{"id":6455,"date":"2025-07-09T18:23:50","date_gmt":"2025-07-09T10:23:50","guid":{"rendered":"https:\/\/alllandpipes.com\/?post_type=etheme_portfolio&p=6455"},"modified":"2025-12-17T18:55:33","modified_gmt":"2025-12-17T10:55:33","slug":"jis-g3444","status":"publish","type":"etheme_portfolio","link":"https:\/\/alllandpipes.com\/fr\/standards\/jis-g3444.html","title":{"rendered":"JIS G3444"},"content":{"rendered":"
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JIS G3444:1994 – Carbon Steel Tubes for General Structural Purposes<\/b><\/strong><\/span><\/h2>

1. D\u00e9finition de la norme et contexte<\/b><\/strong><\/span><\/h3>

JIS G3444 is\u2002the standard of carbon steel tubes for general structural purposes, established by JISC, The Japanese Industrial Standards Committee. (Note) The JIS G3444:1994 standard has been added to this standard. This Standard specifies the carbon steel tubes (hereafter referred to as “tubes”) used for civil engineering, architecture and other\u2002structures. The code promotes structural safety\u2002and economy, through the appropriate use of materials and workmanship.<\/p>

Key Technical Features:<\/b><\/strong><\/p>

Manufacturing Flexibility: We produce plates, seamless, ERW (Electric Resistance Welded), FW (Furnace Welded), and fully continuous arc-welded (spiral\u2002and longitudinal) pipe.<\/p>

Not Heat Treated:Manufacturing typically does not include heat treating to\u2002save on production costs<\/p>

Size: For welded tubes\u2002of \u2264318.5mm OD and for all seamless tubes; For piles \u2265318.5mm OD JIS A5525 is applied<\/p>

Note the above: The JIS system is technically\u2002not compatible with ANSI\/ DIN; the JPI standards gives the ANSI equivalent for interchangeability.<\/p>

2. Champ d'application<\/b><\/strong><\/span><\/h3>

2.1 Applications primaires<\/b><\/strong><\/span><\/h4>
Sector<\/b><\/strong><\/td>Typical Components<\/b><\/strong><\/td>Recommended Grades<\/b><\/strong><\/td><\/tr>
G\u00e9nie civil<\/td>Bridge supports, slope piles<\/td>STK290, STK400<\/td><\/tr>
La construction<\/td>Scaffolding, building frames<\/td>STK290, STK500<\/td><\/tr>
Power Transmission<\/td>Towers, utility poles<\/td>STK400, STK490<\/td><\/tr>
Industrial Systems<\/td>Machinery supports, racks<\/td>STK500, STK540<\/td><\/tr><\/tbody><\/table><\/figure>

2.2 Limitations<\/b><\/strong><\/span><\/h4>

Load Type<\/b><\/strong>: Static loading only (dynamic loads require additional verification)<\/p>

Temp\u00e9rature<\/b><\/strong>: -30\u00b0C to 120\u00b0C (low-temp applications need toughness validation)<\/p>

Environment<\/b><\/strong>: Neutral soils (pH 4-10); corrosive environments require protective coatings<\/p>

3. Material Technical Requirements<\/b><\/strong><\/span><\/h3>

3.1 Grade Classification and Chemical Composition<\/b><\/strong><\/span><\/h4>

Table 1: Chemical Composition (Ladle Analysis, wt%)<\/p>

Grade<\/b><\/strong><\/td>C\u2264<\/b><\/strong><\/td>Si\u2264<\/b><\/strong><\/td>Mn\u2264<\/b><\/strong><\/td>P\u2264<\/b><\/strong><\/td>S\u2264<\/b><\/strong><\/td>Exigences particuli\u00e8res<\/b><\/strong><\/td><\/tr>
STK290<\/td>-<\/td>-<\/td>-<\/td>0.050<\/td>0.050<\/td>-<\/td><\/tr>
STK400<\/td>0.25<\/td>-<\/td>-<\/td>0.040<\/td>0.040<\/td>-<\/td><\/tr>
STK500<\/td>0.24<\/td>0.35<\/td>0.30-1.30<\/td>0.040<\/td>0.040<\/td>-<\/td><\/tr>
STK490<\/td>0.18<\/td>0.55<\/td>1.50<\/td>0.040<\/td>0.040<\/td>Low-carbon design for weldability<\/td><\/tr>
STK540<\/td>0.23<\/td>0.55<\/td>1.50<\/td>0.040<\/td>0.040<\/td>Custom agreement for t>12.5mm<\/td><\/tr><\/tbody><\/table><\/figure>

Key Controls<\/b><\/strong>:<\/p>

Strict P\/S limits (\u22640.040%) to minimize cold brittleness<\/p>

STK490’s low carbon (C\u22640.18%) optimizes weldability<\/p>

Micro-alloying (V, Nb) permitted for grain refinement<\/p>

3.2 Mechanical Properties<\/b><\/strong><\/span><\/h4>

Table 2: Mechanical Requirements<\/p>

Grade<\/b><\/strong><\/td>R\u00e9sistance \u00e0 la traction (MPa)<\/b><\/strong><\/td>Limite d'\u00e9lasticit\u00e9 (MPa)<\/b><\/strong><\/td>\u00c9longation (%)<\/b><\/strong><\/td>Flattening Test (H\u2264)<\/b><\/strong><\/td><\/tr>
STK290<\/td>\u2265290<\/td>\u2265175<\/td>\u226525<\/td>0.85D<\/td><\/tr>
STK400<\/td>\u2265400<\/td>\u2265235<\/td>\u226523<\/td>0.85D<\/td><\/tr>
STK500<\/td>\u2265500<\/td>\u2265355<\/td>\u226515<\/td>0.85D<\/td><\/tr>
STK490<\/td>\u2265490<\/td>\u2265315<\/td>\u226523<\/td>0.85D<\/td><\/tr>
STK540<\/td>\u2265540<\/td>\u2265390<\/td>\u226520<\/td>0.85D<\/td><\/tr><\/tbody><\/table><\/figure>

