FYN’s manufacturing capability is separate from the full dimensional scope of JIS G3456. Actual supply availability is confirmed against the grade, dimensions, manufacturing condition, heat treatment, quantity, and inspection requirements.
JIS G 3456 specifies carbon steel pipes used mainly for piping service at temperatures above 350°C.
Referenced Edition: JIS G 3456:2024
Standard Title: Carbon Steel Pipes for High Temperature Service
The standard covers:
FYN’s product scope focuses on seamless JIS G3456 pipe.
JIS G3456 should be distinguished from JIS G3455, which is intended for high-pressure service at temperatures of 350°C or lower.
JIS G3456 specifies three grades with progressively higher minimum tensile-strength levels.
| Grade | Minimum Tensile Strength | Minimum Yield Point / Proof Stress |
|---|---|---|
| STPT370 | 370 MPa | 215 MPa |
| STPT410 | 410 MPa | 245 MPa |
| STPT480 | 480 MPa | 275 MPa |
Elongation requirements depend on the test-piece type, orientation, and pipe dimensions.
For pipes with an outside diameter below 40 mm and for applicable thin-wall conditions, the relevant JIS G3456 provisions should be applied rather than using one generic elongation value.
| Grade | Selection Considerations |
|---|---|
| STPT370 | Used where the piping design specifies the STPT370 strength level. |
| STPT410 | Provides higher strength than STPT370 for applicable high-temperature piping designs. |
| STPT480 | The highest-strength grade within JIS G3456. Selected according to piping design and fabrication requirements. |
Grade selection should consider design temperature, design pressure, fabrication requirements, and the applicable piping code. Tensile strength alone should not determine material selection.
| Element | STPT370 | STPT410 | STPT480 |
|---|---|---|---|
| Carbon (C) | ≤0.25% | ≤0.30% | ≤0.33% |
| Silicon (Si) | 0.10–0.35% | 0.10–0.35% | 0.10–0.35% |
| Manganese (Mn) | 0.30–0.90% | 0.30–1.00% | 0.30–1.00% |
| Phosphorus (P) | ≤0.035% | ≤0.035% | ≤0.035% |
| Sulfur (S) | ≤0.035% | ≤0.035% | ≤0.035% |
Alloying elements not listed above may be added where permitted by the standard. Intentionally added elements are subject to applicable reporting requirements.
JIS G3456 covers the following manufacturing routes:
| Manufacturing Method | Description |
|---|---|
| Hot-Finished Seamless | Seamless pipe supplied according to the applicable hot-finished requirements |
| Cold-Finished Seamless | Seamless pipe supplied according to the applicable cold-finished requirements |
| Electric Resistance Welded | ERW pipe covered by the standard |
The required manufacturing method should be identified in the purchase order where necessary.
For FYN seamless pipe enquiries, specify whether the project requires hot-finished seamless or cold-finished seamless pipe.
Heat-treatment requirements depend on the grade and manufacturing method.
For seamless pipes, applicable conditions include:
Cold-finished seamless pipes are subject to applicable post-forming heat-treatment requirements.
STPT480 and other specific manufacturing conditions must follow the exact heat-treatment requirements of JIS G3456:2024.
Additional project-specific heat treatment should be stated at the RFQ stage.
JIS G3456 pipes are subject to applicable material, mechanical, dimensional, and integrity verification.
| Inspection Area | Applicable Verification |
|---|---|
| Chemical Composition | Chemical analysis |
| Mechanical Properties | Tensile testing |
| Forming Performance | Flattening testing |
| Dimensions | Dimensional and wall-thickness inspection |
| Surface Condition | Surface inspection |
| Pipe Integrity | Hydrostatic testing or nondestructive examination |
| Identification | Material identification |
Additional purchaser-specified inspection requirements should be stated at the enquiry stage.
