{"id":4428,"date":"2026-05-21T10:51:48","date_gmt":"2026-05-21T10:51:48","guid":{"rendered":"https:\/\/productionscrews.com\/8-8-bolt\/"},"modified":"2026-05-21T10:52:16","modified_gmt":"2026-05-21T10:52:16","slug":"8-8-bolt","status":"publish","type":"post","link":"https:\/\/productionscrews.com\/vi\/8-8-bolt\/","title":{"rendered":"Bu l\u00f4ng 8.8: H\u01b0\u1edbng d\u1eabn \u0111\u1ea7y \u0111\u1ee7 v\u1ec1 bu l\u00f4ng c\u1ea5p 8.8, \u0111\u1ed9 b\u1ec1n v\u00e0 \u1ee9ng d\u1ee5ng"},"content":{"rendered":"<h1>Bu l\u00f4ng 8.8: H\u01b0\u1edbng d\u1eabn \u0111\u1ea7y \u0111\u1ee7 v\u1ec1 bu l\u00f4ng c\u1ea5p 8.8, \u0111\u1ed9 b\u1ec1n v\u00e0 \u1ee9ng d\u1ee5ng<\/h1>\n<p class=\"direct-answer\"><strong>Bu l\u00f4ng 8.8 l\u00e0 m\u1ed9t lo\u1ea1i ch\u1ed1t ren h\u1ec7 m\u00e9t v\u1edbi \u0111\u1ed9 b\u1ec1n k\u00e9o 800 MPa v\u00e0 gi\u1edbi h\u1ea1n ch\u1ea3y 640 MPa, \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c \u1ee9ng d\u1ee5ng \u00f4 t\u00f4, k\u1ebft c\u1ea5u v\u00e0 m\u00e1y m\u00f3c.<\/strong><\/p>\n<p>B\u1ea1n \u0111ang trong qu\u00e1 tr\u00ecnh l\u00e0m vi\u1ec7c, c\u1ea7m m\u1ed9t con bu l\u00f4ng c\u00f3 k\u00fd hi\u1ec7u \u201c8.8\u201d tr\u00ean \u0111\u1ea7u, v\u00e0 c\u00e2u h\u1ecfi xu\u1ea5t hi\u1ec7n: \u0111i\u1ec1u \u0111\u00f3 th\u1ef1c s\u1ef1 c\u00f3 ngh\u0129a l\u00e0 g\u00ec? N\u00f3 c\u00f3 \u0111\u1ee7 m\u1ea1nh cho gi\u00e1 \u0111\u1ee1 \u0111\u1ed9ng c\u01a1 c\u1ee7a b\u1ea1n kh\u00f4ng? C\u00f3 an to\u00e0n cho k\u1ebft n\u1ed1i khung th\u00e9p kh\u00f4ng? B\u1ea1n c\u00f3 th\u1ec3 thay th\u1ebf n\u00f3 b\u1eb1ng lo\u1ea1i Grade 5 mua \u1edf c\u1eeda h\u00e0ng v\u1eadt t\u01b0 kh\u00f4ng? \u0110\u00e2y kh\u00f4ng ph\u1ea3i l\u00e0 nh\u1eefng c\u00e2u h\u1ecfi \u0111\u01a1n gi\u1ea3n \u2014 s\u1eed d\u1ee5ng sai bu l\u00f4ng \u1edf m\u1ed1i n\u1ed1i ch\u1ecbu l\u1ef1c c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn h\u1ecfng h\u00f3c nghi\u00eam tr\u1ecdng. H\u01b0\u1edbng d\u1eabn n\u00e0y s\u1ebd gi\u1ea3i th\u00edch t\u1ea5t c\u1ea3 v\u1ec1 <strong>\u1ed1c v\u00edt 8.8<\/strong>: \u00fd ngh\u0129a c\u1ee7a c\u00e1c con s\u1ed1, \u0111\u1ed9 b\u1ec1n th\u1ef1c s\u1ef1, v\u1ecb tr\u00ed s\u1eed d\u1ee5ng ph\u00f9 h\u1ee3p v\u00e0 n\u01a1i kh\u00f4ng n\u00ean d\u00f9ng.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/productionscrews.com\/wp-content\/uploads\/2026\/05\/01-hero-32.png\" alt=\"Bu l\u00f4ng 8.8 \u2014 h\u00ecnh minh h\u1ecda anh h\u00f9ng cho bu l\u00f4ng l\u1ee5c gi\u00e1c l\u1edbp 8.8 v\u1edbi k\u00fd hi\u1ec7u h\u1ec7 m\u00e9t\" \/><\/p>\n<hr \/>\n<h2>Bu l\u00f4ng 8.8 l\u00e0 g\u00ec?<\/h2>\n<p><strong>Bu l\u00f4ng 8.8 l\u00e0 m\u1ed9t lo\u1ea1i ch\u1ed1t ren h\u1ec7 m\u00e9t \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i theo c\u1ea5p t\u00ednh ch\u1ea5t c\u01a1 h\u1ecdc ISO 8.8<\/strong>, quy \u0111\u1ecbnh hi\u1ec7u su\u1ea5t c\u01a1 h\u1ecdc c\u1ee7a n\u00f3 \u2014 kh\u00f4ng ph\u1ea3i k\u00edch th\u01b0\u1edbc. K\u00fd hi\u1ec7u \u201c8.8\u201d tr\u00ean \u0111\u1ea7u bu l\u00f4ng l\u00e0 k\u00fd hi\u1ec7u c\u1ea5p t\u00ednh ch\u1ea5t theo ISO 898-1, ti\u00eau chu\u1ea9n qu\u1ed1c t\u1ebf quy \u0111\u1ecbnh t\u00ednh ch\u1ea5t c\u01a1 h\u1ecdc c\u1ee7a c\u00e1c lo\u1ea1i ch\u1ed1t th\u00e9p carbon v\u00e0 h\u1ee3p kim.<\/p>\n<p>Hai con s\u1ed1 n\u00e0y l\u00e0 m\u1ed9t m\u00e3:<\/p>\n<ul>\n<li><strong>Ch\u1eef s\u1ed1 \u0111\u1ea7u ti\u00ean (8):<\/strong> M\u1ed9t ph\u1ea7n m\u01b0\u1eddi c\u1ee7a \u0111\u1ed9 b\u1ec1n k\u00e9o danh ngh\u0129a t\u00ednh theo \u0111\u01a1n v\u1ecb 100 MPa. V\u1eady 8 \u00d7 100 = <strong>800 MPa \u0111\u1ed9 b\u1ec1n k\u00e9o danh ngh\u0129a<\/strong>.<\/li>\n<li><strong>Ch\u1eef s\u1ed1 th\u1ee9 hai (8):<\/strong> T\u1ef7 l\u1ec7 gi\u1eefa gi\u1edbi h\u1ea1n ch\u1ea3y v\u00e0 \u0111\u1ed9 b\u1ec1n k\u00e9o, t\u00ednh theo ph\u1ea7n m\u01b0\u1eddi. V\u1eady 8 \u00d7 10 = <strong>T\u1ef7 l\u1ec7 80%<\/strong>, ngh\u0129a l\u00e0 gi\u1edbi h\u1ea1n ch\u1ea3y = 800 \u00d7 0,80 = <strong>640 MPa<\/strong>.<\/li>\n<\/ul>\n<p>\u0110i\u1ec1u n\u00e0y cho b\u1ea1n ba gi\u00e1 tr\u1ecb c\u01a1 h\u1ecdc quan tr\u1ecdng:<\/p>\n<table>\n<tbody>\n<tr>\n<th>Thu\u1ed9c t\u00ednh<\/th>\n<th>Gi\u00e1 tr\u1ecb cho c\u1ea5p 8.8<\/th>\n<\/tr>\n<tr>\n<td>\u0110\u1ed9 b\u1ec1n k\u00e9o danh ngh\u0129a<\/td>\n<td>800 MPa<\/td>\n<\/tr>\n<tr>\n<td>Gi\u1edbi h\u1ea1n ch\u1ea3y (t\u01b0\u01a1ng \u0111\u01b0\u01a1ng t\u1ea3i ch\u1ee9ng minh)<\/td>\n<td>\u2265 640 MPa<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u1ed9 gi\u00e3n d\u00e0i t\u1ed1i thi\u1ec3u khi \u0111\u1ee9t<\/td>\n<td>12%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u0110\u1ed9 gi\u00e3n d\u00e0i t\u1ed1i thi\u1ec3u 12% c\u00f3 ngh\u0129a l\u00e0 bu l\u00f4ng 8.8 kh\u00f4ng gi\u00f2n \u2014 ch\u00fang s\u1ebd bi\u1ebfn d\u1ea1ng r\u00f5 r\u1ec7t tr\u01b0\u1edbc khi b\u1ecb g\u00e3y, \u0111\u00e2y l\u00e0 m\u1ed9t \u0111\u1eb7c t\u00ednh an to\u00e0n quan tr\u1ecdng trong c\u00e1c \u1ee9ng d\u1ee5ng k\u1ebft c\u1ea5u. Theo <a href=\"https:\/\/www.iso.org\/standard\/80529.html\" rel=\"noopener\" target=\"_blank\">ISO 898-1 (ti\u00eau chu\u1ea9n qu\u1ed1c t\u1ebf quy \u0111\u1ecbnh v\u1ec1 c\u00e1c c\u1ea5p t\u00ednh ch\u1ea5t c\u1ee7a bu l\u00f4ng)<\/a>, t\u1ea5t c\u1ea3 c\u00e1c ch\u1ed1t \u0111\u01b0\u1ee3c \u0111\u00e1nh d\u1ea5u \u201c8.8\u201d \u0111\u1ec1u ph\u1ea3i \u0111\u00e1p \u1ee9ng ch\u00ednh x\u00e1c c\u00e1c ng\u01b0\u1ee1ng t\u1ed1i thi\u1ec3u n\u00e0y b\u1ea5t k\u1ec3 nh\u00e0 s\u1ea3n xu\u1ea5t hay qu\u1ed1c gia xu\u1ea5t x\u1ee9.