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Slip-On Flanges

Managing inconsistent weld quality, alignment gaps, and pressure rating mismatches often delays sourcing Slip-On flanges for repeat production. Our Slip-on flanges solve this with hub-fit control, dual-side weld compatibility, and consistent thickness as per ASME or EN norms. 

Standard Specification

ASME B16.5, ASME B16.47, EN 1092-1, DIN 2576, ANSI, MSS SP-44, API 6A

Pressure Rating

Class 150, 300, 600, 900 (PN6 to PN40 for EN standards)

Material

Carbon Steel (ASTM A105), Stainless Steel (ASTM A182 F304/F316), Alloy Steel (ASTM A694 F52)

Nominal Size

½” to 24″ (DN15 to DN600) [Custom sizes up to 48″ (DN1200) available]

Flange Type

Slip-On (SO) – Fits over pipe and welded inside/outside
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Product Description

Each unit supports Class 150 to 900 and sizes from ½” to 24″, with tight-tolerance machining for easier line-up. We also offer customizable ODs, facings, and surface finishes to support non-standard pipe assemblies and legacy retrofits.

Facing Type

Raised Face (RF), Flat Face (FF)

Dimensions

Customizable (OD, Thickness, Bore Size)

Bolt Circle Diameter

ASME B16.5: Standardized per class/size; EN 1092-1: Metric series

Number & Size of Bolt Holes

4 to 24 holes (½” to 1″ bolts, custom patterns available)

Surface Finish

Smooth machined (125–250 RA), Serrated (Stock finish)

Corrosion Resistance

SS316: High resistance; Carbon Steel: Epoxy-coated/galvanized

Temperature Rating

-29°C to +400°C (lower than WN flanges due to double-weld design)

Material Certification

MTR, EN 10204 3.1/3.2, PED 2014/68/EU

Gasket Compatibility

Flat ring gaskets (non-metallic), Spiral-wound (for higher pressure)

Coating/Plating

HDG, Xylan, PTFE, Electroless Nickel (optional)

Manufacturing Method

Forged (ASTM A105/A182), Machined from plate (ASME SA516)

Technical Challenges

Our Slip-On flanges come with raised or flat face options for pipe face tolerance flexibility. Machined from forged blanks or SA516 plate, we maintain bore size matching within ±0.5mm to reduce turbulence. 
We include MTR, EN 10204 3.1, or PED certifications as per customer request for each lot. Optional coatings like PTFE, Xylan, or Electroless Nickel support corrosive or offshore conditions.

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Industry Applications

Pressure Piping in Oil and Gas

Supports low-to-medium pressure headers with quick field welding using standard Class 300-rated flanges in ASTM A105 and A694 F52.

Power Plant Condensate Systems

Used in mild vacuum zones with epoxy-coated carbon steel flanges, fitted with spiral-wound gaskets for thermal stress management.

Fire Protection Pipeline Networks

Preferred for Class 150 PN10 fire loop assemblies using galvanized slip-on flanges that enable low-cost replacements and fast coupling.

Skid-Mounted Pump Assemblies

Supports short bolt circles and flat face mounting for ANSI-compliant pump outlet flanges in mobile and containerized units. 

Chiller Water Systems in HVAC Plants

Common in chilled or condenser water loops using EN 1092-1 DN flanges with rubber gaskets and epoxy-painted surfaces.

Chemical Transfer Lines

Compatible with stainless steel F304/F316 material in low-corrosive lines, ensuring steady line pressure without costly threaded or socket fittings.

Built for Assembly-Critical Flow Lines

We maintain tight hub-to-pipe tolerances and weld-friendly grooves to speed up site welding and reduce rework. With Class 150 to 900 and PN6 to PN40 variants, you can match global project specs without redesign. 
Custom OD, bolt pattern, or facing modifications are available in batch runs for OEM kits. Each order includes inspection logs, dimensional charts, and coating compatibility notes for audit-ready shipment.

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Having Doubts? Our FAQ

Check all our Frequently Asked Question

Can you match the slip-on flange with our existing bolt pattern or non-standard OD?

