{"id":1026,"date":"2026-04-20T22:34:21","date_gmt":"2026-04-21T02:34:21","guid":{"rendered":"https:\/\/www.songhaiflange.com\/?p=1026"},"modified":"2026-04-20T22:35:52","modified_gmt":"2026-04-21T02:35:52","slug":"flange-bolt-torque-values-complete-chart-for-all-pressure-classes","status":"publish","type":"post","link":"https:\/\/www.songhaiflange.com\/vi\/2026\/04\/20\/flange-bolt-torque-values-complete-chart-for-all-pressure-classes\/","title":{"rendered":"Flange Bolt Torque Values Complete Chart for All Pressure Classes"},"content":{"rendered":"<h2>Proper Flange Bolt Torquing Guide<\/h2>\n<p>Correct bolt torque is critical for achieving leak-free flange joints. Under-torquing causes gasket blowout, while over-torquing can damage gaskets or warp flange faces.<\/p>\n<h3>Why Bolt Torque Matters<\/h3>\n<ul>\n<li>Ensures uniform gasket compression<\/li>\n<li>Prevents flange leakage under operating conditions<\/li>\n<li>Compensates for gasket creep and relaxation<\/li>\n<li>Maintains joint integrity during thermal cycling<\/li>\n<\/ul>\n<h3>Class 150 Bolt Torque Values (ft-lbs)<\/h3>\n<table>\n<tr>\n<th>Size<\/th>\n<th>K\u00edch th\u01b0\u1edbc bu-l\u00f4ng<\/th>\n<th>Quantity<\/th>\n<th>Non-Lubricated<\/th>\n<th>Lubricated<\/th>\n<\/tr>\n<tr>\n<td>1\/2&#8243;<\/td>\n<td>1\/2&#8243;-13<\/td>\n<td>4<\/td>\n<td>45<\/td>\n<td>35<\/td>\n<\/tr>\n<tr>\n<td>1&#8243;<\/td>\n<td>5\/8&#8243;-11<\/td>\n<td>4<\/td>\n<td>85<\/td>\n<td>65<\/td>\n<\/tr>\n<tr>\n<td>2&#8243;<\/td>\n<td>3\/4&#8243;-10<\/td>\n<td>4<\/td>\n<td>150<\/td>\n<td>115<\/td>\n<\/tr>\n<tr>\n<td>4&#8243;<\/td>\n<td>5\/8&#8243;-11<\/td>\n<td>8<\/td>\n<td>85<\/td>\n<td>65<\/td>\n<\/tr>\n<tr>\n<td>6&#8243;<\/td>\n<td>3\/4&#8243;-10<\/td>\n<td>8<\/td>\n<td>150<\/td>\n<td>115<\/td>\n<\/tr>\n<tr>\n<td>12&#8243;<\/td>\n<td>7\/8&#8243;-9<\/td>\n<td>12<\/td>\n<td>250<\/td>\n<td>190<\/td>\n<\/tr>\n<\/table>\n<h3>Class 300 Bolt Torque Values (ft-lbs)<\/h3>\n<table>\n<tr>\n<th>Size<\/th>\n<th>K\u00edch th\u01b0\u1edbc bu-l\u00f4ng<\/th>\n<th>Quantity<\/th>\n<th>Non-Lubricated<\/th>\n<th>Lubricated<\/th>\n<\/tr>\n<tr>\n<td>1\/2&#8243;<\/td>\n<td>1\/2&#8243;-13<\/td>\n<td>4<\/td>\n<td>65<\/td>\n<td>50<\/td>\n<\/tr>\n<tr>\n<td>2&#8243;<\/td>\n<td>3\/4&#8243;-10<\/td>\n<td>8<\/td>\n<td>185<\/td>\n<td>140<\/td>\n<\/tr>\n<tr>\n<td>4&#8243;<\/td>\n<td>3\/4&#8243;-10<\/td>\n<td>8<\/td>\n<td>185<\/td>\n<td>140<\/td>\n<\/tr>\n<tr>\n<td>6&#8243;<\/td>\n<td>7\/8&#8243;-9<\/td>\n<td>8<\/td>\n<td>290<\/td>\n<td>220<\/td>\n<\/tr>\n<tr>\n<td>12&#8243;<\/td>\n<td>1&#8243;-8<\/td>\n<td>12<\/td>\n<td>425<\/td>\n<td>320<\/td>\n<\/tr>\n<\/table>\n<h3>Class 600-2500 Torque Guidelines<\/h3>\n<p>Higher pressure classes require significantly higher torque values. Always refer to manufacturer specifications for Class 900, 1500, and 2500 flanges.