JIS G3466


JIS G3466 Steel Pipe

At UNIACERO, we specialize in JIS G3466 carbon steel square and rectangular tubes, designed primarily for structural applications in civil engineering and construction. These tubes are manufactured to the highest standards, ensuring durability, reliability, and efficiency. Whether you’re involved in civil engineering or construction, our JIS standardized tubes provide the structural integrity and strength required for your projects.

JIS G3466 Specification

Our steel tubes are manufactured using advanced techniques, ensuring they meet the highest standards of quality. Available in grades STKR 400 and STKR 490, these tubes undergo rigorous testing to ensure their mechanical and chemical properties are up to mark. With options for galvanized steel sheets or strips, our tubes can be customized to your specific requirements. Additionally, our tubes come with plain ends, but bevel ends can be provided upon request.

StandardJIS G3466
UsageUsed for civil engineering architecture and other sturctures
Steel GradeSTKR400STKR490
Manufacturing ProcessessERW and Seamless into square tubes.
SpecificationSquare20*20 to 350*350
Rectangular30*20 to 400*200
Wall Thickness1.2 – 12.5 mm
1.2 – 12mm
Chemical CompositionCSiMnPS
Mechanical PropertiesTensile Strength(Mpa)Yield Strength(Mpa)Elongation  %
Wall thickness toleranceWeldedUnder 3mm {0.3mm},3mm or over {10%}
SeamlessUnder 45mm {0.6mm},45mm or over {15%}
Reqired TestChemical Analysis
Tensile test
Equivalent StandardASTM A500 {Gr.B  Gr.C}
EN10025 {S275JR  S355J0}
KS {SPSR400   SPSR490}

JIS G3466 Dimension Table


This standardized tubes come in a variety of dimensions to suit your needs:

Square Size: Ranging from 4040mm to 350350mm.
Rectangular Size: Ranging from 2050mm to 200400mm.
Wall Thickness: Ranging from 1.6-12mm.

Chemical Requirements of JIS G3466

The chemical composition of our JIS G3466 tubes is meticulously controlled:

STKR 400: C ≤0.25%, P ≤0.040%, S ≤0.040%.
STKR 490: C ≤0.18%, Si ≤0.55%, Mn ≤1.5%, P ≤0.040%, S ≤0.040%.

Symbol of GradeCSiMnPS
STKR4000.25 max.0.040 max.0.040 max.
STKR4900.18 max.0.55 max.1.50 max.0.040 max.0.040 max.
Note If necessary,Other alloy elements than those given in this table may be added.

Mechanical Requirements of JIS G3466

Our tubes are tested to ensure they meet the required mechanical properties:

STKR 400: Tensile Strength ≥ 400 MPa, Yield Strength ≥ 245 MPa, Elongation ≥ 23%.
STKR 490: Tensile Strength ≥ 490 MPa, Yield Strength ≥ 325 MPa, Elongation ≥ 23%.

Mechanical Properties
Symbol of GradeTensile Strength N/mm2Yield Point or Proof Stress N/mm2Elongation %
Tensile Test pieceTest direction
Test piece No.5Tube axis direction
STKR400400 min.245 min.23 min.
STKR490490 min.325 min.23 min.
NOTE: 1 N/mm2=1 MPa

Steel Grades in JIS G3466

We offer the standardized tubes in two primary steel grades:

STKR 400: Ideal for general structural applications, offering a balanced mix of strength and flexibility.
STKR 490: Provides higher tensile strength, making it suitable for more demanding structural applications.

Production Tolerance of JIS G3466

Table 4.Dimensional TolerancesSpeclfied item and dimensionDimensional tolerancesLength of side100 mm or under±1.5mmOver 100 mm±1.5%Unevenness of flat plate portion of each sideSide length 100 mm or under0.5 mm maxSide length over 100 mmWithin 0.5% of side lengthAnguiarity made by adfacent flat plate portions±1.5%Dimension at corner: s3mm maxLength+ not specifird 0UnstraightnessWithin 0.3% of side lengthWall thicknessSquare steel tube manufactured by weldingUnder 3 mm±0.3mm3 mm or over±10%Seamless square steel tubeUnder 4 mm±0.6mm4 mm or over±15%
Table Dimensional Tolerances
Speclfied item and dimensionDimensional tolerances
Length of side100 mm or under±1.5mm
Over 100 mm±1.5%
Unevenness of flat plate portion of each sideSide length 100 mm or under0.5 mm max
Side length over 100 mmWithin 0.5% of side length
Anguiarity made by adfacent flat plate portions±1.5%
Dimension at corner: s3mm max
Length+ not specifird 0
UnstraightnessWithin 0.3% of side length
Wall thicknessSquare steel tube manufactured by weldingUnder 3 mm±0.3mm
3 mm or over±10%
Seamless square steel tubeUnder 4 mm±0.6mm
4 mm or over±15%

Reference Resource

Our Advantages

  1. Over 25 years of experience in pipeline production and installation.
  2. Comprehensive inspection equipment.
  3. Independent product serial numbers for traceability.
  4. Advanced production equipment – Seamer high-frequency welding machine from the United States.
  5. Complete qualifications – API 5L/API 5CT/FM/UL fire pipe certification, etc.
  6. Wide range of products – independently developed solar torque tubes, highly favored in the European market.
  7. Customers spread across the globe.
  8. Excellent after-sales service and sense of responsibility.

Application Scenarios

Our steel pipes are engineered to withstand high temperatures, corrosive environments, and varying pressures, ensuring reliability and safety in the complex petrochemical processes. 

Whether it’s transferring crude oil, natural gas, or chemical intermediates, the robustness and versatility of steel pipes make them indispensable components of the plant’s infrastructure, contributing to efficient production and maintenance of stringent safety standards.

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