Standards

The standard covers austenitic stainless steel pipes manufactured by a welding process with or without subsequent seam treatment. Pipes according to this standard are intended for operation under high pressure and corrosion.

Key technical specifications:

1. Materials:
   • Made of austenitic stainless steel (e.g., grades 304, 304L, 316, 316L and others).
   • Chemical composition is controlled to ensure high corrosion resistance and strength.
2. Application:
   • Used in the chemical, petrochemical, energy industries, and in the construction of pipelines for the transportation of aggressive media.
   • Suitable for operation in low and high-temperature conditions.
3. Size Range:
   • Outer diameter: from 8 inches (200 mm) and larger.
   • Wall thickness: regulated according to calculated pressure requirements and customer specifications.
4. Mechanical Properties:
   • High tensile and yield strength.
   • Elongation: not less than 30%.
5. Testing and Quality Control:
   • Hydrostatic testing to verify tightness.
   • Inspection of weld seams using non-destructive methods (radiographic or ultrasonic).
   • Verification of chemical composition and mechanical properties in accordance with the specification.
6. Corrosion Resistance:
   • High resistance to intergranular corrosion and the effects of chemically active substances.

The European standard covering welded pipes made of corrosion-resistant stainless steel intended for pressurized applications. Pipes according to this standard are used in the chemical, oil and gas, food and pharmaceutical industries, as well as in drinking water supply systems. Key technical specifications:

1. Materials:
   • Pipes are made of corrosion-resistant stainless steel grades, such as AISI 304, 304L, 316, 316L and other similar composition grades.
   • Steels according to this standard have high corrosion resistance and excellent mechanical strength.
2. Application:
   • Pipelines for transporting liquids and gases under pressure.
   • Used in the food, chemical, pharmaceutical, energy, and other industries where high corrosion resistance is required.
   • Suitable for operation at low and high temperatures.
3. Dimensions and Wall Thickness:
   • The outer diameter of the pipes varies from 6 mm to 2500 mm.
   • The wall thickness is selected depending on the pressure and operating conditions.
4. Mechanical Properties:
   • The yield and tensile strength depend on the steel grade and the type of heat treatment.
   • Elongation at break varies from 20% to 40%, depending on the steel grade.
5. Testing Requirements:
   • Hydrostatic testing: verifying the tightness of the pipe under pressure.
   • Tensile testing: determining the strength and yield strength of the steel.
   • Impact toughness test: performed at low temperatures to check the material’s resistance to brittle fracture.
   • Non-destructive testing of the weld seam: radiographic or ultrasonic testing to detect internal defects.
6. Quality Control:
   • Checking the geometry of the pipe (diameter, wall thickness, ovality).
   • Checking the chemical composition for compliance with regulatory requirements.
   • Visual inspection of welds and the pipe surface for defects (cracks, dents, corrosion).

The technical specifications regulate the requirements for seamless cold-worked and hot-worked pipes made of stainless and corrosion-resistant steel. These pipes are used in various industries, including oil and gas, chemical, energy, and food, where there are increased requirements for metal resistance to corrosion, temperature loads, and mechanical stresses.

1. Main Steel Grades

   Various grades of stainless and corrosion-resistant steels are used for the production of pipes according to TU 14-3R-197-2001, among which:

   • 08Kh18N10T – AISI 321 analogue, used for operation at high temperatures and aggressive environments.
   • 12Kh18N10T – AISI 304/304L analogue, used for transporting aggressive media.
   • 10Kh17N13M2T – improved alloy with increased resistance to corrosion and aggressive media.
   • Other heat-resistant and corrosion-resistant steel grades suitable for specific operating conditions.
2. Dimensions and Tolerances
   • Outer diameter of pipes – from 6 mm to 426 mm (depends on the production method).
   • Wall thickness – from 0.5 mm to 40 mm (for hot-worked pipes – thicker walls).
   • Pipe length – measured and unmeasured length from 1 m to 12 m (as agreed with the customer).
   • Dimensional tolerances – deviations in diameter and wall thickness are minimal for cold-worked pipes and more significant for hot-worked pipes.
3. Mechanical Properties
   • Strength and ductility – pipes according to TU 14-3R-197-2001 have high mechanical properties that depend on the steel grade and processing technology.
   • Hardness – the hardness level meets the requirements for stainless steels (usually no higher than 200 HB).
   • Operating temperature range – from -70°C to +600°C (depending on the steel grade).
   • Corrosion resistance – due to the use of stainless steel grades, the pipes are resistant to corrosion in aqueous media, acids, and alkalis.
4. Quality Control and Testing

   The production process of pipes according to TU 14-3R-197-2001 includes strict quality control, which is carried out in the following areas:

   • Tensile test – tensile and yield strength are checked.
   • Hydraulic test – pipes are tested with water or air pressure to detect leaks.
   • Bending test – the resistance of pipes to bending without cracks and deformations is checked.
   • Non-destructive testing – magnetic and ultrasonic flaw detection is performed to identify internal defects.
   • Geometric dimension control – the outer diameter, wall thickness, and length of the pipe are measured.
5. Advantages of pipes according to TU 14-3R-197-2001
• Strength and durability – the pipes withstand high loads and temperature fluctuations.
• Resistance to aggressive environments – stainless steels are protected from corrosion, which increases the service life of products.
• Tightness – the pipes undergo hydraulic leakage tests.
• High dimensional accuracy – ensured by the use of cold-worked technology.
• Universality of application - pipes are applicable in the chemical, food, oil and gas, energy and other industries.

The State Standard regulating requirements for cold-worked seamless corrosion-resistant (stainless) steel tubes, intended for operation in aggressive environments, high temperatures, and pressure. This standard is used in the petrochemical, chemical, energy, and food industries.

1. Types of Tubes and Manufacturing Methods
   • Type of tubes - cold-worked seamless tubes (as opposed to hot-worked tubes according to GOST 9940-81).
   • Manufacturing process - the tubes are produced by cold deformation, followed by heat treatment, which ensures their precise dimensions and high operational characteristics.
   • Material - corrosion-resistant stainless steel grades:
     • 08Kh18N10T
     • 12Kh18N10T
     • 10Kh17N13M2T
     • Other alloys with the addition of nickel, chromium, and molybdenum to increase resistance to corrosion and temperature effects.
2. Dimensions and Tolerances
   • Outer diameter of tubes - from 2 mm to 426 mm.
   • Wall thickness - from 0.2 mm to 50 mm (depending on the type of tube and purpose).
   • Length of tubes - multiple sizes or measured length from 2 m to 30 m.
   • Tolerances on diameter and wall thickness - for cold-worked tubes, minimum tolerances are provided, which makes them accurate and suitable for precision applications.
3. Mechanical Properties
   • Strength and ductility - the tubes provide high strength under load and retain ductility.
   • Hardness - for various steel grades, the hardness limit is controlled, for example, for 12Kh18N10T - no more than 200 HB.
   • Temperature resistance - the tubes retain their strength characteristics at high temperatures (from -70°C to +600°C).
4. Quality Control and Testing

   The production process of tubes according to GOST 9941-81 is accompanied by strict quality control:

   • Tensile test - checks yield strength and tensile strength.
   • Hydrostatic test - tubes are tested under water or air pressure to check for leaks.
   • Bending test - the ductility of the tube and resistance to bending without the formation of cracks and deformations are checked.
   • Non-destructive testing - ultrasonic or magnetic flaw detection is performed to detect hidden defects.

