GB/T 3091 Spiral Submerged Arc Welded (SSAW) Pipe
GB/T 3091 is the Chinese national standard titled "Welded steel pipes for low-pressure fluid transmission" . This standard explicitly includes spiral submerged arc welded (SSAW/HSAW) pipes and serves as the primary technical specification for their manufacture, inspection, and delivery .
📋 Standard Overview
| Attribute | Description |
|---|---|
| Standard Number | GB/T 3091 |
| Latest Version | GB/T 3091-2025, effective from October 1, 2025 [citation:2, citation:4]. The current version is GB/T 3091-2015 [citation:1, citation:3]. |
| Full Title | "Welded steel pipes for low-pressure fluid transmission" [citation:1, citation:3, citation:4] |
| Scope | Specifies technical requirements for welded steel pipes used to convey low-pressure fluids such as water, air, gas, steam, and for other purposes like structure and heating [citation:3, citation:4]. |
| Pipe Types | Includes spiral submerged arc welded (SSAW/HSAW) pipes, longitudinally submerged arc welded (LSAW) pipes, and electric resistance welded (ERW) pipes [citation:3, citation:4]. |
| Replaces | GB/T 3091-2015 will be replaced by the 2025 version [citation:2, citation:4]. |
🔧 Manufacturing Process
GB/T 3091 spiral submerged arc welded pipes are produced using the following process [citation:3, citation:4]:
Raw Material: Hot-rolled steel coils (typically Q195, Q215, Q235, Q275, etc.)
Forming: The steel strip is continuously spiral-formed at a specific angle to create a cylindrical pipe
Welding: Double-sided submerged arc welding (inside and outside) creates the spiral seam, ensuring deep penetration and high weld quality
Testing: Hydrostatic testing, non-destructive testing (ultrasonic/X-ray), and dimensional inspection
Finishing: End preparation (plain or beveled) and coating as required
📏 Size Range
Based on manufacturer data for SSAW pipes conforming to GB/T 3091 [citation:3, citation:4]:
| Parameter | Typical Range |
|---|---|
| Outside Diameter | 219 mm to 3620 mm (approx. 8" to 142") |
| Wall Thickness | 3.2 mm to 25.4 mm (up to 40 mm available from some manufacturers) |
| Length | 3 m to 18 m (customizable) |
⚙️ Material Grades
GB/T 3091 specifies various carbon steel grades suitable for low-pressure fluid transmission [citation:1, citation:3, citation:4]:
| Grade | Description |
|---|---|
| Q195 | Low strength, economical option for non-critical applications |
| Q215A/Q215B | General purpose, lower strength |
| Q235A/Q235B | Most common grade – good balance of strength, weldability, and cost |
| Q275 | Higher strength option for more demanding applications |
| 10, 20 | High-quality carbon steel (replaced by Q235 in practice) |
📝 Key Technical Requirements
GB/T 3091 specifies the following requirements for spiral submerged arc welded pipes [citation:3, citation:4]:
| Requirement | Description |
|---|---|
| Chemical Composition | Limits for carbon, silicon, manganese, phosphorus, sulfur per grade |
| Tensile Strength | Minimum tensile and yield strength requirements per grade |
| Hydrostatic Testing | Each pipe must withstand hydrostatic pressure without leakage (typical test pressure: 2.5-5.0 MPa depending on pipe size and grade) |
| Non-Destructive Testing | Ultrasonic or X-ray inspection of welds may be required |
| Flattening Test | Verifies ductility and weld integrity |
| Bend Test | Checks formability |
| Surface Quality | No defects harmful to welding or service |
| Dimensional Tolerances | Specified tolerances for OD, wall thickness, straightness, and length |
🏭 Applications
GB/T 3091 spiral welded pipes are widely used for [citation:1, citation:3, citation:4]:
| Application | Description |
|---|---|
| Water Transmission | Municipal and industrial water supply pipelines |
| Low-Pressure Gas | Natural gas and manufactured gas distribution (≤1.6 MPa typical) |
| Air and Steam | Compressed air systems and low-pressure steam lines |
| Heating Systems | District heating and HVAC applications |
| Structural Use | Building supports, scaffolding, piling foundations |
| Irrigation | Agricultural water conveyance |
| Drainage | Storm water and wastewater systems |
🔍 Distinction from Related Standards
| Standard | Application | Key Difference |
|---|---|---|
| GB/T 3091 | Low-pressure fluid transmission (water, gas, air, steam ≤1.6 MPa typical) | General purpose, less stringent than pipeline standards [citation:1, citation:3] |
| GB/T 9711 | Petroleum and natural gas pipelines | Higher pressure, stricter requirements, aligned with API 5L [citation:1, citation:3] |
| GB/T 14291 | Mine fluid service | Specifically for mining environments with more demanding conditions |
| API 5L | Oil and gas transmission | International standard for pipeline transportation systems |
| ASTM A53 | General piping | US standard for welded and seamless pipe |
📊 Comparison: GB/T 3091 vs. GB/T 9711
| Aspect | GB/T 3091 | GB/T 9711 |
|---|---|---|
| Pressure Range | Low-pressure (typically ≤1.6 MPa) | Medium to high-pressure |
| Typical Grades | Q235B, Q275 | L245, L290, L360, L415 (aligned with API 5L) |
| Impact Testing | Not mandatory | Required for many grades |
| NDT Requirements | Optional | Mandatory for many grades |
| Application | General utilities, construction | Oil & gas transmission |
| Cost | Lower | Higher |
📝 Standard Update: GB/T 3091-2025
The new GB/T 3091-2025 version will be implemented from October 1, 2025 [citation:2, citation:4]. Key changes include:
Updated technical requirements aligned with modern manufacturing practices
Harmonization with related standards (GB/T 1591 for Q355 grades)
Clarified testing and inspection procedures
Enhanced quality control requirements
Until October 2025, the current valid version remains GB/T 3091-2015 .
💡 Summary
GB/T 3091 spiral submerged arc welded pipes are the standard choice for low-pressure fluid transmission applications in China and internationally. They offer an economical and reliable solution for water, gas, air, and steam pipelines, as well as structural applications. The standard covers Q195, Q215, Q235, and Q275 grades, with Q235B being the most common [citation:1, citation:3, citation:4]. When specifying these pipes, verify the applicable standard version (2015 or 2025) and select appropriate material grades based on your pressure requirements and service conditions.
