JIS G3101 SS490 is a common and well-established material grade for manufacturing Longitudinal Submerged Arc Welded (LSAW) pipes [citation:1, citation:2, citation:3, citation:5]. This combination is a standard product offered by numerous global manufacturers for higher-strength structural and engineering applications [citation:1, citation:2, citation:5].
It is important to understand that "JIS G3101 SS490" refers to the material grade of the steel plate used as the raw material. The finished LSAW pipe product is manufactured to meet the specifications of this grade and is available from suppliers who list JIS G3101 grades in their production range [citation:1, citation:2, citation:5].
Here is the detailed specification for a JIS G3101 SS490 LSAW pipe:
Key Specifications
| Attribute | Description |
|---|---|
| Material Standard | JIS G3101: Japanese Industrial Standard for "Rolled Steels for General Structure" [citation:2, citation:6]. |
| Steel Grade | SS490: A higher-strength structural steel grade. "SS" stands for "Structural Steel," and "490" indicates the minimum tensile strength of 490 MPa [citation:1, citation:2, citation:3, citation:6]. |
| Process | LSAW (Longitudinal Submerged Arc Welding) : Pipes are manufactured by forming steel plates into a cylinder (using JCOE, UOE, or similar forming processes) and welding the longitudinal seam both internally and externally using a submerged arc process. This process is well-suited for producing large-diameter pipes with thick walls [citation:1, citation:2, citation:4]. |
| Chemical Composition (max %) [citation:1, citation:2, citation:3, citation:6] | |
| Carbon (C): Not specified in standard (typically controlled by manufacturer) | |
| Manganese (Mn): Not specified in standard | |
| Phosphorus (P): ≤ 0.050 | |
| Sulfur (S): ≤ 0.050 | |
| Mechanical Properties [citation:1, citation:2, citation:3, citation:6] | |
| Yield Strength: ≥ 285 MPa (for thickness ≤16mm) | |
| Yield Strength: ≥ 275 MPa (for 16mm < t ≤ 40mm) | |
| Yield Strength: ≥ 255 MPa (for 40mm < t ≤ 100mm) | |
| Yield Strength: ≥ 245 MPa (for t ≥ 100mm) | |
| Tensile Strength: 490-610 MPa [citation:1, citation:2, citation:3, citation:6] | |
| Typical Size Range [citation:2, citation:4] | |
| Outside Diameter: 325 mm to 1625 mm (approx. 12" to 64") | |
| Wall Thickness: 5 mm to 60 mm (up to 75-120mm available from some manufacturers) | |
| Length: 3 m to 18.3 m (customizable, up to 32 m available for piling) | |
| Manufacturing Steps [citation:2, citation:5] | 1. Steel plate selection and edge milling. 2. Edge crimping and forming using JCOE or UOE processes. 3. Internal and external submerged arc welding. 4. Mechanical expanding (for UOE/JCOE). 5. Non-destructive testing (Ultrasonic, X-ray). 6. Hydrostatic testing. 7. End facing and beveling. |
| Common Applications [citation:1, citation:2, citation:3, citation:6] | High-strength structural components; heavy machinery parts; bridge construction; offshore projects; piling foundations; oil and gas transmission pipelines (higher pressure); infrastructure projects requiring greater load-bearing capabilities. |
| Certification | Mill Test Certificate typically to EN 10204 / 3.1 or equivalent [citation:2, citation:4]. |
🔍 Key Points to Understand
What "SS490" Means: The "SS" stands for "Structural Steel," and "490" indicates the minimum tensile strength of 490 MPa. Compared to SS400 (400 MPa tensile strength), SS490 offers significantly higher strength for more demanding applications [citation:1, citation:2, citation:3, citation:6].
Chemical Composition: Like other SS grades, JIS G3101 only specifies maximum limits for phosphorus (≤0.050%) and sulfur (≤0.050%) for SS490. Carbon, manganese, and other elements are not specified in the standard, allowing flexibility for manufacturers to achieve the required mechanical properties [citation:1, citation:2, citation:3, citation:6].
Yield Strength Values: While the standard does not mandate a single yield strength value, it provides specific minimum yield points based on product thickness [citation:1, citation:2, citation:3, citation:6]:
≤16mm thickness: ≥285 MPa
16-40mm thickness: ≥275 MPa
40-100mm thickness: ≥255 MPa
≥100mm thickness: ≥245 MPa
Comparison with Other Grades: SS490 offers higher strength than SS400 (400 MPa tensile) and is suitable for more demanding structural applications. It is positioned between SS400 and SS540 in the JIS G3101 grade family .
Advantages: SS490 provides higher tensile strength and yield strength compared to SS400, making it suitable for applications that require greater load-bearing capabilities while maintaining good toughness and weldability [citation:1, citation:3, citation:6].
Weldability: SS490 has good weldability due to its controlled chemistry, making it suitable for common welding methods including submerged arc welding (SAW), which is the process used for LSAW pipe manufacturing [citation:1, citation:2, citation:3].
📊 SS Grade Comparison
| Grade | Yield Strength (≤16mm) | Tensile Strength | Key Application |
|---|---|---|---|
| SS330 | ≥205 MPa | 330-430 MPa | General structural, low-stress applications |
| SS400 | ≥245 MPa | 400-510 MPa | General construction, most common grade |
| SS490 | ≥285 MPa | 490-610 MPa | High-strength structures, heavy machinery |
| SS540 | ≥400 MPa | ≥540 MPa | Highest strength, demanding applications |
Summary
In conclusion, JIS G3101 SS490 LSAW pipe is a well-established, higher-strength product that combines the robust properties of SS490 structural steel with the versatile LSAW manufacturing process [citation:1, citation:2, citation:5]. It offers significantly higher tensile strength (490-610 MPa) and yield strength (≥285 MPa for ≤16mm thickness) compared to the more common SS400 grade, making it suitable for demanding structural applications, heavy machinery, bridge construction, and higher-pressure fluid transmission [citation:1, citation:2, citation:3, citation:6]. The LSAW process enables the production of large-diameter pipes with thick walls (up to 60-75 mm), providing excellent load-bearing capacity for major infrastructure projects [citation:2, citation:4]. When specifying, it is best practice to reference both the material grade and any applicable product standards based on the intended application.
