{"id":6753,"date":"2021-04-22T12:36:05","date_gmt":"2021-04-22T04:36:05","guid":{"rendered":"https:\/\/xzfastener.com\/?p=6753"},"modified":"2026-06-22T12:37:55","modified_gmt":"2026-06-22T04:37:55","slug":"what-does-8-8-mean-on-a-bolt-buyers-guide","status":"publish","type":"post","link":"https:\/\/xzfastener.com\/fr\/what-does-8-8-mean-on-a-bolt-buyers-guide\/","title":{"rendered":"Que signifie 8.8 sur un boulon\u00a0? Guide de l'acheteur"},"content":{"rendered":"<p>Lorsque les acheteurs voient \u00ab\u00a08.8\u00a0\u00bb sur une t\u00eate de boulon, il est facile de penser qu'il s'agit simplement d'une marque d'usine. Ce n'est pas. Pour les boulons m\u00e9triques, <strong>8.8 is a mechanical property class<\/strong>. It tells you the bolt\u2019s strength level under the relevant metric fastener standard.<\/p>\n\n\n\n<p>This marking is common on industrial bolts used in machinery, steel frames, brackets, equipment bases, and construction assemblies.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What 8.8 Means<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">The Two Numbers Explained<\/h3>\n\n\n\n<p>In simple terms, the first number shows the nominal tensile strength. The second number shows the yield ratio.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Marquage<\/th><th>Signification<\/th><th>Valeur pratique<\/th><\/tr><\/thead><tbody><tr><td>8<\/td><td>Approx. 800 MPa nominal tensile strength<\/td><td>Indicates the bolt\u2019s strength level<\/td><\/tr><tr><td>.8<\/td><td>Yield ratio of about 0.8<\/td><td>Approx. 640 MPa yield strength<\/td><\/tr><tr><td>8.8<\/td><td>Classe de propri\u00e9t\u00e9 m\u00e9trique<\/td><td>Used for carbon steel or alloy steel bolts<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>So, a class 8.8 bolt is stronger than low-grade general fasteners, but it is not the same as 10.9 or 12.9. It is also <strong>not the same as SAE Grade 8<\/strong>, which belongs to the inch fastener system.<\/p>\n\n\n\n<p>Les acheteurs peuvent consulter les informations communes <a href=\"https:\/\/xzfastener.com\/fr\/fastener-type\/bolts\/\">produits de boulons<\/a> et <a href=\"https:\/\/xzfastener.com\/fr\/products-category\/high-strength-fasteners\/\">attaches \u00e0 haute r\u00e9sistance<\/a> when comparing strength grades.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Where 8.8 Bolts Are Used<\/h2>\n\n\n\n<p>Class 8.8 bolts are widely used because they offer a strong balance of strength, availability, and cost.<\/p>\n\n\n\n<p>Les applications courantes incluent\u00a0:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>B\u00e2tis de machines<\/li>\n\n\n\n<li>Supports en acier<\/li>\n\n\n\n<li>Bases d'\u00e9quipement<\/li>\n\n\n\n<li>Quincaillerie de construction<\/li>\n\n\n\n<li>Machines agricoles<\/li>\n\n\n\n<li>Assemblages industriels g\u00e9n\u00e9raux<\/li>\n\n\n\n<li>Medium-load structural connections<\/li>\n<\/ul>\n\n\n\n<p>For many standard industrial jobs, 8.8 is enough. For higher-load or compact assemblies, buyers may need 10.9 or 12.9 instead.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Buyers Should Not Assume<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">8.8 Does Not Define Everything<\/h3>\n\n\n\n<p>A bolt marked 8.8 only tells part of the story. It does not define the full product specification.