JIS G3454 STPG370 Seamless steel pipes
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JIS G3454 STPG370 is a Japanese industrial standard covering carbon steel pipes for pressure service. The specification applies to seamless steel pipes used in piping systems where reliable mechanical strength and pressure resistance are required.
STPG370 pipes are widely used in industrial piping systems, petrochemical plants, oil and gas facilities, power generation plants and general pressure pipelines. The material offers good weldability, stable mechanical properties and reliable performance under moderate temperature and pressure conditions.
Pipes manufactured according to JIS G3454 are typically produced as seamless pipes through hot rolling or cold drawing processes. The standard specifies requirements for chemical composition, mechanical properties, inspection methods and testing procedures.
Chemical Composition
The chemical composition of STPG370 carbon steel is controlled to ensure adequate strength and weldability.
| Element | C | Si | Mn | P | S |
|---|---|---|---|---|---|
| Max % | 0.25 | 0.35 | 0.30–1.00 | 0.040 | 0.040 |
The relatively low carbon content helps maintain good ductility and weldability for piping fabrication and installation.
Mechanical Properties
JIS G3454 STPG370 seamless steel pipes must meet the following minimum mechanical property requirements.
| Property | Value |
|---|---|
| Tensile Strength | ≥ 370 MPa |
| Yield Strength | ≥ 215 MPa |
| Elongation | ≥ 30 % |
These properties ensure reliable performance in pressure piping systems.
JIS G3454 Pipe Dimensions
Steel pipes manufactured to JIS G3454 are commonly supplied in dimensions compatible with international pipe size systems such as ASME B36.10M.
JIS G3454 Pipe Dimensions Table
| Nominal Size (NPS) | DN | Outside Diameter (mm) | SCH 40 (mm) | SCH 80 (mm) |
|---|---|---|---|---|
| 1/2 | DN15 | 21.3 | 2.77 | 3.73 |
| 3/4 | DN20 | 26.7 | 2.87 | 3.91 |
| 1 | DN25 | 33.4 | 3.38 | 4.55 |
| 1 1/4 | DN32 | 42.2 | 3.56 | 4.85 |
| 1 1/2 | DN40 | 48.3 | 3.68 | 5.08 |
| 2 | DN50 | 60.3 | 3.91 | 5.54 |
| 3 | DN80 | 88.9 | 5.49 | 7.62 |
| 4 | DN100 | 114.3 | 6.02 | 8.56 |
| 6 | DN150 | 168.3 | 7.11 | 10.97 |
| 8 | DN200 | 219.1 | 8.18 | 12.70 |
| 10 | DN250 | 273.0 | 9.27 | 15.09 |
| 12 | DN300 | 323.9 | 9.53 | 17.48 |
JIS G3454 CS Pipe Size Specification
| Size | 21.3mm to 1219.2mm |
| Wall Thickness | 2-50mm |
| Length | max 12000mm |
| Standard | JIS G3454, JIS G3445, JIS G3452, JIS G3444 |
| Grade | STPG370, STPG410, STKM13A, STKM14A, SGP, STK290, STK400, STK500 |
| Steel grade | STPG 38, STPG 42 |
| Application | Carbon Steel Pipes for Pressure Service |
| Dimension Range | 10.5-660.4 mm |
Manufacturing Process
JIS G3454 STPG370 pipes are typically manufactured using seamless pipe production methods, including:
-
Hot rolling
-
Cold drawing
Pipes may be supplied in the as-rolled condition or normalized condition depending on production requirements.
Testing Requirements
Pipes manufactured according to JIS G3454 must undergo several inspection and testing procedures to verify compliance with the specification.
Chemical Analysis
Chemical composition must be verified to ensure that the steel meets the specified limits defined by the standard.
Tensile Test
A tensile test is performed to confirm the mechanical properties including tensile strength, yield strength and elongation.
Flattening Test
A flattening test evaluates the ability of the pipe to withstand deformation without cracking.
Bend Test
For certain pipe sizes, bend testing may be conducted to verify ductility.
Hydrostatic Test
Each pipe may be subjected to a hydrostatic pressure test to confirm pressure integrity and ensure there are no leaks.
