Введение

In the complex industrial pipeline network all over Asia, reliability and safety are not negotiable-especially when transporting key fluids such as water, oil and natural gas. This is where JIS G 3454 stands as a cornerstone standard, governing the production and application of carbon steel pipe for pressure service. For engineers, project managers and procurement professionals, understanding this standard is very important to ensure the integrity, compliance and long-term operational efficiency of the system.

industrial carbon steel piping system (stpg 370, jis g3454), including gate valves, flanged fittings, and pressure gauges for fluid transportation.

 

JIS G 3454 is more than just a set of technical specifications; It is a guarantee of quality that has been trusted in industries ranging from petrochemical processing to power generation. As the demand for safe and efficient pressure piping systems continues to grow, the role of JIS G 3454-compliant стальная труба becomes increasingly vital. This comprehensive guide will break everything you need to know about JIS G 3454 from its core definitions to practical application.

What is JIS G 3454?

JIS G 3454 is a Japanese industrial standard (JIS), which specifies carbon steel pipes for pressure service at the highest temperature of about 350 degrees Celsius. These pipes are named “STPG” (general steel pipe pressure), which is mandatory for systems that needs to carry out hydraulic test.

Main points

  • Scope of application: specially designed for pressurized fluids with temperatures lower than 350.
  • Grades: the two most commonly used grades are STPG 370 and STPG 410.
  • Testing: Unlike structural piping (STK), JIS G 3454 requires water pressure testing to ensure fluid tightness.
  • Size: Uses the schedule numbering system (for example. Sch 40, Sch 80) to determine the wall thickness.

Understand this name: What is STPG?

The “STPG” designation is central to understanding JIS G 3454-compliant стальная труба. It is an acronym derived from “Steel Tube Pressure General,” clearly indicating that these pipes are intended for general-purpose pressure service applications.

The numbers immediately following STPG-370 and 410-are equally important. They represent the minimum tensile strength of the carbon steel pipe in n/mm ² (megapascals, MPa). Specifically, STPG 370 has a minimum tensile strength of 370 n/mm ², while STPG 410 has a minimum tensile strength of 410 n/mm ². This grade of tensile strength is a key factor in choosing an appropriate grade for a given application.

JIS G 3454 grades and manufacturing methods

Comparison: STPG 370 vs. STPG 410

When selecting a JIS G 3454 carbon steel pipe, choosing between STPG 370 and STPG 410 depends on the specific requirements of the project.

STPG 370 is often compared to ASTM A 53 Grade A. it offers excellent ductility and machinability, making it ideal for low to medium-pressure applications where ease of installation and processing is a priority. Common uses include water supply lines, air compression systems, and general oil transportation in non-high-pressure scenarios.

On the other hand, STPG 410 is similar to ASTM A 53. It has higher tensile strength and yield strengths, making it suitable for high-pressure pipelines with higher requirements. This grade is often used in petrochemical plants, power generation facilities and other industrial environments, where the стальная труба have to bear greater pressure loads.

Manufacture (Seamless and ERW)

JIS G 3454 covers two primary manufacturing processes for carbon steel pipe: seamless and Electric Resistance Welding (ERW).

Seamless steel pipe is produced by extruding a solid steel billet into a hollow tube, resulting in a pipe with no weld seam. This manufacturing method enhances the structural integrity and pressure resistance of the pipeline, making seamless JIS G 3454 pipeline an ideal choice for high-pressure and high-temperature applications (up to 350 degrees Celsius)

ERW carbon steel pipe is made by rolling steel strips into a tube shape and welding the edges with current. ERW pipeline is cost-effective and suitable for many medium voltage applications. However, they must undergo strict quality control, including non-destructive testing, to ensure the integrity of welding.

Technical specifications (chemistry and machinery)

The chemical and mechanical properties of JIS G 3454 стальная труба are strictly regulated to ensure consistent performance and safety. The following table compares the main specifications of STPG 370 and STPG 410. The data come from official JIS documents and industry standards.

