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Brief introduction

JIS G3444 Tube
Standard: JIS G3444
Grade: STK400, STK500
Method Of Manufacture:
Seamless, Butt-welding, ERW and Arc welding process
Outside Diameter:
SSAW 219MM - 4084MM
LSAW 406MM - 1420MM
ERW 20MM - 660MM
Wall Thickness: 7.75 - 25.4MM(SSAW), 10 - 50MM(LSAW), 1.3 - 16MM(ERW)
Length: Commonly used 5.8M, 6M, 12M, also depends on the requirements
Advantages: High Strength, Durability, Easy to Fabricate.
Application: Transportation water, Construction industry, energy industry.

Chemical composition

CHEMICAL COMPOSITION OF JIS G3444,%MAX
GRADE	C	Si	Mn	P	S
STK 400	0.25%MAX	-	-	0.04%MAX	0.04%MAX
STK 500	0.24%MAX	0.35%MAX	0.3-1.3	0.04%MAX	0.04%MAX

Physical requirements

MECHANICAL PROPERTIES OF JIS G3444
GRADE	Tensile Strength N/mm2	Yield Point or Proof Stress N/mm2	Weld Tensile N/mm2	Flattening Resistance Strength	Bendability
	Tensile Strength N/mm2	Yield Point or Proof Stress N/mm2	Weld Tensile N/mm2	Distance between Flat Plates (H)	Bending Angle, a)	Inside Radius
	Applicable Outside Diameter
	All Outside Diameters	All Outside Diameters	All Outside Diameters	All Outside Diameters	50 mm or under
STK 400	400min	235min	400min	2/3D	90°	6D
STK 500	500min	355min	500min	7/8D	90°	6D

The main application of JIS G3444 welded steel pipe

JIS G3444 is a Japanese industrial standard for structural carbon steel welded steel pipe specification, widely used in construction, machinery manufacturing, transportation equipment and other fields.

1. Construction works

- Scaffolding and temporary support structures:

JIS G3444 steel pipe is often used in construction scaffolding because of its lightweight, high strength and easy processing characteristics. For example, steel pipes with an outer diameter of 27-48.6mm and a wall thickness of 2.0-4.0mm are typical specifications of scaffolding, which can be quickly assembled and disassembled to ensure construction safety.

- Steel frame:

It is used for trusses, columns and other structural parts of light workshops and warehouses to form stable load-bearing frames through welding or bolted connection.

2. Mechanical manufacturing

- Equipment skeleton and transmission components:

In agricultural machinery and construction machinery, JIS G3444 steel pipe is used to manufacture equipment skeleton, hydraulic cylinder jacket, etc., such as 580mm×80mm large size steel pipe can withstand heavy load conditions.

- Conveying system:

In airport fuel pipelines, material conveying pipelines and other scenarios, steel pipes need to have corrosion resistance (through galvanized or coated treatment) and compressive strength, and steel pipes that meet JIS G3444 standards can meet these needs.

3. Traffic and transportation equipment

- Vehicle structural parts:

Used for truck chassis, trailer frame, etc., through high-precision welding process to ensure structural strength and lightweight, reduce transportation energy consumption.

- Railway Facilities:

In facilities such as platform ceiling and rail guardrail, steel pipes need weather resistance and fatigue resistance, and steel numbers such as S235JR/S275JR of JIS G3444 can be adapted to long-term outdoor use.

4. Other industrial sectors

- Power and communication towers:

The steel pipe tower requires high wind load resistance and seismic performance, and high-strength steel grades such as Q345 of JIS G3444 can meet the needs.

- Agricultural greenhouse skeleton:

Galvanized steel pipe corrosion resistance, suitable for wet agricultural environment, extend service life.

The advantages of JIS G3444 welded steel pipe

1. Cost-effective

- Process advantages: Welded steel pipes have lower production costs than seamless steel pipes (such as JIS G3454) and are suitable for large-scale procurement.

- Material utilization: The process of coil welding reduces material waste, especially for thin-walled tubes (such as 2-4mm wall thickness).

2. Stable performance

- Standardized production: JIS G3444 has strict regulations on chemical composition, mechanical properties (tensile strength ≥300MPa) and dimensional tolerances to ensure batch consistency.

- Corrosion resistance: It can improve weather resistance through hot dip galvanizing, plastic coating and other post-treatment, and extend the service life in wet or chemical environments.

3. Flexibility and adaptability

- Variety of specifications: Support external diameter 27mm to 580mm, wall thickness 2.0mm to 80mm customized requirements, covering light to heavy application scenarios.

- Convenient processing: steel pipe is easy to cut, bend and weld, suitable for complex structural design.

4. Security compliance

Seismic and load-bearing capacity: Steel pipes certified by JIS standards can meet the mandatory structural safety requirements of building regulations, such as the Japanese Building Standards Law.

- International recognition: JIS standards and ISO, EN and other international standards (such as S235JR corresponding to the European standard EN 10025), easy to export and cross-border project cooperation.

5. Lightweight design

- Reduce the cost of transportation and installation by optimizing wall thickness and material strength while maintaining load capacity (for example, Q345 steel is more than 30% stronger than Q235).

JIS G3444 Tube

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