{"id":4036,"date":"2026-05-08T18:01:42","date_gmt":"2026-05-08T16:01:42","guid":{"rendered":"https:\/\/steelelement.ee\/steel-grade-selection-s235-s275-s355\/"},"modified":"2026-05-08T18:01:42","modified_gmt":"2026-05-08T16:01:42","slug":"steel-grade-selection-s235-s275-s355","status":"publish","type":"post","link":"https:\/\/steelelement.ee\/en\/steel-grade-selection-s235-s275-s355\/","title":{"rendered":"Steel Grade Selection: S235, S275 and S355 Explained"},"content":{"rendered":"\n<p>One of the first decisions in steel structure design is the choice of steel grade. Under European standards, structural steels are specified according to EN 10025 (hot-rolled products) and EN 10210\/EN 10219 (hollow sections). The most widely used grades are S235, S275, and S355 \u2014 but what do these designations mean, and how do you choose the right grade for your structure?<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Steel Grade Designations: What Do S235, S275, S355 Mean?<\/h2>\n\n\n\n<p>In the designation, <strong>S<\/strong> stands for &#8220;structural steel&#8221; and the following number indicates the minimum yield strength in megapascals (MPa) \u2014 measured on products up to 16 mm thick. For example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>S235<\/strong> \u2014 yield strength \u2265 235 MPa, tensile strength 360\u2013510 MPa<\/li>\n\n<li><strong>S275<\/strong> \u2014 yield strength \u2265 275 MPa, tensile strength 410\u2013560 MPa<\/li>\n\n<li><strong>S355<\/strong> \u2014 yield strength \u2265 355 MPa, tensile strength 470\u2013630 MPa<\/li>\n<\/ul>\n\n\n\n<p>Importantly, yield strength decreases as material thickness increases. For S355, yield strength on 16\u201340 mm products is \u2265 345 MPa, and on products over 63 mm it is \u2265 315 MPa.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Do the Suffixes Mean: JR, J0, J2, K2?<\/h2>\n\n\n\n<p>The suffix after the grade designation describes the impact toughness requirement (CVN \u2014 Charpy V-notch test). This is critical for structures used in cold environments, where the material must retain ductility at low temperatures:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>JR<\/strong> \u2014 27 J impact energy at +20 \u00b0C<\/li>\n\n<li><strong>J0<\/strong> \u2014 27 J impact energy at 0 \u00b0C<\/li>\n\n<li><strong>J2<\/strong> \u2014 27 J impact energy at \u221220 \u00b0C<\/li>\n\n<li><strong>K2<\/strong> \u2014 40 J impact energy at \u221220 \u00b0C<\/li>\n<\/ul>\n\n\n\n<p>In Estonia, where winter temperatures can fall below \u221220 \u00b0C, J2 or K2 grade materials are commonly specified for external structures. JR is generally sufficient for structures operating indoors.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">S235 vs S275 vs S355 \u2014 When to Use Which?<\/h2>\n\n\n\n<p><strong>S235<\/strong> is best suited for:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Non-load-bearing or minor structures<\/li>\n\n<li>Stairs, ladders, access platforms<\/li>\n\n<li>Situations where dimensions are constrained by other factors (e.g. architectural) and load-bearing capacity is not critical<\/li>\n<\/ul>\n\n\n\n<p><strong>S275<\/strong> is a mid-range option used for secondary structures, fa\u00e7ade and roof systems.<\/p>\n\n\n\n<p><strong>S355<\/strong> is today the preferred choice for <a href=\"\/en\/industrial-building-steel-frame-design-stages\/\">main structures in industrial buildings<\/a>, bridges, and crane girders. Its higher yield strength allows smaller cross-sections, which means:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Lower structural weight and therefore reduced fabrication and transport costs<\/li>\n\n<li>Less weld filler material consumption<\/li>\n\n<li>The ability to achieve longer spans without adding intermediate supports<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Weldability and Steel Grade<\/h2>\n\n\n\n<p>Higher-strength steels (S355 and above) demand stricter <a href=\"\/en\/steel-structure-welding-quality-control\/\">welding controls<\/a>: preheating for thicker sections, heat input limitations, and the use of compatible filler materials. S235 and S275 are generally readily weldable without additional requirements at standard thicknesses (up to 25\u201330 mm).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Material Certificates \u2014 EN 10204 3.1 and 3.2<\/h2>\n\n\n\n<p>Every steel used in a <a href=\"\/en\/ce-marking-steel-structures-en-1090\/\">CE-marked<\/a> structure must be supplied with a material test report (mill certificate). Under EN 10204, there are two principal certificate types:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>3.1<\/strong> \u2014 certificate issued by the manufacturer&#8217;s own inspection representative<\/li>\n\n<li><strong>3.2<\/strong> \u2014 certificate issued by an independent third party (required for EXC3\u2013EXC4 structures and most bridge projects)<\/li>\n<\/ul>\n\n\n\n<p>Steel Element O\u00dc retains all material certificates as part of the order documentation and provides them together with the finished structures. Learn more about our <a href=\"\/en\/services\/\">production capabilities and services<\/a>, or request a quote.<\/p>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"\/en\/contact\/\">Request a quote<\/a><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>One of the first decisions in steel structure design is the choice of steel grade. Under European standards, structural steels are specified according to EN 10025 (hot-rolled products) and EN 10210\/EN 10219 (hollow sections). The most widely used grades are S235, S275, and S355 \u2014 but what do these designations mean, and how do you [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[63],"tags":[],"class_list":["post-4036","post","type-post","status-publish","format-standard","hentry","category-technical-information"],"_links":{"self":[{"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/posts\/4036","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/comments?post=4036"}],"version-history":[{"count":0,"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/posts\/4036\/revisions"}],"wp:attachment":[{"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/media?parent=4036"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/categories?post=4036"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/steelelement.ee\/en\/wp-json\/wp\/v2\/tags?post=4036"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}