Non-Destructive Testing
Non-destructive inspection methods may also be applied, including:
-
Ultrasonic testing (UT)
-
Eddy current testing (ET)
These methods help detect internal or surface defects.
Inspection Documentation
Pipes are normally supplied with mill test certificates (MTC) confirming that the material meets the specified chemical composition, mechanical properties and testing requirements.
Inspection documents commonly follow:
Equivalent Materials
JIS G3454 STPG370 pipes have comparable applications to several international carbon steel pipe standards.
| Standard | Equivalent Grade |
|---|---|
| ASTM | ASTM A106 Grade B |
| DIN | St37 |
| EN | P235GH |
| GOST | 20 |
Equivalent materials may be selected depending on project specifications and regional standards.
Applications
JIS G3454 STPG370 seamless steel pipes are widely used in:
-
oil and gas pipelines
-
petrochemical plants
-
refinery piping systems
-
power generation facilities
-
industrial pressure pipelines
The material provides reliable mechanical performance for general pressure service applications.
Related Products
STPG370 pipes are commonly used together with other piping components such as:
JIS Pipe dimension is slightly different from ASTM Pipes
| Nominal size | Outside diameter (mm) |
Carbon steel pipes for ordinary piping <SGP> (JIS G3452) |
Carbon steel pipes for pressure service <STPG>(JIS G3454) |
||||||
| Nominal thickness | |||||||||
| A | B | Thickness (mm) | Sch10 | Sch20 | Sch30 | Sch40 | Sch60 | Sch80 | |
| 6 | 1/8 | 10.5 | 2.0 | – | – | – | 1.7 | 2.2 | 2.4 |
| 8 | 1/4 | 13.8 | 2.3 | – | – | – | 2.2 | 2.4 | 3.0 |
| 10 | 3/8 | 17.3 | 2.3 | – | – | – | 2.3 | 2.8 | 3.2 |
| 15 | 1/2 | 21.7 | 2.8 | – | – | – | 2.8 | 3.2 | 3.7 |
| 20 | 3/4 | 27.2 | 2.8 | – | – | – | 2.9 | 3.4 | 3.9 |
| 25 | 1 | 34.0 | 3.2 | – | – | – | 3.4 | 3.9 | 4.5 |
| 32 | 1.1/4 | 42.7 | 3.5 | – | – | – | 3.6 | 4.5 | 4.9 |
| 40 | 1.1/2 | 48.6 | 3.5 | – | – | – | 3.7 | 4.5 | 5.1 |
| 50 | 2 | 60.5 | 3.8 | – | 3.2 | – | 3.9 | 4.9 | 5.5 |
| 65 | 2.1/2 | 76.3 | 4.2 | – | 4.5 | – | 5.2 | 6.0 | 7.0 |
| 80 | 3 | 89.1 | 4.2 | – | 4.5 | – | 5.5 | 6.6 | 7.6 |
| 90 | 3.1/2 | 101.6 | 4.2 | – | 4.5 | – | 5.7 | 7.0 | 8.1 |
| 100 | 4 | 114.3 | 4.5 | – | 4.9 | – | 6.0 | 7.1 | 8.6 |
| 125 | 5 | 139.8 | 4.5 | – | 5.1 | – | 6.6 | 8.1 | 9.5 |
| 150 | 6 | 165.2 | 5.0 | – | 5.5 | – | 7.1 | 9.3 | 11.0 |
| 200 | 8 | 216.3 | 5.8 | – | 6.4 | 7.0 | 8.2 | 10.3 | 12.7 |
| 250 | 10 | 267.4 | 6.6 | – | 6.4 | 7.8 | 9.3 | 12.7 | 15.1 |
| 300 | 12 | 318.5 | 6.9 | – | 6.4 | 8.4 | 10.3 | 14.3 | 17.4 |
| 350 | 14 | 355.6 | 7.9 | 6.4 | 7.9 | 9.5 | 11.1 | 15.1 | 19.0 |
| 400 | 16 | 406.4 | 7.9 | 6.4 | 7.9 | 9.5 | 12.7 | 16.7 | 21.4 |