Класс Carbon (max) Предел текучести (min) Прочность на разрыв (min) Типовое применение
STPG 370 0.25% 215 N/mm² 370 N/mm² Water, Air, General Oil Transportation
STPG 410 0.30% 245 N/mm² 410 N/mm² High-pressure oil and gas pipeline, petrochemical plant

Source: Japanese Industrial Standards (JIS)

Requirements for hydrostatic pressure test of JIS G 3454 pipeline

One of the most important requirements of JIS G 3454 is to carry out mandatory hydrostatic test for all carbon steel pipelines covered by this standard. This testing process is designed to verify the pipe’s ability to withstand pressure without leaking, a critical safety feature for pressure service applications. Beyond basic leak detection, hydrostatic testing also helps identify potential material defects or manufacturing flaws that could compromise the pipe’s performance under real-world operating conditions. For industrial projects, passing this test is not only a compliance requirement, but also a key step to reduce operational risks, because faulty pressure pipelines can lead to costly downtime, environmental hazards, and even pose a threats to personnel safety. In practical applications, third-party testing institutions often supervise the testing process to ensure strict compliance with JIS G 3454 standards and further improve the credibility of the steel pipe products.

The water pressure test steps of JIS G 3454 steel pipe are as follows:

1. Fill the pipeline with water completely to ensure that there are no bubbles left (bubbles can affect test accuracy).

2. Apply the specified hydrostatic pressure, which varies according to the plan (Sch) number of the pipeline. For example, a minimum pressure of 6.0 MPa is required for Sch 40 pipe, while 12.0 MPa is required for Sch 80 pipe.

3. Maintain the pressure for at least 5 seconds in order to detect any potential leakage.

4. Check whether there is any leakage, deformation or other signs of failure in the pipeline. If no problem is found, the pipeline passes the test.

Why JIS G 3454 is not used for structural purposes (STK confused)

A common and dangerous misunderstanding in the industry is that JIS G 3454 (STPG) carbon steel pipe and JIS G 3444 (STK) structural steel pipe can be used interchangeably. This confusion can lead to serious security risks because these two standards are designed for completely different purposes.

The core difference lies in safety requirements: JIS G 3454 стальная труба has been designed by engineering to ensure fluid tightness. The mandatory hydrostatic pressure test and strict material specifications ensure that the pipeline will not leak when conveying pressurized fluid, which is the key safety feature for any pressure service system.

In contrast, STK structural pipes (JIS G 3444) is specially designed for load-bearing applications. They do not require hydrostatic testing, and their material properties are optimized for structural strength rather than fluid sealing. Using an STK pipe in a pressure service application specified in JIS G 3454 is a serious safety violation, which can lead to leakage, pipe burst and potential catastrophic accidents.

JIS G 3454 frequently asked questions

Q: what is the equivalent ASTM standard for JIS G 3454?

A: JIS G 3454 is usually equivalent to ASTM A 53 or API 5L。STPG 370 is equivalent to ASTM A 53 A, while STPG 410 is in accordance with ASTM A 53 B.

Q: Can I use JIS G 3454 pipe steam?

A: Yes, but it is only applicable to steam applications where the temperature does not exceed 350 degrees Celsius. For higher temperature steam applications, JIS G 3456 (Covered Alloy Steel Pipe) should be used instead.

Q: what does “Sch 40” in JIS G 3454 mean?

A: “Sch 40” refers to the wall thickness grade of the carbon steel pipe. Although the schedule numbering system is similar to American standards, the specific wall thickness (in millimeters) varies with the pipe diameter, so we must refer to JIS G 3454 official size tables.

Conclusions and CTA

JIS G 3454 (STPG) is the preferred standard to ensure the safety and reliability of medium and low pressure fluid conveying systems across Asia. Its strict specifications for carbon steel pipes, including specified grades, mandatory hydrostatic pressure tests and clear size standards, make it a cornerstone of industrial pipeline integrity.

Choosing the correct grade (STPG 370 for general applications and STPG 410 for high pressure demand) and manufacturing technology (seamless or ERW) is very important to meet the project requirements and ensuring long-term performance. By following the JIS G 3454 standards, you can avoid common traps, such as replacing pressure service with structural STK pipes, thus protecting your system, personnel and investment.Looking for high-quality JIS G 3454 pipeline for your project? Allland provides a full range of STPG 370 and 410 pipes, which have undergone rigorous water pressure test. Our стальная труба products fully meet the JIS G 3454 standards, ensuring the reliability and safety required for your project. Contact us now to learn more about our product line and get a customized quotation.