<\/p>\n<h3>Bolt Torquing Procedure<\/h3>\n<ol>\n<li><strong>Clean:<\/strong> Remove dirt, rust, and old gasket material from flange faces<\/li>\n<li><strong>Inspect:<\/strong> Check flange faces for damage or warping<\/li>\n<li><strong>Lubricate:<\/strong> Apply anti-seize compound to bolt threads and nut faces<\/li>\n<li><strong>Insert:<\/strong> Place gasket centered on flange face<\/li>\n<li><strong>Hand-tighten:<\/strong> Snug all nuts finger-tight<\/li>\n<li><strong>Pattern:<\/strong> Use star\/cross pattern for even compression<\/li>\n<li><strong>Sequence:<\/strong> Torque to 30%, then 60%, then 100% of final value<\/li>\n<li><strong>Verify:<\/strong> Recheck all bolts after initial torque<\/li>\n<\/ol>\n<h3>Important Considerations<\/h3>\n<ul>\n<li><strong>Gasket Type:<\/strong> Different gaskets require different compression loads<\/li>\n<li><strong>Bolt Material:<\/strong> ASTM A193 B7 vs B16 have different strength ratings<\/li>\n<li><strong>Lubrication:<\/strong> Reduces required torque by 20-25%<\/li>\n<li><strong>Temperature:<\/strong> Hot torquing may be required for high-temperature service<\/li>\n<li><strong>Re-torquing:<\/strong> Consider re-torquing after thermal cycles<\/li>\n<\/ul>\n<h3>Nh\u1eefng sai l\u1ea7m th\u01b0\u1eddng g\u1eb7p c\u1ea7n tr\u00e1nh<\/h3>\n<ul>\n<li>Using impact wrenches without calibration<\/li>\n<li>Torquing in circular pattern instead of star pattern<\/li>\n<li>Skipping the multi-step torque sequence<\/li>\n<li>Reusing damaged or stretched bolts<\/li>\n<li>Ignoring gasket manufacturer torque recommendations<\/li>\n<\/ul>\n<p>Proper bolt torquing is essential for leak-free flange joints. Always follow established procedures and use calibrated torque tools.<\/p>","protected":false},"excerpt":{"rendered":"<p>Proper Flange Bolt Torquing Guide Correct bolt torque is critical for achieving leak-free flange joints. Under-torquing causes gasket blowout, while over-torquing can damage gaskets or warp flange faces. Why Bolt Torque Matters Ensures uniform gasket compression Prevents flange leakage under operating conditions Compensates for gasket creep and relaxation Maintains joint integrity during thermal cycling Class [&hellip;]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[87,66,88,72],"class_list":["post-1026","post","type-post","status-publish","format-standard","hentry","category-blog","tag-bolt-torque","tag-flange","tag-gasket","tag-rating"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/posts\/1026","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/comments?post=1026"}],"version-history":[{"count":1,"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/posts\/1026\/revisions"}],"predecessor-version":[{"id":1027,"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/posts\/1026\/revisions\/1027"}],"wp:attachment":[{"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/media?parent=1026"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/categories?post=1026"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.songhaiflange.com\/vi\/wp-json\/wp\/v2\/tags?post=1026"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}