{"id":4948,"date":"2026-10-15T00:00:00","date_gmt":"2026-10-14T16:00:00","guid":{"rendered":"https:\/\/ptfesuppliers.com\/?p=4948"},"modified":"2026-10-15T00:00:00","modified_gmt":"2026-10-14T16:00:00","slug":"corrugated-ptfe-gaskets-metal-corrugated-sheets","status":"publish","type":"post","link":"https:\/\/ptfesuppliers.com\/fr\/corrugated-ptfe-gaskets-metal-corrugated-sheets\/","title":{"rendered":"Corrugated PTFE Gaskets: Metal Corrugated Sheet Sealing Guide"},"content":{"rendered":"<div class=\"container\">\n<p>A corrugated PTFE gasket is a sealing component made by bonding (or loosely assembling) a virgin or filled PTFE facing onto a metal corrugated sheet core. The metal corrugations create concentrated sealing lines that multiply contact pressure at the flange face, while the PTFE layer provides chemical resistance and a low-friction, non-stick surface. The result is a gasket that holds high bolt load with low creep and seals aggressive media in narrow, lightweight flanges where a solid PTFE gasket would cold-flow and leak.<\/p>\n<p>By the end of this article you will be able to identify when a corrugated PTFE gasket is the correct choice, install one correctly with the right bolt torque sequence, and diagnose the three most common failure modes before they cause a leak.<\/p>\n<div class=\"toc\">\n<h2>Table of Contents<\/h2>\n<ul>\n<li><a href=\"#principle\">1. Why the Corrugated PTFE + Metal Sheet Combination Works<\/a><\/li>\n<li><a href=\"#howto\">2. How to Install a Corrugated PTFE Gasket (Step by Step)<\/a><\/li>\n<li><a href=\"#mistakes\">3. Three Common Mistakes and How to Fix Them<\/a><\/li>\n<li><a href=\"#faq\">4. FAQ: Beginner Questions Answered<\/a><\/li>\n<\/ul>\n<\/div>\n<h2 id=\"principle\">1. Why the Corrugated PTFE + Metal Sheet Combination Works<\/h2>\n<p><img decoding=\"async\" src=\"https:\/\/ptfesuppliers.com\/wp-content\/uploads\/2026\/09\/Corrugated_PTFE_Gaskets__Combi_00.jpg\" alt=\"Cross-section of a corrugated PTFE gasket showing the metal corrugated core and PTFE facings between two flange faces\" loading=\"lazy\" style=\"max-width:100%; border-radius:8px;\"><\/p>\n<p>The sealing mechanism has three parts. First, the <strong>metal corrugated core<\/strong> acts as a spring. When you compress it, it stores elastic energy that keeps pushing back against the flange faces as the joint relaxes under thermal cycling. Second, the <strong>corrugation peaks<\/strong> concentrate the bolt load into narrow contact lines, so the local pressure at each peak is far higher than the average flange pressure. Third, the <strong>PTFE facing<\/strong> flows into the micro-roughness of the flange surface at those peaks and fills the leak path without the bulk cold-flow that destroys a plain PTFE gasket.<\/p>\n<p>Compare the numbers. A plain 3 mm PTFE gasket in a 4-inch Class 150 flange typically requires 35\u201345 N\u00b7m per bolt to reach a usable stress, and still creeps 15\u201325% within 24 hours at 100 \u00b0C. A corrugated PTFE gasket of the same thickness reaches the same sealing stress at roughly 20\u201325 N\u00b7m because the corrugations multiply contact pressure, and creep stays under 5% because the metal core carries the load.<\/p>\n<table>\n<caption>Typical behaviour comparison (4-inch Class 150, 3 mm thickness, 100 \u00b0C)<\/caption>\n<thead>\n<tr>\n<th>Propri\u00e9t\u00e9<\/th>\n<th>Plain PTFE gasket<\/th>\n<th>Corrugated PTFE gasket<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Bolt torque to seal<\/td>\n<td>35\u201345 N\u00b7m<\/td>\n<td>20\u201325 N\u00b7m<\/td>\n<\/tr>\n<tr>\n<td>Creep after 24 h<\/td>\n<td>15\u201325%<\/td>\n<td>&lt; 5%<\/td>\n<\/tr>\n<tr>\n<td>Recoverable spring-back<\/td>\n<td>Low<\/td>\n<td>High (metal core)<\/td>\n<\/tr>\n<tr>\n<td>Best use case<\/td>\n<td>Low-pressure, ambient<\/td>\n<td>Thermal cycling, vacuum, narrow flanges<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The authoritative basis for these design rules is <a href=\"https:\/\/www.asme.org\/codes-standards\/find-codes-standards\/bpvc-section-viii-rules-construction-pressure-vessels\" rel=\"nofollow noopener\" target=\"_blank\">ASME BPVC Section VIII, Division 1, Appendix 2<\/a>, which defines the gasket seating stress and the m and y factors you use to size bolt load. PTFE&#8217;s y factor is low (about 7 MPa for virgin PTFE), which is exactly why the corrugated metal core is needed to add mechanical spring-back. For the metal side of the assembly, <a href=\"https:\/\/ptfesuppliers.com\/fr\/product\/metal-corrugated-gaskets\/\">metal corrugated gaskets for extreme pressure and temperature<\/a> share the same corrugation principle and are worth comparing when the PTFE facing is not required.