
JIS G3443-1 STW290 STW370 STW400 Seamless Steel Tube Coated Steel Pipes For Water Service
Material
The JIS G3443-1 standard specifies the requirements for seamless steel tubes used in water service applications. The primary materials used in the production of these tubes are carbon steel grades, which are designed to provide excellent corrosion resistance and mechanical properties.
Specification
The seamless steel tubes covered under JIS G3443-1 are categorized into different grades based on their mechanical properties and chemical composition. The standard outlines the dimensions, tolerances, and testing methods to ensure the quality and performance of the tubes.
Key Features
- Seamless Construction: Provides enhanced strength and durability.
- Corrosion Resistance: Coated to prevent rust and degradation.
- High Pressure Tolerance: Suitable for various water service applications.
- Versatile Applications: Can be used in different environments and conditions.
Chemical Composition
Grade | Carbon (C) | Manganese (Mn) | Phosphorus (P) | Sulfur (S) | Silicon (Si) |
STW290 | 0.18 max | 0.60 - 0.90 | 0.030 max | 0.030 max | 0.10 - 0.40 |
STW370 | 0.20 max | 0.60 - 0.90 | 0.030 max | 0.030 max | 0.10 - 0.40 |
STW400 | 0.25 max | 0.60 - 0.90 | 0.030 max | 0.030 max | 0.10 - 0.40 |
Mechanical Properties
Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) |
STW290 | 290 | 410 - 540 | 20 |
STW370 | 370 | 490 - 620 | 20 |
STW400 | 400 | 510 - 640 | 20 |
Steel Grade
The steel grades specified in JIS G3443-1 include STW290, STW370, and STW400. Each grade is designed to meet specific mechanical and chemical property requirements, making them suitable for various applications in water service.
Application
These seamless steel tubes are primarily used in:
- Water supply systems
- Irrigation systems
- Industrial water pipelines
- Construction projects requiring water service lines
Possible Alternative Grades
While STW290, STW370, and STW400 are the primary grades specified in JIS G3443-1, alternative grades that may be considered for similar applications include:
- ASTM A53
- ASTM A106
- EN 10216-1





TORICH Group, an one-stop service provider of raw materials engaged in raw material production, R&D and
trade, has 30+ years of experience in the market, exported to 56 +countries, and won good reputation and
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The company's production plant covers an area of over 10,000 square meters, with an annual production
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The group holds shares in more than ten domestic production entities, whose main products include
seamless steel pipes ( carbon steel and stainless steel), welded pipes ( carbon steel and stainless steel), pipe fittings ( carbon steel and stainless steel), titanium (titanium tubes, titanium rods, titanium cakes, titanium plates, etc.), aluminum (aluminum tubes, aluminum rods, aluminum die casting, aluminum casting, CNC machining), and CNC deep processing of metal materials such as tubes, rods, and casting parts.
Over the past 30 years, the company has been gradually developing new technologies and materials to meet
the growing needs of customers and various diversified needs, exporting to more than 56 countries and still
increasing the number of exporting countries, aiming to help customers to solve the demand for raw materials, and to facilitate one-stop purchasing for customers.





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