PTFE Coated Studs, Bolts and Nuts
Model:PTFE Coated Studs
PTFE coated studs, bolts and nuts for petrochemical, water works and general industrial flanges. B7 studs with 2H nuts the most common combination. PTFE coating up to +260 °C, salt spray 3,000 h (ASTM B117), kinetic friction coefficient 0.06–0.08, coating thickness 20–45 μm. Custom sizes and grades available. Reply within 2 business hours.
PTFE Coated Fasteners
PTFE Coated Studs, Bolts and Nuts for Petrochemical, Chemical and Water Works Flanges
When flange bolting has to survive corrosive atmospheres, marine air, chemical vapours and repeated make-up and break-out without galling or seizing, bare steel, hot-dip galvanized and zinc-plated fasteners fall short. PTFE coated studs, bolts and nuts are the standard answer — and Kaxite supplies them coated to the project requirement, with a metallic base coat that protects the fastener even if the topcoat is scratched during assembly.
- Petrochemical flanges — ASTM A193 B7 studs with ASTM A194 2H nuts
- Water works — hex-head bolts for underground service
- Chemical plants — anti-corrosion protection in acid and alkali vapour
- Stainless steel fasteners — coated for lubricity and anti-galling in high-alloy service
Available in UNC, UNF, metric and BSW thread forms; sizes from M10 to M56 and 1/2 in to 2-1/4 in; coating thickness uniform 20 ± 5 to 45 ± 5 microns. Custom grades and thread forms to drawing.
Send your stud size, thread form, grade, nut grade, quantity and coating requirement — our technical team replies with a material recommendation and price within 2 business hours.
At a glance
PTFE Coated Studs, Bolts and Nuts
- +260 °Cmax working temperature
- 3,000 hsalt spray (ASTM B117)
- 0.06–0.08kinetic friction coefficient
- 20–45 μmcoating thickness
- 100,000 psioperating pressure
Most common combination: ASTM A193 B7 studs with ASTM A194 2H nuts. Custom sizes and grades available on request.
+260 °CMax temp.
3,000 hSalt spray
0.06–0.08Friction coeff.
20–45 μmCoating
B7 / 2HMost common
Who makes these PTFE coated fasteners Reviewed by the Kaxite sealing engineering team
Kaxite Sealing (Ningbo Kaxite Sealing Materials Co., Ltd.) has manufactured PTFE products, compression sheets, gaskets and fasteners since 1990. Our PTFE coated studs, bolts and nuts are produced from qualified substrate material and coated with a fluoropolymer system that has been tested to ASTM B117, ASTM D3363-92A, ASTM D2794-93 and ASTM D3359-95.
Every order can be supplied with a material declaration, coating certificate and batch traceability record. Third-party inspection by SGS, BV or TUV can be arranged or hosted. Mill certificates for the substrate material are also available on request.
- 30+Years sealing & fastener manufacturing
- ASTMB117 · D3363 · D2794 · D3359
- BatchCoating and material traceability
- SGS/BV/TUVThird-party inspection supported
What Buyers Get From Kaxite
01Full substrate grade range
Carbon steel, alloy steel (B7, B7M, B16), stainless steel (B8, B8M) and equivalent grades. See the grade comparison table.
02Standard and custom thread forms
UNC, UNF, metric and BSW as standard. Non-standard thread forms, stud lengths and head configurations produced to drawing.
03Metallic base coat
Our coating system includes a metallic base coat that continues to protect the fastener even if the topcoat is scratched during assembly.
04Low MOQ
Small quantities for qualification and pilot runs accepted. Bulk pricing for production quantities. Technical reply within 2 business hours.
05Honest lead times
Standard sizes normally ship in 7–15 working days. Custom sizes and thread forms quoted against real production capacity. See packaging & shipping.
06Quality you can audit
Coating thickness, adhesion and friction tested per batch. Material declaration and third-party inspection (SGS / BV / TUV) supported. See our quality process.