<\/p>\n<h2 id=\"howto\">2. How to Install a Corrugated PTFE Gasket (Step by Step)<\/h2>\n<p><img decoding=\"async\" src=\"https:\/\/ptfesuppliers.com\/wp-content\/uploads\/2026\/09\/Corrugated_PTFE_Gaskets__Combi_01.jpg\" alt=\"Technician installing a corrugated PTFE gasket on a flange and tightening bolts in a star pattern with a torque wrench\" loading=\"lazy\" style=\"max-width:100%; border-radius:8px;\"><\/p>\n<p>Follow these steps in order. Do not skip the cleaning step; most corrugated PTFE gasket failures trace back to contaminated flange faces.<\/p>\n<ol>\n<li><strong>Verify the gasket matches the flange.<\/strong> Check the inner diameter, outer diameter, and bolt-hole circle against the flange. A corrugated gasket must sit inside the bolt circle without covering any bolt hole.<\/li>\n<li><strong>Clean both flange faces.<\/strong> Remove all old gasket residue, rust, and oil with a wire brush and solvent. Wipe dry. The faces must be bare metal with no visible film.<\/li>\n<li><strong>Inspect for damage.<\/strong> Run a straight edge across each flange face. Any gap greater than 0.2 mm across the sealing area means you must resurface the flange first.<\/li>\n<li><strong>Align the flanges.<\/strong> Bring the pipe ends together and insert at least half the bolts finger-tight so the gap is even all around. A misaligned flange will crush one side of the corrugations.<\/li>\n<li><strong>Insert the gasket.<\/strong> Slide the corrugated PTFE gasket between the flanges. Do not bend it. If the gasket has a metal core with a locating ring, seat the ring against the bolt.<\/li>\n<li><strong>Lubricate the bolt threads and nuts.<\/strong> Apply a thin, even film of molybdenum disulfide or nickel anti-seize. Dry threads need 30\u201340% more torque for the same load.<\/li>\n<li><strong>Tighten in a star pattern, in three passes.<\/strong> Pass 1: 30% of final torque. Pass 2: 60%. Pass 3: 100%. Always move to the bolt diagonally opposite the one you just tightened.<\/li>\n<li><strong>Re-torque after 24 hours.<\/strong> Thermal cycling relaxes the joint. Bring every bolt back to final torque in one star-pattern pass.<\/li>\n<\/ol>\n<p>Use this torque table as a starting point, then confirm against the gasket manufacturer&#8217;s data sheet.<\/p>\n<table>\n<caption>Starting bolt torque for corrugated PTFE gaskets (lubricated threads)<\/caption>\n<thead>\n<tr>\n<th>Flange size<\/th>\n<th>Bolt size<\/th>\n<th>Class 150<\/th>\n<th>Class 300<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>1 inch<\/td>\n<td>M12<\/td>\n<td>15 N\u00b7m<\/td>\n<td>20 N\u00b7m<\/td>\n<\/tr>\n<tr>\n<td>2 inch<\/td>\n<td>M16<\/td>\n<td>25 N\u00b7m<\/td>\n<td>35 N\u00b7m<\/td>\n<\/tr>\n<tr>\n<td>4 inch<\/td>\n<td>M16<\/td>\n<td>25 N\u00b7m<\/td>\n<td>40 N\u00b7m<\/td>\n<\/tr>\n<tr>\n<td>6 inch<\/td>\n<td>M20<\/td>\n<td>45 N\u00b7m<\/td>\n<td>65 N\u00b7m<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>For reference on PTFE&#8217;s chemical compatibility with your specific medium, check the <a href=\"https:\/\/www.chemours.com\/en\/products-and-brands\/teflon\" rel=\"nofollow noopener\" target=\"_blank\">Chemours Teflon technical library<\/a>, which publishes compatibility charts by fluid and temperature.<\/p>\n<h2 id=\"mistakes\">3. Three Common Mistakes and How to Fix Them<\/h2>\n<h3>Mistake 1: Over-torquing to stop a leak<\/h3>\n<p><strong>Symptom:<\/strong> The joint leaks at low pressure, you add torque, and the leak gets worse or the gasket extrudes out of the flange gap.<\/p>\n<p><strong>Cause:<\/strong> Once the corrugations are flattened, the metal core can no longer spring back, and the PTFE facing is squeezed past the flange edge.<\/p>\n<p><strong>Fix:<\/strong> Never exceed the manufacturer&#8217;s maximum torque. If the joint still leaks at the correct torque, the flange faces are damaged or the gasket is the wrong size. Replace the gasket and resurface the flange.<\/p>\n<h3>Mistake 2: Reusing the gasket<\/h3>\n<p><strong>Symptom:<\/strong> A joint that sealed perfectly for a year starts weeping after a maintenance shutdown where the gasket was reused.