Home > Welded Pipes > Fabricated Welded Pipes
Inox Steel India is a leading manufacturer and exporter of fabricated welded pipes, engineered for applications where standard pipe sizes, grades, or thicknesses are not suitable. These pipes are custom-built using rolled plates and precision welding to achieve special diameters, heavy wall thicknesses, and exotic alloy compositions.
We supply fabricated pipes for chemical plants, pressure vessels, desalination units, fertilizer plants, off-shore structures, refineries, and heat-intensive process industries.
Each pipe is manufactured according to ASME B31.3 / B31.1, ASME Section VIII, project specifications, and international standards like ASTM A358, A671, A672, B619, B626.
With advanced rolling machines, automated welding, solution annealing, PMI testing, and TPI inspection (SGS, BV, DNV, TÜV, Lloyd’s), our fabricated pipes deliver exceptional performance in high-temperature, high-pressure, and high-corrosion environments.
We manufacture custom diameters from 100 mm to 5000 mm, wall thickness up to 80 mm, and lengths up to 6–12 meters, making Inox Steel India a preferred supplier for global EPC contractors, engineering consultants, and OEMs.
Fabricated welded pipes are pipes manufactured by rolling steel plates into cylindrical shapes and welding them longitudinally using GTAW, SAW, SMAW, PAW, or multi-pass welding procedures.
Unlike standard seamless or ERW pipes, fabricated pipes allow:
These pipes are used where standard mill-made pipes cannot meet design, pressure, temperature, or corrosion requirements.
Types of Fabricated Pipes We Manufacture
1️⃣ Plate Selection & Testing
Plates are selected based on grade, thickness, and project requirements. All plates undergo UT, PMI, chemical analysis, and mechanical testing.
2️⃣ Plate Cutting & Edge Preparation
Edges are machined, beveled, and prepared for weld penetration.
3️⃣ Plate Rolling / Bending
Plates are rolled on heavy-duty rolling machines to achieve the desired pipe diameter with precise roundness.
4️⃣ Root Pass (GTAW / SMAW)
Initial weld is made using controlled heat input for crack-free fusion.
5️⃣ Fill & Cap Pass (SAW / GTAW / SMAW)
Multiple welding passes are applied until the required thickness is achieved.
6️⃣ Heat Treatment (If Required)
Depending on grade:
7️⃣ Non-Destructive Testing (NDT)
RT, UT, DP, visual inspection, weld analysis, macro test, and dimensional verification are performed.
8️⃣ Hydrostatic Testing
Ensures pressure integrity.
9️⃣ Surface Treatment & Coating
Pickling, passivation, anti-corrosion coating, paint, epoxy lining (if required).
🔟 Final Inspection, Marking & Export Packing
Pipes are marked with grade, heat number, OD/WT, process, and certificates before dispatch.
Chemical & Petrochemical Plants
Sulfuric acid lines, caustic lines, chemical transfer, reactor feed lines.
Refineries & Oil/Gas Processing
Heater inlet/outlet, flare lines, high-temperature service lines.
Desalination & Water Treatment
Large-diameter intake/discharge, brine lines, evaporator shells.
Fertilizer, Urea & Ammonia Plants
High-pressure feed lines, corrosive process lines.
Power Plants & Boilers
Steam lines, HRSG modules, high-temperature alloy lines.
Offshore Platforms & Marine Structures
Titanium, duplex, and nickel alloy fabricated pipes for seawater exposure.
Structural & Mechanical Applications
Heavy-wall columns, casings, piles, custom support structures.
Fabricated welded pipes are specially engineered for applications where standard pipe sizes, wall thicknesses, or materials do not meet design or service requirements. These pipes are produced by rolling plates into cylindrical shapes and welding them with precision multi-pass welding techniques such as GTAW, SAW, SMAW, PAW depending on the alloy and application.
This type of pipe is widely used in industries where corrosion resistance, custom diameters, high-temperature performance, ultra-thick walls, or rare materials are required — such as chemical processing, refineries, desalination plants, fertilizers, power generation, and offshore structures.