Why PTFE Coating and Not Galvanizing or Zinc Plating
For decades hot-dip galvanized and zinc-plated fasteners were the standard in industrial flange bolting. They still work for moderate environments, but they cannot stand up to the corrosive atmospheres found in petrochemical, chemical, offshore and water works service. PTFE coated fasteners deliver three things that plated fasteners cannot:
- Corrosion resistance. Salt spray up to 3,000 h to ASTM B117, with nuts that stay free and do not seize even after long exposure.
- Consistent tensioning. A kinetic friction coefficient of 0.06–0.08 means the torque you apply translates into a predictable bolt load, so flange joints seal correctly the first time.
- Anti-galling and easy removal. Stainless steel fasteners in particular benefit from coating — the PTFE layer prevents thread galling, which is the most common cause of seized studs during maintenance.
Because the coating is a fluoropolymer rather than a sacrificial metal layer, it does not consume itself the way zinc does. Combined with a metallic base coat, the system continues to provide protection even when the topcoat is scratched during assembly — something that plated and single-layer fluoropolymer coatings cannot do.
Standard Substrate Grades and Coating Systems
The substrate grade determines the mechanical strength and temperature rating of the fastener; the coating determines its corrosion resistance, friction and anti-galling behaviour. Most projects specify both. The table below lists the combinations we produce most often.
| Substrate grade | Standard | Typical nut grade | Temperature range | Typical application |
|---|---|---|---|---|
| B7 (this product) | ASTM A193 | 2H (ASTM A194) | −40 °C to +425 °C (substrate) | Petrochemical flanges, high pressure |
| B7M | ASTM A193 | 2HM | −40 °C to +425 °C | NACE MR0175 sour service |
| B16 | ASTM A193 | 2H / 4 / 7 | Up to +550 °C | High-temperature steam and HP service |
| B8 | ASTM A193 | 8 (ASTM A194) | Up to +650 °C | Stainless flange bolting |
| B8M | ASTM A193 | 8M | Up to +650 °C | Stainless, higher corrosion resistance |
The +260 °C figure is the maximum continuous working temperature of the PTFE coating. Above this temperature, use uncoated fasteners or consult Kaxite on alternative coating systems.
All grades above are available with PTFE coating as standard. Custom grades and other standards (ASTM A320, ASTM A453, equivalent DIN / EN / JIS) can be produced on request.
Technical Specifications
- Product
- PTFE Coated Studs, Bolts and Nuts
- Substrate materials
- Carbon steel, alloy steel (B7, B7M, B16), stainless steel (B8, B8M), and equivalents on request
- Coating system
- PTFE / fluoropolymer coating with metallic base coat
- Thread forms
- UNC, UNF, metric, BSW and custom on request
- Common sizes
- M10 to M56; 1/2 in to 2-1/4 in
- Working temperature (coating)
- Up to +260 °C
- Corrosion resistance
- Salt spray up to 3,000 h (ASTM B117), nuts not frozen
- Pencil hardness
- 5H–6H (ASTM D3363-92A)
- Kinetic friction coefficient
- 0.06–0.08
- Coating thickness
- Nominal 0.001 in (1 mil); uniform 20 ± 5 to 45 ± 5 microns
- Impact resistance
- 160 in·lb (ASTM D2794-93)
- Adhesion
- 5B (ASTM D3359-95)
- Elongation
- 35% – 50%
- Tensile strength
- 4,000 psi
- Operating pressure
- Up to 100,000 psi
- Certificates
- Material declaration, coating certificate, mill certificate, batch traceability; third-party inspection (SGS / BV / TUV) on request
Note on coating thickness: The coating is applied at a nominal 0.001 in (1 mil) thickness, with a uniform range of 20 ± 5 to 45 ± 5 microns across the threaded section. This is thin enough that the thread fit remains within standard tolerances, so the fastener does not need special nuts or tapped holes. Tell us your tolerance requirement and we will confirm the applicable coating range.
Where PTFE Coated Fasteners Are Used
PTFE coated studs, bolts and nuts are specified wherever a flange joint has to be made up and broken out repeatedly in a corrosive environment, or wherever stainless steel fasteners must be protected from galling. Typical installations include:
PetrochemicalRefinery flanges
ChemicalAcid & alkali service
Water worksUnderground service
Power plantsSteam & HP flanges
OffshoreMarine atmosphere
Pulp & paperWet corrosive service
Stainless flange boltingAnti-galling protection
High-pressure flangesUp to 100,000 psi
Related products in the same PTFE family include PTFE rods, PTFE tube, PTFE balls, PTFE O-rings, PTFE guide strips, PTFE film, PTFE parts, PTFE tape and PTFE lining.