Control of geometric parameters - measurements of outer diameter, wall thickness, and curvature of the tube.

The State Standard establishes requirements for seamless pipes made of corrosion-resistant (stainless) steel, used for various technical purposes, including operation under high pressure, at high temperatures, and in aggressive environments.

1.Key provisions and characteristics

Purpose and Scope Pipes according to GOST 9940-81 are used in the following industries:

• Oil and gas industry (transportation of aggressive substances);
• Chemical and petrochemical industry (aggressive environments and high temperatures);
• Power engineering (pipelines for steam and hot water);
• Food and pharmaceutical industry (where hygienic safety and corrosion resistance are required).

2. Material

• Pipes are made of stainless steel of various grades, for example, 08Kh18N10T, 12Kh18N10T, 10Kh17N13M2T, and others.

3. Dimensions and Permissible Deviations

• Pipe diameter – from 5 mm to 426 mm
• Wall thickness – from 0.5 mm to 50 mm (depends on the production method and application).
• Pipe length – multiple sizes or measured length from 2.0 m to 30 m.
• Ovality and curvature – regulated by tolerances for ovality and deviations from straightness.

4. Mechanical Properties

Mechanical properties depend on the steel grade and heat treatment method. Approximate parameters:

• Tensile strength (σв) – from 490 to 590 MPa (depending on the steel grade).
• Elongation (δ) – from 35% to 40%.
• Hardness – no more than 200 HB (for austenitic stainless steels).

5. Heat Treatment

• To improve mechanical properties and eliminate internal stresses, the pipes are subjected to quenching and tempering.
• Heat treatment of welds is possible to improve the metal structure.

6. Quality Control and Testing

The production process of pipes according to GOST 9940-81 is accompanied by strict quality control:

• Tensile test – checks yield strength and tensile strength.
• Bending test – the pipe must withstand bending without failure.
• Hydrostatic test – checks for tightness under pressure.
• Impact toughness test – especially important at low temperatures.
• Geometry control – measurement of outer diameter, wall thickness, and pipe curvature.

Non-destructive testing – ultrasonic testing to detect hidden defects.

The standard applies to seamless and welded stainless duplex steel pipes intended for service in highly corrosive and high-pressure conditions. Key technical specifications:

1. Materials:
   • Manufactured from duplex stainless steel (austenitic-ferritic), including grades UNS S31803 (2205), S32750 (2507), S32760, and others.
   • Materials provide high corrosion resistance, including resistance to pitting corrosion, stress corrosion cracking, and erosion corrosion.
2. Application:
   • Used in marine environments, the oil and gas industry, the chemical industry, and in the production of water desalination equipment.
   • Suitable for transporting corrosive liquids, chemicals, and gases.
3. Size Range:
   • Outside diameter of pipes: from 1/8 inch (3.2 mm) and larger.
   • Wall thickness varies according to pipeline schedules (Schedule 10, 40, 80, and others).
4. Mechanical Properties:
   • Tensile Strength: not less than 620 MPa (90,000 psi) for most steel grades.
   • Yield Strength: not less than 450 MPa (65,000 psi).
   • Elongation at Break: 25% and higher.
5. Corrosion Resistance:
   • High resistance to corrosion in chloride-containing environments.
   • Excellent resistance to intergranular corrosion.
6. Testing and Inspection:
   • Hydrostatic testing.
   • Testing for corrosion resistance and verification of mechanical properties.
   • Weld seam inspection (for welded pipes), including non-destructive testing methods.

ASTM A312 standard covers seamless, welded, and heavily cold worked austenitic stainless steel pipes intended for high temperature and general corrosive service.

Materials:

• Pipes are manufactured from austenitic stainless steel grades 304, 316, 321, 347, and others.
• Materials provide high corrosion resistance and mechanical strength.

Application:

• Intended for operation in aggressive environments, high temperatures, and pressures.
• Used in the oil and gas, chemical, and energy industries.

Size Range:

• Outside diameter of pipes: from 1/8 inch (3.2 mm) to 30 inches (762 mm).
• Wall thickness: varies depending on standard schedules (Schedule 5S, 10S, 40S, and others).

Mechanical Properties:

• Minimum Tensile Strength: 515 MPa (75,000 psi).
• Minimum Yield Strength: 205 MPa (30,000 psi).
• Elongation at Break: Not less than 35% for most steel grades.

Testing and Inspection:

• Hydrostatic test to check for leaks.
• Non-destructive quality control of the weld seam (for welded pipes).
• Verification of dimensions, chemical composition, and mechanical properties.

ASTM A269 standard specifies the requirements for seamless and welded austenitic stainless steel tubing for general service, including applications involving corrosive media and high temperatures.

Materials: Tubes are manufactured from austenitic stainless steel grades, such as 304, 316, 316L, and others, providing corrosion resistance.

Size Range:

• Outside diameter of tubes: from 1/8 inch (3.2 mm) to 5 inches (127 mm).
• Wall thickness: from 0.020 inch (0.51 mm) and greater.

Dimensional Tolerances: Deviations in outside diameter, wall thickness, and tube length are strictly regulated according to customer requirements.

Mechanical Properties:

• Minimum Tensile Strength: 515 MPa (75,000 psi).
• Minimum Yield Strength: 205 MPa (30,000 psi).
• Elongation at Break: Not less than 30%.

Tests and Inspections:

• Mandatory hydrostatic testing.
• Non-destructive testing, including checks for weld integrity (for welded tubes).

ASTM A213 standard specifies the requirements for seamless ferritic and austenitic alloy stainless steel tubes of grades TP 304, TP 316, TP 304L, TP 316L, TP 321, intended for use in boilers, heat exchangers, and other high-temperature applications.

Chemical Composition: the tubes are manufactured from austenitic stainless steel grades such as 304, 316, 321, etc., with a chromium (Cr) content ranging from 18% to 20% and a nickel (Ni) content ranging from 8% to 14%, depending on the alloy.

Mechanical Properties:

• Tensile Strength: Minimum 515 MPa (75,000 psi).
• Yield Strength: Minimum 205 MPa (30,000 psi).
• Elongation at Break: Not less than 35% (for standard tube diameters).

Dimensional Tolerances:

• Tube diameters range from 1/8 inch (3.2 mm) to 30 inches (762 mm).
• Wall thickness – from a minimum thickness of 1.24 mm to required values as per order.

Tests and Inspections: each tube must undergo a hydrostatic test, as well as checks for radiographic soundness of welds (for welded tubes) and corrosion resistance.

The standard establishes the technical conditions for seamless and welded steel pipelines for the oil, gas, and other industries, intended for operation under pressure and temperature.

