1. Main Content of GB/T 9948-2025 Standard
GB/T 9948 is titled "Seamless steel tubes and pipes for petrochemical and chemical facilities". It is one of the most critical standards for the petrochemical industry, specifically designed for piping systems operating in high-temperature, high-pressure, and corrosive environments.
Key Changes & Features (2025 Edition):
Standard Integration (4-in-1): The new standard not only includes the content of the original "Petroleum Cracking Tube" but also integrates "High-pressure Fertilizer Equipment Tubes," "High-pressure Alloy Tubes for Polyethylene," and "Stainless Steel Tubes for Hydrogenation Industrial Furnaces". This unifies procurement and selection, reducing complexity.
Broader Operating Range: Applicable to extreme environments with operating temperatures up to 650℃, working pressures ≥10 MPa, and corrosive media containing Hydrogen Sulfide (H₂S) or Carbon Dioxide (CO₂).
Material System Upgrade: Added 12 new steel grades, including the Q355 series for low-temperature environments and super-high-temperature alloy steels (e.g., 10Cr9Mo1VNbN). It strictly controls carbon equivalent and residual elements to improve weldability and safety.
Strict Quality Control: Requires hydrostatic testing for every single pipe and non-destructive testing (Ultrasonic or Eddy Current) to ensure internal integrity.
2. Common Steel Grade Selection Table (by Application)
Selection in the petrochemical industry focuses on "temperature resistance", "pressure rating", and corrosion considerations.
表格
| Application Environment | Recommended Grade (GB/T 9948) | Corresponding ASTM | Typical Uses | Key Advantages & Characteristics |
|---|---|---|---|---|
| General Petrochemical Piping | 20 | A106 Gr.B | Low-temp/low-pressure pipes, water walls, general fluid transport | Cost-effective. Carbon steel with excellent workability and weldability; the most widely used grade. |
| Medium-High Temp/Pressure | 15CrMo | A335 P11 | Heat exchangers, boiler tubes, 300℃-500℃ operations | Good Hydrogen Resistance. Chrome-Moly alloy steel with high thermal strength and oxidation resistance at elevated temperatures. |
| High Temp / Hydrogenation | 12Cr1MoVG | A335 P22 | Reactor temp control systems, high-pressure boilers, 600℃+ | Structural Stability. Chrome-Moly-Vanadium alloy with high creep rupture strength and hydrogen resistance for extreme conditions. |
| H₂S Corrosion Resistance | 20 + H₂S | A106 Gr.B (HIC) | Sour crude processing units, acidic environment piping | Anti-Cracking. Special smelting controls for Phosphorus/Sulfur content and hardness (≤190HBW) to prevent Sulfide Stress Corrosion Cracking. |
| Strong Corrosion/Furnace | 06Cr19Ni10 (304) | A312 TP304 | Hydrogenation furnace tubes, strong corrosive media transport | Corrosion & Heat Resistant. Austenitic stainless steel with excellent corrosion resistance in oxidizing media and high-temperature performance. |
| Low Temperature Environments | Q355D / Q355E | A333 Gr.6 | Outdoor piping in northern winters, cryogenic separation units | Low-Temp Toughness. Included in the new standard, guaranteeing impact toughness at -40℃ or lower to prevent brittle fracture. |
