Mild Steel Pipe / Low Carbon Steel Pipe

I. Product Introduction

Carbon steel pipes with a carbon content of ≤0.25% are categorized into seamless pipes and welded pipes (including ERW, LSAW, and SSAW types). They are commonly referred to as "MS Pipe."

Common Grades: 20#, Q235B, A53 Gr.B, A106 Gr.B, API 5L Gr.B (L245)
Key Characteristics
1. Excellent weldability and high plasticity; easy to bend and process.
2. Moderate strength and high cost-effectiveness; serves as a foundational piping material for industrial applications.
3. Limited inherent corrosion resistance; for long-distance oil and gas transmission, pipes are typically treated with anti-corrosion coatings such as 3PE/3LPE, fusion-bonded epoxy (FBE), or galvanization.
4. Not resistant to highly corrosive media (e.g., strong acids or high-salinity environments) and unsuitable for extreme high-temperature or high-pressure conditions.

II. Main Applications

1. Oil and Gas Industry
- API 5L Line Pipe: Used for the transmission of crude oil, natural gas, water, and oil-gas mixtures (mainlines and branch lines). Widely utilized in oilfield projects across South America and the Middle East, typically featuring 3PE external anti-corrosion coatings.
- Oilfield water injection systems and basic wellhead process piping.
- Low-pressure process piping for oil and gas stations/facilities.
2. Fluid Transport
Water supply, compressed air, low-pressure steam, municipal gas distribution, and fire-protection piping.
3. Engineering Structures
Construction supports, pile foundations, guardrails, structural steel columns, and bridge components.
4. General Machinery
Equipment frames, conveyor cylinders, and components for construction machinery. 5. Power Plants / Chemical Industry
Process piping for medium-to-low temperature and low-pressure applications (A106 Gr.B seamless low-carbon steel pipe is preferred for high-temperature service conditions).


Selection Criteria:
High-pressure or critical process applications → Seamless low-carbon steel pipe
- Large-diameter long-distance oil and gas pipelines → LSAW (Longitudinally Submerged Arc Welded) / SSAW (Spiral Submerged Arc Welded) pipes
- Small-to-medium diameter low-pressure fluid transport → ERW (Electric Resistance Welded) pipes

III. Common Standard


American Standards (Most commonly used by clients in South America and the Middle East)

1. API 5L: Line pipe for oil and gas transmission (Gr.B, X42/X46/X52; PSL1/PSL2—PSL2 requires higher impact toughness and is the industry standard for oil and gas projects). Equivalent to ISO 3183.
2. ASTM A53: General-purpose carbon steel pipe (Grade A/B; available as seamless or welded). Used for low-pressure water, gas, and structural applications; typically specified with SCH40/SCH80 wall thicknesses.
3. ASTM A106 Gr.B: Seamless carbon steel pipe for high-temperature service. Used in boilers and process piping for medium-to-high temperature, low-pressure conditions. **Available only as seamless pipe.**
4. ASME B36.10M: Standard for steel pipe dimensions (outside diameter and wall thickness/Schedule).

European Standards

- EN 10216-1: Seamless steel pipes for pressure purposes; EN 10217: Welded steel pipes for pressure purposes; St37.0: Low-carbon steel.