Key Technical Characteristics:

Purpose:

• The standard applies to pipes that are used to transport oil, gas, and chemical substances, as well as in pipeline systems of various industrial sectors.
• Pipes can be used in both underground and above-ground pipelines, as well as in equipment subject to high temperature and mechanical loads.

Pipe Types:

• The standard covers both seamless and welded pipes.
• Carbon and low-alloy steels are used, which provide the required strength and corrosion resistance in various operating conditions.

Pipe Sizes:

• The pipe diameter varies from 32 mm to 530 mm.
• The wall thickness of the pipes can be from 3 mm to 40 mm.

Mechanical Characteristics:

• Pipes are subject to requirements for tensile strength and elongation.
• The tensile strength must be at least 370 MPa, and the elongation must be at least 20%.
• Testing for corrosion resistance.

Testing:

• Pipes undergo hydraulic tests for leak tightness at high pressure.
• Tests for strength and hardness are carried out to confirm mechanical properties.
• Non-destructive testing methods are mandatory to detect possible defects (e.g., ultrasonic flaw detection).

The standard specifies technical conditions for seamless and welded steel pipes intended for use in the oil, gas, chemical, and other industries.

Key Characteristics:

Pipe Types:

• Seamless and welded pipes made of carbon and low-alloy steels, which are intended for use in various industrial sectors, including the petrochemical, gas, and chemical industries.

Materials:

• Carbon steels (e.g., 20, 45, 10G2F) and low-alloy steels (e.g., 15KhM, 12Kh1MF).
• Pipelines for operation in moderate temperature and pressure conditions.

Diameters and Wall Thickness:

• Pipelines can be of various diameters: from 25 to 530 mm.
• Pipe wall thickness: from 2 to 30 mm, depending on the purpose and steel grade.

Application:

• Used for pipeline systems in the petrochemical, gas, chemical, and other industries, including equipment that operates at normal and elevated temperatures.
• Also used for the manufacture of pipes for water and gas supply systems.

Testing and Quality Control:

• Mechanical tests for strength, elongation, and hardness.
• Hydraulic tests to check the tightness of pipes under pressure.
• Non-destructive testing - ultrasonic inspection for defects.
• Inspection for external defects: chips, cracks, bent areas, etc.

The standard specifies the technical conditions for the manufacture and control of seamless steel pipes manufactured by hot and cold deformation methods. GOST 8731-74 is used in conjunction with GOST 8732-78 (for hot-deformed pipes) and GOST 8734-75 (for cold-deformed pipes). This standard is used in the oil and gas, petrochemical, energy, and mechanical engineering industries.

Key Characteristics:

Pipe Type:

• Seamless hot-deformed and cold-deformed pipes.

Application:

• Production of pipes for pipeline systems operating under pressure.
• Use in petrochemistry, oil refining, heat power engineering, and mechanical engineering.
• Heat transfer systems (steam pipes and heating networks) and gas pipelines.

Materials:

• Carbon steels (e.g., grades St10, St20).
• Alloy steels (e.g., 09G2S, 15KhM, 12Kh1MF) - for operation in conditions of elevated temperatures and corrosive media.

Pipe Diameters and Sizes:

• Outer diameter of pipes: from 20 to 550 mm (for hot-deformed).
• Wall thickness: from 2.5 to 75 mm.
• For cold-deformed pipes, the diameter and wall thickness may vary within smaller ranges.

Quality Control and Testing:

• Mechanical tests: checking the strength, elongation, and impact toughness.
• Hydraulic tests: checking the tightness of pipes under water pressure.
• Ultrasonic testing: inspection for internal defects and cracks.
• Visual inspection: checking the surface for defects (laps, cracks, shells).

Features:

• Pipes can be manufactured with normal and increased accuracy in wall thickness and diameter.
• Can have definite and random length (usually from 4 to 12 meters).

The standard specifies the technical conditions for seamless pipes made of carbon and alloy steels intended for operation in conditions requiring resistance to high temperatures and pressures. This standard applies to pipes used in heat power engineering, the petrochemical and oil industry, as well as in mechanical engineering.

Key Characteristics:

Pipe Types:

• Seamless pipes manufactured by hot and cold deformation methods.
• Used in pipelines operating at high pressures and temperatures.

Materials:

• Carbon and alloy steels (e.g., 15KhS, 15KhM, 12Kh1MF, 09G2S, and others).
• Pipelines for operation in aggressive environments.

Diameter and Wall Thickness:

• Pipe diameter: from 25 to 530 mm (for hot-deformed pipes).
• Wall thickness: from 2 to 50 mm (depending on the pipe diameter).

Application:

• Pipelines for transporting oil, gas, and chemical substances.
• Steam pipes and heat pipelines operating in high-temperature conditions.
• Elements of heat exchangers, boilers, and other units in the power industry.

Use in mechanical engineering and shipbuilding for the manufacture of various parts of mechanisms.

Testing and Quality Control:

• Mechanical tests for strength, elongation, and impact toughness.
• Hydraulic tests to check the tightness of pipes under pressure.
• Ultrasonic inspection for internal defects.
• Visual inspection of the surface to identify external defects.

The standard regulates the production of seamless hot-deformed steel pipes. These pipes are used in the petrochemical, oil and gas, energy, construction, and other industries where strong and reliable piping systems operating under high pressure and high temperatures are required.

Key characteristics:

Pipe Type:

Seamless, hot-deformed steel pipes.

Application:

Pipelines for transporting oil, gas, and chemical products.

Heating networks and heat exchange systems.

Production of pipeline fittings, flanges, and other connecting elements.

Pipe Diameters:

Outer diameter: 25 mm – 550 mm.

Wall Thickness:

2.5 mm – 75 mm, depending on the pipe diameter and operating requirements.

Pipe Length:

Definite length: from 4 to 12 meters (as ordered).

Random length: from 4 to 12.5 meters.

Material:

Carbon and alloy steel (steel grades St10, St20, 09G2S, 12Kh1MF, and others).

Materials are selected depending on the operating conditions (corrosive environment, temperature, pressure).

Classification by Manufacturing Accuracy:

Normal accuracy.

Increased accuracy (for individual customer requirements).

Testing and Control:

Visual inspection of the surface (free from cracks, laps, shells).

Ultrasonic and hydraulic testing for tightness and strength.

Control of mechanical properties (testing for tensile strength, impact toughness, elongation).

This international standard specifies the requirements for carbon or low-alloy steel pipes for pipelines used to transport oil, gas, and water in high-pressure systems.

Key Characteristics:

1. Material: Carbon and low-alloy steel.
2. Pipe Types:
• Seamless — for increased strength and resistance requirements.
• Electric Resistance Welded (ERW, HFW, LSAW) — used for longer pipelines.
3. Strength Levels (Specification Levels):
• PSL 1 — standard quality for normal operating conditions.
• PSL 2 — increased requirements for strength, impact toughness, and chemical composition.
4. Pipe Grades: From Grade A to Grade X80 (the number X indicates the minimum yield strength value, for example, X42 — 42,000 psi ≈ 290 MPa).
5. Application:
• Transportation of oil, gas, and water over long distances.
• Used in the oil and gas, energy, and water supply industries.