<\/p>\n<h3>Th\u00e0nh ph\u1ea7n v\u1eadt li\u1ec7u c\u1ee7a bu l\u00f4ng c\u1ea5p 8.8<\/h3>\n<p>H\u1ea7u h\u1ebft bu l\u00f4ng 8.8 \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb <strong>th\u00e9p cacbon trung b\u00ecnh (h\u00e0m l\u01b0\u1ee3ng cacbon 0,25\u20130,55%)<\/strong>, c\u00f3 th\u1ec3 l\u00e0 th\u00e9p th\u01b0\u1eddng ho\u1eb7c th\u00e9p h\u1ee3p kim. Kh\u00e1c v\u1edbi c\u00e1c lo\u1ea1i bu l\u00f4ng c\u1ea5p th\u1ea5p l\u00e0m t\u1eeb th\u00e9p m\u1ec1m, bu l\u00f4ng c\u1ea5p 8.8 \u0111\u01b0\u1ee3c <strong>t\u00f4i v\u00e0 ram<\/strong> \u2014 m\u1ed9t quy tr\u00ecnh x\u1eed l\u00fd nhi\u1ec7t gi\u00fap t\u0103ng c\u01b0\u1eddng \u0111\u1ed9 b\u1ec1n m\u00e0 kh\u00f4ng l\u00e0m gi\u1ea3m \u0111\u1ed9 d\u1ebbo dai. \u0110\u00e2y l\u00e0 \u0111i\u1ec3m kh\u00e1c bi\u1ec7t gi\u1eefa bu l\u00f4ng 8.8 v\u1edbi bu l\u00f4ng c\u1ea5p 4.6 ho\u1eb7c 5.8 l\u00e0m t\u1eeb nguy\u00ean li\u1ec7u t\u01b0\u01a1ng t\u1ef1.<\/p>\n<p>\u0110\u1ed1i v\u1edbi bu l\u00f4ng k\u00edch th\u01b0\u1edbc M16 tr\u1edf xu\u1ed1ng, m\u1ed9t s\u1ed1 nh\u00e0 s\u1ea3n xu\u1ea5t s\u1eed d\u1ee5ng th\u00e9p boron cacbon trung b\u00ecnh. \u0110\u01b0\u1eddng k\u00ednh l\u1edbn h\u01a1n (M16 tr\u1edf l\u00ean) th\u01b0\u1eddng y\u00eau c\u1ea7u th\u00e9p h\u1ee3p kim cacbon trung b\u00ecnh \u0111\u1ec3 \u0111\u00e1p \u1ee9ng y\u00eau c\u1ea7u v\u1ec1 \u0111\u1ed9 b\u1ec1n k\u00e9o tr\u00ean to\u00e0n b\u1ed9 ti\u1ebft di\u1ec7n.<\/p>\n<h3>H\u1ec7 th\u1ed1ng k\u00fd hi\u1ec7u c\u1ea5p t\u00ednh ch\u1ea5t<\/h3>\n<p>M\u1ed7i bu l\u00f4ng 8.8 ch\u00ednh h\u00e3ng \u0111\u1ec1u \u0111\u01b0\u1ee3c \u0111\u00e1nh d\u1ea5u \u201c8.8\u201d tr\u00ean \u0111\u1ea7u v\u00e0, t\u00f9y theo nh\u00e0 s\u1ea3n xu\u1ea5t, c\u00f3 th\u1ec3 c\u00f3 th\u00eam k\u00fd hi\u1ec7u v\u1ecb tr\u00ed m\u1eb7t \u0111\u1ed3ng h\u1ed3 ho\u1eb7c logo. N\u1ebfu m\u1ed9t bu l\u00f4ng kh\u00f4ng c\u00f3 k\u00fd hi\u1ec7u n\u00e0o, h\u00e3y coi \u0111\u00f3 l\u00e0 lo\u1ea1i kh\u00f4ng x\u00e1c \u0111\u1ecbnh \u2014 kh\u00f4ng s\u1eed d\u1ee5ng trong b\u1ea5t k\u1ef3 m\u1ed1i n\u1ed1i k\u1ebft c\u1ea5u ho\u1eb7c an to\u00e0n n\u00e0o.<\/p>\n<hr \/>\n<h2>C\u00e1c lo\u1ea1i v\u00e0 bi\u1ebfn th\u1ec3 c\u1ee7a bu l\u00f4ng c\u1ea5p 8.8<\/h2>\n<p>C\u1ea5p 8.8 l\u00e0 <strong>c\u1ea5p \u0111\u1ed9 b\u1ec1n<\/strong>, kh\u00f4ng ph\u1ea3i ki\u1ec3u \u0111\u1ea7u bu l\u00f4ng. B\u1ea1n c\u00f3 th\u1ec3 t\u00ecm th\u1ea5y bu l\u00f4ng 8.8 \u1edf nhi\u1ec1u d\u1ea1ng v\u1eadt l\u00fd kh\u00e1c nhau, ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c ph\u01b0\u01a1ng ph\u00e1p l\u1eafp r\u00e1p v\u00e0 \u0111i\u1ec1u ki\u1ec7n t\u1ea3i kh\u00e1c nhau.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/productionscrews.com\/wp-content\/uploads\/2026\/05\/02-types-20.png\" alt=\"Bu l\u00f4ng 8.8 \u2014 h\u00ecnh minh h\u1ecda c\u00e1c lo\u1ea1i g\u1ed3m l\u1ee5c gi\u00e1c, v\u00edt \u0111\u1ea7u l\u1ee5c gi\u00e1c v\u00e0 bi\u1ebfn th\u1ec3 m\u1eb7t b\u00edch\" \/><\/p>\n<h3>Bu l\u00f4ng l\u1ee5c gi\u00e1c (ren to\u00e0n ph\u1ea7n v\u00e0 ren m\u1ed9t ph\u1ea7n)<\/h3>\n<p>D\u1ea1ng ph\u1ed5 bi\u1ebfn nh\u1ea5t. M\u1ed9t <strong>bu l\u00f4ng l\u1ee5c gi\u00e1c ren m\u1ed9t ph\u1ea7n<\/strong> c\u00f3 ph\u1ea7n th\u00e2n tr\u01a1n n\u1eb1m trong l\u1ed7 bu l\u00f4ng v\u00e0 ch\u1ecbu t\u1ea3i c\u1eaft hi\u1ec7u qu\u1ea3 h\u01a1n bu l\u00f4ng ren to\u00e0n ph\u1ea7n. \u0110\u1ed1i v\u1edbi c\u00e1c \u1ee9ng d\u1ee5ng ch\u1ecbu c\u1eaft (l\u1ef1c t\u00e1c \u0111\u1ed9ng vu\u00f4ng g\u00f3c v\u1edbi tr\u1ee5c bu l\u00f4ng), lu\u00f4n \u01b0u ti\u00ean s\u1eed d\u1ee5ng bu l\u00f4ng l\u1ee5c gi\u00e1c 8.8 ren m\u1ed9t ph\u1ea7n v\u1edbi ph\u1ea7n th\u00e2n n\u1eb1m trong m\u1eb7t ph\u1eb3ng ch\u1ecbu c\u1eaft.<\/p>\n<p><strong>Bu l\u00f4ng l\u1ee5c gi\u00e1c ren su\u1ed1t<\/strong> (\u0111\u00f4i khi g\u1ecdi l\u00e0 v\u00edt l\u1ee5c gi\u00e1c ho\u1eb7c v\u00edt kh\u00f4ng th\u00e2n) \u0111\u01b0\u1ee3c \u01b0u ti\u00ean s\u1eed d\u1ee5ng khi chi\u1ec1u d\u00e0i k\u1eb9p ng\u1eafn v\u00e0 m\u1ed1i n\u1ed1i ho\u00e0n to\u00e0n d\u1ef1a v\u00e0o l\u1ef1c k\u1eb9p (ti\u1ec1n t\u1ea3i k\u00e9o), kh\u00f4ng ph\u1ea3i kh\u1ea3 n\u0103ng ch\u1ecbu c\u1eaft.<\/p>\n<h3>V\u00edt \u0111\u1ea7u ch\u1ee5p l\u1ee5c gi\u00e1c (SHCS) c\u1ea5p 8.8<\/h3>\n<p>V\u00edt \u0111\u1ea7u ch\u1ee5p l\u1ee5c gi\u00e1c (\u1ed5 c\u1eafm l\u1ee5c gi\u00e1c) c\u00f3 s\u1eb5n \u1edf c\u1ea5p 8.8. Lo\u1ea1i n\u00e0y cho ph\u00e9p si\u1ebft m\u00f4-men cao h\u01a1n so v\u1edbi bu l\u00f4ng l\u1ee5c gi\u00e1c t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u00ec \u1ed5 c\u1eafm b\u00ean trong ch\u1ed1ng tr\u01b0\u1ee3t hi\u1ec7u qu\u1ea3. Ch\u00fang ph\u1ed5 bi\u1ebfn trong m\u00e1y m\u00f3c, \u0111\u1ed3 g\u00e1 v\u00e0 khu\u00f4n khi c\u1ea7n v\u00edt ch\u00ecm ho\u1eb7c \u00e2m.<\/p>\n<h3>Bu l\u00f4ng m\u1eb7t b\u00edch c\u1ea5p 8.8<\/h3>\n<p>Bu l\u00f4ng m\u1eb7t b\u00edch t\u00edch h\u1ee3p m\u1ed9t m\u1eb7t b\u00edch gi\u1ed1ng nh\u01b0 long \u0111en d\u01b0\u1edbi \u0111\u1ea7u, ph\u00e2n b\u1ed5 l\u1ef1c k\u1eb9p tr\u00ean di\u1ec7n t\u00edch l\u1edbn h\u01a1n. \u0110i\u1ec1u n\u00e0y h\u1eefu \u00edch v\u1edbi v\u1eadt li\u1ec7u n\u1ec1n m\u1ec1m ho\u1eb7c n\u01a1i rung \u0111\u1ed9ng c\u00f3 th\u1ec3 l\u00e0m long \u0111en ti\u00eau chu\u1ea9n b\u1ecb x\u00ea d\u1ecbch. <strong>Bu l\u00f4ng m\u1eb7t b\u00edch c\u1ea5p 8.8 c\u1ef1c k\u1ef3 ph\u1ed5 bi\u1ebfn trong h\u1ec7 th\u1ed1ng \u0111\u1ed9ng c\u01a1 v\u00e0 x\u1ea3 \u00f4 t\u00f4<\/strong> n\u01a1i rung \u0111\u1ed9ng v\u00e0 chu k\u1ef3 nhi\u1ec7t di\u1ec5n ra li\u00ean t\u1ee5c.<\/p>\n<h3>Bu l\u00f4ng \u0111\u1ea7u tr\u00f2n v\u00e0 bu l\u00f4ng c\u00e0y c\u1ea5p 8.8<\/h3>\n<p>Bu l\u00f4ng \u0111\u1ea7u tr\u00f2n (\u0111\u1ea7u tr\u00f2n v\u1edbi c\u1ed5 vu\u00f4ng ch\u1ed1ng xoay) c\u00f3 s\u1eb5n c\u1ea5p 8.8 cho c\u00e1c \u1ee9ng d\u1ee5ng n\u1ed1i g\u1ed7 v\u1edbi th\u00e9p ho\u1eb7c th\u00e9p v\u1edbi th\u00e9p khi \u0111\u1ea7u bu l\u00f4ng c\u1ea7n ph\u1eb3ng ho\u1eb7c nh\u1eb5n m\u1ed9t m\u1eb7t. \u00cdt ph\u1ed5 bi\u1ebfn h\u01a1n lo\u1ea1i l\u1ee5c gi\u00e1c nh\u01b0ng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong thi\u1ebft b\u1ecb n\u00f4ng nghi\u1ec7p v\u00e0 r\u01a1-mo\u00f3c.