Special Provisions<\/b><\/strong>:<\/p>

Thin-Wall Adjustment<\/b><\/strong>: For t<8mm, elongation may decrease 1.5% per 1mm thickness reduction<\/p>

R\u00e9sistance de la soudure<\/b><\/strong>: Welded tube joints must achieve \u226595% of base metal strength<\/p>

4. Dimensions and Tolerances<\/b><\/strong><\/span><\/h3>

4.1 Size Ranges<\/b><\/strong><\/span><\/h4>

Diam\u00e8tre ext\u00e9rieur (OD)<\/b><\/strong>: 10.2\u2013318.5 mm (welded tubes)<\/p>

Wall Thickness (t)<\/b><\/strong>: Agreement-based (refer to JIS G3454<\/a> Sch series)<\/p>

4.2 Key Tolerances<\/b><\/strong><\/span><\/h4>

Table 3: Geometric Tolerances<\/p>

Param\u00e8tres<\/b><\/strong><\/td>\u00c9cart admissible<\/b><\/strong><\/td>Conditions<\/b><\/strong><\/td><\/tr>
Diam\u00e8tre ext\u00e9rieur<\/b><\/strong><\/td>\u00b10.5mm or \u00b10.5% OD<\/td>OD\u226450mm \/ OD>50mm<\/td><\/tr>
\u00c9paisseur de la paroi<\/b><\/strong><\/td>\u00b112,5% t (l\u00e9ger) \/ \u00b110% t (lourd)<\/td>Per manufacturing agreement<\/td><\/tr>
Ovalit\u00e9 de l'extr\u00e9mit\u00e9 du tube<\/b><\/strong><\/td>\u22641% OD<\/td>Within 100mm from end<\/td><\/tr>
Rectitude<\/b><\/strong><\/td>\u22640.2% de la longueur du tube<\/td>Full-length measurement<\/td><\/tr><\/tbody><\/table><\/figure>

Special Cases<\/b><\/strong>:<\/p>

Welded tubes >350mm OD: End tolerance \u00b10.5mm; body tolerance \u00b10.5%<\/p>

Large-diameter measurement: Use circumference method (\u03c0=3.14)<\/p>

5. Essais et contr\u00f4le de la qualit\u00e9<\/b><\/strong><\/span><\/h3>

5.1 Tests obligatoires<\/b><\/strong><\/span><\/h4>

Essais m\u00e9caniques<\/b><\/strong>:<\/p>

Tensile Test<\/b><\/strong>: 2 samples per \u2264100-tube batch (weld excluded)<\/p>

Flattening Test<\/b><\/strong>: Mandatory for welded tubes; compress to H\u22640.85D without cracking<\/p>

Essai de flexion<\/b><\/strong>\u00a0(Optional): 90\u00b0 bend with mandrel radius \u22648t upon request<\/p>

Non-Destructive Testing<\/b><\/strong>:<\/p>

100% UT or RT for welded tubes (RT acceptance: JIS Z3104)<\/p>

5.2 Traitement des d\u00e9fauts<\/b><\/strong><\/span><\/h4>

D\u00e9fauts de surface<\/b><\/strong>: Repair\/remove if depth >12.5% wall thickness<\/p>

Weld Defects<\/b><\/strong>: No lack of fusion or through-thickness cracks permitted<\/p>

6. Engineering Applications and Evolution<\/b><\/strong><\/span><\/h3>

6.1 Grade Selection Guide<\/b><\/strong><\/span><\/h4>
Application<\/b><\/strong><\/td>Recommended Grade<\/b><\/strong><\/td>Avantage principal<\/b><\/strong><\/td><\/tr>
Low-cost scaffolding<\/td>STK290<\/td>Cost-effective, El\u226525%<\/td><\/tr>
High-strength supports<\/td>STK540<\/td>Tensile strength \u2265540 MPa<\/td><\/tr>
Welded-intensive frames<\/td>STK490<\/td>Superior weldability (C\u22640.18%)<\/td><\/tr><\/tbody><\/table><\/figure>

6.2 Limitations and Development<\/b><\/strong><\/span><\/h4>

Wall\u2002thickness series: No standard series, depends on agreements<\/p>

Compatibility and interoperability International Working : Technically NOT\u2002compatible with ANSI\/DIN, but acceptable for use with JPI standards<\/p>

Future\u2002Prospects: High strength steels (STK600) and environment-friendly weathering steel<\/p>

7. Conclusion and Implementation<\/b><\/strong><\/span><\/h3>

JIS G3444 serves as Japan’s cornerstone standard for structural tubing through:<\/p>

Strength-Graded Design<\/b><\/strong>: Five grades for optimized material selection<\/p>

Process Efficiency<\/b><\/strong>: No-heat-treatment requirement reduces costs<\/p>

Safety Assurance<\/b><\/strong>: Strict P\/S controls (\u22640.040%) ensure low-temperature toughness<\/p>

Critical Implementation Notes<\/b><\/strong>:<\/p>

Avoid STK290 for dynamic loads (e.g., seismic bracing); use STK400+<\/p>

Specify weld inspection method (UT\/RT) and acceptance criteria in orders<\/p>

Measure large-diameter tubes (OD>350mm) via circumference method<\/p>

Standard Transition<\/b><\/strong>:<\/p>

For piles \u2265318.5mm: Use JIS A5525<\/p>

For pressure piping: Apply JIS G3454 (Sch thickness series)<\/p>\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

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