{"id":5931,"date":"2026-05-07T08:00:33","date_gmt":"2026-05-07T06:00:33","guid":{"rendered":"https:\/\/www.gns-nederland.nl\/?p=5931"},"modified":"2026-05-12T13:25:38","modified_gmt":"2026-05-12T11:25:38","slug":"letter-code-for-quality-in-bolts-nuts-etc","status":"publish","type":"post","link":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/","title":{"rendered":"Letter code for material quality bolts, nuts, etc."},"content":{"rendered":"<p>With standard fasteners, a strength class designation such as 8.8 or 10.9 primarily indicates:<\/p>\n<ul>\n<li>Tensile strength (Rm)<\/li>\n<li>Yield strength (Rp0.2%)<\/li>\n<li>Properties at room temperature<\/li>\n<\/ul>\n<p>This is usually sufficient for applications up to 100\u00b0C.<\/p>\n<p>However, when used at higher temperatures, the behaviour of steel changes rapidly. In such cases, other material properties play a greater role, such as:<\/p>\n<ul>\n<li>creep resistance | slow deformation under prolonged loading at high temperatures<\/li>\n<li>heat resistance | retention of strength at, for example, 500\u2013650 \u00b0C<\/li>\n<li>oxidation resistance | resistance to scaling and burning<\/li>\n<li>relaxation behaviour | loss of preload in bolted joints due to temperature<\/li>\n<\/ul>\n<p>For this reason, when used at high temperatures, the designation \u201810.9\u2019 alone, for example, is not sufficient. A standard 10.9 bolt can, at high temperatures:<\/p>\n<p>rapidly lose strength,<br \/>\ncreep,<br \/>\nlose its preload,<br \/>\nand eventually break.<\/p>\n<p>For this reason, special alloys are used at high temperatures. These are often <strong>CrMo steels, CrMoV steels or heat-resistant (stainless steel) grades<\/strong>.<\/p>\n<p>If there is <strong>insufficient space to mark the material number<\/strong>, these fasteners are marked with a letter referring to the material type.<\/p>\n<p>For example:<\/p>\n<ul>\n<li><strong>V = Material 1.4923<\/strong><\/li>\n<\/ul>\n<p>The material coding below is <strong>not officially standardised<\/strong> but is \u2013 in most cases \u2013 used worldwide.<\/p>\n<table width=\"545\">\n<tbody>\n<tr>\n<td width=\"70\"><span style=\"color: #de5307;\">Letter<\/span><\/td>\n<td width=\"175\"><span style=\"color: #de5307;\">Material number<\/span><\/td>\n<td width=\"300\"><span style=\"color: #de5307;\">Material type<\/span><\/td>\n<\/tr>\n<tr>\n<td width=\"70\"><\/td>\n<td width=\"175\"><\/td>\n<td width=\"300\"><\/td>\n<\/tr>\n<tr data-start=\"485\" data-end=\"537\">\n<td width=\"70\" data-start=\"485\" data-end=\"493\" data-col-size=\"sm\"><span style=\"color: #ffffff;\">.<\/span><\/td>\n<td width=\"175\" data-start=\"493\" data-end=\"502\" data-col-size=\"sm\"><\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"502\" data-end=\"512\"><\/td>\n<\/tr>\n<tr data-start=\"538\" data-end=\"591\">\n<td width=\"70\" data-start=\"538\" data-end=\"546\" data-col-size=\"sm\">C<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"546\" data-end=\"555\">1.0503<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"555\" data-end=\"561\">C45<\/td>\n<\/tr>\n<tr data-start=\"592\" data-end=\"654\">\n<td width=\"70\" data-start=\"592\" data-end=\"600\" data-col-size=\"sm\">D<\/td>\n<td width=\"175\" data-start=\"600\" data-end=\"609\" data-col-size=\"sm\">1.4462<\/td>\n<td width=\"300\" data-start=\"609\" data-end=\"622\" data-col-size=\"sm\">Alloy 225, Superduplex, AISI 318<\/td>\n<\/tr>\n<tr data-start=\"655\" data-end=\"729\">\n<td