<\/p>\n<h3>C\u00e1c lo\u1ea1i ho\u00e0n thi\u1ec7n b\u1ec1 m\u1eb7t c\u00f3 s\u1eb5n<\/h3>\n<table>\n<tbody>\n<tr>\n<th>Ho\u00e0n thi\u1ec7n<\/th>\n<th>M\u00f4 t\u1ea3<\/th>\n<th>S\u1eed d\u1ee5ng \u0111i\u1ec3n h\u00ecnh<\/th>\n<\/tr>\n<tr>\n<td>Th\u00e9p tr\u01a1n (kh\u00f4ng m\u1ea1)<\/td>\n<td>Kh\u00f4ng c\u00f3 b\u1ea3o v\u1ec7 ch\u1ed1ng \u0103n m\u00f2n<\/td>\n<td>M\u00e1y m\u00f3c trong nh\u00e0, ng\u00e2m d\u1ea7u<\/td>\n<\/tr>\n<tr>\n<td>M\u1ea1 \u0111i\u1ec7n k\u1ebdm (v\u00e0ng ho\u1eb7c tr\u1eafng)<\/td>\n<td>Ch\u1ed1ng \u0103n m\u00f2n nh\u1eb9<\/td>\n<td>M\u1ee5c \u0111\u00edch chung, trong nh\u00e0 ho\u1eb7c n\u01a1i c\u00f3 m\u00e1i che<\/td>\n<\/tr>\n<tr>\n<td>M\u1ea1 k\u1ebdm nh\u00fang n\u00f3ng (HDG)<\/td>\n<td>B\u1ea3o v\u1ec7 ch\u1ed1ng \u0103n m\u00f2n cao<\/td>\n<td>K\u1ebft c\u1ea5u ngo\u00e0i tr\u1eddi, v\u00f9ng ven bi\u1ec3n<\/td>\n<\/tr>\n<tr>\n<td>Dacromet \/ geomet<\/td>\n<td>M\u00e0ng m\u1ecfng, kh\u00f4ng c\u00f3 nguy c\u01a1 gi\u00f2n hydro<\/td>\n<td>\u00d4 t\u00f4, ch\u1ecbu t\u1ea3i cao<\/td>\n<\/tr>\n<tr>\n<td>Ph\u1ee7 \u0111en<\/td>\n<td>B\u1ea3o v\u1ec7 t\u1ed1i thi\u1ec3u, gi\u1ea3m hi\u1ec7n t\u01b0\u1ee3ng d\u00ednh tr\u01b0\u1ee3t<\/td>\n<td>M\u00e1y m\u00f3c ch\u00ednh x\u00e1c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<blockquote><p><strong>L\u01b0u \u00fd:<\/strong> Bu l\u00f4ng ti\u00eau chu\u1ea9n m\u1ea1 \u0111i\u1ec7n l\u1edbp 8.8 d\u1ec5 b\u1ecb <strong>gi\u00f2n do hydro<\/strong> n\u1ebfu m\u1ea1 kh\u00f4ng \u0111\u00fang c\u00e1ch. \u0110\u1ed1i v\u1edbi c\u00e1c m\u1ed1i n\u1ed1i quan tr\u1ecdng v\u1ec1 an to\u00e0n, h\u00e3y ch\u1ec9 \u0111\u1ecbnh s\u1eed d\u1ee5ng bu l\u00f4ng \u0111\u00e3 \u0111\u01b0\u1ee3c t\u00f4i sau khi m\u1ea1 (gi\u1ea3m gi\u00f2n) ho\u1eb7c s\u1eed d\u1ee5ng l\u1edbp ph\u1ee7 Dacromet\/geomet thay th\u1ebf.<\/p><\/blockquote>\n<hr \/>\n<h2>\u1ee8ng d\u1ee5ng trong c\u00f4ng nghi\u1ec7p v\u00e0 c\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng<\/h2>\n<p>Bu l\u00f4ng 8.8 \u0111\u00f4i khi \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cc\u1ea5p \u0111\u1ed9 \u0111a n\u0103ng\u201d \u2014 \u0111\u1ee7 m\u1ea1nh cho ph\u1ea7n l\u1edbn c\u00e1c nhi\u1ec7m v\u1ee5 l\u1eafp r\u00e1p c\u00f4ng nghi\u1ec7p, nh\u01b0ng kh\u00f4ng qu\u00e1 c\u1ee9ng \u0111\u1ec3 tr\u1edf n\u00ean gi\u00f2n. Hi\u1ec3u r\u00f5 \u1ee9ng d\u1ee5ng ph\u00f9 h\u1ee3p (v\u00e0 kh\u00f4ng ph\u00f9 h\u1ee3p) gi\u00fap tr\u00e1nh c\u1ea3 vi\u1ec7c thi\u1ebft k\u1ebf qu\u00e1 m\u1ee9c v\u00e0 thi\u1ebft k\u1ebf thi\u1ebfu.<\/p>\n<h3>K\u1ef9 thu\u1eadt \u00f4 t\u00f4<\/h3>\n<p>Bu l\u00f4ng l\u1edbp 8.8 xu\u1ea5t hi\u1ec7n ph\u1ed5 bi\u1ebfn trong c\u00e1c c\u1ee5m l\u1eafp r\u00e1p \u00f4 t\u00f4. Bu l\u00f4ng n\u1ed1i kh\u1ed1i \u0111\u1ed9ng c\u01a1 v\u1edbi v\u1ecf h\u1ed9p s\u1ed1, bu l\u00f4ng khung ph\u1ee5 h\u1ec7 th\u1ed1ng treo, bu l\u00f4ng g\u1eafn gi\u00e1 \u0111\u1ee1 l\u00e1i, v\u00e0 \u1ed1c ch\u00e2n c\u1ed5 x\u1ea3 th\u01b0\u1eddng l\u00e0 lo\u1ea1i 8.8. Ti\u00eau chu\u1ea9n n\u00e0y r\u1ea5t ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c \u1ee9ng d\u1ee5ng n\u00e0y v\u00ec:<\/p>\n<ul>\n<li><strong>Gi\u1edbi h\u1ea1n ch\u1ea3y 640 MPa<\/strong> ch\u1ecbu \u0111\u01b0\u1ee3c t\u1ea3i \u0111\u1ed9ng do rung \u0111\u1ed9ng \u0111\u1ed9ng c\u01a1 v\u00e0 va \u0111\u1eadp \u0111\u01b0\u1eddng m\u00e0 kh\u00f4ng b\u1ecb bi\u1ebfn d\u1ea1ng v\u0129nh vi\u1ec5n.<\/li>\n<li><strong>\u0110\u1ed9 gi\u00e3n d\u00e0i t\u1ed1i thi\u1ec3u 12%<\/strong> cho ph\u00e9p m\u1ed9t ch\u00fat d\u1ebbo dai khi si\u1ebft qu\u00e1 l\u1ef1c \u2014 t\u1ea1o bi\u00ean an to\u00e0n th\u1ef1c t\u1ebf khi b\u1ea3o d\u01b0\u1ee1ng ngo\u00e0i hi\u1ec7n tr\u01b0\u1eddng.<\/li>\n<li><strong>C\u1ea5u tr\u00fac t\u00f4i v\u00e0 ram<\/strong> ch\u1ecbu \u0111\u01b0\u1ee3c chu k\u1ef3 nhi\u1ec7t \u0111\u1ed9 trong m\u00f4i tr\u01b0\u1eddng khoang \u0111\u1ed9ng c\u01a1.<\/li>\n<\/ul>\n<p>Th\u1ef1c t\u1ebf, ch\u00fang t\u00f4i nh\u1eadn th\u1ea5y bu l\u00f4ng 8.8 \u1edf v\u00f9ng nhi\u1ec7t \u0111\u1ed9 cao (g\u1ea7n c\u1ed5 x\u1ea3 ho\u1eb7c turbo t\u0103ng \u00e1p) n\u00ean \u0111\u01b0\u1ee3c ki\u1ec3m tra hi\u1ec7n t\u01b0\u1ee3ng gi\u1ea3m \u1ee9ng su\u1ea5t trong c\u00e1c k\u1ef3 b\u1ea3o d\u01b0\u1ee1ng \u0111\u1ecbnh k\u1ef3. Ti\u1ebfp x\u00fac l\u00e2u d\u00e0i v\u1edbi nhi\u1ec7t \u0111\u1ed9 tr\u00ean 300\u00b0C g\u00e2y hi\u1ec7n t\u01b0\u1ee3ng ch\u1ea3y d\u1ebbo \u1edf th\u00e9p cacbon trung b\u00ecnh, d\u1ea7n l\u00e0m gi\u1ea3m l\u1ef1c k\u1eb9p.<\/p>\n<h3>K\u1ebft n\u1ed1i th\u00e9p c\u1ea5u tr\u00fac<\/h3>\n<p>Trong k\u1ef9 thu\u1eadt k\u1ebft c\u1ea5u, <strong>bu l\u00f4ng l\u1edbp 8.8 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i l\u00e0 \u201cbu l\u00f4ng k\u1ebft c\u1ea5u c\u01b0\u1eddng \u0111\u1ed9 cao\u201d<\/strong> theo ti\u00eau chu\u1ea9n Eurocode 3 (EN 1993) v\u00e0 c\u00e1c ti\u00eau chu\u1ea9n t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. Ch\u00fang \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c li\u00ean k\u1ebft m\u00f4 men, b\u1ea3n c\u1eaft, g\u00f3c li\u00ean k\u1ebft v\u00e0 li\u00ean k\u1ebft b\u1ea3n cu\u1ed1i \u1edf c\u1ea7u, nh\u00e0 c\u00f4ng nghi\u1ec7p v\u00e0 c\u1ed9t truy\u1ec1n t\u1ea3i.<\/p>\n<p>Theo <a href=\"https:\/\/www.phd.eng.br\/wp-content\/uploads\/2015\/12\/en.1993.1.8.2005.pdf\" rel=\"noopener\" target=\"_blank\">EN 1993-1-8 (Eurocode 3 \u2014 Thi\u1ebft k\u1ebf li\u00ean k\u1ebft)<\/a>, l\u1ef1c si\u1ebft thi\u1ebft k\u1ebf cho bu l\u00f4ng l\u1edbp 8.8 l\u00e0:<\/p>\n<blockquote><p>Fp,C = 0,7 \u00d7 fub \u00d7 As<\/p><\/blockquote>\n<p>Trong \u0111\u00f3 fub = 800 MPa (gi\u1edbi h\u1ea1n b\u1ec1n k\u00e9o \u0111\u1ee9t) v\u00e0 As = di\u1ec7n t\u00edch ch\u1ecbu l\u1ef1c c\u1ee7a bu l\u00f4ng. \u0110\u1ed1i v\u1edbi bu l\u00f4ng M20 c\u1ea5p 8.8 (As = 245 mm\u00b2), l\u1ef1c si\u1ebft thi\u1ebft k\u1ebf x\u1ea5p x\u1ec9 <strong>137 kN<\/strong> \u2014 m\u1ed9t l\u1ef1c k\u1eb9p \u0111\u00e1ng k\u1ec3.