Custom Machined Flanges
CNC machined flanges
ASME B16.5 Custom Flanges: Dimensions | Specifications | Material Grade | Standards | About Custom Flange | All Product Types
Nutech Overseas is a trusted manufacturer and exporter of custom machined flanges, engineered with precision for high-demand industrial applications. These flanges are uniquely fabricated based on client-supplied technical drawings, CAD models, or bespoke design specifications, allowing absolute flexibility in dimensions, tolerances, and facing configurations.
Unlike standard flanges, custom flanges are often used where project-specific requirements cannot be met by conventional designs. We offer advanced CNC machining capabilities to produce flanges with custom features such as tight-tolerance bores, stepped faces, counterbores, thread tapping, and intricate bolt-hole layouts — all executed to meet international standards such as ASME, DIN, EN, ISO, or JIS, or completely non-standard configurations.
Our CNC machined flanges are produced from premium raw materials including forged stainless steel, carbon steel, alloy steel, and high nickel alloys, ensuring the highest level of structural integrity, corrosion resistance, and durability. Whether it’s a single-piece prototype or a large-volume OEM production, we maintain consistent quality with micron-level precision.
Key highlights of our custom flange machining service:
- Design flexibility for non-standard dimensions and geometries
- Surface finish control based on sealing requirements
- Machining of special faces like tongue & groove, serrated, or smooth
- Compatible with gasket types including spiral wound, RTJ, and metal-jacketed
- Delivered with complete dimensional and material traceability
These made-to-order flanges are ideal for critical installations in industries such as petrochemical plants, subsea operations, heat exchangers, refineries, pressure vessels, nuclear piping, and shipbuilding, where standard flanges often do not meet project requirements.
With in-house multi-axis CNC machines, vertical turning lathes (VTL), and CMM inspection, Nutech provides clients with the capability to order custom machined flanges up to 60" NB, with pressure classes ranging from Class 150 to 2500 / PN6 to PN400, and custom drilling templates or gasket seating surfaces upon request.
We also offer additional services like reverse engineering, 3D scanning, and material advisory to support EPC contractors, OEMs, and end users worldwide.
Custom Machined Flanges Manufactured to Precise Tolerances for Critical Piping, Pressure Vessels & Non-Standard Equipment Interfaces
For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our ANSI B16.5 Custom Flanges, please download the full Catalog PDF below.
CNC-Engineered Flange Solutions for OEMs, EPC Contractors & Specialized Industries Requiring Tailor-Made Flange Designs
Technical Specifications of Custom Flanges
| Specification | Details |
|---|---|
| Type | Custom Machined Flanges – as per client drawings, prototypes, or engineered specifications |
| Design Standard | Based on ASME B16.5, B16.47, API 6A, MSS-SP, DIN, EN 1092-1, ISO 7005, or completely custom standards |
| Machining Process | CNC Turning, Drilling, Milling, Boring, Tapping, Facing, Threading, Surface Finishing |
| Size Capability | From ½″ NB to 60″ NB (DN15 to DN1500), or as per project needs |
| Pressure Ratings | Class 150 to 2500, PN6 to PN400, or custom pressure classes as per system requirements |
| Facing Options | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove, Male & Female, Smooth, Serrated |
| Drilling Templates | Standard or Non-Standard – based on bolt circle diameter (BCD), hole pattern, and stud size |
| Tolerance & Accuracy | ±0.05 mm or as per customer specification; critical dimensions verified with CMM inspection |
| Surface Finish | Stock Finish, Smooth Machined, Spiral Serrated, Mirror Finish – per sealing or gasket type |
| Gasket Compatibility | Compatible with Spiral Wound, RTJ, CAF, Metal-Jacketed, Graphite, or Custom Gaskets |
| Customization Support | Reverse Engineering, 2D/3D CAD Support, Material Selection, Project-Specific Engineering |
| Testing & Inspection | Dimensional, PMI, Ultrasonic/Magnetic Particle, Hydrotest (if required), Visual QC |
| Certifications | EN 10204 Type 3.1/3.2, NACE MR0175, ISO 9001:2015, PED 2014/68/EU, IBR (if applicable) |
| Application Sectors | Oil & Gas, Power Plants, Pressure Vessel Fabrication, Desalination, Shipbuilding, Subsea, Nuclear, etc. |
| Origin | Made in India (by Nutech Overseas) |
| Export Network | USA, Europe, and Middle East |
Complete Material Grade Chart - Class 150 Custom Machined Flange
| Material Category | Custom Machined Flange Grades |
|---|---|
| Stainless Steel Custom Flange | ASTM A182 F304 / F304L / F304H, F316 / F316L / F316Ti, F310, F309S, F317 / F317L, F321 / F321H, F347 / F347H, F904L, ASTM A351 CF3 / CF3M / CF8 / CF8M / CF8C, DIN 1.4301, 1.4306, 1.4307, 1.4311, 1.4401, 1.4404, 1.4408, 1.4409, 1.4541, 1.4571, 1.4550, 1.4435, 1.4539 |
| Duplex Steel Custom Flange | ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205 |
| Super Duplex Steel Custom Flange | ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760 |
| Carbon Steel Custom Flange | ASTM A105 / A105N, ASTM A350 LF2, ASTM A694 F52 / F56 / F60 / F65 / F70 / F80, ASTM A216 WCB, DIN 1.0460 / 1.0402 / 1.0619, Die Steel, Mild Steel |
| Alloy Steel Custom Flange | ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140 |
| Nickel Alloy Custom Flange | Nickel 200 / 201, ASTM B564 |
| Monel Custom Flange | Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564 |
| Inconel Custom Flange | Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564 |
| Incoloy Custom Flange | Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564 |
| Hastelloy Custom Flange | Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564 |