API 5L is used for the production of main pipelines, providing high reliability and resistance to mechanical loads, corrosion, and pressure.

ASTM A106 (Grade A, B, C) - intended for seamless carbon steel pipes used in high-temperature and high-pressure applications.

Key technical specifications for Grades A and B:

Chemical Composition (in %):

• Grade A:
• Carbon (C): up to 0.25%
• Manganese (Mn): 0.27-0.93%
• Phosphorus (P): no more than 0.035%
• Sulfur (S): no more than 0.035%
• Silicon (Si): at least 0.10%
• Grade B:
• Carbon (C): up to 0.30%
• Manganese (Mn): 0.29-1.06%
• Phosphorus (P): no more than 0.035%
• Sulfur (S): no more than 0.035%
• Silicon (Si): at least 0.10%

• Yield Strength (Re):
• Grade A: not less than 205 MPa
• Grade B: not less than 240 MPa
• Tensile Strength (Rm):
• Grade A: 330-485 MPa
• Grade B: 415-585 MPa
• Elongation (A):
• Depends on the wall thickness and pipe diameter, typically around 20-30%.

• Pipe Diameters: from NPS 1/8” to NPS 48”.
• Wall Thickness: in accordance with Schedules 20, 40, 80 and higher.

• Hydrostatic pressure tests, non-destructive testing (e.g., ultrasonic and eddy current testing) are performed.
• Tensile, flattening, and bending tests.

• Used in high-pressure and high-temperature systems, such as oil and gas pipelines, heat exchangers, boiler installations, and other process lines in the petrochemical and energy industries.

Main difference between A and B:

Grade A has lower mechanical characteristics compared to Grade B and is used in less demanding conditions. Grade B is more in demand for pipelines with high requirements for mechanical strength.

This European standard specifies requirements for seamless pipes made of carbon and alloy steel for use in pipelines operating at high pressures and temperatures. The standard includes two parts:

• EN 10216-1 — general technical delivery conditions for pipes, including mechanical properties and testing.
• EN 10216-2 — specific requirements for pipes made of alloy steels intended for use at high temperatures.

Key characteristics of the second section of the EN 10216-2 standard include:

1. Materials:

   Pipes are made of alloy steels that have improved mechanical properties and can withstand high temperatures. The materials used include steels with additives such as Cr (chromium), Mo (molybdenum), and other alloying elements that increase heat resistance and corrosion resistance.

2. Mechanical Properties:
   • Minimum tensile strength for pipes up to 50 mm in diameter:

   • 500 MPa — for steel 13CrMo4-5.

   • 510 MPa — for steel X10CrMoVNb9-1.

   • Minimum yield strength:

   • 225 MPa — for steel 13CrMo4-5.

   • 250 MPa — for steel X10CrMoVNb9-1.

   • Minimum elongation at 50 mm (in percent):

   • 22% for 13CrMo4-5.

   • 20% for X10CrMoVNb9-1.

   • Minimum impact toughness:

   • 27 J at a temperature of -20°C for steel 13CrMo4-5.

   • 40 J at -20°C for steel X10CrMoVNb9-1.

3. Dimensions and Tolerances:
   • Pipe diameters: from 10 mm to 273 mm.
   • Wall thickness: from 1.0 mm to 30 mm (depending on the pipe diameter).
   • Diameter tolerances: ± 0.5 mm for pipes with a diameter of up to 100 mm, ± 1.0 mm for pipes with a diameter of more than 100 mm.
   • Wall thickness tolerances: ± 10% of the nominal thickness
4. Testing:
   • Hydrostatic testing: pipelines are subject to leakage testing with a hydrostatic pressure equal to at least 1.5 times the nominal working pressure.

Tensile testing: pipe specimens undergo tensile testing according to EN 10216-2, complying with the minimum strength values.

This international standard specifies requirements for seamless and welded pipes made of low-temperature carbon and alloy steel. These pipes are intended for service at low temperatures and retain their strength characteristics even at extremely low temperatures, such as -45°C and below. Their main applications include cryogenic plants, the oil and gas industry, and the chemical and energy industries.

1. Steel Grades

   ASTM A333 includes several steel grades that differ in chemical composition and mechanical properties:

   • Grade 1 — carbon steel, widely used for low-temperature conditions.
   • Grade 6 — alloy steel with improved impact toughness characteristics.
   • Grades 3, 4, 7, 8, 9, 10, 11 — special steel grades for operation in even more extreme conditions.

The steel grades include alloying elements such as manganese (Mn), silicon (Si), phosphorus (P), sulfur (S), and small amounts of other additives.

2. Main Pipe Dimensions
   • Outer diameter of pipes — from 10.3 mm to 1219 mm (from 1/8 inch to 48 inches).
   • Wall thickness — from 1.65 mm to 40 mm (0.065 inches and above).
   • Pipe length — pipes are supplied in random length, definite length, and cut length as per customer request.
3. Mechanical Properties

   Pipes according to ASTM A333 have the following properties:

   • Yield Strength — the minimum value depends on the grade and is about 240–415 MPa.
   • Tensile Strength — not less than 415 MPa.
   • Elongation — determined according to the standard and depends on the wall thickness.
   • Impact Toughness — pipes undergo impact testing at low temperatures to check their resistance to brittle fracture.
4. Testing and Quality Control

   The pipe control process according to ASTM A333 includes:

   • Impact testing — checking the toughness of the metal at low temperatures (e.g., at -45°C).
   • Tensile testing — checking the strength and elongation of the material.
   • Hydraulic testing — pipes are checked under pressure to ensure their tightness.
   • Non-destructive testing — ultrasonic and magnetic flaw detection are performed to detect cracks and defects.

Dimensional and geometric control — measuring the outer diameter, wall thickness, and length of the pipe.

GOST 17379-2001 is a Russian standard that regulates the technical requirements for flanges for piping systems operating at high pressures. The standard describes flanges used to connect pipelines operating in high temperature and pressure conditions and is used in various industries, such as oil and gas, chemical, energy, and others.

Main Provisions of GOST 17379-2001:

• Scope:
  • The standard applies to flanges used in pipelines operating under a pressure of 1.6 MPa to 25 MPa and higher.
  • It covers flanges for piping systems that can be operated at high pressures and temperatures, including systems operating with aggressive chemicals.
• Flange Types:
  • GOST 17379-2001 flanges can be flat, welded, and weld-on, as well as with various types of connections.
  • Depending on the operating conditions, the flanges may have different wall thicknesses, the diameter of which varies from 15 mm (DN 15) to 1500 mm (DN 1500) and more.
• Materials:
  • Flanges manufactured according to GOST 17379-2001 can be made of carbon, alloy, and stainless steels.
  • Depending on the operating conditions, the flanges can be made of materials more resistant to corrosion and high pressure, such as 12Kh18N10T, 15Kh5M, 20, 09G2S, and others.
• Pressure Classes:
  • The standard establishes several pressure classes for which the flanges are intended, including 16 MPa, 25 MPa, 40 MPa, and others, depending on the requirements for the piping system.
  • Flanges manufactured according to GOST 17379-2001 can be used for pipelines operating in extreme conditions, such as in oil and gas wells, heat exchangers, and other highly loaded systems.
• Testing:
  • All flanges manufactured according to GOST 17379-2001 must undergo a hydrostatic pressure test with a pressure that exceeds the working pressure by 1.5 times to check their tightness and strength.
  • Additional tests may also be carried out for resistance to high pressure, temperature fluctuations, and exposure to aggressive chemicals.
• Application:
  • GOST 17379-2001 is used for piping systems in the oil and gas industry, chemical industry, energy sector, as well as in other industries where the use of piping systems operating under high pressure and temperature is required.
  • This standard is applicable for pipelines that transport oil, gas, chemicals, as well as for systems used in heat exchangers and other highly loaded installations.

