1. Main Content of GB/T 12771 Standard
GB/T 12771 is the core Chinese national standard for welded stainless steel pipes for fluid transport. The current version is GB/T 12771-2019, which came into effect on September 1, 2020, replacing the 2008 version.
This standard specifies the classification, technical requirements, test methods, and inspection rules for welded stainless steel pipes (including longitudinal welded pipes). Compared to the 2008 version, the 2019 edition features significant upgrades in material range (adding 12 new steel grades), dimensional accuracy (divided into Advanced and Ordinary grades), and non-destructive testing requirements, better meeting modern industrial demands for fluid transport.
Key Elements Include:
Scope: Primarily used for transporting water, oil, gas, and other fluids. Widely applied in industrial piping, municipal water supply, and architectural decoration.
Manufacturing Process: Covers resistance welding, TIG (Tungsten Inert Gas) welding, and plasma arc welding, requiring stable weld quality.
Dimensions: Nominal outside diameter typically ranges from 15mm to 2000mm (commonly 15mm-323.9mm), with customizable wall thickness.
Delivery Condition: Includes as-welded, heat-treated (solution annealed), and surface-finished states (e.g., mechanical polishing, electropolishing).
2. Common Steel Grade Selection Table (by Application)
To assist sales personnel in matching customer needs, common grades from GB/T 12771-2019 are categorized by application scenario below (Note: Corresponding ASTM grades are included for reference):
表格
| Application Environment | Recommended Grade (GB/T) | Corresponding ASTM | Typical Uses | Key Advantages & Characteristics |
|---|---|---|---|---|
| General Fluid/Potable Water | 022Cr19Ni10 | 304L | Municipal water, drinking water, general industrial fluid | Low-carbon version of 304; no heat treatment needed after welding; good intergranular corrosion resistance; cost-effective. |
| General Industrial Piping | 06Cr19Ni10 | 304 | Food processing, pharma equipment, general chemical piping | The most versatile stainless steel with good corrosion resistance and formability. |
| Coastal/Chloride Environments | 022Cr17Ni12Mo2 | 316L | Coastal buildings, desalination, chemical & paper industries | Contains Molybdenum (Mo); significantly better pitting resistance than 304, ideal for chloride environments. |
| High-Temp/Heat Resistant | 06Cr25Ni20 | 310S | Boiler heat exchangers, high-temp pipelines, burners | High Chromium and Nickel content; excellent oxidation resistance and high-temperature performance (up to 1000°C+). |
| Strong Corrosion/Special Chem | 015Cr20Ni18Mo6CuN | 254 SMO | Seawater piping, flue gas desulfurization, acid transport | Super austenitic stainless steel with high PREN value; extremely resistant to chloride stress corrosion. |
| Acidic Env./Welded Parts | 06Cr18Ni11Ti | 321 | Aviation, exhaust pipes, heat treatment equipment | Stabilized with Titanium (Ti) to prevent intergranular corrosion during welding. |
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