{"id":937,"date":"2026-04-11T01:57:14","date_gmt":"2026-04-11T05:57:14","guid":{"rendered":"https:\/\/www.songhaiflange.com\/?p=937"},"modified":"2026-04-11T01:59:36","modified_gmt":"2026-04-11T05:59:36","slug":"the-complete-guide-to-flange-bolt-torquing-procedures","status":"publish","type":"post","link":"https:\/\/www.songhaiflange.com\/fr\/2026\/04\/11\/the-complete-guide-to-flange-bolt-torquing-procedures\/","title":{"rendered":"Le guide complet des proc\u00e9dures de serrage des boulons de bride"},"content":{"rendered":"<h2>Introduction<\/h2>\n<p>Proper bolt torquing is critical for achieving a leak-free flange joint. Incorrect torque can lead to gasket damage, flange warping, or insufficient sealing pressure. This guide covers best practices for flange bolt torquing.<\/p>\n<h2>Why Proper Torque Matters<\/h2>\n<p>Under-torquing causes:<\/p>\n<ul>\n<li>Insufficient gasket compression<\/li>\n<li>Leak paths through the gasket<\/li>\n<li>Vibration-induced loosening<\/li>\n<\/ul>\n<p>Over-torquing causes:<\/p>\n<ul>\n<li>Gasket crushing and extrusion<\/li>\n<li>Flange face damage<\/li>\n<li>Bolt stretching or failure<\/li>\n<li>Uneven load distribution<\/li>\n<\/ul>\n<h2>Torque Calculation<\/h2>\n<h3>Basic Formula<\/h3>\n<p>T = K \u00d7 D \u00d7 P<\/p>\n<ul>\n<li>T = Torque (Nm or ft-lbs)<\/li>\n<li>K = Nut factor (typically 0.2 for lubricated bolts)<\/li>\n<li>D = Bolt nominal diameter (mm or inches)<\/li>\n<li>P = Desired bolt preload (N or lbs)<\/li>\n<\/ul>\n<h3>Industry Standard Torque Values<\/h3>\n<p>For ASME B16.5 flanges with spiral wound gaskets:<\/p>\n<ul>\n<li>Class 150: 50-70% of bolt yield strength<\/li>\n<li>Class 300-600: 60-75% of bolt yield strength<\/li>\n<li>Class 900-2500: 70-80% of bolt yield strength<\/li>\n<\/ul>\n<h2>Step-by-Step Torquing Procedure<\/h2>\n<h3>Step 1: Preparation<\/h3>\n<ul>\n<li>Clean flange faces and inspect for damage<\/li>\n<li>Verify gasket type and condition<\/li>\n<li>Lubricate bolt threads and nut faces<\/li>\n<li>Check bolt length (should protrude 2-3 threads)<\/li>\n<\/ul>\n<h3>Step 2: Hand Tightening<\/h3>\n<ul>\n<li>Insert all bolts finger-tight<\/li>\n<li>Ensure gasket is properly centered<\/li>\n<li>Verify flange alignment<\/li>\n<\/ul>\n<h3>Step 3: Initial Torque (30%)<\/h3>\n<ul>\n<li>Use crisscross pattern (star pattern)<\/li>\n<li>Apply 30% of final torque to all bolts<\/li>\n<li>Number bolts sequentially for tracking<\/li>\n<\/ul>\n<h3>Step 4: Intermediate Torque (60%)<\/h3>\n<ul>\n<li>Follow same crisscross pattern<\/li>\n<li>Increase to 60% of final torque<\/li>\n<li>Check flange gap for evenness<\/li>\n<\/ul>\n<h3>Step 5: Final Torque (100%)<\/h3>\n<ul>\n<li>Apply 100% torque in crisscross pattern<\/li>\n<li>Go around twice to ensure uniformity<\/li>\n<li>Record all torque values<\/li>\n<\/ul>\n<h2>Torque Pattern Examples<\/h2>\n<h3>4-Bolt Flange<\/h3>\n<p>Pattern: 1 \u2192 3 \u2192 2 \u2192 4 (opposite bolts)<\/p>\n<h3>8-Bolt Flange<\/h3>\n<p>Pattern: 1 \u2192 5 \u2192 3 \u2192 7 \u2192 2 \u2192 6 \u2192 4 \u2192 8<\/p>\n<h3>12-Bolt Flange<\/h3>\n<p>Pattern: 1 \u2192 7 \u2192 4 \u2192 10 \u2192 2 \u2192 8 \u2192 5 \u2192 11 \u2192 3 \u2192 9 \u2192 6 \u2192 12<\/p>\n<h2>Tools and Equipment<\/h2>\n<ul>\n<li><strong>Calibrated torque wrench:<\/strong> Essential for accuracy<\/li>\n<li><strong>Hydraulic