JIS G3444 Stk400/Stk500/Stk540 Carbon Steel Seamless Mechanical Structural Tubes

• Customization: Available
• After-sales Service: 1 Years
• Warranty: /
• Model NO.: JIS G3444 STK400/STK500/STK540 Structural Tubes
• Name: JIS G3444 ERW/Hfw Welded Pipe
• Steel Grade: Stk290 Stk40d Stk50d Stk490 Stk540
• Size Standard: JIS G3444
• Wall Thickness: 1.0–12.0 mm (±10% Tolerance)
• Process: Polished/Black Paint
• Condition: ERW/Hfw
• End: Plain End/Bevel End
• Length: 4–12m (Cut-to-Length Customization Available
• Od: 15 mm to 250 mm
• Stock: Size Can Customized
• Processing: Customized
• Thickness: 1-150mm
• Certifications: JIS Mark, ISO 9001, Ks D 3564 (Korean Equivalent)
• Packing: Standard Export Packing
• Delivery Time: 10-30 Working Days
• Transport Package: Woven Bag/Wooden Case
• Specification: SCH 5S-SCH160
• Trademark: EZS
• Origin: China
• Production Capacity: 10, 000, 000 Kgs/Year

Product Description

Product Description

 

1. Standard

• Primary Standard: JIS G3444 (Carbon Steel Tubes for Machine Structural Purposes)

• Complementary Standards: JIS G3474 (Automotive Exhaust Tubes), JIS G3452 (Carbon Steel Pipes for Piping).

2. Dimensional Specifications

Parameter	Tolerance
OD Tolerance (Cold-Drawn)	±0.5 mm (OD ≤50 mm) / ±1.0% (OD >50 mm)
Wall Thickness Tolerance	±10% (Standard) / ±7% (Customized)
Straightness	≤1.5 mm/m (Cold-Drawn) / ≤2.0 mm/m (ERW)

3. Performance Advantages

• High Precision: Cold-drawn tubes achieve ±0.5 mm OD accuracy for CNC machining compatibility.

• Weldability: Low carbon content (C ≤0.35%) ensures crack-free welding for structural joints.

• Cost Efficiency: ERW process reduces production costs for non-critical pressure applications.

4. Quality Assurance

• Chemical Composition (STK500 Example):

  Element	STK500 Requirement
  C	0.25-0.35%
  Mn	0.60-1.40%
  P	≤0.040%
  S	≤0.040%

• Mechanical Tests:

  • Tensile Strength: STK400: 400-510 MPa / STK540: ≥540 MPa

  • Yield Strength: ≥245 MPa (STK400) / ≥345 MPa (STK540)

  • Elongation: ≥20% (STK400, 50mm Gauge Length).

5. Application Scenarios

• Industrial Machinery: Hydraulic cylinders, conveyor rollers, press frames.

• Construction: Scaffolding, support columns, crane booms.

• Automotive: Axle sleeves, chassis components, trailer frames.

6. Packaging and Delivery

• Rust Prevention: VCI (Volatile Corrosion Inhibitor) paper wrapping for humid environments.

• Custom Packaging: Wooden crates for fragile galvanized surfaces (Additional Cost).

 

Detailed Photos

 

 

 

Production Line