<\/p>\n<h3>S\u1ea3n xu\u1ea5t m\u00e1y m\u00f3c v\u00e0 thi\u1ebft b\u1ecb c\u00f4ng nghi\u1ec7p<\/h3>\n<p>M\u00e1y c\u00f4ng c\u1ee5 CNC, m\u00e1y \u00e9p c\u00f4ng nghi\u1ec7p, h\u1ec7 th\u1ed1ng b\u0103ng t\u1ea3i, t\u1ea5m l\u1eafp b\u01a1m v\u00e0 v\u1ecf h\u1ed9p s\u1ed1 th\u01b0\u1eddng xuy\u00ean s\u1eed d\u1ee5ng bu l\u00f4ng c\u1ea5p 8.8. C\u1ea5p \u0111\u1ed9 b\u1ec1n n\u00e0y ph\u00f9 h\u1ee3p v\u1edbi y\u00eau c\u1ea7u t\u1ea3i tr\u1ecdng, v\u00e0 vi\u1ec7c bu l\u00f4ng 8.8 c\u00f3 s\u1eb5n r\u1ed9ng r\u00e3i v\u1edbi c\u00e1c k\u00edch th\u01b0\u1edbc t\u1eeb M4 \u0111\u1ebfn M64 gi\u00fap kh\u00f4ng c\u1ea7n \u0111\u1eb7t h\u00e0ng \u0111\u1eb7c bi\u1ec7t cho h\u1ea7u h\u1ebft c\u00e1c ho\u1ea1t \u0111\u1ed9ng s\u1ea3n xu\u1ea5t.<\/p>\n<h3>Thi\u1ebft b\u1ecb n\u00f4ng nghi\u1ec7p v\u00e0 x\u00e2y d\u1ef1ng<\/h3>\n<p>Khung m\u00e1y x\u00fac, kh\u1edbp n\u1ed1i m\u00e1y k\u00e9o, s\u00e0n m\u00e1y g\u1eb7t \u0111\u1eadp li\u00ean h\u1ee3p v\u00e0 kh\u1edbp g\u1ea7u m\u00e1y \u0111\u00e0o th\u01b0\u1eddng s\u1eed d\u1ee5ng bu l\u00f4ng 8.8. C\u1ea5p 8.8 l\u00e0 l\u1ef1a ch\u1ecdn h\u1ee3p l\u00fd cho t\u1ea3i \u0111\u1ed9ng l\u1eb7p l\u1ea1i cao \u2014 tuy nhi\u00ean v\u1edbi c\u00e1c ch\u1ed1t tr\u1ee5c v\u00e0 kh\u1edbp ch\u1ecbu s\u1ed1c c\u1ef1c l\u1edbn (nh\u01b0 g\u00e1 h\u00e0m m\u00e1y nghi\u1ec1n \u0111\u00e1), th\u01b0\u1eddng \u01b0u ti\u00ean d\u00f9ng c\u1ea5p 10.9 ho\u1eb7c 12.9.<\/p>\n<hr \/>\n<h2>C\u00e1ch ch\u1ecdn v\u00e0 ch\u1ec9 \u0111\u1ecbnh bu l\u00f4ng 8.8 ph\u00f9 h\u1ee3p<\/h2>\n<p>Ch\u1ecdn \u0111\u00fang bu l\u00f4ng 8.8 kh\u00f4ng ch\u1ec9 \u0111\u01a1n gi\u1ea3n l\u00e0 ch\u1ecdn \u0111\u00fang \u0111\u01b0\u1eddng k\u00ednh. B\u01b0\u1edbc ren, chi\u1ec1u d\u00e0i th\u00e2n, ki\u1ec3u \u0111\u1ea7u, l\u1edbp m\u1ea1 v\u00e0 m\u00f4-men si\u1ebft \u0111\u1ec1u ph\u1ea3i ph\u00f9 h\u1ee3p v\u1edbi \u1ee9ng d\u1ee5ng. Sai m\u1ed9t y\u1ebfu t\u1ed1 c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn m\u1ed1i gh\u00e9p b\u1ecb h\u1ecfng ho\u1eb7c thi\u1ebft k\u1ebf b\u1ecb l\u00e3ng ph\u00ed do qu\u00e1 m\u1ee9c c\u1ea7n thi\u1ebft.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/productionscrews.com\/wp-content\/uploads\/2026\/05\/03-howto-22.png\" alt=\"Bu l\u00f4ng 8.8 \u2014 s\u01a1 \u0111\u1ed3 quy tr\u00ecnh l\u1ef1a ch\u1ecdn th\u1ec3 hi\u1ec7n d\u00f2ng quy\u1ebft \u0111\u1ecbnh v\u1ec1 k\u00edch th\u01b0\u1edbc, c\u1ea5p v\u00e0 \u1ee9ng d\u1ee5ng\" \/><\/p>\n<h3>B\u01b0\u1edbc 1 \u2014 X\u00e1c \u0111\u1ecbnh l\u1ef1c k\u1eb9p c\u1ea7n thi\u1ebft<\/h3>\n<p>B\u1eaft \u0111\u1ea7u t\u1eeb y\u00eau c\u1ea7u c\u1ee7a m\u1ed1i gh\u00e9p, kh\u00f4ng ph\u1ea3i theo th\u00f3i quen. T\u00ednh to\u00e1n ho\u1eb7c \u01b0\u1edbc l\u01b0\u1ee3ng t\u1ea3i tr\u1ecdng ph\u1ee5c v\u1ee5 l\u1edbn nh\u1ea5t (k\u00e9o, c\u1eaft ho\u1eb7c k\u1ebft h\u1ee3p), sau \u0111\u00f3 \u00e1p d\u1ee5ng h\u1ec7 s\u1ed1 an to\u00e0n. V\u1edbi t\u1ea3i tr\u1ecdng t\u0129nh, h\u1ec7 s\u1ed1 an to\u00e0n 2,0\u20132,5 tr\u00ean t\u1ea3i ki\u1ec3m ch\u1ee9ng k\u00e9o l\u00e0 ph\u1ed5 bi\u1ebfn. V\u1edbi t\u1ea3i \u0111\u1ed9ng ho\u1eb7c m\u1ecfi, t\u0103ng l\u00ean 3,0\u20134,0 v\u00e0 c\u00e2n nh\u1eafc s\u1eed d\u1ee5ng bu l\u00f4ng c\u1ea5p cao h\u01a1n (10.9) \u0111\u1ec3 tr\u00e1nh g\u00e3y m\u1ecfi.<\/p>\n<h3>B\u01b0\u1edbc 2 \u2014 Ch\u1ecdn \u0111\u01b0\u1eddng k\u00ednh v\u00e0 b\u01b0\u1edbc ren<\/h3>\n<p>Bu l\u00f4ng h\u1ec7 m\u00e9t c\u00f3 c\u00e1c lo\u1ea1i <strong>b\u01b0\u1edbc ren th\u00f4 (chu\u1ea9n)<\/strong> v\u00e0 <strong>b\u01b0\u1edbc ren m\u1ecbn<\/strong> C\u00e1c bi\u1ebfn th\u1ec3. Ren th\u00f4 l\u00e0 ti\u00eau chu\u1ea9n cho h\u1ea7u h\u1ebft c\u00e1c \u1ee9ng d\u1ee5ng k\u1ebft c\u1ea5u v\u00e0 m\u00e1y m\u00f3c \u2014 d\u1ec5 l\u1eafp r\u00e1p nhanh v\u00e0 ch\u1ecbu b\u1ea9n t\u1ed1t h\u01a1n. Ren m\u1ecbn \u0111\u01b0\u1ee3c \u01b0u ti\u00ean khi:<\/p>\n<ul>\n<li>Chi\u1ec1u d\u00e0i k\u1eb9p r\u1ea5t ng\u1eafn (ren m\u1ecbn ki\u1ec3m so\u00e1t m\u00f4-men si\u1ebft v\u00e0 l\u1ef1c k\u1eb9p t\u1ed1t h\u01a1n)<\/li>\n<li>C\u1ee5m l\u1eafp ch\u1ecbu rung \u0111\u1ed9ng l\u1edbn (ren m\u1ecbn c\u00f3 g\u00f3c xo\u1eafn l\u1edbn h\u01a1n, t\u0103ng ma s\u00e1t)<\/li>\n<li>V\u1eadt li\u1ec7u m\u1ecfng ho\u1eb7c m\u1ec1m (ren m\u1ecbn gi\u1ea3m nguy c\u01a1 tu\u1ed1t ren)<\/li>\n<\/ul>\n<p><strong>C\u00e1c k\u00edch th\u01b0\u1edbc bu l\u00f4ng 8.8 ph\u1ed5 bi\u1ebfn v\u00e0 b\u01b0\u1edbc ren th\u00f4 c\u1ee7a ch\u00fang:<\/strong><\/p>\n<table>\n<tbody>\n<tr>\n<th>\u0110\u01b0\u1eddng k\u00ednh<\/th>\n<th>B\u01b0\u1edbc ren (th\u00f4)<\/th>\n<th>Di\u1ec7n t\u00edch ch\u1ecbu l\u1ef1c (mm\u00b2)<\/th>\n<th>T\u1ea3i tr\u1ecdng ki\u1ec3m tra (kN)<\/th>\n<\/tr>\n<tr>\n<td>M6<\/td>\n<td>1.0 mm<\/td>\n<td>20.1<\/td>\n<td>11.4<\/td>\n<\/tr>\n<tr>\n<td>M8<\/td>\n<td>1.25 mm<\/td>\n<td>36.6<\/td>\n<td>20.7<\/td>\n<\/tr>\n<tr>\n<td>M10<\/td>\n<td>1.5 mm<\/td>\n<td>58.0<\/td>\n<td>32.8<\/td>\n<\/tr>\n<tr>\n<td>M12<\/td>\n<td>1.75 mm<\/td>\n<td>84.3<\/td>\n<td>47.7<\/td>\n<\/tr>\n<tr>\n<td>M16<\/td>\n<td>2.0 mm<\/td>\n<td>157<\/td>\n<td>88.8<\/td>\n<\/tr>\n<tr>\n<td>M20<\/td>\n<td>2,5 mm<\/td>\n<td>245<\/td>\n<td>138.6<\/td>\n<\/tr>\n<tr>\n<td>M24<\/td>\n<td>3,0 mm<\/td>\n<td>353<\/td>\n<td>199.7<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>B\u01b0\u1edbc 3 \u2014 T\u00ednh m\u00f4-men si\u1ebft<\/h3>\n<p>\u0110\u1ed1i v\u1edbi bu l\u00f4ng c\u1ea5p 8.8, m\u00f4-men si\u1ebft ti\u00eau chu\u1ea9n (\u0111\u1ec3 \u0111\u1ea1t kho\u1ea3ng 70% t\u1ea3i ki\u1ec3m tra) c\u00f3 th\u1ec3 \u01b0\u1edbc t\u00ednh b\u1eb1ng:<\/p>\n<p><strong>T \u2248 K \u00d7 d \u00d7 F<\/strong><\/p>\n<p>Trong \u0111\u00f3 K l\u00e0 h\u1ec7 s\u1ed1 m\u00f4-men (th\u01b0\u1eddng l\u00e0 0,20 cho ren b\u00f4i tr\u01a1n, 0,22 cho ren kh\u00f4), d l\u00e0 \u0111\u01b0\u1eddng k\u00ednh danh ngh\u0129a (m), v\u00e0 F l\u00e0 l\u1ef1c si\u1ebft m\u1ee5c ti\u00eau (N). \u0110\u1ed1i v\u1edbi bu l\u00f4ng M12 8.8 v\u1edbi ren kh\u00f4:<\/p>\n<p>T \u2248 0,22 \u00d7 0,012 m \u00d7 47.700 N \u2248 <strong>126 N\u00b7m<\/strong><\/p>\n<p>Lu\u00f4n tham kh\u1ea3o b\u1ea3ng m\u00f4-men si\u1ebft do nh\u00e0 s\u1ea3n xu\u1ea5t ch\u1ed1t cung c\u1ea5p \u2014 K thay \u0111\u1ed5i \u0111\u00e1ng k\u1ec3 t\u00f9y theo t\u00ecnh tr\u1ea1ng ren, c\u00f3 ho\u1eb7c kh\u00f4ng c\u00f3 v\u00f2ng \u0111\u1ec7m, v\u00e0 lo\u1ea1i ch\u1ea5t b\u00f4i tr\u01a1n.<\/p>\n<h3>B\u01b0\u1edbc 4 \u2014 Ch\u1ecdn chi\u1ec1u d\u00e0i ph\u00f9 h\u1ee3p<\/h3>\n<p><strong>Chi\u1ec1u d\u00e0i bu l\u00f4ng ph\u1ea3i \u0111\u1ee7 \u0111\u1ec3 \u00edt nh\u1ea5t 1\u20131,5 b\u01b0\u1edbc ren ho\u00e0n ch\u1ec9nh v\u01b0\u1ee3t qua \u0111ai \u1ed1c sau khi si\u1ebft.<\/strong> Qu\u00e1 ng\u1eafn, \u0111ai \u1ed1c s\u1ebd t\u00ec l\u00ean ph\u1ea7n ren ch\u01b0a ho\u00e0n ch\u1ec9nh, l\u00e0m gi\u1ea3m hi\u1ec7u qu\u1ea3 k\u1eb9p. Qu\u00e1 d\u00e0i s\u1ebd l\u00e3ng ph\u00ed v\u1eadt li\u1ec7u v\u00e0 c\u00f3 th\u1ec3 g\u00e2y c\u1ea3n tr\u1edf c\u00e1c b\u1ed9 ph\u1eadn l\u00e2n c\u1eadn.<\/p>\n<p>\u0110\u1ed1i v\u1edbi \u1ee9ng d\u1ee5ng l\u1ed7 ren, chi\u1ec1u d\u00e0i \u0103n kh\u1edbp ren n\u00ean t\u1ed1i thi\u1ec3u b\u1eb1ng 1\u00d7 \u0111\u01b0\u1eddng k\u00ednh bu l\u00f4ng \u0111\u1ed1i v\u1edbi th\u00e9p, 1,5\u00d7 \u0111\u1ed1i v\u1edbi nh\u00f4m, v\u00e0 2\u00d7 \u0111\u1ed1i v\u1edbi gang ho\u1eb7c v\u1eadt li\u1ec7u m\u1ec1m.<\/p>\n<h3>Nh\u1eefng l\u1ed7i ph\u1ed5 bi\u1ebfn c\u1ea7n tr\u00e1nh khi l\u1ef1a ch\u1ecdn<\/h3>\n<ul>\n<li><strong>Tr\u1ed9n l\u1eabn h\u1ec7 m\u00e9t v\u00e0 h\u1ec7 inch:<\/strong> C\u1ea5p 8.8 l\u00e0 k\u00fd hi\u1ec7u h\u1ec7 m\u00e9t. N\u00f3 kh\u00f4ng t\u01b0\u01a1ng \u1ee9ng tr\u1ef1c ti\u1ebfp v\u1edbi SAE Grade 5 ho\u1eb7c Grade 8 (d\u00f9 Grade 8 c\u00f3 \u0111\u1ed9 b\u1ec1n k\u00e9o g\u1ea7n t\u01b0\u01a1ng \u0111\u01b0\u01a1ng \u2014 s\u1ebd n\u00f3i th\u00eam b\u00ean d\u01b0\u1edbi).<\/li>\n<li><strong>B\u1ecf qua b\u01b0\u1edbc ren trong l\u1ed7 ren:<\/strong> L\u1eafp m\u1ed9t bu l\u00f4ng M10 \u00d7 1.25 b\u01b0\u1edbc ren nh\u1ecf v\u00e0o m\u1ed9t l\u1ed7 ren M10 \u00d7 1.5 b\u01b0\u1edbc ren l\u1edbn s\u1ebd l\u00e0m h\u1ecfng c\u1ea3 hai b\u1ed9 ph\u1eadn.<\/li>\n<li><strong>T\u00e1i s\u1eed d\u1ee5ng bu l\u00f4ng si\u1ebft \u0111\u1ebfn gi\u1edbi h\u1ea1n ch\u1ea3y:<\/strong> Nhi\u1ec1u bu l\u00f4ng \u0111\u1ea7u m\u00e1y hi\u1ec7n \u0111\u1ea1i v\u00e0 bu l\u00f4ng k\u1ebft c\u1ea5u quan tr\u1ecdng v\u1ec1 an to\u00e0n \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 si\u1ebft v\u01b0\u1ee3t qu\u00e1 gi\u1edbi h\u1ea1n ch\u1ea3y. Nh\u1eefng bu l\u00f4ng n\u00e0y tuy\u1ec7t \u0111\u1ed1i kh\u00f4ng \u0111\u01b0\u1ee3c t\u00e1i s\u1eed d\u1ee5ng \u2014 h\u00e3y lo\u1ea1i b\u1ecf v\u00e0 thay th\u1ebf sau khi th\u00e1o ra.<\/li>\n<li><strong>S\u1eed d\u1ee5ng bu l\u00f4ng 8.8 m\u1ea1 \u0111i\u1ec7n trong m\u00f4i tr\u01b0\u1eddng d\u1ec5 b\u1ecb gi\u00f2n hydro:<\/strong> M\u1ea1 \u0111i\u1ec7n c\u00e1c ch\u1ed1t c\u01b0\u1eddng \u0111\u1ed9 cao l\u00e0m t\u0103ng nguy c\u01a1 h\u1ea5p th\u1ee5 hydro. H\u00e3y s\u1eed d\u1ee5ng l\u1edbp ph\u1ee7 geomet ho\u1eb7c Dacromet trong m\u00f4i tr\u01b0\u1eddng c\u00f3 t\u00ednh axit ho\u1eb7c \u0111\u01b0\u1ee3c b\u1ea3o v\u1ec7 b\u1eb1ng ph\u01b0\u01a1ng ph\u00e1p cat\u1ed1t.<\/li>\n<\/ul>\n<hr \/>\n<h2>Bu l\u00f4ng c\u1ea5p 8.8 so v\u1edbi c\u00e1c c\u1ea5p bu l\u00f4ng kh\u00e1c<\/h2>\n<p>Hi\u1ec3u v\u1ecb tr\u00ed c\u1ee7a 8.8 trong h\u1ec7 th\u1ed1ng ph\u00e2n c\u1ea5p \u0111\u1ed9 b\u1ec1n ch\u1ed1t gi\u00fap b\u1ea1n \u0111\u01b0a ra quy\u1ebft \u0111\u1ecbnh k\u1ef9 thu\u1eadt t\u1ed1t h\u01a1n \u2014 v\u1eeba tr\u00e1nh thi\u1ebfu th\u00f4ng s\u1ed1 v\u1eeba tr\u00e1nh l\u1ea1m d\u1ee5ng ph\u1ea7n c\u1ee9ng c\u1ea5p cao \u0111\u1eaft ti\u1ec1n khi 8.8 \u0111\u00e3 \u0111\u1ee7.<\/p>\n<h3>C\u1ea5p 8.8 so v\u1edbi c\u1ea5p 10.9<\/h3>\n<p>Bu l\u00f4ng 10.9 c\u00f3 \u0111\u1ed9 b\u1ec1n k\u00e9o 1040 MPa v\u00e0 gi\u1edbi h\u1ea1n ch\u1ea3y 940 MPa \u2014 cao h\u01a1n kho\u1ea3ng 17% v\u1ec1 \u0111\u1ed9 b\u1ec1n k\u00e9o v\u00e0 47% v\u1ec1 gi\u1edbi h\u1ea1n ch\u1ea3y so v\u1edbi 8.8. \u0110\u1ed1i v\u1edbi c\u00e1c m\u1ed1i n\u1ed1i m\u00e0 l\u1ef1c si\u1ebft tr\u01b0\u1edbc l\u00e0 c\u01a1 ch\u1ebf ch\u1ecbu t\u1ea3i ch\u00ednh (k\u1ebft n\u1ed1i ki\u1ec3u ma s\u00e1t, m\u1ed1i n\u1ed1i m\u1eb7t b\u00edch ch\u1ecbu \u00e1p su\u1ea5t b\u00ean trong), 10.9 cho ph\u00e9p s\u1eed d\u1ee5ng bu l\u00f4ng \u0111\u01b0\u1eddng k\u00ednh nh\u1ecf h\u01a1n v\u1edbi c\u00f9ng l\u1ef1c k\u1eb9p, ti\u1ebft ki\u1ec7m tr\u1ecdng l\u01b0\u1ee3ng v\u00e0 kh\u00f4ng gian.<\/p>\n<p>Tuy nhi\u00ean, bu l\u00f4ng 10.9 <strong>\u00edt ch\u1ecbu l\u1ed7i l\u1eafp \u0111\u1eb7t h\u01a1n<\/strong>. \u1ede \u0111\u1ed9 c\u1ee9ng cao h\u01a1n (HRC 32\u201339), ch\u00fang d\u1ec5 b\u1ecb gi\u00f2n hydro v\u00e0 n\u1ee9t do \u0103n m\u00f2n \u1ee9ng su\u1ea5t. Trong m\u00f4i tr\u01b0\u1eddng \u0103n m\u00f2n, 10.9 v\u1edbi l\u1edbp b\u1ea3o v\u1ec7 b\u1ec1 m\u1eb7t k\u00e9m c\u00f3 th\u1ec3 b\u1ecb h\u1ecfng \u0111\u1ed9t ng\u1ed9t, trong khi 8.8 \u1edf c\u00f9ng m\u00f4i tr\u01b0\u1eddng c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n g\u1ec9 s\u00e9t v\u00e0 suy gi\u1ea3m t\u1eeb t\u1eeb tr\u01b0\u1edbc.