Inox Steel India manufactures fabricated pipes in carbon steel, stainless steel, alloy steel, chrome-moly, duplex, super duplex, nickel alloys, and titanium, following ASME, ASTM, and project-specific codes.
| Parameter / Property | Fabricated Welded Pipes (Custom Diameter) | Fabricated Special Alloy Pipes (Nickel / Duplex / Titanium) | Fabricated Heavy-Thickness Pipes (Pressure / Structure) |
|---|---|---|---|
| Standard / Specification | Made as per ASME B31.3 / B31.1, Project Specs | ASTM B619/B626 (Nickel), ASTM A928/A790 (Duplex), ASTM B861/B862 (Titanium) | ASME VIII Div 1/2, ASTM A358/A671/A672 |
| Material Type | Carbon Steel / Mild Steel / Boiler Quality | Nickel Alloys (Inconel 625/825, Monel 400, Hastelloy C22/C276), Duplex/Super Duplex, Titanium Gr 2/5 | Carbon Steel, Alloy Steel, Chrome-Moly Grades |
| Manufacturing Process | Rolled plate cylinder + longitudinal welding (SMAW/GTAW/SAW) | Precision rolling + GTAW/PAW/SAW high-purity weld | Plate bending + multiple pass welding (SAW/GTAW) |
| UNS Designation | Depends on grade | N06625, N08825, N04400, N06022, S31803, S32750, R50400 | Depending on ASTM grade |
| Equivalent EN / DIN | EN 10025, EN 10253, DIN 28011 | EN 1.4462 / 1.4410 / 2.4602 | EN 10210 / DIN 17175 |
| Chemical Composition (% Max) | As per plate grade | As per alloy specification | As per pressure vessel grade |
| Tensile Strength (MPa) | 350 – 600 | 600 – 760 | 415 – 760 |
| Yield Strength (MPa) | 220 – 350 | 275 – 550 | 240 – 485 |
| Elongation (%) | ≥ 20 | ≥ 30 | ≥ 20 |
| Hardness (HB) | ≤ 200 | ≤ 230 | ≤ 235 |
| Corrosion Resistance | Medium | Very High (Excellent for acids, chlorides) | Grade dependent |
| Temperature Range (°C) | -20°C to 450°C | -196°C to 1100°C | -29°C to 600°C |
| Typical Applications | Custom ducting, exhaust, water lines, fabricated spools, manifolds | Chemical process lines, high-corrosion services, heat exchangers | Pressure vessels, boilers, load-bearing columns |
| Available Sizes (OD) | Fully custom: 100 mm – 5000 mm | 200 mm – 3000 mm | 200 mm – 4000 mm |
| Wall Thickness | 3 mm – 50 mm | 3 mm – 30 mm | 6 mm – 80 mm |
| Schedules Available | Custom (SCH 10 – SCH 160 equivalent) | SCH 10–SCH 80 | Heavy-wall |
| End Finishes | Bevelled / Plain / Flanged / Custom Machined | Bevelled / Plain | Bevelled / Plain |
| Testing Requirements | RT, UT, Hydro, DP, Visual, Dimensional | RT, UT, PMI, Hydro, Corrosion Test | RT, UT, Hydro, PWHT |
| HSN Code | 7306.40 / 7306.19 | 7507.xx (Nickel) / 8108.xx (Titanium) | 7306.29 |
| Equivalent ASTM / ASME | ASME B31.1 / B31.3 | ASTM B619/B626, ASTM B862, ASTM A928 | ASTM A358, A671, A672 |
| Supply Condition | As-welded / Stress Relieved | Solution Annealed, Pickled & Passivated | PWHT / Normalized |
| Certifications & Documentation | MTC 3.1/3.2, WPS/PQR, RT Film, Hydro Test, PMI, TPI available | MTC, PMI, Corrosion Test, TPI | MTC, PWHT Chart, RT/UT Reports |
Fabricated pipes from Inox Steel India are produced in a wide range of materials:
Carbon Steel / Mild Steel
Alloy Steel (High Temperature)
Stainless Steel
Duplex & Super Duplex
Nickel Alloys
Titanium
Engineers typically select fabricated pipes when the design requires:
✔ Non-standard diameters
Large OD: 100 mm to 5000 mm
✔ Heavy wall thickness
Up to 80 mm for structural / pressure service.
✔ Exotic corrosion-resistant alloys
Nickel alloys, duplex, titanium.
✔ Short-run or one-off custom items
Prototype systems, small batch manufacturing.
✔ Very high temperature service
Chrome-moly alloy steels and nickel alloys.
✔ Highly corrosive chemical service
Hastelloy, Incoloy, Monel.
