{"id":22839,"date":"2025-12-05T15:11:10","date_gmt":"2025-12-05T07:11:10","guid":{"rendered":"https:\/\/alllandpipes.com\/?p=22839"},"modified":"2025-12-05T15:26:10","modified_gmt":"2025-12-05T07:26:10","slug":"what-is-jis-g3444-guide-to-carbon-steel-structural-tubing","status":"publish","type":"post","link":"https:\/\/alllandpipes.com\/fr\/blogs\/what-is-jis-g3444-guide-to-carbon-steel-structural-tubing.html","title":{"rendered":"Qu'est-ce que la norme JIS G3444 ? Guide des tubes de construction en acier au carbone"},"content":{"rendered":"<div data-elementor-type=\"wp-post\" data-elementor-id=\"22839\" class=\"elementor elementor-22839\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-7cf54ae2 e-flex e-con-boxed e-con e-parent\" data-id=\"7cf54ae2\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-3f3687c9 elementor-widget elementor-widget-text-editor\" data-id=\"3f3687c9\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\n<h2><span style=\"color: #046cb5;\"><strong>Introduction<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">In construction of civil engineering structures, architecture and high-rise buildings, JIS G3444 is the most popular, widely used standard for\u2002carbon steel pipe in Asia and also in the world. But it&#8217;s surprising how many global engineers have never heard of its weird unique &#8220;STK&#8221; grade system, and many even mistake\u2002it for the ASTM or API standards that have other names. This article is a definitive technical white paper to\u2002understand the JIS G3444 specification. We&#8217;ll review its\u2002five principal steel grades (ranging from STK290 to STK540), highlight the important differences in chemical and mechanical characteristics, and consider key uses in piling, civil infrastructure and heavy construction so you can specify the best material with total assurance.<\/p>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>What is JIS G3444?<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/alllandpipes.com\/standards\/jis-g3444.html\">JIS G3444<\/a>\u00a0is the Japanese standard describing \u201cCarbon Steel Tubes\u2002for General Structural Purpose.\u201dAs its name suggests its main scope is carbon steel tubes for civil engineering, architectural, steel tower, scaffolding, piles, and\u2002so on. It is not for fluid transport or pressure\u2002service (drainage is addressed in a separate JIS standard, <a href=\"https:\/\/alllandpipes.com\/standards\/jis-g3454.html\">JIS G3454<\/a>).<\/p>\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"437\" class=\"wp-image-22840\" src=\"https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process.webp\" alt=\"lsaw pipe welding process.\" srcset=\"https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process.webp 800w, https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process-300x164.webp 300w, https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process-768x420.webp 768w, https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process-600x328.webp 600w, https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process-1x1.webp 1w, https:\/\/alllandpipes.com\/wp-content\/uploads\/2025\/12\/lsaw-pipe-welding-process-10x5.webp 10w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/figure>\n\n<p class=\"wp-block-paragraph\">\u00a0<\/p>\n\n<h3 class=\"wp-block-heading\"><strong>Decoding the Name: What does &#8220;STK&#8221; Mean?<\/strong><\/h3>\n\n<p class=\"wp-block-paragraph\">The designation system is logical but distinct from American standards.<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>S:<\/strong>\u00a0Acier<\/li>\n\n<li><strong>T:<\/strong>\u00a0Tube<\/li>\n\n<li><strong>K:<\/strong>\u00a0Koki (Structural\/General)<\/li>\n\n<li><strong>The Number (e.g., 400, 490):<\/strong>\u00a0This is the most critical distinction. The number represents the <strong>R\u00e9sistance minimale \u00e0 la traction<\/strong>\u00a0in N\/mm\u00b2 (or MPa).\n<ul>\n<li><em>Remarque :<\/em>\u00a0This differs from API 5L (where X52 = Yield Strength) or <a class=\"wpil_keyword_link\" href=\"https:\/\/alllandpipes.com\/standards\/astm-a500.html\"   title=\"ASTM A500\" data-wpil-keyword-link=\"linked\"  data-wpil-monitor-id=\"548\">ASTM A500<\/a> (where Grade B is arbitrary).<\/li>\n<\/ul>\n\n<ul class=\"wp-block-list\">\n<li><strong>Example:\u200b<\/strong>STK400 steel pipe\u00a0has a minimum <em>tensile<\/em>\u00a0strength of 400 N\/mm\u00b2.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\"><strong>Manufacturing Methods<\/strong><\/h3>\n\n<p class=\"wp-block-paragraph\">The standard is versatile regarding production. It covers:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Sans couture :<\/strong>\u00a0Manufactured from a solid billet.