<\/p>\n\n\n\n<p>You still need to confirm:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Article de la demande de prix<\/th><th>Pourquoi c'est important<\/th><\/tr><\/thead><tbody><tr><td>Norme<\/td><td>DIN, ISO, EN, or drawing controls dimensions<\/td><\/tr><tr><td>Taille<\/td><td>Diam\u00e8tre, longueur, pas et longueur de filetage<\/td><\/tr><tr><td>Terminer<\/td><td>Zinc, black, HDG, zinc flake, or plain<\/td><\/tr><tr><td>Qualit\u00e9 des noix<\/td><td>Weak nuts can strip before the bolt performs<\/td><\/tr><tr><td>Type de laveuse<\/td><td>Soft washers may reduce preload<\/td><\/tr><tr><td>Demande<\/td><td>Load, vibration, corrosion, and temperature matter<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>For common items, buyers can start from <a href=\"https:\/\/xzfastener.com\/fr\/products-category\/standard-fasteners\/\">attaches standards<\/a>. For coating choices, review <a href=\"https:\/\/xzfastener.com\/fr\/products-category\/various-coated-fasteners\/\">diverses attaches enduites<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Erreurs courantes des acheteurs<\/h2>\n\n\n\n<p>\u00c9vitez ces probl\u00e8mes\u00a0:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Ordering \u201c8.8 bolt\u201d without standard or size details.<\/li>\n\n\n\n<li>Matching 8.8 bolts with low-grade nuts.<\/li>\n\n\n\n<li>Assuming zinc plating improves strength.<\/li>\n\n\n\n<li>Using 8.8 in severe corrosion without coating review.<\/li>\n\n\n\n<li>Replacing 10.9 with 8.8 to reduce cost without engineering approval.<\/li>\n\n\n\n<li>Mixing metric 8.8 with inch Grade 8 specifications.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">RFQ Checklist for 8.8 Bolts<\/h2>\n\n\n\n<p>Une demande de prix claire doit inclure\u00a0:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Norme de produit<\/li>\n\n\n\n<li>Diam\u00e8tre, longueur et pas de filetage<\/li>\n\n\n\n<li>Filetage complet ou filetage partiel<\/li>\n\n\n\n<li>Class 8.8 requirement<\/li>\n\n\n\n<li>Finition superficielle<\/li>\n\n\n\n<li>\u00c9crous et rondelles assortis<\/li>\n\n\n\n<li>Quantit\u00e9 et emballage<\/li>\n\n\n\n<li>Rapports d'inspection requis<\/li>\n<\/ol>\n\n\n\n<p>For special lengths, head styles, or thread requirements, use <a href=\"https:\/\/xzfastener.com\/fr\/products-category\/custom-non-standard-fasteners\/\">fixations non standard sur mesure<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Conseil final<\/h2>\n\n\n\n<p>The \u201c8.8\u201d mark means the bolt has a defined metric strength class. It is useful, but it is not a complete specification.<\/p>\n\n\n\n<p>For safe purchasing, confirm the grade, standard, size, thread, finish, nut, washer, and working condition before production.<\/p>\n\n\n\n<p><\/p>","protected":false},"excerpt":{"rendered":"<p>When buyers see \u201c8.8\u201d on a bolt head, it is easy to think it is just a factory mark. It is not. For metric bolts, 8.8 is a mechanical property class. It tells you the bolt\u2019s strength level under the relevant metric fastener standard. This marking is common on industrial bolts used in machinery, steel [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[479],"tags":[504],"class_list":["post-6753","post","type-post","status-publish","format-standard","hentry","category-fastener-knowledge-library","tag-strength-grades-mechanical-properties"],"acf":[],"_links":{"self":[{"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/posts\/6753","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/comments?post=6753"}],"version-history":[{"count":1,"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/posts\/6753\/revisions"}],"predecessor-version":[{"id":6754,"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/posts\/6753\/revisions\/6754"}],"wp:attachment":[{"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/media?parent=6753"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/categories?post=6753"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xzfastener.com\/fr\/wp-json\/wp\/v2\/tags?post=6753"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}