GOST 17376-2001 is a Russian standard that regulates the production of flanges and pipeline connections for systems operating under pressure. The standard is more focused on flanges with large diameters and for higher pressures. It includes stricter requirements for flanges for special operating conditions.

It establishes requirements for flanges used in piping systems, including their dimensions, materials, testing methods, and quality. This standard applies in various industries, including oil and gas, chemical, and energy.

Key Technical Specifications

• Flange Types:
  • Welded flanges (for connections with pipes by welding).
  • Flanges with large diameters, which are used in larger and more heavily loaded pipelines.
• Diameter Range:
  • GOST 17376-2001 flanges can be manufactured for pipelines with diameters from 50 mm (DN 50) to 2500 mm (DN 2500) and larger.
• Pressure Classes:
  • GOST 17376-2001 flanges are designed to operate at higher pressures, for example, 6.3 MPa, 10 MPa, 16 MPa, 25 MPa, and higher.
• Materials:
  • Carbon steels (e.g., 20, 09G2S, 09G2).
  • Stainless steels (e.g., 12Kh18N10T).
  • Alloy steels (e.g., 15Kh5M, 16GS).
• Wall Thickness and Dimensions:
  • The standard establishes precise dimensions for flanges, including wall thickness, hole diameter, and other parameters, to ensure the strength of connections and their tightness.

• Material Quality:
  • All materials for the manufacture of flanges must comply with established quality standards and have appropriate certificates confirming their compliance with mechanical and chemical requirements.
• Welding and Connections:
  • For welded flanges, strict requirements must be observed for the quality of welds to avoid defects such as cracks, pores, and other damages.
• Testing:
  • Flanges must undergo a hydrostatic pressure test, which exceeds the operating pressure, to check the tightness and strength of the connections.
• Surface Treatment:
  • Flange surfaces must be cleaned of contaminants, rust, and other defects, and treated to prevent corrosion and improve sealing properties.

GOST 17375-2001 is a Russian standard that regulates the production of flanges for piping systems operating under pressure. It defines technical requirements, testing methods, as well as requirements for the quality and materials of flanges used in pipelines in various industries, including oil and gas, chemical, energy, and others.

Purpose

GOST 17375-2001 standard is intended for flanges used to connect piping systems operating under pressure. It provides standardization of dimensions, materials, mechanical properties, and testing methods, which allows ensuring the reliability and safety of pipeline connections.

Key Technical Specifications

• Flange Types:
  • Flat flanges (for connections with bolts and nuts).
  • Welded flanges (for connections with pipes by welding).
  • Weld-on flanges.
• Diameter Range:
  • From 15 mm (DN 15) to 1500 mm (DN 1500) and more, depending on the pressure class and flange type.
• Pressure Classes:
  • The standard covers flanges intended for operation at medium pressures, for example, 0.25 MPa, 0.6 MPa, 1.0 MPa, 1.6 MPa, 2.5 MPa, 4.0 MPa.
• Materials:
  • Carbon steels (e.g., 20, 09G2S).
  • Stainless steels (e.g., 12Kh18N10T).
  • Alloy steels (e.g., 15Kh5M).
• Wall Thickness and Dimensions:
  • The wall thickness of flanges and other geometric parameters are strictly regulated by the standard to ensure the strength and tightness of connections.

Key Requirements

• Material Quality:
  • Materials for the manufacture of flanges must comply with the steel grades specified in the standard and have quality certificates confirming their compliance with mechanical and chemical requirements.
• Welding and Connections:
  • For welded flanges, high-quality control of welds is required to avoid defects such as cracks, pores, and other damages.
• Testing:
  • Flanges must undergo hydrostatic pressure tests, which exceed the operating pressure, to check the tightness and strength of the connections.
• Surface Treatment:
  • Flange surfaces must be cleaned of contaminants, rust, and other defects, and treated to prevent corrosion and improve sealing properties.

Application Areas

• Oil and Gas Industry: for transporting oil, gas, and processed products.
• Chemical Industry: for working with aggressive chemicals and liquids.
• Energy Sector: for steam pipes, heat exchange systems, and other piping networks.
• General Industrial Applications: for water supply, heating, and other engineering systems.

GOST 33259-2015 — Steel flanges for connecting pipelines, fittings, and equipment

1. Purpose

GOST 33259-2015 establishes the requirements for steel flanges used to connect pipelines, shut-off valves, and equipment. The standard regulates the main dimensions, types of sealing surfaces, materials, and quality control methods for flanges.

2. Flange Types

Depending on the method of attachment and construction, the standard includes the following types of flanges:

• Weld neck flanges (type 11) — butt-welded to the pipe;
• Flat flanges (type 01) — lap-welded to the pipe;
• Threaded flanges (type 13) — attached by a threaded connection;
• Lapped flanges (type 02) — used with weld-on rings or stubs;
• Blind flanges (type 05) — used to seal the ends of pipelines.

3. Key Technical Specifications

• Diameters: From DN 10 to DN 4000 (nominal diameters).
• Pressure Classes: From PN 2.5 to PN 250 (from 0.25 to 25 MPa).
• Materials:
  • Carbon steel (steels 20, 09G2S, and others).
  • Stainless steel (12Kh18N10T, AISI 304, 316, etc.).
  • Alloy steel (15Kh5M and other steels for operation in aggressive environments and at high temperatures).

4. Sealing Surfaces

GOST 33259-2015 describes the following types of sealing surfaces for flanges:

• Flat Face (FF) — used at low pressures.
• Raised Face (RF) — standard option for operation at medium and high pressures.
• Tongue and Groove (TG) — provides a more reliable tight connection.
• Male and Female (MF) — similar to tongue and groove, but with a different geometry.
• Ring Type Joint (RTJ) — used for ultra-high pressures.

5. Key Dimensions and Tolerances

• Bolt Hole Diameters: Depending on the nominal diameter (DN) and nominal pressure (PN).
• Flange Thickness: Depends on the pressure and diameter. For example, for DN 50 and PN 40, the flange thickness is 20 mm, and for DN 1000 and PN 2.5, it is up to 40 mm.
• Number and Size of Bolts: Increases depending on the pressure class and diameter. For example, for DN 100 and PN 10, 4 bolts with a diameter of 18 mm are provided, and for DN 1000 and PN 250 — up to 36 bolts with a diameter of 52 mm.

