JIS G3101 is a standard for Rolled Steel for General Structure.
Longitudinally Submerged Arc Welded (L-SAW) Pipe is typically governed by JIS G 3454 or JIS G 3455.
It's a common conflation because JIS G3101 specifies the base steel plate that is often used to manufacture welded pipes like L-SAW pipes. Here's a detailed breakdown of what you're likely referring to.
1. JIS G3101 - The Base Material Standard
This standard covers hot-rolled mild steel plates, sheets, and strips for general structural purposes (buildings, bridges, etc.). The most common grades are:
SS330, SS400, SS490, SS540
The "SS" stands for "Structural Steel," and the number indicates the minimum tensile strength in MPa.
These steels are characterized by excellent weldability and formability, making them ideal raw material for manufacturing welded pipes.
2. Longitudinally Submerged Arc Welded (L-SAW) Pipe - The Product
This is the manufacturing process for the pipe itself.
Process: Steel plates (from standards like JIS G3101) are formed into a cylindrical shape. The longitudinal seam is welded on the inside and outside using the Submerged Arc Welding (SAW) process, which provides deep penetration, high strength, and a smooth weld.
Typical Applications: Large-diameter pipes for piling, foundation, structural supports, and lower-pressure fluid transmission.
3. The Correct Pipe Standards (which reference G3101 steel)
The finished L-SAW pipe is certified under different JIS standards. The most relevant are:
| Standard | Title | Typical Use | Connection to G3101 |
|---|---|---|---|
| JIS G 3454 | Carbon Steel Arc-Welded Steel Pipes | Pressure service, heat exchangers, plumbing. Higher grade requirements. | May use SS400, SS490 steel as a base, but with stricter controls. |
| JIS G 3455 | Carbon Steel Pipes for Piling | Foundation piles, civil engineering structures. Most common for general L-SAW pipes. | Explicitly lists SS400 and SS490 from JIS G3101 as the base steel material. |
| JIS G 3444 | Carbon Steel Tubes for General Structural Purposes | Mechanical structures, building frames. | Also explicitly specifies the use of SS grades from JIS G3101. |
Key Specifications of L-SAW Pipes made from JIS G3101 Steel
Common Steel Grade: SS400 is the most frequently used for general structures and piling.
Dimensions: Typically large outside diameters (OD), from 406 mm (16") up to over 2,500 mm. Wall thickness can range from 6 mm to over 25 mm.
Manufacturing Tolerance: Governed by the pipe standard (e.g., JIS G 3455) for dimensions like OD, wall thickness, and straightness.
Testing: Includes mechanical tests (tensile, bend, flattening), non-destructive testing (often ultrasonic or X-ray inspection of the weld seam), and visual inspection.
Typical Ordering/Marketing Specification
A complete specification for such a pipe would be:
Longitudinally Submerged Arc Welded (L-SAW) Pipe to JIS G 3455, STPY400
Material: JIS G3101 SS400
OD: 812.8 mm, WT: 12.7 mm, Length: 12,000 mm
End Finish: Plain End / Beveled for welding
Summary
JIS G3101 provides the raw steel plate (SS400, SS490).
Longitudinally Submerged Arc Welding (L-SAW) is the manufacturing process.
The finished product is certified as a pipe under standards like JIS G 3454 or JIS G 3455, which specify the dimensions, tolerances, and testing for the final tubular product.
Therefore, when you refer to "JIS G3101 L-SAW Pipe," you are effectively describing a longitudinally submerged arc welded pipe manufactured from steel plates conforming to JIS G3101.