<\/p>\n<h3>C\u1ea5p 8.8 so v\u1edbi c\u1ea5p 12.9<\/h3>\n<p>C\u1ea5p 12.9 (\u0111\u1ed9 b\u1ec1n k\u00e9o 1220 MPa, gi\u1edbi h\u1ea1n ch\u1ea3y 1100 MPa) \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong ng\u00e0nh h\u00e0ng kh\u00f4ng, \u0111ua xe v\u00e0 m\u00e1y m\u00f3c cao c\u1ea5p n\u01a1i vi\u1ec7c gi\u1ea3m tr\u1ecdng l\u01b0\u1ee3ng l\u00e0 quan tr\u1ecdng v\u00e0 l\u1eafp r\u00e1p \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t nghi\u00eam ng\u1eb7t. \u0110\u1ed5i l\u1ea1i: bu l\u00f4ng 12.9 \u0111\u1eaft h\u01a1n nhi\u1ec1u, ph\u1ea3i l\u1eafp b\u1eb1ng d\u1ee5ng c\u1ee5 \u0111\u00e3 hi\u1ec7u chu\u1ea9n v\u00e0 r\u1ea5t nh\u1ea1y c\u1ea3m v\u1edbi \u0103n m\u00f2n v\u00e0 gi\u00f2n hydro. Ch\u00fang kh\u00f4ng ph\u00f9 h\u1ee3p cho l\u1eafp r\u00e1p ngo\u00e0i hi\u1ec7n tr\u01b0\u1eddng n\u1ebfu kh\u00f4ng c\u00f3 ki\u1ec3m so\u00e1t ch\u1ea5t l\u01b0\u1ee3ng nghi\u00eam ng\u1eb7t.<\/p>\n<h3>C\u1ea5p 8.8 so v\u1edbi SAE Grade 8 (h\u1ec7 inch)<\/h3>\n<p>\u0110\u00e2y l\u00e0 c\u00e2u h\u1ecfi so s\u00e1nh ph\u1ed5 bi\u1ebfn nh\u1ea5t. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 so s\u00e1nh tr\u1ef1c ti\u1ebfp:<\/p>\n<table>\n<tbody>\n<tr>\n<th>Thu\u1ed9c t\u00ednh<\/th>\n<th>C\u1ea5p 8.8 (h\u1ec7 m\u00e9t)<\/th>\n<th>SAE Grade 8 (h\u1ec7 inch)<\/th>\n<\/tr>\n<tr>\n<td>\u0110\u1ed9 b\u1ec1n k\u00e9o<\/td>\n<td>800 MPa (116 ksi)<\/td>\n<td>150 ksi (1034 MPa)<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u1ed9 b\u1ec1n ch\u1ea3y<\/td>\n<td>640 MPa (92,8 ksi)<\/td>\n<td>130 ksi (896 MPa)<\/td>\n<\/tr>\n<tr>\n<td>T\u1ea3i ki\u1ec3m ch\u1ee9ng<\/td>\n<td>~600 MPa<\/td>\n<td>120 ksi (827 MPa)<\/td>\n<\/tr>\n<tr>\n<td>Ti\u00eau chu\u1ea9n<\/td>\n<td>ISO 898-1<\/td>\n<td>SAE J429<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>C\u1ea5p 8 m\u1ea1nh h\u01a1n \u0111\u00e1ng k\u1ec3 so v\u1edbi c\u1ea5p 8.8<\/strong> \u2014 kho\u1ea3ng 29% cao h\u01a1n v\u1ec1 \u0111\u1ed9 b\u1ec1n k\u00e9o v\u00e0 40% cao h\u01a1n v\u1ec1 \u0111\u1ed9 b\u1ec1n ch\u1ea3y. Ch\u00fang <strong>kh\u00f4ng th\u1ec3 ho\u00e1n \u0111\u1ed5i cho nhau<\/strong>. M\u1ed9t bu l\u00f4ng c\u1ea5p 8 l\u1eafp v\u00e0o l\u1ed7 ren m\u00e9t s\u1ebd b\u1ecb l\u1ec7ch ren v\u00e0 h\u1ecfng; n\u1ebfu thay th\u1ebf b\u1eb1ng bu l\u00f4ng c\u1ea5p 8.8 khi y\u00eau c\u1ea7u c\u1ea5p 8 th\u00ec c\u00f3 th\u1ec3 kh\u00f4ng \u0111\u1ee7 \u0111\u1ed9 b\u1ec1n. Lu\u00f4n tu\u00e2n th\u1ee7 \u0111\u00fang th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt, kh\u00f4ng ch\u1ec9 d\u1ef1a v\u00e0o h\u00ecnh th\u1ee9c b\u00ean ngo\u00e0i.<\/p>\n<h3>C\u1ea5p 8.8 so v\u1edbi SAE c\u1ea5p 5 (Imperial)<\/h3>\n<p>C\u1ea5p 5 (\u0111\u1ed9 b\u1ec1n k\u00e9o 120 ksi \/ \u0111\u1ed9 b\u1ec1n ch\u1ea3y 92 ksi) m\u1ea1nh h\u01a1n m\u1ed9t ch\u00fat so v\u1edbi c\u1ea5p 8.8 v\u1ec1 \u0111\u1ed9 b\u1ec1n k\u00e9o nh\u01b0ng y\u1ebfu h\u01a1n v\u1ec1 \u0111\u1ed9 b\u1ec1n ch\u1ea3y. Trong th\u1ef1c t\u1ebf, c\u00e1c k\u1ef9 s\u01b0 th\u01b0\u1eddng coi ch\u00fang t\u01b0\u01a1ng \u0111\u01b0\u01a1ng trong \u0111\u00e1nh gi\u00e1 kh\u00f4ng ch\u00ednh th\u1ee9c \u2014 nh\u01b0ng kh\u00f4ng n\u00ean s\u1eed d\u1ee5ng chung trong c\u00f9ng m\u1ed9t m\u1ed1i gh\u00e9p, v\u00e0 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 b\u01b0\u1edbc ren gi\u1eefa h\u1ec7 m\u00e9t\/h\u1ec7 inch khi\u1ebfn ch\u00fang kh\u00f4ng t\u01b0\u01a1ng th\u00edch v\u1ec1 m\u1eb7t v\u1eadt l\u00fd trong l\u1ed7 ren. <a href=\"https:\/\/en.wikipedia.org\/wiki\/ISO_metric_screw_thread\" rel=\"noopener\" target=\"_blank\">Nh\u01b0 b\u00e0i vi\u1ebft Wikipedia v\u1ec1 ren v\u00edt ISO h\u1ec7 m\u00e9t<\/a> gi\u1ea3i th\u00edch, d\u1ea1ng ren v\u00e0 b\u01b0\u1edbc ren c\u1ee7a h\u1ec7 m\u00e9t v\u00e0 h\u1ec7 inch th\u1ed1ng nh\u1ea5t kh\u00e1c nhau v\u00e0 kh\u00f4ng th\u1ec3 thay th\u1ebf an to\u00e0n cho nhau.<\/p>\n<hr \/>\n<h2>Xu h\u01b0\u1edbng t\u01b0\u01a1ng lai trong c\u00f4ng ngh\u1ec7 bu l\u00f4ng c\u01b0\u1eddng \u0111\u1ed9 cao (2026+)<\/h2>\n<p>Bu l\u00f4ng 8.8 \u0111\u00e3 l\u00e0 ti\u00eau chu\u1ea9n c\u00f4ng nghi\u1ec7p trong nhi\u1ec1u th\u1eadp k\u1ef7, nh\u01b0ng ng\u00e0nh c\u00f4ng nghi\u1ec7p bu l\u00f4ng \u0111ang ph\u00e1t tri\u1ec3n. Hi\u1ec3u \u0111\u01b0\u1ee3c xu h\u01b0\u1edbng th\u1ecb tr\u01b0\u1eddng gi\u00fap c\u00e1c k\u1ef9 s\u01b0 mua h\u00e0ng v\u00e0 thi\u1ebft k\u1ebf d\u1ef1 \u0111o\u00e1n s\u1ef1 thay \u0111\u1ed5i th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt v\u00e0 \u0111\u1ed5i m\u1edbi v\u1eadt li\u1ec7u.<\/p>\n<h3>L\u1edbp ph\u1ee7 ch\u1ed1ng gi\u00f2n hydro<\/h3>\n<p>Th\u00e1ch th\u1ee9c k\u1ef9 thu\u1eadt l\u1edbn nh\u1ea5t \u0111\u1ed1i v\u1edbi bu l\u00f4ng c\u1ea5p 8.8 v\u00e0 c\u1ea5p cao h\u01a1n l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng gi\u00f2n hydro (HE) trong qu\u00e1 tr\u00ecnh m\u1ea1 \u0111i\u1ec7n. Ng\u00e0nh c\u00f4ng nghi\u1ec7p \u0111ang chuy\u1ec3n sang <strong>l\u1edbp m\u1ea1 quy tr\u00ecnh crom h\u00f3a tr\u1ecb ba (TCP)<\/strong> v\u00e0 <strong>m\u1ea1 k\u1ebdm c\u01a1 h\u1ecdc<\/strong> (trong \u0111\u00f3 b\u1ed9t k\u1ebdm \u0111\u01b0\u1ee3c h\u00e0n l\u1ea1nh, kh\u00f4ng sinh ra hydro). Theo <a href=\"https:\/\/www.indfast.org\/\" rel=\"noopener\" target=\"_blank\">Vi\u1ec7n Li\u00ean k\u1ebft Qu\u1ed1c t\u1ebf (IFI)<\/a>, c\u00e1c s\u1ef1 c\u1ed1 li\u00ean quan \u0111\u1ebfn gi\u00f2n hydro chi\u1ebfm t\u1ef7 l\u1ec7 \u0111\u00e1ng k\u1ec3 trong c\u00e1c tr\u01b0\u1eddng h\u1ee3p h\u1ecfng bu l\u00f4ng c\u01b0\u1eddng \u0111\u1ed9 cao ngo\u00e0i th\u1ef1c t\u1ebf, v\u00e0 c\u00e1c ti\u00eau chu\u1ea9n ng\u00e0nh \u0111ang si\u1ebft ch\u1eb7t y\u00eau c\u1ea7u ki\u1ec3m tra gi\u00f2n h\u00f3a.