Dimensional Tolerances:

• Flange Thickness: ±1 mm for DN up to 600 mm, ±2 mm for DN over 600 mm.
• Flatness Deviation: up to 0.5 mm for DN up to 500 mm and up to 1 mm for DN over 500 mm.

6. Inspection and Testing

• Visual inspection — the geometry, absence of cracks and defects on the surface are checked.
• Ultrasonic testing — is used to detect internal defects in the metal.
• Mechanical tests — control of hardness, impact toughness, tensile, and other parameters.
• Dimensional control — checks the compliance of thickness, diameters, and other dimensions with the established tolerances.

7. Application

Flanges according to GOST 33259-2015 are used in the following industries:

• Oil and gas industry — connection of pipelines for transporting oil, gas, and petroleum products.
• Chemical industry — for working with aggressive environments.
• Energy industry — at thermal and nuclear power plants.
• Municipal systems — water supply and heating pipelines.

8. Advantages

• Wide range of sizes and pressures — from small to extra-large flanges.
• Versatility — the ability to work in high-temperature and aggressive environments.
• Tightness of connections — thanks to sealing surfaces of different types.
• Strength and stability — the ability to work at high pressures (up to 25 MPa) and temperatures.

GOST 12822-80 — Flat steel flanges for pipeline connections

Purpose

GOST 12822-80 establishes requirements for flat steel flanges used to connect pipelines, fittings, and process equipment. These flanges provide a reliable and tight connection and are used at various operating pressures and temperatures.

Key Technical Specifications

• Flange Type: Flat welded flange (lap welding).
• Diameters: Nominal diameters (DN) from 10 mm to 1600 mm.
• Pressure Classes: From Ру 0.1 to Ру 2.5 MPa (from 1 to 25 kgf/cm²).
• Materials: Carbon steel, low-alloy steel, stainless steel.
• Sealing Surface Type:
  • Smooth;
  • Raised face;
  • Recess;
  • Raised face and recess;
  • Tongue and groove.

Dimensions and Tolerances

• Flange Thickness: Depends on the diameter (DN) and pressure (Ру). For DN 50 mm and Ру 1 MPa, the thickness is 12 mm, and for DN 1600 mm and Ру 2.5 MPa, it is up to 40 mm.
• Bolt Hole Diameter: Regulated for each DN and Ру.
• Number and Diameter of Bolts: Depends on the diameter and pressure class. For example, for DN 50 mm and Ру 1 MPa, 4 bolts with a diameter of 14 mm are used, and for DN 1600 mm and Ру 2.5 MPa, 32 bolts with a diameter of 36 mm are used.
• Dimensional Tolerances:
  • Flange Thickness: ±1.0 mm for DN up to 600 mm, ±2.0 mm for DN over 600 mm.
  • Flatness Deviation: up to 0.5 mm for DN up to 500 mm and up to 1 mm for DN over 500 mm.

Application

Flat flanges according to GOST 12822-80 are used for installing pipelines, fittings, and equipment in systems with low and medium pressure. Main application areas:

• Oil and gas industry;
• Chemical and petrochemical industry;
• Water supply and heating systems;
• Energy and metallurgical industry.

GOST 12821-80 — Steel weld neck flanges for pipeline connections

1.Purpose

GOST 12821-80 establishes the requirements for steel weld neck flanges used to connect pipelines, fittings, and equipment. Weld neck flanges provide a reliable, tight connection at high pressures and temperatures.

2.Key Technical Specifications

• Diameters: Nominal diameters (DN) from 10 mm to 1600 mm.
• Pressure Classes: From Ру 1.0 to Ру 20.0 MPa (from 10 to 200 kgf/cm²).
• Connection Type: Butt welding.
• Materials: Carbon, low-alloy, and stainless steel.
• Sealing Surface Type:
  • Smooth;
  • Raised face and recess;
  • Tongue and groove.

3.Dimensions and Tolerances

• Neck Thickness: Depends on the pressure and nominal diameter. For DN 10 mm at Ру 1 MPa, the thickness is 16 mm, and for DN 1600 mm at Ру 20 MPa, it is up to 90 mm.
• Sealing Surface Diameter: Regulated by the tables of the standard for each DN and Ру.
• Dimensional Deviations:
• Thickness: ±1.0 mm for diameters up to 600 mm and ±2.0 mm for diameters over 600 mm.
• Flatness Deviation: For DN up to 500 mm — 0.3 mm; for DN from 500 mm and above — 0.5 mm.

4.Application

Weld neck flanges according to GOST 12821-80 are used for installing pipelines, fittings, and equipment in conditions of increased requirements for tightness and resistance to high pressures and temperatures. Used in the following industries:

• Oil and gas industry;
• Chemical industry;
• Energy sector;
• Metallurgical industry.

5.Advantages of weld neck flanges

• High strength due to the “butt welding” connection;
• Resistance to high pressures and temperatures;
• Increased tightness due to various options for sealing surfaces;
• Durability and corrosion resistance when using stainless and alloy steels.

This standard ensures the versatility and reliability of pipeline connections and is widely used in high-pressure and high-temperature industrial systems.

GOST 12820-80 — Flat steel flanges for pipeline connections

1.Purpose

GOST 12820-80 establishes the requirements for flat steel flanges used to connect pipelines, fittings, and other equipment. These flanges are used for systems with a nominal pressure from 0.1 to 2.5 MPa (1–25 kgf/cm²).

2.Key Technical Specifications

• Diameters: Nominal diameters (DN) from 10 mm to 1600 mm.
• Pressure Classes: From Ру 0.1 to Ру 2.5 MPa (from 1 to 25 kgf/cm²).
• Materials: Carbon, low-alloy, and stainless steel.
• Flange Type: Flat flange (butt-welded).
• Sealing Surface Shape: Smooth surface, tongue-and-groove, or raised face-and-recess.

3.Dimensions and Tolerances

• Flange Thickness: Depending on the diameter and pressure, the thickness varies from 12 mm to 58 mm.
• Thickness Tolerances: ±1.0 mm.
• Diameter Tolerances: For seating surfaces — ±1 mm for DN up to 500 mm and ±3 mm for DN over 500 mm.
• Flatness Deviation: For flanges with a diameter up to 500 mm — up to 0.3 mm, for flanges larger than 500 mm — up to 0.5 mm.

4.Application

GOST 12820-80 is used in the oil and gas, chemical, energy, and other industries for connecting piping systems to equipment or fittings.

The standard regulates the requirements for spectacle blind flanges (or line blinds) for use in piping systems. These flanges are intended for use in pipeline sections where it is necessary to provide the possibility of rotating the flange or blind relative to the axis of the pipe to compensate for possible axial and angular deviations. Spectacle blind flanges are widely used in pipelines where connections are needed that allow components to rotate without changing their position relative to other parts of the system.