| Alloy 20 Custom Flange | Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462 |
| 254 SMO Custom Flange | SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182 |
| Copper Nickel Custom Flange | Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152 |
| Copper Custom Flange | TP1, TP2, T1, T2, C10100–C12300, C14200–C17200, C21000–C71520, including C10930, C11000, C11400, C12000, C12200, C26000, C28000, C33000, C44300, C70600, etc. |
| Brass Custom Flange | Grades 3602, 2604, H59, H62, etc. |
| Aluminium Custom Flange | Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc. |
| Titanium Custom Flange | ASTM B381 Gr.1 / Gr.2 / Gr.4 / Gr.5 / Gr.7, UNS R50250 / R50400 / R50550 / R50700 / R52400 / R53400 / R56320 / R56400 |
| Other Special Grades | Al6XN, Tin Bronze, Aluminium Bronze, Lead Bronze, Nimonic 75 / 80A / 90 |
International Flange Standards We Manufacture & Supply
Custom machined flanges are precision-engineered flanges manufactured to exact client specifications, rather than following standard designs like ASME B16.5 or EN 1092-1. These are typically required when:
- The piping system involves non-standard sizes, unusual pressure or temperature ratings
- There is a need for retrofitting or replacement in legacy equipment
- The flange must match customized drilling patterns or face types
- Specialized industries like nuclear, aerospace, or defense demand tighter tolerances and certified machining processes
- OEMs or EPCs are working on bespoke projects that don’t comply with generic flange standards
Such flanges are often CNC-machined from raw forgings or billets and undergo advanced QA/QC to ensure dimensional accuracy.
Tolerances and machining precision are critical factors in the performance and reliability of custom flanges, especially in high-stress or high-pressure applications. Here's how they matter:
- Sealing Integrity: Tight machining tolerances ensure a perfect match between the flange face and gasket, reducing the risk of leaks.
- Bolt Hole Alignment: Accurate drilling ensures easy alignment during installation, minimizing stress on bolts and piping.
- Surface Finish Quality: Proper machining of sealing surfaces (e.g., spiral serrated, smooth, or RTJ grooves) enhances gasket compatibility and system pressure retention.
- Reduced Vibration and Fatigue: Precision machining reduces uneven load distribution, minimizing long-term fatigue or vibration-related failures.
- Compliance with Design Codes: Critical industries (oil & gas, petrochemical, nuclear) require flanges to meet specific dimensional tolerances as per drawings or standards like ISO, ASME, or client specifications.
For custom flanges, even minor deviation in dimensions can lead to system misalignment, leakage, or premature failure, making CNC machining and strict QA/QC protocols essential.
Yes, custom machined flanges are often the ideal solution for obsolete or legacy systems where standard flange dimensions are no longer available or compatible. Here's how they help:
- Reverse Engineering: With physical samples or outdated drawings, manufacturers can recreate exact flange replicas using modern machining techniques.
- Custom Drilling Patterns: Legacy systems may follow old or non-standard bolt-hole arrangements—custom flanges can replicate these precisely.
- Non-Standard Sizes: Older systems might use inch-based or metric dimensions that don’t match today’s standards; custom machining ensures compatibility.
- Material Substitution: Original materials may be phased out—modern equivalents can be used while retaining the same mechanical performance.
- Reduced Downtime: Tailor-made flanges help in retrofitting without requiring a complete system overhaul, saving both time and cost.
This makes custom machined flanges crucial for plant refurbishment, maintenance, and piping system upgrades in industries like power generation, refineries, and defense.
To produce a precise and high-performance custom machined flange, accurate and detailed design inputs are essential. The more information you provide, the better the manufacturing outcome. Key design parameters include:
- Flange Type: Slip-on, Weld Neck, Blind, Male & Female, Tongue & Groove, Threaded, Lap Joint, or a completely custom type.
- Dimensions: Outer diameter (OD), inner diameter (ID), thickness, bolt circle diameter (BCD), number and size of bolt holes.
- Facing Type: Raised Face (RF), Flat Face (FF), Ring-Type Joint (RTJ), Male-Female, or Tongue & Groove.
- Material Grade: Specific alloy or metal required for the application (based on pressure, temperature, and media compatibility).
- Pressure Class: ANSI/ASME pressure ratings such as Class 150, 300, 600, 900, etc.
- Drilling Pattern: Bolt hole arrangement (number, spacing, alignment), which may need to match non-standard or legacy equipment.
- Surface Finish Requirements: Roughness average (Ra) for sealing face — stock finish, spiral serrated, or mirror-polished.
- Special Requirements: NACE compliance, IBR certification, coatings (galvanized, anti-rust), heat treatments, or testing protocols (UT, RT, PMI, etc.).
Nutech Overseas proudly exports high-quality Custom Machined Flanges to a wide network of global clients across diverse industries. Our international reach includes:
- Middle East: UAE, Saudi Arabia, Qatar, Oman, Kuwait, Bahrain
- Europe: Germany, Italy, Spain, Netherlands, Turkey
- Africa: South Africa, Egypt
- Asia-Pacific: Singapore, Malaysia, Vietnam, Philippines
- South Asia: Bangladesh, Sri Lanka
- North America: United States of America (USA)
We serve industries such as Oil & Gas, Power Generation, Petrochemical, Marine, Water Treatment, Shipbuilding, and Process Plants. We ensures that all exports comply with international standards and project-specific requirements — from dimensional accuracy to material certification.
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