<\/p>\n<p>D\u1ef1 ki\u1ebfn \u0111\u1ebfn n\u0103m 2026\u20132027, c\u00e1c phi\u00ean b\u1ea3n m\u1edbi c\u1ee7a ASTM F3125 v\u00e0 ISO 4042 s\u1ebd bao g\u1ed3m ki\u1ec3m tra gi\u1ea3i ph\u00f3ng gi\u00f2n h\u00f3a b\u1eb1ng nhi\u1ec7t b\u1eaft bu\u1ed9c \u0111\u1ed1i v\u1edbi bu l\u00f4ng c\u1ea5p t\u00ednh ch\u1ea5t 8.8 tr\u1edf l\u00ean.<\/p>\n<h3>Bu l\u00f4ng th\u00f4ng minh v\u00e0 c\u1ea3m bi\u1ebfn nh\u00fang<\/h3>\n<p>H\u1ec7 th\u1ed1ng gi\u00e1m s\u00e1t s\u1ee9c kh\u1ecfe k\u1ebft c\u1ea5u (SHM) cho c\u1ea7u, tuabin gi\u00f3 v\u00e0 n\u1ec1n t\u1ea3ng ngo\u00e0i kh\u01a1i ng\u00e0y c\u00e0ng t\u00edch h\u1ee3p c\u00f4ng ngh\u1ec7 c\u1ea3m bi\u1ebfn tr\u1ef1c ti\u1ebfp v\u00e0o bu l\u00f4ng. V\u00f2ng \u0111\u1ec7m \u00e1p \u0111i\u1ec7n v\u00e0 bu l\u00f4ng t\u00edch h\u1ee3p \u0111\u1ea7u d\u00f2 si\u00eau \u00e2m cho ph\u00e9p gi\u00e1m s\u00e1t l\u1ef1c c\u0103ng theo th\u1eddi gian th\u1ef1c m\u00e0 kh\u00f4ng c\u1ea7n th\u00e1o r\u1eddi. C\u1ea5p 8.8, l\u00e0 lo\u1ea1i bu l\u00f4ng k\u1ebft c\u1ea5u ch\u1ee7 \u0111\u1ea1o, l\u00e0 n\u1ec1n t\u1ea3ng ch\u00ednh cho c\u00e1c ph\u00e1t tri\u1ec3n bu l\u00f4ng th\u00f4ng minh n\u00e0y.<\/p>\n<h3>S\u1ea3n xu\u1ea5t bu l\u00f4ng b\u1ec1n v\u1eefng<\/h3>\n<p>M\u1ea1 k\u1ebdm nh\u00fang n\u00f3ng bu l\u00f4ng c\u1ea5p 8.8 t\u1ea1o ra kh\u00f3i k\u1ebdm v\u00e0 ch\u1ea5t th\u1ea3i axit \u2014 m\u1ed9t g\u00e1nh n\u1eb7ng m\u00f4i tr\u01b0\u1eddng \u0111ang th\u00fac \u0111\u1ea9y vi\u1ec7c \u00e1p d\u1ee5ng <strong>m\u1ea1 khu\u1ebfch t\u00e1n nhi\u1ec7t (sherardizing)<\/strong> v\u00e0 <strong>l\u1edbp ph\u1ee7 v\u1ea3y k\u1ebdm<\/strong> (Geomet, Dacromet). C\u00e1c ph\u01b0\u01a1ng \u00e1n thay th\u1ebf n\u00e0y \u0111\u00e1p \u1ee9ng ho\u1eb7c v\u01b0\u1ee3t hi\u1ec7u su\u1ea5t ch\u1ed1ng \u0103n m\u00f2n c\u1ee7a m\u1ea1 k\u1ebdm nh\u00fang n\u00f3ng trong khi gi\u1ea3m \u0111\u00e1ng k\u1ec3 ch\u1ea5t th\u1ea3i v\u00e0 kh\u00ed th\u1ea3i \u0111\u1ed9c h\u1ea1i trong qu\u00e1 tr\u00ecnh s\u1ea3n xu\u1ea5t.<\/p>\n<p>\u0110\u1ed1i v\u1edbi c\u00e1c \u0111\u1ed9i mua h\u00e0ng: d\u1ef1 ki\u1ebfn bu l\u00f4ng c\u1ea5p 8.8 v\u1edbi l\u1edbp ph\u1ee7 v\u1ea3y k\u1ebdm s\u1ebd c\u00f3 gi\u00e1 cao h\u01a1n m\u1ed9t ch\u00fat so v\u1edbi h\u00e0ng m\u1ea1 \u0111i\u1ec7n truy\u1ec1n th\u1ed1ng trong giai \u0111o\u1ea1n 2025\u20132027, nh\u01b0ng t\u1ed5ng chi ph\u00ed s\u1edf h\u1eefu th\u01b0\u1eddng \u01b0u ti\u00ean l\u1edbp ph\u1ee7 m\u1edbi khi t\u00ednh \u0111\u1ebfn tu\u1ed5i th\u1ecd s\u1eed d\u1ee5ng v\u00e0 chu k\u1ef3 b\u1ea3o tr\u00ec.<\/p>\n<hr \/>\n<h2>H\u1ecfi \u0111\u00e1p: Bu l\u00f4ng c\u1ea5p 8.8 \u2014 Gi\u1ea3i \u0111\u00e1p th\u1eafc m\u1eafc c\u1ee7a b\u1ea1n<\/h2>\n<p><strong>S\u1ed1 8.8 tr\u00ean bu l\u00f4ng c\u00f3 \u00fd ngh\u0129a g\u00ec?<\/strong> D\u1ea5u \u201c8.8\u201d \u0111\u00f3ng tr\u00ean \u0111\u1ea7u bu l\u00f4ng l\u00e0 m\u00e3 c\u1ea5p t\u00ednh ch\u1ea5t theo ISO. S\u1ed1 \u201c8\u201d \u0111\u1ea7u ti\u00ean ngh\u0129a l\u00e0 \u0111\u1ed9 b\u1ec1n k\u00e9o 800 MPa; s\u1ed1 \u201c8\u201d th\u1ee9 hai ngh\u0129a l\u00e0 gi\u1edbi h\u1ea1n ch\u1ea3y b\u1eb1ng 80% c\u1ee7a gi\u00e1 tr\u1ecb \u0111\u00f3 (640 MPa). N\u00f3 kh\u00f4ng li\u00ean quan \u0111\u1ebfn \u0111\u01b0\u1eddng k\u00ednh hay b\u01b0\u1edbc ren c\u1ee7a bu l\u00f4ng.<\/p>\n<p><strong>Bu l\u00f4ng 8.8 c\u00f3 gi\u1ed1ng c\u1ea5p 8 kh\u00f4ng?<\/strong> Kh\u00f4ng. C\u1ea5p 8 (theo h\u1ec7 inch) c\u00f3 \u0111\u1ed9 b\u1ec1n k\u00e9o 1034 MPa (150 ksi), cao h\u01a1n kho\u1ea3ng 29% so v\u1edbi 800 MPa c\u1ee7a c\u1ea5p 8.8. \u0110\u00e2y l\u00e0 hai ti\u00eau chu\u1ea9n kh\u00e1c nhau \u2014 ISO v\u00e0 SAE \u2014 v\u00e0 ren c\u1ee7a ch\u00fang kh\u00f4ng t\u01b0\u01a1ng th\u00edch. Kh\u00f4ng bao gi\u1edd thay th\u1ebf lo\u1ea1i n\u00e0y cho lo\u1ea1i kia trong c\u00f9ng m\u1ed9t m\u1ed1i n\u1ed1i.<\/p>\n<p><strong>M\u00f4-men si\u1ebft cho bu l\u00f4ng 8.8 l\u00e0 bao nhi\u00eau?<\/strong> T\u00f9y thu\u1ed9c v\u00e0o \u0111\u01b0\u1eddng k\u00ednh v\u00e0 b\u00f4i tr\u01a1n. Tham kh\u1ea3o: M10 8.8 = ~47 N\u00b7m kh\u00f4; M12 8.8 = ~81 N\u00b7m kh\u00f4; M16 8.8 = ~200 N\u00b7m kh\u00f4. Lu\u00f4n s\u1eed d\u1ee5ng b\u1ea3ng m\u00f4-men si\u1ebft do nh\u00e0 s\u1ea3n xu\u1ea5t bu l\u00f4ng c\u00f4ng b\u1ed1 v\u00e0 t\u00ednh \u0111\u1ebfn ch\u1ea5t b\u00f4i tr\u01a1n, v\u00ec ren c\u00f3 d\u1ea7u c\u00f3 th\u1ec3 thay \u0111\u1ed5i m\u00f4-men si\u1ebft t\u1eeb 20\u201330%.<\/p>\n<p><strong>S\u1ed1 8.8 tr\u00ean k\u00edch th\u01b0\u1edbc bu l\u00f4ng c\u00f3 ngh\u0129a l\u00e0 g\u00ec \u2014 c\u00f3 ph\u1ea3i ch\u1ec9 \u0111\u01b0\u1eddng k\u00ednh kh\u00f4ng?<\/strong> Kh\u00f4ng \u2014 \u201c8.8\u201d ch\u1ec9 m\u00f4 t\u1ea3 c\u1ea5p \u0111\u1ed9 b\u1ec1n, kh\u00f4ng ph\u1ea3i k\u00edch th\u01b0\u1edbc. K\u00edch th\u01b0\u1edbc bu l\u00f4ng \u0111\u01b0\u1ee3c ghi ri\u00eang b\u1eb1ng \u0111\u01b0\u1eddng k\u00ednh v\u00e0 b\u01b0\u1edbc ren (v\u00ed d\u1ee5: M10 \u00d7 1.5). C\u1ea3 M6 v\u00e0 M24 \u0111\u1ec1u c\u00f3 th\u1ec3 l\u00e0 c\u1ea5p 8.8.<\/p>\n<p><strong>Bu l\u00f4ng 8.8 l\u00e0 lo\u1ea1i bu l\u00f4ng h\u1ec7 m\u00e9t hay h\u1ec7 ti\u00eau chu\u1ea9n (imperial)?<\/strong> L\u1edbp 8.8 l\u00e0 k\u00fd hi\u1ec7u ho\u00e0n to\u00e0n thu\u1ed9c h\u1ec7 m\u00e9t theo ti\u00eau chu\u1ea9n ISO 898-1. Kh\u00f4ng c\u00f3 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng tr\u1ef1c ti\u1ebfp n\u00e0o trong h\u1ec7 ti\u00eau chu\u1ea9n. C\u1ea5p g\u1ea7n nh\u1ea5t v\u1ec1 \u0111\u1ed9 b\u1ec1n l\u00e0 SAE Grade 5, m\u1eb7c d\u00f9 Grade 8 g\u1ea7n h\u01a1n v\u1ec1 gi\u1edbi h\u1ea1n ch\u1ea3y.<\/p>\n<p><strong>T\u00f4i c\u00f3 th\u1ec3 t\u00e1i s\u1eed d\u1ee5ng bu l\u00f4ng 8.8 kh\u00f4ng?