Packing and Shipping
PTFE coated studs, bolts and nuts are supplied in sealed plastic bags or cardboard boxes with the size and grade marked, packed flat on wooden pallets suitable for sea and air freight. Customer labels, size markings and packing lists are available on request. See packaging & shipping.
Shipping is by sea, rail or air depending on your schedule and destination. Standard sizes normally ship within 7–15 working days of order confirmation. Custom thread forms and non-standard grades are quoted against real production capacity.
Buyer FAQ
What is the difference between PTFE coated fasteners and hot-dip galvanized or zinc-plated fasteners?
Hot-dip galvanized and zinc-plated fasteners provide galvanic protection but cannot survive long-term exposure to the corrosive atmospheres found in petrochemical, chemical and offshore service. PTFE coating provides both corrosion resistance (up to 3,000 h salt spray to ASTM B117) and a low friction coefficient of 0.06–0.08, giving consistent tensioning, easy installation and removal, and anti-galling protection. This is why PTFE coated fasteners have largely replaced galvanized and plated fasteners in these industries.
What is the most common PTFE coated stud and nut combination?
The most widely used combination is ASTM A193 B7 studs with ASTM A194 2H nuts, both PTFE coated. This is standard practice on petrochemical flanges. Other common grades include B7M, B16, B8 and B8M, with matching nuts. Tell us your flange standard, bolt size, thread form and process media and we will confirm the correct grade.
What is the maximum working temperature of PTFE coated fasteners?
The PTFE coating is rated for continuous service up to +260 °C. Above this temperature the coating begins to degrade. If your operating temperature exceeds +260 °C, tell us the actual temperature profile and we will confirm whether an uncoated or alternative-coated fastener is more suitable.
What sizes and thread forms are available?
UNC, UNF, metric and BSW thread forms are available as standard, plus custom thread forms to drawing. Common stud sizes from M10 to M56 and 1/2 in to 2-1/4 in are held in production. Tell us the size, thread form, grade and quantity and we will confirm feasibility and price.
Can you supply PTFE coated fasteners to a specific project specification?
Yes. We regularly produce PTFE coated studs, bolts and nuts to project specifications that call out ASTM A193, ASTM A194, ASTM A320, ASTM A453 or equivalent standards, with coating thickness, friction coefficient and salt spray requirements specified. Send your datasheet or project specification and we will confirm compliance.
What documentation is available with the fasteners?
Material declaration, coating certificate, batch traceability record and third-party inspection certificate (SGS, BV, TUV or client-nominated) are available on request. Mill certificates for the substrate are also available. State your documentation requirements in the inquiry and we will include them in the quotation.
What is the minimum order quantity?
No rigid minimum. Small quantities for qualification and pilot runs are accepted. Larger production quantities are quoted at a lower unit price. Fasteners are normally supplied in sealed bags or boxes with the size and grade marked.
How quickly can you quote and ship?
Send the stud or bolt size, thread form, grade, nut grade, quantity and coating requirement. With these details we can give you a technical recommendation and price within 2 business hours. Standard sizes normally ship within 7–15 working days of order confirmation.
Request a Quotation for PTFE Coated Fasteners
Send us your stud or bolt size, thread form, substrate grade, nut grade, quantity and coating requirement — or a copy of your project specification or datasheet — and we will come back with a material recommendation, price and realistic delivery date.
- Tel: 0086-574-87527771
- E-mail: kaxite@seal-china.com
- Address: No. 432 Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang, China
Send Inquiry
Contact Info
-
Address
No. 432 Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang China
-
-
Email
Request a Quote or Technical Consultation
Share your sealing requirement and our technical sales team will respond within 24 business hours. For fastest service, include your flange specification, operating pressure, temperature, and process media in the message below.
News Recommendations