Depending on the ordered specification, applicable integrity testing can include:
The required test method and any project-specific acceptance criteria should be included in the purchase specification.
| Parameter | JIS G3455 | JIS G3456 |
|---|---|---|
| Standard Title | Carbon Steel Pipes for High Pressure Service | Carbon Steel Pipes for High Temperature Service |
| Intended Service | High-pressure piping at temperatures ≤350°C | Piping used mainly at temperatures >350°C |
| Grades | STS370 / STS410 / STS480 | STPT370 / STPT410 / STPT480 |
The two standards have similar room-temperature strength levels, but they should not be treated as interchangeable.
Material selection must follow the design temperature, design pressure, applicable piping code, and project material specification.
| Standard | Intended Service | Grades |
|---|---|---|
| JIS G3454 | Carbon Steel Pipes for Pressure Service | STPG370 / STPG410 |
| JIS G3456 | Carbon Steel Pipes for High Temperature Service | STPT370 / STPT410 / STPT480 |
For elevated-temperature piping, select the applicable material specification according to the system design. The availability of matching pipe dimensions alone does not establish material suitability.
| Parameter | FYN Capability |
|---|---|
| Product Form | Seamless Carbon Steel Pipe |
| Grades | STPT370 / STPT410 / STPT480 |
| Manufacturing Process | Cold Drawn / Cold Rolled |
| Outside Diameter | 6–114 mm |
| Wall Thickness | 0.8–25 mm |
| Length | Up to 40 m |
| Inspection | Hydrostatic / UT / ET, as specified |
| Documentation | MTC / Inspection Documentation / Third-Party Inspection, as required |
Actual JIS G3456 supply availability is confirmed according to:
For steam systems operating mainly above 350°C where JIS G3456 carbon steel material is specified by the piping design.
For applicable steam and auxiliary piping systems in thermal power plants.
For boiler-associated pressure piping where STPT370, STPT410, or STPT480 is specified by the equipment or piping design.
For high-temperature process lines carrying compatible process fluids under the applicable design conditions.
For industrial plants requiring carbon steel pressure piping for elevated-temperature steam distribution.
For maintenance projects where existing piping documentation specifies JIS G3456.
Replacement material should be verified against:
Available documentation can include:
Required documentation should be specified at the RFQ stage.
Typical packing options include:
End preparation can be supplied according to piping fabrication requirements.
Long-length pipes may require special packing and transportation arrangements.
| Item | Details |
|---|---|
| Custom Requirements | Subject to grade and technical review |
| Minimum Order Quantity | According to grade, dimensions, and production requirements |
| Lead Time | According to grade, dimensions, quantity, heat treatment, and inspection requirements |
| End Preparation | According to piping fabrication requirements |
| Special Packing | According to project and transport requirements |
| Item | Information to Provide |
|---|---|
| Standard | JIS G 3456 and required edition, if specified |
| Grade | STPT370 / STPT410 / STPT480 |
| Product Form | Seamless / ERW |
| Pipe Size | Nominal Size / Outside Diameter |
| Wall Thickness | Wall Thickness / Schedule |
| Length | Required pipe length |
| Quantity | Required order quantity |
| Manufacturing Condition | Hot-finished / Cold-finished, if specified |
| Heat Treatment | Required treatment or delivery condition |
| Design Conditions | Design pressure, design temperature, and service medium |
| Design Code | Applicable piping design code |
| Testing | Hydrostatic / NDT requirements |
| End Preparation | Required pipe-end condition |
| Surface Condition | Project-specific surface requirements |
| Documentation | Required inspection documents |
| Third-Party Inspection | Required scope, if applicable |
| Delivery | Destination |
For high-temperature piping projects, send your material take-off (MTO), piping specification, or technical drawing for review.
Please send your requirements in the following format:
JIS G 3456 + Grade + Nominal Size / OD + Wall Thickness / Schedule + Length + Quantity
Available Grades: STPT370 / STPT410 / STPT480
For high-temperature piping projects, also include:
Design Pressure + Design Temperature + Service Medium + Applicable Design Code + NDT Requirements
For replacement projects, provide the existing MTC, piping specification, or drawing for material verification.