<\/strong> \u0110\u1ed1i v\u1edbi h\u1ea7u h\u1ebft c\u00e1c \u1ee9ng d\u1ee5ng th\u00f4ng th\u01b0\u1eddng, c\u00f3 \u2014 mi\u1ec5n l\u00e0 bu l\u00f4ng kh\u00f4ng c\u00f3 d\u1ea5u hi\u1ec7u h\u01b0 h\u1ecfng, m\u00f2n, ho\u1eb7c bi\u1ebfn d\u1ea1ng, v\u00e0 kh\u00f4ng b\u1ecb si\u1ebft qu\u00e1 m\u1ee9c v\u01b0\u1ee3t qu\u00e1 gi\u1edbi h\u1ea1n ch\u1ea3y. Tuy nhi\u00ean, c\u00e1c bu l\u00f4ng \u0111\u01b0\u1ee3c ch\u1ec9 \u0111\u1ecbnh l\u00e0 \u201csi\u1ebft \u0111\u1ebfn gi\u1edbi h\u1ea1n ch\u1ea3y\u201d (th\u01b0\u1eddng g\u1eb7p \u1edf bu l\u00f4ng \u0111\u1ea7u m\u00e1y) tuy\u1ec7t \u0111\u1ed1i kh\u00f4ng \u0111\u01b0\u1ee3c t\u00e1i s\u1eed d\u1ee5ng, b\u1ea5t k\u1ec3 t\u00ecnh tr\u1ea1ng b\u00ean ngo\u00e0i.<\/p>\n<p><strong>\u0110\u1ed9 b\u1ec1n c\u1eaft c\u1ee7a bu l\u00f4ng 8.8 l\u00e0 bao nhi\u00eau?<\/strong> \u0110\u1ed9 b\u1ec1n c\u1eaft kh\u00f4ng \u0111\u01b0\u1ee3c quy \u0111\u1ecbnh tr\u1ef1c ti\u1ebfp trong ISO 898-1, nh\u01b0ng m\u1ed9t \u01b0\u1edbc t\u00ednh k\u1ef9 thu\u1eadt ph\u1ed5 bi\u1ebfn l\u00e0 60% \u0111\u1ed9 b\u1ec1n k\u00e9o. \u0110\u1ed1i v\u1edbi l\u1edbp 8.8, gi\u00e1 tr\u1ecb x\u1ea5p x\u1ec9 <strong>480 MPa \u0111\u1ed9 b\u1ec1n c\u1eaft<\/strong>. \u0110\u1ed1i v\u1edbi M10 8.8 (di\u1ec7n t\u00edch ch\u1ecbu l\u1ef1c 58 mm\u00b2), kh\u1ea3 n\u0103ng ch\u1ecbu c\u1eaft \u01b0\u1edbc t\u00ednh \u2248 27,8 kN. \u0110\u1ed1i v\u1edbi li\u00ean k\u1ebft ch\u1ecbu l\u1ef1c, s\u1eed d\u1ee5ng di\u1ec7n t\u00edch c\u1eaft (ti\u1ebft di\u1ec7n th\u00e2n bu l\u00f4ng, \u03c0\/4 \u00d7 d\u00b2), kh\u00f4ng ph\u1ea3i di\u1ec7n t\u00edch ch\u1ecbu l\u1ef1c.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/productionscrews.com\/wp-content\/uploads\/2026\/05\/04-closing-26.png\" alt=\"Bu l\u00f4ng 8.8 \u2014 h\u00ecnh \u1ea3nh k\u1ebft th\u00fac cho th\u1ea5y d\u1ea3i bu l\u00f4ng l\u1edbp 8.8 h\u1ec7 m\u00e9t trong m\u00f4i tr\u01b0\u1eddng c\u00f4ng nghi\u1ec7p\" \/><\/p>\n<hr \/>\n<h2>K\u1ebft lu\u1eadn<\/h2>\n<p>C\u00e1c <strong>\u1ed1c v\u00edt 8.8<\/strong> \u0110\u01b0\u1ee3c m\u1ec7nh danh l\u00e0 \u201cng\u1ef1a th\u1ed3\u201d c\u00f4ng nghi\u1ec7p v\u1edbi l\u00fd do ch\u00ednh \u0111\u00e1ng: \u0111\u1ed9 b\u1ec1n k\u00e9o 800 MPa, gi\u1edbi h\u1ea1n ch\u1ea3y 640 MPa, \u0111\u1ed9 gi\u00e3n d\u00e0i 12%, v\u00e0 c\u00f3 s\u1eb5n \u1edf m\u1ecdi k\u00edch th\u01b0\u1edbc h\u1ec7 m\u00e9t t\u1eeb M4 \u0111\u1ebfn M64, khi\u1ebfn n\u00f3 tr\u1edf th\u00e0nh l\u1ef1a ch\u1ecdn \u0111\u00fang cho ph\u1ea7n l\u1edbn c\u00e1c nhi\u1ec7m v\u1ee5 li\u00ean k\u1ebft k\u1ebft c\u1ea5u, \u00f4 t\u00f4 v\u00e0 m\u00e1y m\u00f3c. M\u00e3 l\u1edbp t\u00ednh ch\u1ea5t \u0111\u01b0\u1ee3c quy \u0111\u1ecbnh ch\u00ednh x\u00e1c v\u00e0 ti\u00eau chu\u1ea9n to\u00e0n c\u1ea7u theo ISO 898-1 \u2014 khi b\u1ea1n hi\u1ec3u \u00fd ngh\u0129a c\u00e1c con s\u1ed1, vi\u1ec7c ch\u1ecdn \u0111\u00fang bu l\u00f4ng tr\u1edf n\u00ean \u0111\u01a1n gi\u1ea3n.<\/p>\n<p>Cho \u1ee9ng d\u1ee5ng ti\u1ebfp theo c\u1ee7a b\u1ea1n: n\u1ebfu t\u1ea3i n\u1eb1m trong ph\u1ea1m vi t\u1ea3i ki\u1ec3m ch\u1ee9ng c\u1ee7a l\u1edbp 8.8, m\u00f4i tr\u01b0\u1eddng kh\u00f4ng qu\u00e1 \u0103n m\u00f2n, v\u00e0 l\u1eafp r\u00e1p kh\u00f4ng y\u00eau c\u1ea7u tr\u1ecdng l\u01b0\u1ee3ng t\u1ed1i thi\u1ec3u tuy\u1ec7t \u0111\u1ed1i, h\u00e3y b\u1eaft \u0111\u1ea7u v\u1edbi l\u1edbp 8.8. D\u00e0nh l\u1edbp 10.9 v\u00e0 12.9 cho c\u00e1c m\u1ed1i n\u1ed1i m\u00e0 b\u1ea1n \u0111\u00e3 ph\u00e2n t\u00edch t\u1ea3i ch\u1ee9ng minh c\u1ea7n c\u1ea5p cao h\u01a1n \u2014 kh\u00f4ng ph\u1ea3i n\u00e2ng c\u1ea5p m\u1eb7c \u0111\u1ecbnh. Ch\u1ecdn l\u1edbp ph\u1ee7 b\u1ec1 m\u1eb7t ph\u00f9 h\u1ee3p v\u1edbi m\u00f4i tr\u01b0\u1eddng \u0103n m\u00f2n, si\u1ebft theo th\u00f4ng s\u1ed1 b\u1eb1ng d\u1ee5ng c\u1ee5 \u0111\u00e3 hi\u1ec7u chu\u1ea9n, v\u00e0 ki\u1ec3m tra \u0111\u1ecbnh k\u1ef3. Bu l\u00f4ng s\u1ebd ho\u1ea1t \u0111\u1ed9ng \u1ed5n \u0111\u1ecbnh trong nhi\u1ec1u th\u1eadp k\u1ef7.<\/p>\n<p>\u0110\u1ec3 t\u00ecm ngu\u1ed3n bu l\u00f4ng l\u1edbp 8.8 h\u1ec7 m\u00e9t v\u1edbi truy xu\u1ea5t ngu\u1ed3n g\u1ed1c s\u1ea3n xu\u1ea5t v\u00e0 ch\u1ee9ng nh\u1eadn c\u01a1 h\u1ecdc \u0111\u1ed3ng nh\u1ea5t, h\u00e3y kh\u00e1m ph\u00e1 <a href=\"https:\/\/productionscrews.com\/vi\/\" rel=\"noopener\" target=\"_blank\">d\u1ea3i s\u1ea3n ph\u1ea9m bu l\u00f4ng l\u1ee5c gi\u00e1c l\u1edbp 8.8 v\u00e0 v\u00edt \u0111\u1ea7u l\u1ee5c gi\u00e1c c\u1ee7a productionscrews.com<\/a> \u2014 c\u00f3 s\u1eb5n t\u1eeb M4 \u0111\u1ebfn M36 v\u1edbi nhi\u1ec1u l\u1ef1a ch\u1ecdn l\u1edbp ph\u1ee7.<\/p>","protected":false},"excerpt":{"rendered":"<p>T\u1ea5t c\u1ea3 nh\u1eefng g\u00ec b\u1ea1n c\u1ea7n bi\u1ebft v\u1ec1 bu l\u00f4ng c\u1ea5p 8.8: \u00fd ngh\u0129a c\u1ee7a c\u00e1c con s\u1ed1 c\u1ea5p t\u00ednh ch\u1ea5t, \u0111\u1ed9 b\u1ec1n k\u00e9o v\u00e0 gi\u1edbi h\u1ea1n ch\u1ea3y, c\u00e1c lo\u1ea1i, m\u00f4-men si\u1ebft v\u00e0 c\u00e1ch ch\u1ecdn bu l\u00f4ng 8.8 ph\u00f9 h\u1ee3p cho c\u00e1c \u1ee9ng d\u1ee5ng \u00f4 t\u00f4, k\u1ebft c\u1ea5u v\u00e0 m\u00e1y m\u00f3c.<\/p>","protected":false},"author":1,"featured_media":4424,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4428","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-screws-flange-tutorial"],"_links":{"self":[{"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/posts\/4428","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/comments?post=4428"}],"version-history":[{"count":1,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/posts\/4428\/revisions"}],"predecessor-version":[{"id":4429,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/posts\/4428\/revisions\/4429"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/media\/4424"}],"wp:attachment":[{"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/media?parent=4428"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/categories?post=4428"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/productionscrews.com\/vi\/wp-json\/wp\/v2\/tags?post=4428"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}