JIS G3456:2024 High-Temperature Carbon Steel Pipes is applicable to high-temperature conditions of 400℃–600℃ (power plant boilers, steam boilers, high-temperature pipelines, high-temperature medium transportation in petrochemical industries, high-temperature pressure vessel components, etc.), and is suitable for medium- and high-pressure high-temperature collaborative working scenarios. It is a core pipe material for high-temperature fluid transportation. 

Mainstream materials: 

STPT370, STPT410, STPT450 (most commonly used in engineering, graded according to high-temperature resistance level, suitable for different temperature and pressure combinations).

Material Introduction: 

STPT370 is the most widely used medium-temperature high-temperature carbon steel pipe in the JIS G3456 standard. It belongs to the low-carbon structural high-temperature steel category, with a carbon content ≤0.25%. Optimized composition enhances its high-temperature stability, resulting in excellent creep resistance and oxidation resistance. It is suitable for medium-temperature and high-temperature applications of 400℃–450℃, such as auxiliary pipelines for ordinary power plant boilers and medium-temperature steam transmission pipelines. Its strong versatility allows it to directly meet the needs of medium-temperature and high-temperature projects in the Asia-Pacific region.

STPT410 is a medium-temperature high-temperature carbon steel pipe with higher strength and high-temperature resistance than STPT370. Its carbon content is controlled below 0.28%, and its manganese content is optimized and increased to 1.50%. It combines high-temperature strength with good processing and welding performance, exhibiting outstanding impact resistance and creep resistance. Suitable for medium-temperature and high-temperature applications of 450℃–500℃, such as main steam pipelines in power plants and supporting pipelines for high-temperature reactors in petrochemical industries, it is a leading grade for mid-to-high-end high-temperature projects. 

STPT450 is a high-temperature grade carbon steel pipe, representing the highest high-temperature performance grade in this standard. With a carbon content of ≤0.30%, it utilizes a manganese-based strengthening process to enhance its high-temperature load-bearing capacity. It can withstand temperatures below 600℃ and exhibits superior creep and oxidation resistance compared to the previous two grades. Suitable for heavy-duty high-temperature applications ranging from 500℃ to 600℃, such as superheaters in large power plant boilers, high-temperature and high-pressure steam transportation, and special high-temperature containers, it is primarily used in high-end, customized, and demanding high-temperature projects.

Product Advantages

JIS G3456:2024 is the core standard for high-temperature carbon steel pipes in Japan and the Asia-Pacific region. Its technology is highly compatible with international standards such as ISO 9329-1 and ISO 9330-1. Specifically designed for high-temperature conditions of 400-600℃, it has no project acceptance threshold and is suitable for high-temperature projects in power plants and petrochemical plants in markets such as Japan, South Korea, Australia, Southeast Asia, and the Middle East. It can be directly used in local high-temperature pipeline projects.

It boasts excellent high-temperature performance and stable, reliable operation. Covering the full range from medium to high temperatures, STPT370, STPT410, and STPT450 are precisely matched to different high-temperature requirements. It exhibits no embrittlement or leakage during long-term service below 600℃, with excellent creep resistance, oxidation resistance, and impact resistance. Its low P and low S design (P≤0.040%, S≤0.040%) ensures high steel purity and few internal defects, making it suitable for core scenarios such as high-temperature steam and high-temperature media transportation. It offers high safety and meets the requirements for long-term operation under high-temperature conditions.

With a low-carbon/medium-carbon optimized design and low carbon equivalent, the risk of cold cracking during welding is small. It is compatible with conventional welding processes such as manual arc welding, TIG welding, and submerged arc welding. It can meet the requirements of high-temperature service without complicated heat treatment after welding. It is easy to bend, flare, drill, and bevele, and has high on-site installation efficiency. It can meet the needs of rapid construction and delivery of projects. The pipe ends can be customized as needed.

Chemical composition (mass fraction %)

Mechanical properties(At room temperature, wall thickness ≤ 16mm)

Statistics on the popular models and common specifications of carbon steel pipes

Select materials based on application

For general fluid transportation (water, gas, oil): 20#, Q235B, A53 Gr.B, STPG370

The best cost-performance ratio, globally applicable

For high-temperature / steam / boiler pipes: A106 Gr.B, 20G, 15CrMoG, P235TR1/P235GH

Better resistance to high temperature and pressure

For oil and gas pipelines: API 5L Gr.B, X42, X52, X60

High strength and good toughness, suitable for long-distance pipelines

For low-temperature environments (cold storage, LNG support): A333 Gr.1/Gr.3, 16MnDG

Resistant to low temperature without cracking

For structural pipes (supports, machinery, steel structures): Q355B (old 16Mn), St44.2, A36

High strength and good load-bearing capacity