<\/li>\n\n<li><strong>Electric Resistance Welded (ERW):<\/strong>\u00a0For small-to-medium diameters.<\/li>\n\n<li><strong>Butt-Welded:<\/strong>\u00a0(Less common in modern structural use).<\/li>\n\n<li><strong>Automatic Arc Welded:<\/strong>\u00a0This includes <strong>LSAW (Longitudinal Submerged Arc Welded)<\/strong>\u00a0et <strong>SSAW (Spiral Submerged Arc Welded)<\/strong>\u00a0pipes, which are the primary focus for large-scale infrastructure and <strong>Allland's<\/strong>\u00a0core capability.<\/li>\n<\/ul>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>The Core Grades: STK400 vs. STK490<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">While the standard lists five grades (STK290, STK400, STK490, STK500, STK540), two grades dominate the market: STK400 and STK490.<\/p>\n\n<h3 class=\"wp-block-heading\"><strong>1. <\/strong>STK400 Steel Pipe<strong>\u00a0(The General Purpose Choice)<\/strong><\/h3>\n\n<ul class=\"wp-block-list\">\n<li><strong>Characteristics:<\/strong>\u00a0STK400 is\u2002also the best-selling grade. It has good ductility and\u2002weldability.Its reduced carbon content allows easy forming and welding on the field without elaborate pre-heating\u2002treatments.<\/li>\n\n<li><strong>Primary Applications:<\/strong>\u00a0General civil engineering works, standard scaffolding, support columns, fence posts, and light structural frames.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\"><strong>2. <\/strong>STK490 Steel Pipe<strong>\u00a0(The High-Strength Choice)<\/strong><\/h3>\n\n<ul class=\"wp-block-list\">\n<li><strong>Characteristics:<\/strong>\u00a0STK490 is a significant step up in performance. With a minimum tensile strength of 490 N\/mm\u00b2 and a minimum yield point of 315 N\/mm\u00b2, it is approximately <strong>34% stronger<\/strong>\u00a0(in yield) than STK400.<\/li>\n\n<li><strong>Engineering Value:<\/strong>\u00a0The\u2002result is that engineers can design lighter structures. You can use a thinner wall thickness\u2002for the same bearing load, which reduces the total steel tonnage and the load on the foundation.<\/li>\n\n<li><strong>Primary Applications:<\/strong>\u00a0Heavy-duty transmission towers, JIS G3444 piles\u00a0for large buildings, landslide prevention piles, and massive offshore structural components.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\"><strong>3. STK500 &amp; STK540 (The Ultra-High Strength)<\/strong><\/h3>\n\n<p class=\"wp-block-paragraph\">These grades are used in specialty\u2002applications for extreme bearing loads, such as very large truss bridges or deep-sea piles.They usually need more precise welding techniques because of the higher\u2002strength chemistry.<\/p>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>Quantitative Analysis: Technical Data Sheets<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">This section provides the data required for engineering calculations.<\/p>\n\n<h3 class=\"wp-block-heading\"><strong>Table 1: Chemical Composition (%)<\/strong><\/h3>\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<tbody>\n<tr>\n<td><strong>Grade<\/strong><\/td>\n<td><strong>C (Carbone)<\/strong><\/td>\n<td><strong>Si (Silicon)<\/strong><\/td>\n<td><strong>Mn (mangan\u00e8se)<\/strong><\/td>\n<td><strong>P (phosphore)<\/strong><\/td>\n<td><strong>S (soufre)<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>STK290<\/strong><\/td>\n<td>-<\/td>\n<td>-<\/td>\n<td>-<\/td>\n<td>0.050 max<\/td>\n<td>0.050 max<\/td>\n<\/tr>\n<tr>\n<td><strong>STK400<\/strong><\/td>\n<td>0.25 max<\/td>\n<td>-<\/td>\n<td>-<\/td>\n<td>0.040 max<\/td>\n<td>0.040 max<\/td>\n<\/tr>\n<tr>\n<td><strong>STK490<\/strong><\/td>\n<td>0.18 max<\/td>\n<td>0.55 max<\/td>\n<td>1.50 max<\/td>\n<td>0.040 max<\/td>\n<td>0.040 max<\/td>\n<\/tr>\n<tr>\n<td><strong>STK500<\/strong><\/td>\n<td>0.23 max<\/td>\n<td>0.55 max<\/td>\n<td>1.50 max<\/td>\n<td>0.040 max<\/td>\n<td>0.040 max<\/td>\n<\/tr>\n<tr>\n<td><strong>STK540<\/strong><\/td>\n<td>0.23 max<\/td>\n<td>0.55 max<\/td>\n<td>1.60 max<\/td>\n<td>0.040 max<\/td>\n<td>0.040 max<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n\n<p class=\"wp-block-paragraph\"><strong>Engineer&#8217;s Analysis:<\/strong>\u00a0Note that for STK400, only Carbon is capped (besides P\/S), allowing mills flexibility. However, for <strong>STK490<\/strong>, the chemistry is much strictly controlled (low Carbon, high Manganese) to achieve high strength while maintaining weldability.