GOST9940 Seamless Hot-deformed Stainless Steel Pipes Used in Industrial Applications

When ordering pipes according to GOST 9940, the following must be specified:  

- Pipe dimensions (outer diameter, wall thickness, length)  

- Steel grade (chemical composition)  

- Mechanical property requirements (tensile strength, yield strength, elongation)  

- Type of heat treatment (annealed, quenched, etc.)  

- Non-destructive testing (NDT) requirements (ultrasonic, hydraulic, eddy current)  

- Additional testing (intergranular corrosion resistance, flattening, flaring, etc.)  

- Marking and packaging requirements

The standard covers austenitic, ferritic, and martensitic stainless steels, including:  

- Austenitic grades: 12Х18Н10Т (AISI 321), 08Х18Н10 (AISI 304), 10Х17Н13М2Т (AISI 316Ti), etc.  

- Ferritic/martensitic grades: 12Х13 (AISI 410), 20Х13 (AISI 420), etc.  

Key requirements:  

- Chemical composition must comply with GOST 5632 or equivalent international standards (e.g., ASTM, EN).  

- Permissible deviations in alloying elements are specified.

- Pipes are produced by hot deformation (piercing, rolling, or extrusion).  

- Heat treatment (annealing, quenching, tempering) is mandatory unless otherwise agreed.  

- Surface finish must be free from cracks, laps, and other defects affecting performance.

- Tensile strength, yield strength, and elongation must meet standard values based on steel grade.  

- Hardness requirements (for martensitic grades).  

- Impact toughness (if specified).

- Non-destructive testing (NDT):  

  - Ultrasonic testing (for defect detection).  

  - Hydraulic pressure testing (optional, as per customer request).  

  - Eddy current testing (for surface defects).  

- Destructive testing (sampling-based):  

  - Flattening test (for ductility verification).  

  - Flaring test (for pipe ends).  

  - Intergranular corrosion test (for austenitic grades, per GOST 6032).  

- Dimensional inspection:  

  - Outer diameter, wall thickness, and length tolerances must comply with GOST 9940.

- Each pipe must be marked with:  

  - Manufacturer’s name/trademark.  

  - Steel grade.  

  - Heat number.  

  - Pipe dimensions.  

  - Standard number (GOST 9940).  

- Packaging: Pipes are bundled, crated, or wrapped to prevent damage during transport.

- Manufacturer must provide a certificate of conformity including:  

  - Chemical composition.  

  - Mechanical test results.  

  - Heat treatment details.  

  - NDT reports (if applicable).  

Conclusion  

GOST 9940 ensures the quality of seamless hot-deformed stainless steel pipes through strict chemical, mechanical, and NDT requirements. Compliance with this standard guarantees suitability for high-pressure, high-temperature, and corrosive environments.