Fabricated pipes follow WPS, PQR, WPQ approved welding procedures with full NDT to meet ASME process piping codes.
| Application Sector | Recommended Material / Grade | Why Used |
|---|---|---|
| Chemical Processing | Hastelloy C22/C276, SS316L, Duplex | High corrosion resistance |
| Petrochemicals | 321/347, Alloy Steel A387 | High temperature + oxidation resistance |
| Refineries | Chrome-Moly (A387 Gr 11/22) | Heater lines, high-temp service |
| Fertilizer (Urea/Ammonia) | Titanium Gr 2, 316L Mod | Corrosion + purity |
| Power Plants | Alloy Steel P11/P22/P91 | Elevated temperature + pressure |
| Desalination | Duplex/Super Duplex | Chloride resistance |
| Offshore / Marine | Super Duplex, Monel 400 | Seawater resistance |
| Structural Piles | Carbon Steel / A252 | High load-bearing strength |
| Parameter | Capability |
|---|---|
| OD (Outside Diameter) | 100 mm – 5000 mm |
| Wall Thickness | 3 mm – 80 mm |
| Length | 6 m – 12 m (longer on request) |
| Weld Type | GTAW, SMAW, SAW, PAW |
| Ends | Bevelled, Plain, Flanged, Custom Machined |
| Form | Cylindrical, Conical (Reducers), Custom Shapes |
| Material / Grade | Price (INR/kg) | Price (USD/kg) |
|---|---|---|
| Carbon Steel / MS | ₹ 110 – ₹ 180 | $ 1.6 – $ 2.5 |
| Alloy Steel (A387) | ₹ 200 – ₹ 350 | $ 3.0 – $ 4.9 |
| Stainless Steel (304/316) | ₹ 300 – ₹ 550 | $ 3.8 – $ 6.8 |
| Duplex / Super Duplex | ₹ 600 – ₹ 950 | $ 8.0 – $ 12.0 |
| Nickel Alloys (Inconel/Hastelloy) | ₹ 2,800 – ₹ 4,500 | $ 34 – $ 55 |
| Titanium | ₹ 1,700 – ₹ 2,800 | $ 20 – $ 32 |
Prices depend on plate grade, thickness, welding type, NDT requirements, heat treatment & quantity.
Fabricated pipes by Inox Steel India undergo:
✔ Non-Destructive Testing (NDT)
GCC & Middle East:
Africa:
Europe:
Americas:
Used in pipelines, desalination units, fertilizer plants, offshore structures, chemical plants & refineries.
Fabricated welded pipes play a critical role in industries where standard-size pipes cannot meet process, corrosion, or temperature demands. Inox Steel India has become a trusted supplier for EPC contractors and global MNCs because we deliver pipes engineered to exact project specifications, backed by certified welding procedures, controlled heat treatment, and complete documentation.
We are preferred for:
Our strength lies in manufacturing challenging, high-performance, corrosion-resistant, pressure-rated fabricated pipes that are not available as mill-made products.
High-diameter spiral welded pipes require robust protection to maintain weld seam strength, surface quality, and coating integrity.
Fabricated pipes require careful handling due to:
We ensure:
Export Ports
JNPT (Nhava Sheva), Mundra, Hazira, Chennai.
Regions Served
GCC, Middle East, Africa, Europe, USA, Canada, South America, Southeast Asia.
For custom-diameter pipes, exotic alloys, corrosion-resistant materials, heavy-wall pressure pipes, or specialized fabricated spools, Inox Steel India provides world-class manufacturing, certified welding, and project-specific documentation.
52-A, Mulji Thackersi Bldg, Islampura Street, Shop No. 10, Near Alankar Cinema, Mumbai – 400 004
alloy@inoxsteelindia.in, steel@inoxsteelindia.in
+91 9930796690
They allow custom diameters, heavy wall thicknesses, and special alloys not available as mill-made products.
Carbon steel, alloy steel, stainless steel, duplex, nickel alloys, and titanium.
Yes — with proper PWHT, multi-pass welding, and full RT/UT testing, fabricated pipes meet ASME pressure standards.
Yes, fabricated pipes are ideal for prototype, replacement, or one-time project items.
Yes — complete welding documentation is included.
Yes — we export to GCC, Africa, Europe, USA, Canada, South America & more.
Our engineers can assist with drawings, WPS/PQR, material selection, corrosion data, pressure design, and export documentation.