Yes, we support custom OD and bolt circle adjustments based on provided drawings or mating flange samples. Our machining team aligns bore and thickness tolerances to match without compromising flange face integrity. This allows seamless fitment in legacy systems or project-specific pipe spools.

Are double-side welds mandatory for pressure integrity on Slip-On flanges?

Yes, both inner and outer welds are needed to maintain pressure sealing as per ASME or EN guidelines. We design the hub length and pipe insertion depth to allow sufficient weld volume on both sides. This avoids leaks during thermal expansion or cyclic loading. 

Can you provide coating certificates or test reports for offshore or chemical zone use?

Yes, we share coating batch numbers with test reports for HDG, Xylan, PTFE, or electroless nickel finishes. These include salt spray results and adhesion tests when required by offshore specs. Each report is tagged to its corresponding flange batch.

How do you control flange flatness during bulk manufacturing?

We machine flange faces using calibrated lathes and check warpage using dial gauge and flatness jigs. Deviations are kept within 0.3mm for raised face and 0.2mm for flat face. Flatness reports can be issued upon request.

Can your Slip-On flanges be used for vacuum or low-pressure gas lines?

Yes, for low-pressure gas or vacuum systems, we offer FF or smooth face options with compatible gaskets. Material selection and welding length are adjusted to reduce leak paths under mild suction. Surface finish below 125 RA can also be provided for gasket sealing support. 

Can Frigate support bulk orders with phased delivery schedules?
  • Yes, we plan production in batches aligned with your project timeline. 
  • Partial dispatches can be scheduled to match site readiness or installation phases. 
  • Each batch is traceable with heat numbers and inspection records. 
  • We maintain buffer stock for repeat sizes to reduce lead time in staggered orders. 
Do you provide pre-assembled flange kits with gaskets and fasteners?
  • Yes, we supply complete flange kits including gaskets, bolts, and nuts. 
  • Material compatibility is ensured across all components in the kit. 
  • Kits are packed and labeled per line item or spool requirement. 
  • This reduces on-site sorting and speeds up installation. 
How does Frigate handle urgent or short lead-time requirements?
  • We prioritize critical orders through dedicated machining slots. 
  • Common sizes and materials are kept ready as semi-finished inventory. 
  • Expedited inspection and documentation workflows are available. 
  • Logistics support ensures faster dispatch, including export shipments. 
Can you support third-party inspection and client audits?
  • Yes, we accommodate TPI agencies like BV, TUV, DNV, and SGS. 
  • All inspection stages (raw material to final machining) are open for review. 
  • We provide complete documentation: MTC, dimensional reports, coating reports. 
  • Virtual inspections and live video audits can also be arranged. 
Do you offer marking, tagging, or traceability customization?
  • Yes, we provide laser marking, stamping, or paint marking as required. 
  • Each flange can include heat number, size, class, and client-specific codes. 
  • Barcode or QR-based traceability can be added for large projects. 
  • Tags and documentation are aligned with project QA/QC systems. 
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LOCATIONS

Registered Office

10-A, First Floor, V.V Complex, Prakash Nagar, Thiruverumbur, Trichy-620013, Tamil Nadu, India.

Operations Office

9/1, Poonthottam Nagar, Ramanandha Nagar, Saravanampatti, Coimbatore-641035, Tamil Nadu, India. ㅤ

Other Locations

  • Bhilai
  • Chennai
  • India
  • Germany
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LOCATIONS

Registered Office

10-A, First Floor, V.V Complex, Prakash Nagar, Thiruverumbur, Trichy-620013, Tamil Nadu, India.

Other Locations

  • Bangalore
  • Chennai
  • India
  • Germany
Become a Frigatian
Become a Supplier

GENERAL ENQUIRIES

  • +91 96778 64606
  • manufacture@frigate.ai
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slip on flanges

Slip-On Flanges

Need reliable wires and cables for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

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slip on flanges

Slip-On Flanges

Need reliable Machining for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

Get Latest Price

Get Price Form