width=\"70\" data-start=\"655\" data-end=\"663\" data-col-size=\"sm\">F<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"663\" data-end=\"672\">1.4571<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"672\" data-end=\"696\">AISI 316Ti<\/td>\n<\/tr>\n<tr data-start=\"730\" data-end=\"785\">\n<td width=\"70\" data-start=\"730\" data-end=\"738\" data-col-size=\"sm\">G<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"738\" data-end=\"747\">1.7258<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"747\" data-end=\"757\">24CrMo5<\/td>\n<\/tr>\n<tr data-start=\"786\" data-end=\"845\">\n<td width=\"70\" data-start=\"786\" data-end=\"795\" data-col-size=\"sm\">GA<\/td>\n<td width=\"175\" data-start=\"795\" data-end=\"804\" data-col-size=\"sm\">1.7709<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"804\" data-end=\"817\">21CrMoV5-7<\/td>\n<\/tr>\n<tr data-start=\"846\" data-end=\"896\">\n<td width=\"70\" data-start=\"846\" data-end=\"855\" data-col-size=\"sm\">GB<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"855\" data-end=\"864\">1.7711<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"864\" data-end=\"877\">40CrMoV4-6<\/td>\n<\/tr>\n<tr data-start=\"897\" data-end=\"941\">\n<td width=\"70\" data-start=\"897\" data-end=\"906\" data-col-size=\"sm\">GC<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"906\" data-end=\"915\">1.7225<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"915\" data-end=\"925\">42CrMo4<\/td>\n<\/tr>\n<tr data-start=\"942\" data-end=\"1024\">\n<td width=\"70\" data-start=\"942\" data-end=\"950\" data-col-size=\"sm\">H<\/td>\n<td width=\"175\" data-start=\"950\" data-end=\"968\" data-col-size=\"sm\">1.7709<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"968\" data-end=\"997\">21CrMo45-7<\/td>\n<\/tr>\n<tr data-start=\"1025\" data-end=\"1073\">\n<td width=\"70\" data-start=\"1025\" data-end=\"1034\" data-col-size=\"sm\">KA<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1034\" data-end=\"1043\">1.7219<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1043\" data-end=\"1053\">26CrMo4<\/td>\n<\/tr>\n<tr data-start=\"1074\" data-end=\"1133\">\n<td width=\"70\" data-start=\"1074\" data-end=\"1083\" data-col-size=\"sm\">KB<\/td>\n<td width=\"175\" data-start=\"1083\" data-end=\"1092\" data-col-size=\"sm\">1.5680<\/td>\n<td width=\"300\" data-start=\"1092\" data-end=\"1101\" data-col-size=\"sm\">X12Ni5<\/td>\n<\/tr>\n<tr data-start=\"1134\" data-end=\"1182\">\n<td width=\"70\" data-start=\"1134\" data-end=\"1143\" data-col-size=\"sm\">KG<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1143\" data-end=\"1152\">1.7218<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1152\" data-end=\"1162\">25CrMo4<\/td>\n<\/tr>\n<tr data-start=\"1183\" data-end=\"1268\">\n<td width=\"70\" data-start=\"1183\" data-end=\"1191\" data-col-size=\"sm\">L<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1191\" data-end=\"1200\">1.4301<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"672\" data-end=\"696\">AISI 304<\/td>\n<\/tr>\n<tr data-start=\"1269\" data-end=\"1357\">\n<td width=\"70\" data-start=\"1269\" data-end=\"1277\" data-col-size=\"sm\">M<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1277\" data-end=\"1286\">1.4404<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1286\" data-end=\"1334\">AISI 316L<\/td>\n<\/tr>\n<tr data-start=\"1358\" data-end=\"1419\">\n<td width=\"70\" data-start=\"1358\" data-end=\"1366\" data-col-size=\"sm\">P<\/td>\n<td width=\"175\" data-start=\"1366\" data-end=\"1375\" data-col-size=\"sm\">1.4903<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1375\" data-end=\"1391\">X10CrMoVNb9-1<\/td>\n<\/tr>\n<tr