<\/p>\n<p><strong>Cause:<\/strong> The corrugations take a permanent set after the first compression. Reusing the gasket means you start with flattened peaks and zero spring-back.<\/p>\n<p><strong>Fix:<\/strong> Always install a new corrugated PTFE gasket. There is no safe reuse case for this design.<\/p>\n<h3>Mistake 3: Mixing bolt materials or skipping lubrication<\/h3>\n<p><strong>Symptom:<\/strong> Bolts on one side of the flange are tight while the other side is still loose, and the gasket crushes unevenly.<\/p>\n<p><strong>Cause:<\/strong> Different friction coefficients between dry and lubricated threads, or mixing stainless and carbon steel bolts, changes the actual load for the same torque reading.<\/p>\n<p><strong>Fix:<\/strong> Use identical bolts throughout, lubricate all threads the same way, and tighten in the three-pass star pattern described above.<\/p>\n<h2 id=\"faq\">4. FAQ: Beginner Questions Answered<\/h2>\n<h3>What temperature can a corrugated PTFE gasket handle?<\/h3>\n<p>Virgin PTFE facings are rated from \u2212200 \u00b0C to +260 \u00b0C. Above 260 \u00b0C the PTFE begins to degrade. If your process runs hotter, use a filled PTFE (glass or graphite filled) facing, which extends the upper limit to about 300 \u00b0C with reduced chemical resistance. A <a href=\"https:\/\/ptfesuppliers.com\/fr\/product\/ptfe-graphite-filled-gasket\/\">PTFE graphite filled gasket<\/a> is a common upgrade for these higher-temperature, thermally cycled joints.<\/p>\n<h3>Can I use a corrugated PTFE gasket on a raised-face flange?<\/h3>\n<p>Yes, provided the gasket outer diameter fits inside the raised face. Measure the raised-face diameter and confirm the gasket OD is at least 2 mm smaller. On a flat-face flange, the gasket must cover the full sealing area.<\/p>\n<h3>How do I know if my gasket has a metal corrugated core or is a spiral-wound type?<\/h3>\n<p>Look at the edge. A corrugated PTFE gasket shows a continuous wavy metal sheet between two PTFE layers. A spiral-wound gasket shows alternating concentric rings of metal and filler. They are not interchangeable.<\/p>\n<h3>What bolt load do I need for vacuum service?<\/h3>\n<p>Vacuum service needs the highest seating stress because the pressure differential pulls the flanges apart. Use the upper end of the torque table and re-torque after the first thermal cycle. For vacuum below 10 mbar, consult the gasket supplier&#8217;s vacuum-rated data.<\/p>\n<h3>Does the corrugation direction matter?<\/h3>\n<p>No. Corrugations run either concentrically or in a parallel pattern, and both seal the same way. What matters is that the gasket sits flat with no folds or bends before you tighten the bolts.<\/p>\n<p>For a deeper background on gasket seating stress and flange design, the <a href=\"https:\/\/www.asme.org\/codes-standards\/find-codes-standards\/bpvc-section-viii-rules-construction-pressure-vessels\" rel=\"nofollow noopener\" target=\"_blank\">ASME Boiler and Pressure Vessel Code<\/a> remains the primary reference used by engineers worldwide. When the application calls for a fully PTFE-facing solution instead of a metal core, a <a href=\"https:\/\/ptfesuppliers.com\/fr\/product\/pure-ptfe-gasket-high-purity-chemical-resistant-flange-seal\/\">pure PTFE gasket for high-purity chemical resistant flange sealing<\/a> is the natural alternative to evaluate.<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Learn how corrugated PTFE gaskets combine with metal corrugated sheets to seal flanges. Step-by-step installation, torque values, and common mistakes.<\/p>","protected":false},"author":1,"featured_media":4779,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[168],"class_list":["post-4948","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry-news","tag-corrugated-ptfe-gaskets-metal-corrugated-sheets"],"_links":{"self":[{"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/posts\/4948","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/comments?post=4948"}],"version-history":[{"count":1,"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/posts\/4948\/revisions"}],"predecessor-version":[{"id":4983,"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/posts\/4948\/revisions\/4983"}],"wp:attachment":[{"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/media?parent=4948"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/categories?post=4948"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ptfesuppliers.com\/fr\/wp-json\/wp\/v2\/tags?post=4948"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}