torque wrench:<\/strong> For large diameter flanges<\/li>\n<li><strong>Torque multiplier:<\/strong> For high-torque applications<\/li>\n<li><strong>Bolt tensioner:<\/strong> For critical high-pressure joints<\/li>\n<\/ul>\n<h2>Common Mistakes to Avoid<\/h2>\n<ul>\n<li>\u2717 Using impact wrenches (causes uneven torque)<\/li>\n<li>\u2717 Skipping the crisscross pattern<\/li>\n<li>\u2717 Not lubricating threads<\/li>\n<li>\u2717 Reusing damaged or stretched bolts<\/li>\n<li>\u2717 Ignoring torque wrench calibration (should be calibrated annually)<\/li>\n<li>\u2717 Torquing in circular sequence instead of crisscross<\/li>\n<\/ul>\n<h2>Post-Installation Checks<\/h2>\n<ul>\n<li>Visual inspection for even gasket compression<\/li>\n<li>Check flange parallelism (gap should be uniform)<\/li>\n<li>Document all torque values for maintenance records<\/li>\n<li>Schedule re-torque after 24 hours if required<\/li>\n<\/ul>\n<h2>Conclusion<\/h2>\n<p>Proper bolt torquing is both an art and a science. Following standardized procedures ensures safe, leak-free operation and extends the service life of your flange joints. Always train personnel on proper techniques and maintain calibrated tools.<\/p>\n<p><strong>WhatsApp :<\/strong>\u00a0+86-18658777855<\/p>\n<p><strong>Courriel :<\/strong>\u00a01007788887@qq.com<\/p>\n<p>\u2713 MTR with NDT reports \u2713 Third-party inspection welcome<a href=\"https:\/\/www.720yun.com\/vr\/a6ajt7ynrw0\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-884\" src=\"http:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4.webp\" alt=\"\" width=\"1290\" height=\"2317\" srcset=\"https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4.webp 1290w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-167x300.webp 167w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-570x1024.webp 570w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-768x1379.webp 768w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-855x1536.webp 855w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-1140x2048.webp 1140w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-7x12.webp 7w, https:\/\/www.songhaiflange.com\/wp-content\/uploads\/2026\/04\/4-416x747.webp 416w\" sizes=\"auto, (max-width: 1290px) 100vw, 1290px\" \/><\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Ma\u00eetrisez le serrage des boulons \u00e0 bride gr\u00e2ce \u00e0 ce guide complet qui couvre le calcul du couple, les proc\u00e9dures, les mod\u00e8les et les erreurs courantes.<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-937","post","type-post","status-publish","format-standard","hentry","category-blog"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/posts\/937","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/comments?post=937"}],"version-history":[{"count":3,"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/posts\/937\/revisions"}],"predecessor-version":[{"id":945,"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/posts\/937\/revisions\/945"}],"wp:attachment":[{"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/media?parent=937"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/categories?post=937"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.songhaiflange.com\/fr\/wp-json\/wp\/v2\/tags?post=937"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}