oxy-fuel | SAW, ESW (electroslag) | Heavy machinery bases, press frames, large bridge girders |
Base Plate Fabrication
Steel base plates connect structural steel columns to their concrete foundations through anchor bolts. Base plate fabrication involves cutting plate to size, drilling or burning holes for anchor bolts, and welding shear studs or stiffener plates if required. Base plate thickness in Indian industrial structures typically ranges from 20mm to 80mm depending on column load and anchor bolt arrangement. All base plates are designed to IS 800:2007 and must be checked for bearing pressure, bending, and weld capacity.
IS Standards for Plate Fabrication in India
- IS 800:2007 — Structural steel design — governs plate girder design, base plate design, and connection plate design.
- IS 2062:2011 — Structural steel plate material standard.
- IS 2002:2009 — Pressure vessel plate material.
- IS 7215:1974 — Tolerances for fabrication of structural steel.
- IS 9595:1996 — Metal arc welding standards and weld symbols.
- IS 3658 — Code of practice for liquid penetrant flaw detection (DPT).
- IS 4260 — Ultrasonic testing of welds.
- IS 1182 — Radiographic examination of fusion welded joints.
Plate Fabrication for Industry — Suncorporation
Suncorporation Fabricators & Engineers provides structural steel plate fabrication services for industrial projects across India — including plate girder fabrication, built-up box columns, heavy base plates, equipment skids, and gusset and connection plates. Our workshop is equipped for heavy plate cutting, fit-up, SAW welding, and NDT inspection to IS standards.
Our plate fabrication capability supports all our structural steel services — structural steel fabrication, steel truss fabrication, industrial shed fabrication, high-rise steel construction, and stadium steelwork. Every plate fabrication supply comes with mill test certificates, weld inspection records, and dimensional inspection reports.
We serve plate fabrication projects across India — Hyderabad, Bengaluru, Chennai, Mumbai, Delhi NCR, and Kolkata. Contact us with your drawings and specifications for a detailed quotation.