data-start=\"1420\" data-end=\"1493\">\n<td width=\"70\" data-start=\"1420\" data-end=\"1428\" data-col-size=\"sm\">S<\/td>\n<td width=\"175\" data-start=\"1428\" data-end=\"1437\" data-col-size=\"sm\">1.4986<\/td>\n<td width=\"300\" data-start=\"1437\" data-end=\"1456\" data-col-size=\"sm\">X7CrNiMoBNb16-16<\/td>\n<\/tr>\n<tr data-start=\"1494\" data-end=\"1563\">\n<td width=\"70\" data-start=\"1494\" data-end=\"1503\" data-col-size=\"sm\">SB<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1503\" data-end=\"1512\">2.4952<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1512\" data-end=\"1525\">NiCr20TiAl<\/td>\n<\/tr>\n<tr data-start=\"1564\" data-end=\"1643\">\n<td width=\"70\" data-start=\"1564\" data-end=\"1573\" data-col-size=\"sm\">SD<\/td>\n<td width=\"175\" data-start=\"1573\" data-end=\"1582\" data-col-size=\"sm\">1.4980<\/td>\n<td width=\"300\">A-286\/Alloy 660<\/td>\n<\/tr>\n<tr data-start=\"1644\" data-end=\"1711\">\n<td width=\"70\" data-start=\"1644\" data-end=\"1653\" data-col-size=\"sm\">SM<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1653\" data-end=\"1663\">1.4547<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1663\" data-end=\"1691\">F44, 254SMO<\/td>\n<\/tr>\n<tr data-start=\"1712\" data-end=\"1768\">\n<td width=\"70\" data-start=\"1712\" data-end=\"1720\" data-col-size=\"sm\">T<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1720\" data-end=\"1729\">1.7711<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1729\" data-end=\"1740\">CrMoV6-9<\/td>\n<\/tr>\n<tr data-start=\"1769\" data-end=\"1827\">\n<td width=\"70\" data-start=\"1769\" data-end=\"1777\" data-col-size=\"sm\">V<\/td>\n<td width=\"175\" data-start=\"1777\" data-end=\"1786\" data-col-size=\"sm\">1.4923<\/td>\n<td width=\"300\" data-start=\"1786\" data-end=\"1799\" data-col-size=\"sm\">X22CrMoV12<\/td>\n<\/tr>\n<tr data-start=\"1970\" data-end=\"2030\">\n<td width=\"70\" data-start=\"1970\" data-end=\"1978\" data-col-size=\"sm\">VW<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"1978\" data-end=\"1987\">1.4913<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1987\" data-end=\"2008\">X19<\/td>\n<\/tr>\n<tr data-start=\"1828\" data-end=\"1895\">\n<td width=\"70\" data-start=\"1828\" data-end=\"1836\" data-col-size=\"sm\">W<\/td>\n<td width=\"175\" data-start=\"1836\" data-end=\"1845\" data-col-size=\"sm\">1.4980<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"1845\" data-end=\"1861\">Alloy 800H\/HT<\/td>\n<\/tr>\n<tr data-start=\"2031\" data-end=\"2079\">\n<td width=\"70\" data-start=\"2031\" data-end=\"2040\" data-col-size=\"sm\">YB<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"2040\" data-end=\"2049\">1.5511<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"2049\" data-end=\"2056\">35B2<\/td>\n<\/tr>\n<tr data-start=\"2126\" data-end=\"2184\">\n<td width=\"70\" data-start=\"2126\" data-end=\"2134\" data-col-size=\"sm\">Z<\/td>\n<td width=\"175\" data-col-size=\"sm\" data-start=\"2134\" data-end=\"2143\">1.7709<\/td>\n<td width=\"300\" data-col-size=\"sm\" data-start=\"2143\" data-end=\"2156\">21CrMoV5-7<\/td>\n<\/tr>\n<tr>\n<td><span style=\"color: #ffffff;\">.<\/span><\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"color: #de5307;\">!<\/span> There is a possibility that a manufacturer may use a different letter code to mark its products. It is therefore important not to rely solely on the letter indicated on the material. You should also consult the manufacturer\u2019s documentation, material certificates in accordance with EN 10204, etc., to ensure that the letter marked on the material corresponds to the grade ordered.