Description
Product Detail
A PTFE lined blind flange is a solid flange designed to block off pipeline ends, nozzle outlets or future branch connections in corrosive service. It combines a forged or machined metal backing flange with a PTFE-lined wetted surface to resist aggressive media such as acids, alkalis, chlorides and solvent-bearing fluids. Typical applications include chemical processing, pickling lines, dosing systems, water treatment and marine utility piping.
SASA FLANGE supplies PTFE blind flanges in standard and custom dimensions according to ASME B16.5, EN 1092-1, DIN, JIS and GB requirements. Each order can be supported by chemical analysis, mechanical testing of the backing material, dimensional inspection, lining integrity checks, PMI testing where applicable, EN 10204 3.1 certificate and full heat number traceability for reliable project documentation.
- ✓Product Name: PTFE Lined Blind Flange
- ✓Material Grade: ASTM A105 / A350 LF2 / A182 F304 / F316 with virgin PTFE lining
- ✓Product Type: Blind Flange with corrosion-resistant PTFE lined wetted face
- ✓Main Feature: High chemical resistance, leak-tight end closure, durable steel backing strength
- ✓Applications: Chemical plants, acid and alkali pipelines, water treatment, marine and process systems
Product Parameters
| Product Name | PTFE Lined Blind Flange |
| Material Grade | Backing flange: ASTM A105, A350 LF2, A182 F304/F304L/F316/F316L; Liner: Virgin PTFE |
| Material Type | Carbon Steel / Stainless Steel / Alloy Steel with PTFE lining |
| Product Form | Forged and machined blind flange, plate-machined blind flange, lined blind flange |
| Size Range | DN15 – DN600 (1/2 inch – 24 inch) |
| Pressure Class | Class 150 – 300 / PN10 – PN40 / JIS 5K – 20K |
| Sealing Face | RF, FF, PTFE faced FF, PTFE faced RF |
| Surface Treatment | Anti-rust oil, black paint, hot-dip galvanized, passivated, PTFE lined wetted surface |
| Standard | ASME B16.5, EN 1092-1, DIN 2527, JIS B2220, GB/T 9119 or customer specification |
| Inspection | Chemical Analysis, Mechanical Test, PMI Test, Dimensional, Lining Thickness and Spark Test |
| Certificate | EN 10204 3.1 Material Certificate available |
| Processing Service | Cutting, CNC Machining, Custom Drilling, Custom Size Processing |
Chemical Composition
The following chemical composition is for reference for a common backing flange grade used in PTFE blind flanges. Final composition depends on the selected metal grade, applicable material standard and actual mill test certificate. PTFE lining composition is not shown in the metallic analysis table and is supplied according to project requirements.
| Element | C | Si | Mn | P | S | Cr | Ni | Mo | Other |
|---|---|---|---|---|---|---|---|---|---|
| ASTM A105 Content % | 0.35 max | 0.10-0.35 | 0.60-1.05 | 0.035 max | 0.040 max | 0.30 max | 0.40 max | 0.12 max | Cu 0.40 max, V 0.08 max |
Mechanical Properties
Mechanical properties below refer to typical backing flange materials used for PTFE blind flanges. Actual values may vary with grade, heat treatment condition, product size and manufacturing route. PTFE lining provides corrosion resistance to the wetted surface, while mechanical strength is mainly determined by the metallic backing flange.