<\/p>\n\n<h3 class=\"wp-block-heading\"><strong>Table 2: Mechanical Properties<\/strong><\/h3>\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<tbody>\n<tr>\n<td><strong>Grade<\/strong><\/td>\n<td><strong>Min. Tensile Strength (N\/mm\u00b2)<\/strong><\/td>\n<td><strong>Min. Yield Point <\/strong><strong>(N\/mm\u00b2)<\/strong><\/td>\n<td><strong>Min. Elongation (%) <\/strong><strong>(Longitudinal)<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>STK290<\/strong><\/td>\n<td>290<\/td>\n<td>-<\/td>\n<td>30<\/td>\n<\/tr>\n<tr>\n<td><strong>STK400<\/strong><\/td>\n<td><strong>400<\/strong><\/td>\n<td><strong>235<\/strong><\/td>\n<td><strong>23<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>STK490<\/strong><\/td>\n<td><strong>490<\/strong><\/td>\n<td><strong>315<\/strong><\/td>\n<td><strong>23<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>STK500<\/strong><\/td>\n<td>500<\/td>\n<td>355<\/td>\n<td>15<\/td>\n<\/tr>\n<tr>\n<td><strong>STK540<\/strong><\/td>\n<td>540<\/td>\n<td>390<\/td>\n<td>20<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n\n<p class=\"wp-block-paragraph\"><strong>Key Takeaway:<\/strong>\u00a0The jump from STK400 to STK490 provides a massive gain in Yield Strength (235 to 315 MPa), which is the primary design parameter for structural columns.<\/p>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>Tolerances &amp; Manufacturing Quality<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">JIS standards are renowned for their strict adherence to dimensional accuracy. <strong>JIS G3444<\/strong>\u00a0specifies rigorous tolerances for:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Outside Diameter (OD):<\/strong>\u00a0Divided into Class 1, Class 2, and Class 3 tolerances depending on diameter size.<\/li>\n\n<li><strong>\u00c9paisseur de la paroi :<\/strong>\u00a0Typically allows for a deviation of + Not Specified \/ -12.5% (similar to <a class=\"wpil_keyword_link\" href=\"https:\/\/alllandpipes.com\/standards\/api-5l.html\"   title=\"API 5L\" data-wpil-keyword-link=\"linked\"  data-wpil-monitor-id=\"678\">API 5L<\/a>), but specific tolerances apply based on the manufacturing method.<\/li>\n\n<li><strong>Appearance:<\/strong>\u00a0The tube\u2002shall be useful and straight, and the ends shall be cut at right angles to the axis of the tube. The surface should be\u2002clean and regular without cracks or flakes that could prevent application.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">L'avantage Allland :<\/p>\n\n<p class=\"wp-block-paragraph\">Manufacturing large-diameter carbon steel tubes for general structural purposes to these tight tolerances requires advanced equipment. Allland\u2019s LSAW (JCOE) and SSAW production lines are equipped with precision forming presses and automated sizing equipment. This ensures that every pipe\u2014whether a 20-inch foundation pile or a 60-inch tower base\u2014meets the strict geometric requirements of the JIS G3444 specification.<\/p>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>Applications in Civil Engineering<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">The versatility of the JIS G3444 specification\u00a0makes it a staple in three key sectors where <strong>Allland<\/strong>\u00a0actively supplies material.<\/p>\n\n<h3 class=\"wp-block-heading\"><strong>1. Steel Pipe Piling (Piles)<\/strong><\/h3>\n\n<p class=\"wp-block-paragraph\">This is the single largest application for large-diameter pipe under this standard.<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Landslide Prevention Piles:<\/strong>\u00a0In mountainous regions (common in Japan and Asia), heavy-wall STK490 pipes are driven into slopes to prevent soil movement.<\/li>\n\n<li><strong>Foundation Piles:<\/strong>\u00a0Used for bridges, buildings, and port structures.<\/li>\n\n<li><strong>Why SSAW?<\/strong>\u00a0For these applications, <a href=\"https:\/\/alllandpipes.com\/product\/allland-steel-pipe\/ssaw-steel-pipe.html\"><strong>SSAW (spirale)<\/strong>\u00a0tuyau<\/a>\u00a0is the preferred manufacturing method due to its ability to produce large diameters and long lengths economically.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\"><strong>2. Steel Towers &amp; Masts<\/strong><\/h3>\n\n<ul class=\"wp-block-list\">\n<li><strong>Transmission Towers:<\/strong>\u00a0The legs of massive electrical pylons often use high-strength <strong>STK490<\/strong>\u00a0ou <strong>STK540<\/strong>\u00a0pipe.<\/li>\n\n<li><strong>Wind Turbine Foundations:<\/strong>\u00a0Jacket structures often specify JIS G3444 due to its proven reliability.<\/li>\n\n<li><strong>Why LSAW?<\/strong>\u00a0For the critical, high-stress legs of these towers, <a href=\"https:\/\/alllandpipes.com\/product\/allland-steel-pipe\/lsaw-steel-pipe.html\"><strong>LSAW (Longitudinal)<\/strong>\u00a0tuyau<\/a>\u00a0is often specified for its superior toughness and thick-wall capability.