JIS G3460 STPL380 Alloy Steel Seamless Pipe for Low-Temperature Service

Material Overview (What is this product?)
This is a low-temperature service carbon steel pipe conforming to the Japanese Industrial Standard JIS G3460, grade STPL380. It is manufactured as either seamless or electric resistance welded (ERW) and is designed for piping applications at temperatures at or below the freezing point.

Specifications

• Standard: JIS G3460 – Steel pipes for low-temperature service.

• Grade: STPL380

• Manufacturing Methods:

  • Seamless or Electric Resistance Welded (ERW) with weld bead removal to maintain smooth surface, unless otherwise specified.

• Dimensions

  • Outside Diameter: approximately 10.5 mm to 660.4 mm (Nominal 6A to 650A, or 1/8B to 26B)

  • Wall thickness: typically Sch10 to Sch160; tolerances ~±1% for OD and ±1.6 mm for WT

Chemical Composition

Below are maximum limits for key elements (wt%):

Mechanical Properties

To provide a broader view, here is a table comparing STPL380 with STPL450 and STPL690, all under JIS G3460, as they are the most closely aligned grades in the same standard:

Key Features

• Low‑temperature toughness: STPL380 maintains high impact energy (≥ 21 J at –45 °C), ensuring suitability in cold environments.

• Solid mechanical performance: Balanced tensile strength, yield, and elongation offer durability and ductility in harsh conditions.

• Manufactured for reliability: Heat-treated (normalizing, tempering, or quenching + tempering) to enhance grain structure and strength.

• Versatile production options: Available in both seamless and ERW formats to fit varied fabrication needs.

• Smooth finish: Surface treated to remove weld beads for seamless fluid dynamics and stress distribution.

• Fine-grained material: Manufactured from killed steel, improving toughness and uniformity.

Applicable Standards

• JIS G3460 — Japanese Industrial Standard governing low-temperature carbon steel pipes.

• Equivalent international standards (approximate alignment):

  • ASTM A333 Grade 1 (carbon grade for low temperatures)

  • EN 10216-4 P215NL

  • ISO 9329-3 PL21

  • GB/T 18984 16MnDG

Applications

General Domain: Low-temperature fluid transport in cold and cryogenic conditions.

Specific Use Cases:

• Oil & Gas pipelines in cold regions or cryogenic processing plants.

• LNG and refrigeration systems, for handling liquefied gases such as nitrogen, oxygen, or natural gas.

• Chemical and petrochemical plants, particularly in cold service sections.

• Energy & power plants, such as for turbine inlet/outlet or chilled water circuits.

• Marine and shipbuilding, in offshore or refrigerated compartments exposed to freezing temperatures.
  Designed to sustain mechanical integrity in environments at or below –45 °C, while ensuring smooth flow and corrosion resistance.

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