| Grade | Tensile Strength | Yield Strength | Elongation | Hardness | Density |
|---|---|---|---|---|---|
| ASTM A105 | 485 MPa min | 250 MPa min | 22% min | 187 HB max | 7.85 g/cm3 |
| ASTM A182 F316L | 485 MPa min | 170 MPa min | 30% min | 95 HB max | 8.00 g/cm3 |
Common Size Table
| Size Range | Pressure Class | Sealing Face | Material | Availability |
|---|---|---|---|---|
| DN15 – DN50 | Class 150 – 300 | FF / RF | A105 + PTFE / F316L + PTFE | Stock / Production |
| DN65 – DN300 | Class 150 – 300 | FF / RF | A105 + PTFE / A350 LF2 + PTFE | Stock / Production |
| DN350 – DN600 | Class 150 – 300 | FF / RF | A105 + PTFE / F316 + PTFE | Production |
| DN700 – DN1500 | PN10 – PN16 | FF | Plate flange + PTFE lining | Made to Order |
Different Specifications Comparison
| Type | Description | Typical Use |
|---|---|---|
| Raised Face PTFE Blind Flange | Blind flange with PTFE-lined raised sealing area for controlled gasket compression | ASME chemical lines and corrosive process piping |
| Flat Face PTFE Blind Flange | Full flat sealing surface lined with PTFE for low to medium pressure service | FRP-lined systems, water treatment and plastic valve connections |
| Carbon Steel Backed PTFE Blind Flange | Economical steel backing flange with PTFE wetted face for corrosion protection | General chemical transfer and acid/alkali service |
| Stainless Steel Backed PTFE Blind Flange | Stainless backing flange plus PTFE lining for enhanced external and internal corrosion resistance | High-purity, marine or aggressive media applications |
Equivalent Standards and International Names
PTFE blind flanges are manufactured to international flange dimensional standards, while the backing material grade is selected separately according to project specification. Equivalent grade names may vary by region, and PTFE lining thickness, molding method and face style are confirmed during order review together with the material test certificate.
| Standard / Region | Standard Code | Typical Grade / Equivalent |
|---|---|---|
| USA | ASME B16.5 | ASTM A105 / A182 F316L backing flange + PTFE lining |
| Europe | EN 1092-1 | P245GH / 1.4301 / 1.4404 backing flange + PTFE lining |
| Germany | DIN 2527 / 2566 | C22.8 / 1.4571 backing flange + PTFE lining |
| Japan | JIS B2220 | SS400 / SUS304 / SUS316 backing flange + PTFE lining |
| China | GB/T 9119 | 20# / 304 / 316L backing flange + PTFE lining |
Production Process Flow
PTFE blind flange production requires strict control of both metal flange machining and fluoropolymer lining quality. SASA FLANGE controls raw material traceability, dimensional accuracy, lining fit and final inspection to ensure stable corrosion-resistant performance.
- 1. Raw Material Selection
- 2. Forging / Cutting
- 3. Heat Treatment
- 4. Rough Machining
- 5. Finish Machining
- 6. Drilling
- 7. Surface Treatment
- 8. Inspection
- 9. Marking
- 10. Packing
- 11. Delivery
| Process Step | Description | Quality Control Point |
|---|---|---|
| Raw Material | Select certified forging billets or plates | Material certificate and traceability |
| Forging | Hot forging to achieve required shape | Forging temperature and reduction ratio |
| Heat Treatment | Normalizing, tempering or annealing | Temperature and holding time control |
| Machining | Sealing face, bolt holes, dimensions | Dimensional accuracy and surface finish |
| Inspection | Final inspection before shipment | Dimension, lining thickness, spark test, PMI |
Product Inspection
1. Chemical Composition Inspection
Chemical analysis is performed on the metallic backing material to verify compliance with the specified grade such as ASTM A105 or A182 F316L. Incoming material certificates are checked and, when required, sample verification is conducted to confirm carbon, manganese, chromium, nickel and molybdenum limits before production release.
2. Mechanical Properties Testing
Mechanical testing of the backing flange material includes tensile strength, yield strength, elongation and hardness according to the relevant ASTM or EN material standard. These tests confirm that the blind flange body provides the required structural strength for bolting loads, pressure service and safe long-term operation.
3. Dimensional Inspection
Each PTFE blind flange is inspected for outside diameter, thickness, bolt circle, bolt hole diameter, hole quantity and facing dimensions according to ASME, EN, DIN, JIS or GB standards. Special attention is given to sealing face flatness and lined-face fit to ensure proper gasket seating and leak-tight assembly.
4. PMI Testing and Hydrostatic Testing
PMI testing is available to confirm the metallic backing grade, especially for stainless steel and alloy materials. For lined products, lining integrity checks such as spark testing and visual examination are commonly applied; hydrostatic or assembly pressure testing can be provided according to project scope. EN 10204 3.1 certificate is supplied with traceable inspection records.