<\/p>\n<p>Interested in our range of special fasteners? Click here <a href=\"https:\/\/www.gns-nederland.nl\/wp-content\/uploads\/2025\/06\/Bouten-moeren-ringen-schroeven-draadeinden-hoog-corrosievast-hittebestendig-High-corrosion-resistant-heat-resistant-fasteners.pdf\"><span style=\"text-decoration: underline;\"><span style=\"color: #ff6600; text-decoration: underline;\">here<\/span><\/span><\/a><\/p>\n<p>Despite the care taken in compiling the above article, we cannot guarantee its accuracy.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>With standard fasteners, a strength class designation such as 8.8 or 10.9 primarily indicates: Tensile strength (Rm) Yield strength (Rp0.2%) Properties at room temperature This is usually sufficient for applications up to 100\u00b0C. However, when used at higher temperatures, the behaviour of steel changes rapidly. In such cases, other material properties play a greater role, [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":5925,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_pin_for_all":"","_relevanssi_pin_keywords":"","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"","_relevanssi_noindex_reason":"","footnotes":""},"categories":[14],"tags":[],"class_list":["post-5931","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Letter code for material quality bolts, nuts, etc. - GNS Nederland<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Letter code for material quality bolts, nuts, etc. - GNS Nederland\" \/>\n<meta property=\"og:description\" content=\"With standard fasteners, a strength class designation such as 8.8 or 10.9 primarily indicates: Tensile strength (Rm) Yield strength (Rp0.2%) Properties at room temperature This is usually sufficient for applications up to 100\u00b0C. However, when used at higher temperatures, the behaviour of steel changes rapidly. 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However, when used at higher temperatures, the behaviour of steel changes rapidly. In such cases, other material properties play a greater role, [&hellip;]","og_url":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/","og_site_name":"GNS Nederland","article_published_time":"2026-05-07T06:00:33+00:00","article_modified_time":"2026-05-12T11:25:38+00:00","og_image":[{"width":1920,"height":1280,"url":"https:\/\/www.gns-nederland.nl\/wp-content\/uploads\/2026\/05\/X22CrMoV12-1-1.4923-bout-bolt-GNS-Nederland.jpg","type":"image\/jpeg"}],"author":"GNS Nederland","twitter_card":"summary_large_image","twitter_misc":{"Written by":"GNS Nederland","Est. reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/#article","isPartOf":{"@id":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/"},"author":{"name":"GNS Nederland","@id":"https:\/\/www.gns-nederland.nl\/#\/schema\/person\/3a11ca5e7dc4db0b13b50c52b94c54f2"},"headline":"Letter code for material quality bolts, nuts, etc.","datePublished":"2026-05-07T06:00:33+00:00","dateModified":"2026-05-12T11:25:38+00:00","mainEntityOfPage":{"@id":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/"},"wordCount":355,"image":{"@id":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/#primaryimage"},"thumbnailUrl":"https:\/\/www.gns-nederland.nl\/wp-content\/uploads\/2026\/05\/X22CrMoV12-1-1.4923-bout-bolt-GNS-Nederland.jpg","inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/","url":"https:\/\/www.gns-nederland.nl\/en\/letter-code-for-quality-in-bolts-nuts-etc\/","name":"Letter code for material quality bolts, nuts, etc. - 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