

GOST 9940 applies to seamless hot-deformed stainless steel pipes intended for general industrial use, including heat exchangers, chemical processing, and high-temperature applications.
GOST 9940 applies to seamless hot-deformed stainless steel pipes intended for general industrial use, including heat exchangers, chemical processing, and high-temperature 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).
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.
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