Product Packaging
- ✓Wooden Case Packaging: Suitable for high-pressure and large-diameter products
- ✓Pallet Packing with Shrink Wrap: Suitable for batch shipments and standard sizes
- ✓Anti-rust Oil Coating + Waterproof Paper: Used for ocean freight protection
- ✓Individual Plastic Bag + Carton: Used for small fittings and threaded products
- ✓Clear Marking: Grade, size, pressure class, heat number and PO number
Applications
PTFE blind flanges are widely used where the line end must be positively sealed and the process media is corrosive. The PTFE-lined wetted face protects the metallic body from chemical attack, while the solid blind design allows safe shutdown, maintenance isolation and future expansion points in process piping systems.
| Industry | Typical Applications | Why This Product Is Used |
|---|---|---|
| Oil and Gas | Chemical injection skids, produced water treatment, utility chemical lines | Provides secure end closure with improved resistance to corrosive chemicals |
| Chemical Processing | Acid transfer lines, alkali systems, chlorinated media piping, reactor nozzles | PTFE lining resists aggressive media and reduces corrosion risk at dead ends |
| Power Generation | Demineralized water, flue gas desulfurization chemicals, dosing pipelines | Suitable for chemical service where metal-only blind flanges may corrode |
| Water Treatment | Dosing systems, sodium hypochlorite lines, acid cleaning circuits | Offers corrosion resistance and reliable isolation in treatment plants |
| Marine and Offshore | Seawater chemical treatment units, scrubber systems, corrosive utility lines | Combines mechanical strength with durable chemical protection in harsh environments |
Why Choose SASA FLANGE?
- ✓Professional manufacturer of Blind Flanges for global industrial projects
- ✓Customized size, pressure class and material grade according to drawings
- ✓Full standard support: ASME, EN, DIN, JIS, GB, GOST and customer specifications
- ✓Material traceability with heat number control and EN 10204 3.1 material certificate
- ✓Chemical analysis, mechanical testing, PMI testing, hydrostatic and dimensional inspection
- ✓Stock availability for standard items, lead time 3-7 days; custom production 15-30 days
- ✓Export-grade packaging for sea, air and land transportation
- ✓15+ years experience supplying 50+ countries worldwide
FAQ
Q: What is a PTFE blind flange?
A: A PTFE blind flange is a solid flange used to close the end of a pipeline, vessel nozzle or branch connection, with a PTFE-lined wetted face for corrosion resistance. It combines the pressure-bearing strength of a steel or stainless backing flange with the chemical resistance of polytetrafluoroethylene for aggressive process media.
Q: What materials are available for PTFE blind flanges?
A: SASA FLANGE can supply PTFE blind flanges with carbon steel, low-temperature carbon steel and stainless steel backing materials, including ASTM A105, A350 LF2, A182 F304, F304L, F316 and F316L. The lining is typically virgin PTFE, while modified PTFE or PFA can be discussed for specific operating conditions.
Q: What pressure class is supported?
A: PTFE blind flanges are commonly supplied in ASME Class 150 and Class 300, as well as EN PN10, PN16, PN25 and PN40, depending on size and construction. Higher pressure service is generally reviewed case by case because lining design, temperature and media compatibility must be evaluated together with the backing flange strength.
Q: Can SASA FLANGE supply custom sizes?
A: Yes. SASA FLANGE can manufacture PTFE blind flanges to custom drilling patterns, non-standard outside diameters, special bolt holes, custom thicknesses and project-specific sealing faces. We can also match mating flange dimensions, selected backing materials and lining requirements according to drawings, sample parts or end-user specifications.
Q: What certificate is provided?
A: Standard documentation can include EN 10204 3.1 material certificate for the metallic backing flange, mill test certificate, dimensional inspection report and lining inspection records. PMI testing is available for stainless and alloy grades, and additional testing such as spark testing, hardness testing or project-specific pressure testing can be arranged upon request.
Contact Us
If you are looking for blind flange ptfe or related custom flange products, please contact SASA FLANGE with your required size, pressure class, material grade, standard, surface treatment, quantity and inspection requirements. Our team will provide professional technical solutions and competitive quotation within 24 hours.
- 📧 Email: sales@sasaflange.com
- 📱 WhatsApp: +86 13764965049
- ☎️ Tel: +86 21 52236361
- 🌐 Website: www.sasaflange.com
