Putian ASME PTFE Gasket

QS Gasket: Putian ASME PTFE Gasket

Product: Putian ASME PTFE Gasket
Size: 1 1/2 Inch
Material: PTFE
Class: 150 LBS
Standard: ASME B16.21
Thickness:1.5mm

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What Is an ASME PTFE Gasket?
An ASME PTFE gasket is a sealing component manufactured to ASME dimensional standards,

designed to be compressed between two pipe flanges to create a leak-tight joint.

PTFE (polytetrafluoroethylene) offers near-universal chemical resistance across a pH range of 0–14,

making it the material of choice in chemical processing, pharmaceutical manufacturing,

and food processing where product purity and corrosion resistance are non-negotiable.

ASME PTFE gaskets are available in two primary configurations: full-face (FF) gaskets for flat-face flanges and ring-type gaskets for raised-face (RF) flanges,

with dimensional requirements governed by ASME B16.21 for non-metallic sheet gaskets and ASME B16.20 for spiral-wound types with PTFE filler.

Temperature & Pressure Limits: What the Specs Really Say
The commonly cited maximum service temperature of 500°F (260°C) applies to virgin and filled PTFE grades.

However, PTFE exhibits cold flow (creep) under sustained bolt load at elevated temperatures. Above 260°C,

PTFE begins to decompose at 327°C, and the joint loses seal integrity.

Critical rule: never specify PTFE gaskets for services where both temperature and pressure simultaneously approach their maximum ratings.

For applications above 260°C, spiral-wound gaskets with flexible graphite filler or solid metal gaskets should be used instead.

ASME B16.20: The Inner Ring Requirement You Can't Ignore
A frequently overlooked requirement: ASME B16.20 mandates that all spiral-wound gaskets with PTFE filler material shall be furnished with inner rings to prevent inward buckling of the winding under compression.Inner ring thickness must be 2.97–3.33 mm (0.117–0.131 in).

Inner ring material should match the piping material to avoid galvanic corrosion—a carbon steel inner ring in a stainless steel system will corrode and contaminate the process fluid.

This is not optional. If your purchase order specifies PTFE-filled spiral wound gaskets without inner rings,

the supplier may still stamp them as B16.20-compliant, but they will not perform as intended.

Correct Sizing: Beyond Inside Diameter
Gasket sizing for ASME PTFE gaskets requires four parameters: inner diameter (ID), outer diameter (OD) , thickness, and bolt circle diameter (for full-face types).

Ordering by NPS alone is a common and costly error—a Class 150 gasket and a Class 600 gasket for the same nominal pipe size

are physically different components with different raised-face diameters and bolt circle dimensions.

For ring-type gaskets, the ID must match the flange bore; for full-face gaskets, the OD must match the flange OD and bolt holes must align with the flange bolt pattern.

Always specify by NPS + pressure class + gasket type + standard (e.g., “2″ Class 300 Ring Type, ASME B16.21”).

Manufacturing Excellence from Putian
Putian, a city in Fujian Province, China, has developed into a recognized manufacturing hub for advanced polymer and composite sealing products.

The Putian industrial cluster has steadily evolved into a key supplier hub for oil, gas, and chemical infrastructure,

with decades of accumulated expertise in precision molding and high-pressure sealing technologies.

PTFE gasket manufacturers in Putian operate integrated production facilities covering material compounding, CNC machining,

dimensional inspection, and export packaging. Local suppliers hold ISO 9001 and API 6A-equivalent certifications,

and the proximity of raw material suppliers, precision machining units,

and export logistics within the Putian industrial zone reduces lead times and enables rapid prototyping for custom gasket geometries.

For procurement teams evaluating global sourcing options, Putian offers a compelling combination of material expertise, dimensional precision,

and cost-effective production scale—particularly for ASME PTFE gasket orders requiring FDA-compliant material grades or custom dimensions.

Applications Where ASME PTFE Gaskets Excel
- Chemical processing: PTFE resists virtually all industrial chemicals, solvents, and caustics
- Pharmaceutical: FDA-compliant grades conform to 21 CFR 177.1550 for direct food and drug contact
- Food & beverage: Non-porous surface prevents bacterial retention; suitable for CIP/SIP cleaning cycles
- Cryogenic service: PTFE maintains sealing integrity down to -268°C (-450°F)
- High-purity systems: Minimal extractables and leachables compared to elastomeric alternatives

Installation Essentials
Effective sealing with ASME PTFE gaskets depends on correct installation practice:

1. Never reuse a gasket after disassembly—PTFE takes a permanent compression set and cannot re-conform.
2. Match gasket type to flange face: full-face for FF flanges, ring-type for RF flanges, ring joint (R/RX/BX) for RTJ flanges.
3. Torque in a star pattern in a minimum of three passes (30%, 60%, 100% of target torque) per ASME PCC-1.
4. Verify bolt load sufficiency—PTFE requires adequate compressive stress to overcome its limited elastic recovery.

FAQ

Q1: Can I use PTFE gaskets in steam service above 260°C?
No. Above 260°C, PTFE undergoes cold flow and eventual decomposition.

Q2: What is the typical MOQ and lead time for ASME PTFE gaskets from Putian suppliers?
Most Putian PTFE gasket manufacturers accept MOQs starting at 100 pieces for standard sizes, with lead times of 7–15 days for production orders.

Q3: Can Putian manufacturers produce custom PTFE gaskets for non-standard flange dimensions?

Yes. Putian’s precision molding and CNC machining ecosystem supports custom gasket production from 2D/3D drawings,

including non-circular configurations, V-shaped seals, and oversized diameters for large-diameter pipeline applications.

Our Quotation

Russia Mexico Customers Quotation
Xiamen Qishine
Email:qishine@qishine.com		Website: www.cnqishine.com
Tel: +86-592-5255951		Date:
Quotation Ref.:		Contact Person: Amy
Price Valid Time: 7 days from the date of quotation.
Payment Terms: T/T 100% in advance to start the production.
Production time: 35 days from the date of receiving your advance payment.
Documents: CI&PL, B/L and Mill Test Certificates EN.10204.3.1.

Item	ASME PTFE Gasket Description	Unit	Qty
1	Insulation gasket 8'', #300 PTFE	Set	10
2	Insulation gasket 8'', #150 PTFE	Set	10
3	Insulation gasket 6'', #300 PTFE	Set	10
4	Insulation gasket 6'', #150 PTFE	Set	10
Total

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