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\"><strong>3. General Civil Structures<\/strong><\/h3>\n\n<p class=\"wp-block-paragraph\">From signposts and lighting columns to strutting systems for subway excavation, STK400 serves as the reliable, weldable backbone of urban infrastructure.<\/p>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>Conclusion<\/strong><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">To conclude JIS G3444 is a tough tensile strength based standard which has become the foundation of\u2002structural engineering in Asia and provides a well-defined grade system from flexible STK400 through high quality STK490 and STK540. Whether your engineering is for a simple scaffold or a giant\u2002infrastructure foundation pile, knowing the chemical and mechanical-specifics demands within this standard is your starting point for structural integrity and project success. At Allland, we have profound knowledge about\u2002Japanese industrial standards and long-time experiences to produce large diameter LSAW and SSAW steel pipes under stringent requirements of JIS G3444. Whether your project is based in Japan or is an international infrastructure build employing JIS specifications, we can deliver fully compliant, high quality solutions in structural\u2002tubing tailored to your specific project needs.<\/p>\n\n<h2 class=\"wp-block-heading\"><span style=\"color: #046cb5;\"><strong>Foire aux questions (FAQ)<\/strong><\/span><\/h2>\n\n<h4>Q1: What is the JIS G3444 equivalent ASTM standard?<\/h4>\n\n<p class=\"wp-block-paragraph\">A1: There is no single, perfect equivalent, but the closest approximations are:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>For STK400:<\/strong>\u00a0Roughly equivalent to <strong>ASTM A500, nuance B<\/strong>\u00a0(Round) or \u200b<strong>ASTM A252 Grade 2<\/strong>\u200b.<\/li>\n\n<li><strong>For STK490:<\/strong>\u00a0Roughly equivalent to <strong>ASTM A500 Grade C<\/strong>\u00a0(Round) or \u200b<strong>ASTM A252 Grade 3<\/strong>\u200b.<\/li>\n\n<li><em>Remarque :<\/em>\u00a0Always have a structural engineer verify the mechanical properties before substituting, as chemical requirements differ.<\/li>\n<\/ul>\n\n<h4>Q2: Does JIS G3444 pipe require hydrostatic testing?<\/h4>\n\n<p class=\"wp-block-paragraph\">A2: Generally, no. Since JIS G3444 is for &#8220;General Structural Purposes,&#8221; it is not intended for pressure containment. Therefore, hydrostatic testing is usually not a mandatory requirement of the standard unless specifically agreed upon between the buyer and manufacturer. If you need pipe for fluid pressure, you should look at JIS G3454 (STPG).<\/p>\n\n<h4>Q3: What does the number &#8220;400&#8221; mean in STK400?<\/h4>\n\n<p class=\"wp-block-paragraph\">A3: It represents the Minimum Tensile Strength of the steel in N\/mm\u00b2 (or MPa). So, STK400 has a min tensile strength of 400 MPa. This is a key difference from API or some ASTM standards, which often name grades based on Yield Strength (e.g., X52 = 52,000 psi Yield). Be careful not to confuse the two when comparing specs.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"<p>Introduction In construction of civil engineering structures, architecture and high-rise buildings, JIS G3444 is the most popular, widely used standard for\u2002carbon steel pipe&#8230;<\/p>","protected":false},"author":1,"featured_media":22841,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"A complete guide to JIS G3444 (STK400\/STK490). We analyze chemical composition, mechanical properties, and ASTM equivalents for structural steel pipe.","_seopress_robots_index":"","_gspb_post_css":"","footnotes":""},"categories":[1],"tags":[86],"class_list":["post-22839","post","type-post","status-publish","format-standard","has-post-thumbnail","category-blogs","tag-engineering-standards"],"acf":[],"_links":{"self":[{"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/posts\/22839","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/comments?post=22839"}],"version-history":[{"count":3,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/posts\/22839\/revisions"}],"predecessor-version":[{"id":24093,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/posts\/22839\/revisions\/24093"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/media\/22841"}],"wp:attachment":[{"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/media?parent=22839"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/categories?post=22839"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alllandpipes.com\/fr\/wp-json\/wp\/v2\/tags?post=22839"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}