Key characteristics and requirements of ASME B16.48 for Spectacle Blind Flanges:

• Diameters:
  • Flanges covered by this standard can be made in the range from 1/2 inch (DN 15) to 60 inches (DN 1500) and larger, depending on the pressure class and pipe diameter.
• Pressure Classes:
  • ASME B16.48 flanges can be made for pressure classes from 150 to 2500.
• Flange Types:
  • The standard describes spectacle blind flanges with the ability to rotate for connections providing mobility. These flanges can be with one hole or with several bolt holes.
• Materials:
  • Flanges can be made of various materials, including carbon steel, alloy steel, stainless steel, and other alloys, meeting the operating requirements for a specific application.
• Wall Thickness:
  • The minimum blind thickness is determined based on the pressure class and nominal diameter. For each class (150-2500), the thickness increases proportionally to the pressure and diameter.
• Dimensional Tolerances:
  • Thickness Tolerances: The permissible thickness deviation is ±0.25 mm or 1% of the nominal thickness, whichever is greater.
  • Diameter Tolerances: The tolerance on the diameter of the blind bore is usually ±1 mm for small diameters and up to ±3 mm for larger sizes.
  • Geometric Deviations: The flatness deviation should not exceed 0.3-0.5 mm for every 500 mm of diameter.

This European standard covers flanges for piping systems. It specifies requirements for flanges used to connect pipelines, valves, pumps, and other equipment, and includes standards for various pressure classes, flange types, and their materials.

Key characteristics and requirements according to EN 1759-1:

• Flange Types:
  • Weld Neck Flanges,
  • Plate Flanges,
  • Slip-On Flanges,
  • Threaded Flanges.
• Pressure Classes:
  • Flanges can be classified by pressure, for example, PN 6, PN 10, PN 16, PN 25, PN 40, etc.
  • The standard covers flanges with pressure classes up to PN 400.
• Materials:
  • Various materials are used, including carbon steel, stainless steel, and alloy steels. Materials comply with European standards for chemical composition and mechanical properties.
• Sizes:
  • Flange diameters vary depending on the type and class, ranging from DN 10 to DN 4000 (from 1/8” to 160”).
• Dimensional Tolerances:
  • The standard defines tolerances for diameter, wall thickness, hole diameter, as well as standard dimensions for each class of flange.
• Testing and Inspections:
  • Includes requirements for testing flanges for leak tightness and strength.

This European standard describes flanges used for pipeline connections. The standard covers flanges of various types and classes, including flanged flanges (e.g., weld neck flanges, slip-on flanges, threaded and lapped flanges).

Key characteristics and requirements according to EN 1092-1:

• Flange Types:
  • Weld Neck Flanges,
  • Slip-on Flanges,
  • Threaded Flanges,
  • Plate Flanges.
• Materials:
  • Carbon steel, alloy steel, stainless steel,
  • Materials comply with standards for different operating conditions.
• Diameters:
  • Flanges are available for pipe diameters from DN 10 to DN 4000 (from 1/8” to 160”).
• Pressure Classes:
  • Pressure classes from PN 2.5 to PN 400.
• Wall Thickness and Tolerances:
  • Depend on the pressure class, diameter, and type of flange, including tolerances on the flange diameter and wall thickness to ensure a tight connection.
• Additional Requirements:
  • Surface treatment (e.g., grinding and polishing),
  • Requirements for the chemical composition of materials,
  • Leak testing.

This standard is used in pipeline systems in various industries, such as the petrochemical industry, the gas industry, the energy sector, and others, where a high-quality and durable pipeline connection is required.

ASME B16.47 Series A and B are standards developed by the American Society of Mechanical Engineers (ASME) that describe requirements for large diameter flanges for use in piping systems. These standards include two different types of flanges depending on the design:

1. ASME B16.47 Series A — flanges with larger diameters and higher wall thickness, designed for use in heavy-duty applications, such as in the petrochemical and gas industry. They are often manufactured to stricter design standards and are intended for higher loads.
2. ASME B16.47 Series B — flanges with less thick walls and more lenient requirements for materials and their processing. These flanges are intended for less demanding applications where such high strength is not required, as with Series A flanges.

Diameters: Flanges according to this standard can have diameters from 12 to 60 inches for Series A and from 12 to 48 inches for Series B.

Pressure Classes: Flanges are available in pressure classes from 150 to 2500, depending on the type of flange and its application.

Materials: Flanges can be made of carbon steel, alloy steel, stainless steel, and other materials, depending on the operating conditions and requirements for corrosion resistance.

Flange Types: Include weld neck flanges, slip-on flanges, as well as lap joint and threaded flanges.

Sizes:

• Series A: 12” - 60” (305 mm - 1524 mm).
• Series B: 12” - 48” (305 mm - 1219 mm).

Wall Thickness:

• For 12” to 24” in class 150: 0.375” (9.525 mm).
• For 12” to 24” in class 2500: 1.125” (28.575 mm).
• For 30” to 48” in class 150: 0.500” (12.7 mm).
• For 30” to 48” in class 2500: 1.250” (31.75 mm).

Tolerances:

• Bore Diameter: ±0.125” (±3.175 mm).
• Flange Diameter (12” - 24”): ±0.250” (±6.35 mm); (30” - 60”): ±0.375” (±9.525 mm).
• Wall Thickness: ±0.0625” (±1.5875 mm).

ASME B16.36 standard regulates flanges intended for use in pipe, valve, pump, and other equipment connections where pressure fluctuations are possible at the connection point.

1.Types of Flanges according to ASME B16.36

• Weld Neck Flanges (WN)
  • Have a tapered conical transition to the pipe to reduce stress concentration.
  • Used for heavy-duty operating conditions and high pressures.
  • Comply with pressure classes: 300, 400, 600, 900, 1500, and 2500 psi.
• Lap Joint Flanges (LJ)
  • Not welded to the pipe but rest on a special pipe end (nipple or flanged end).
  • Facilitate installation because the flange rotates freely around the pipe.
  • Comply with pressure class: 300 psi.
• Threaded Flanges (THD)
  • A thread is cut into the inside of the flange bore for connection to the pipe.
  • Used for small-diameter pipes or when welding is not possible.
  • Comply with pressure class: 300 psi.

2.Flange Materials

Carbon, alloy, and stainless steels complying with the following standards are used to manufacture flanges according to ASME B16.36:

• ASTM A105 — carbon steel for flanges used at high temperatures.
• ASTM A182 — stainless and alloy steel.
• ASTM A350 — low-temperature carbon steel.

3.Diameters and Dimensions of Flanges according to ASME B16.36

Nominal Pipe Size (NPS): from ½” to 24” (from 15 mm to 600 mm).

Element Dimensions:

• Diameter of the nozzle (collar) bore — according to ASME B16.36.
• Thickness of the flange part, diameter of the outer edge, location and size of bolt holes — depending on the pressure class and NPS.

4.Application: Oil and gas, chemical, petrochemical, energy industries.

5.Quality Control: Visual inspection, geometry control, hydraulic testing, material verification.

