JIS G3429 Steel Pipe for Gas Cylinder
JIS G3429 Steel Pipe for Gas Cylinder: Chemical Composition and Grades
JIS G3429 is a Japanese standard that specifies seamless steel tubes for high-pressure gas cylinders. These steel tubes are designed to withstand high-pressure environments and are commonly used in the manufacturing of gas cylinders for various applications. In this article, we will explore the chemical composition and grades of JIS G3429 steel pipes for gas cylinders.
Applications
JIS G3429 steel pipes for gas cylinders find applications in different sectors where high-pressure gas storage is required. Let’s take a closer look at some of the common applications:
Fire-Fighting Gas Cylinders
Fire-fighting gas cylinders are essential equipment used by firefighters to store and transport compressed gases for fire suppression. These cylinders are designed to withstand high pressures and provide a reliable source of extinguishing agents, such as carbon dioxide or dry chemical powder. JIS G3429 steel pipes are widely used in the manufacturing of fire-fighting gas cylinders due to their excellent strength and pressure resistance.
Industrial Gas Cylinders
Industrial gas cylinders are used in various industries for storing and transporting gases that are crucial for different processes. These cylinders are commonly used for gases such as oxygen, nitrogen, hydrogen, and argon, among others. JIS G3429 steel pipes are well-suited for industrial gas cylinders due to their high-pressure capabilities and durability.
Vehicle Gas Cylinders
Vehicle gas cylinders, also known as automotive gas cylinders or CNG (compressed natural gas) cylinders, are used in vehicles powered by natural gas. These cylinders store compressed natural gas, which is an alternative fuel source that offers environmental benefits. JIS G3429 steel pipes are utilized in the manufacturing of vehicle gas cylinders to ensure their safety and reliability on the road.
Chemical Composition
The chemical composition of JIS G3429 steel pipes for gas cylinders is crucial in determining their mechanical properties and suitability for high-pressure applications. The composition may vary depending on the specific grade of the steel pipe. Here is a general overview of the chemical composition requirements for the grades specified in JIS G3429:
Grade STH11
- Carbon (C): 0.15% max
- Silicon (Si): 0.35% max
- Manganese (Mn): 0.60-1.00%
- Phosphorus (P): 0.035% max
- Sulfur (S): 0.035% max
Grade STH12
- Carbon (C): 0.20% max
- Silicon (Si): 0.35% max
- Manganese (Mn): 0.60-1.00%
- Phosphorus (P): 0.035% max
- Sulfur (S): 0.035% max
Grade STH21
- Carbon (C): 0.20% max
- Silicon (Si): 0.35% max
- Manganese (Mn): 0.60-1.00%
- Phosphorus (P): 0.035% max
- Sulfur (S): 0.035% max
Grade STH22
- Carbon (C): 0.25% max
- Silicon (Si): 0.35% max
- Manganese (Mn): 0.60-1.00%
- Phosphorus (P): 0.035% max
- Sulfur (S): 0.035% max
It is important to note that these are general guidelines, and the specific chemical composition may vary slightly depending on the manufacturer and production process. It is always recommended to refer to the official JIS G3429 standard or consult the manufacturer for precise chemical composition information.
Grades
JIS G3429 specifies four grades of steel pipes for gas cylinders: STH11, STH12, STH21, and STH22. Each grade has its own unique properties and applications. Let’s take a closer look at each grade:
Grade STH11
Grade STH11 is a low-carbon steel grade suitable for gas cylinders with a maximum working pressure of 1.6 MPa. It offers good weldability and is commonly used for low-pressure gas cylinders.
Grade STH12
Grade STH12 is a medium-carbon steel grade suitable for gas cylinders with a maximum working pressure of 3.2 MPa. It offers good weldability and is commonly used for medium-pressure gas cylinders.
Grade STH21
Grade STH21 is a low-alloy steel grade suitable for gas cylinders with a maximum working pressure of 5.4 MPa. It offers good mechanical properties and is commonly used for high-pressure gas cylinders.
Grade STH22
Grade STH22 is a low-alloy steel grade suitable for gas cylinders with a maximum working pressure of 7.0 MPa. It offers excellent mechanical properties and is commonly used for high-pressure gas cylinders.
It is important to select the appropriate grade based on the specific requirements of the gas cylinder application, including the maximum working pressure and environmental conditions.
37Mn
37Mn is a grade specified in JIS G3429 and is widely used in the manufacturing of gas cylinders. It is a low-alloy steel grade that offers excellent mechanical properties and high-pressure resistance. The 37Mn grade is known for its good weldability and is commonly used for various gas cylinder applications.
34Mn2V
34Mn2V is another grade specified in JIS G3429 and is suitable for gas cylinders. It is a low-alloy steel grade that provides good mechanical properties and enhanced toughness. The 34Mn2V grade is commonly used in applications where high impact resistance is required, making it suitable for gas cylinders subjected to rough handling or extreme conditions.
30CrMo
30CrMo is a low-alloy steel grade specified in JIS G3429 and is commonly used for gas cylinders. It offers excellent strength, high-pressure resistance, and good machinability. The 30CrMo grade is often utilized in applications where a combination of high strength and toughness is required.
35CrMo
35CrMo is another low-alloy steel grade specified in JIS G3429 and is suitable for gas cylinders. It provides excellent mechanical properties, including high tensile strength and good impact resistance. The 35CrMo grade is commonly used in gas cylinder applications where superior strength and durability are essential.
Conclusion
JIS G3429 steel pipes for gas cylinders are designed to withstand high-pressure environments and are crucial components in the manufacturing of gas cylinders. The chemical composition of these steel pipes plays a significant role in determining their mechanical properties and suitability for high-pressure applications. The grades specified in JIS G3429, including STH11, STH12, STH21, and STH22, offer different levels of strength and are suitable for various pressure ranges. When selecting JIS G3429 steel pipes for gas cylinders, it is essential to consider the specific requirements of the application and consult the official standard or the manufacturer for precise chemical composition information.