ASME B16.5 Standard for Pipe Flanges and Flanged Fittings: Regulates the design, dimensions, tolerances, materials, and testing methods for flanges and flanged fittings for pipelines and equipment used in the petrochemical, gas, and energy industries. Key characteristics of the standard include:

1. Flange Types

• Plate Flanges, Flat Face (FF)
• Weld Neck (WN)
• Threaded (THD)
• Slip-On (SO)
• Blind (BL)
• Lap Joint (LJ)

2. Diameters and Pressure Classes

• Nominal Pipe Sizes (NPS): from ½” to 24”
• Pressure Classes: 150, 300, 400, 600, 900, 1500, 2500 (in pounds per square inch, psi)

3. Flange Materials

The standard allows the use of carbon, stainless, and alloy steels, as well as non-ferrous metals. The most commonly used are:

• ASTM A105 (carbon steel)
• ASTM A182 (stainless and alloy steel)
• ASTM A350 (low-temperature steels)
• ASTM B462 (non-ferrous metals)

4. Design Features

• Types of jointing faces:
  • Raised Face (RF)
  • Flat Face (FF)
  • Ring Type Joint (RTJ)
• Gasket types: gaskets made of metal, graphite, and composite materials are used to ensure tightness.

5. Mechanical Properties and Quality Control

• Tightness control: hydraulic and pneumatic tests.
• Mechanical properties: strength and ductility depend on the material (for example, for ASTM A105, the tensile strength is 485 MPa, the yield strength is 250 MPa).
• Corrosion resistance: materials resistant to corrosive environments (e.g., H₂S) are used, which complies with NACE MR0175.

6. Application

ASME B16.5 flanges are used in:

• Oil and gas industry (main pipelines, refinery equipment)
• Petrochemical industry (reactors, heat exchangers)
• Energy (steam and hot water boilers, turbines)

The international standard that regulates the requirements for equipment and components used in the oil and gas industry. This standard covers flanges, valves, fittings, and other equipment elements operating under high pressure.

Scope of Application

• API 6A applies to the following elements:
• Flanges and connecting elements;
• Valves (valves, gates);
• Crosses and tees;
• Components and equipment parts for subsea oil and gas production.

Materials and their Control

• Materials must be resistant to aggressive environments (H₂S, CO₂) and corrosion.
• High-strength carbon and alloy steels are used with control of impurity content.
• Mechanical properties control is applied:
  • Tensile Strength (UTS): 550–950 MPa (80,000–137,800 psi)
  • Yield Strength (YS): 355–758 MPa (51,500–110,000 psi)
  • Hardness: no more than 22 HRC or 250 HB for resistance to cracking in H₂S environments (in accordance with NACE MR0175)
  • Operating temperature classes: from -46°C to +180°C depending on the requirements of the classes (L, U, X, Y)

Types of Flanges (by construction)

• Weld Neck Flanges — for high pressures and temperatures.
• Blind Flanges — for sealing pipelines.
• RTJ Flanges (Ring Type Joint) — to ensure tightness under pressure.
• End Flanges — for connections at the ends of pipelines.

Pressure Ratings

API 6A classifies flanges and elements by pressure levels (PSL — Product Specification Level) from 2000 psi to 20,000 psi.

• 2000, 3000, 5000, 10,000, 15,000, 20,000 psi — depending on operating conditions.

Types of Sealing Connections

• RTJ (Ring Type Joint) — metal rings for high pressures and temperatures.
• RF (Raised Face) — sealing surface with a raised face for additional tightness.

Testing and Quality Control

• Hydraulic testing — checking for leaks under pressure.
• Non-destructive testing (NDT) — ultrasonic and radiographic diagnostics of welds and surfaces.
• Tests for resistance to H₂S exposure (hydrogen sulfide environment) according to NACE MR0175/ISO 15156.

Product Specification Levels (PSL 1 - PSL 4)

• PSL 1 — basic level, the simplest with minimal requirements.
• PSL 2 — increased requirements for the quality of materials and control methods.
• PSL 3 — strict quality control and complete test documentation.
• PSL 4 — maximum requirements for subsea production systems (Subsea).

ASME B16.11 — Standard for Forged Fittings, Socket-Welding and Threaded

Purpose

ASME B16.11 establishes the requirements for small diameter fittings (up to 4 inches) for threaded and socket-welding connections. These fittings are used to create leak-proof connections in pipelines operating under high pressure and at high temperatures.

Types of Fittings

• Threaded Fittings:
  • Couplings (connecting pipes of the same diameter).
  • Elbows (90° and 45°) — changing the direction of the pipeline.
  • Tees (straight and reducing) — creating branches.
  • Plugs (plugs and caps) — sealing the ends of the pipeline.
  • Nipples and adapters — connecting various elements of the pipeline.
• Socket-Welding Fittings:
  • Elbows (90°, 45°).
  • Tees (straight and reducing).
  • Couplings and Half-Couplings.
  • Crosses — creating cross connections.
  • Caps (end caps).

Key Technical Specifications

• Diameters: from 1/8” to 4” (from 6 mm to 100 mm).
• Pressure classes: 2000, 3000, 6000 and 9000 (depending on the type of fitting and application).
• Wall thickness: corresponds to the parameters of the pipeline and pressure class.
• Materials: carbon, alloy and stainless steel.

Tolerances and Accuracy

• Thread: according to ASME B1.20.1 (NPT thread).

Fitting Geometry: strict tolerances on angles, diameters and dimensions of sockets and threads.

Surface quality: fittings should not have cracks, pits and other defects.

Application

• Oil and gas industry.
• Oil refineries (refineries).
• High pressure systems.
• Pipelines for aggressive media and high temperatures.

Advantages of ASME B16.11 Standard

• Ensuring reliable connections in high pressure systems.
• Resistance to vibrations and shock loads.
• Ease of installation and dismantling during maintenance.

ASME B16.11 is widely used for small diameter fittings, providing ease of installation and tightness of connections in high pressure systems, including at oil and gas, chemical and energy facilities.

ASME B16.9 — Standard for Pipe Fittings

Purpose

ASME B16.9 establishes the requirements for seamless and welded steel pipe fittings. These fittings are used for connecting pipes, changing their direction or diameter, and plugging the ends of pipelines.

Types of Fittings

• Elbows (45°, 90°, 180°) — changing the direction of the pipeline.
• Tees (straight and reducing) — creating branches in the pipeline.
• Reducers (concentric and eccentric) — connecting pipes of different diameters.
• Caps — hermetically sealing the end of the pipeline.

Key Technical Specifications

1. Diameters: from 1/2” to 48” (from 15 mm to 1200 mm).
2. Wall thickness: corresponds to pipes according to ASME B36.10 and B36.19 standards.
3. Materials: carbon, alloy, and stainless steel.
4. Pressure classes: from Class 150 to Class 2500 (depending on the applicable pipe standard).

Accuracy and Tolerances

1. Ovality: ovality is allowed no more than 1% of the outer diameter of the pipe.
2. Wall thickness: the minimum wall thickness must comply with the pipeline standard.
3. Dimensions and length of straight sections: strict tolerances on length and dimensions are defined for tees, elbows, and reducers.

Application

• Oil and gas industry.
• Oil refineries (refineries).
• Energy and chemical industry.
• High pressure and temperature pipeline systems.

ASME B16.9 is an internationally recognized standard that is used worldwide for the production of fittings that provide a reliable connection of pipelines in harsh operating conditions.