— A Complete Guide to Russian Nuclear and Supercritical Power Plant High-Temperature, High-Pressure Piping Materials

Sanonpipe – Your Trusted Supplier of Russian ТУ Standard Boiler Tubes

I. Standard System Positioning: A “Special Technical Specification” for Nuclear and Thermal Power Boiler Tubes

ТУ 3-923-75 is a dedicated technical specification (ТУ – Technical Conditions) developed by Russia for seamless steel tubes used in nuclear power plant and thermal power plant boiler systems. Unlike general national standards (ГОСТ), ТУ standards are typically tailored for specific industrial applications, imposing stricter and more targeted technical requirements.

This standard is primarily applied by major Russian heavy machinery manufacturers such as НКМЗ (Novokramatorsk Machine-Building Plant) and is one of the core material standards for high-temperature, high-pressure piping systems in Russian nuclear and thermal power sectors. Across Russia and the CIS market, this standard is widely used for nuclear power main steam pipelines, boiler superheater tubes, reheater tubes, and other critical equipment, making it an essential technical basis for pipe procurement in nuclear and thermal power generation.

Key features of the standard: ТУ 3-923-75 imposes stringent requirements on chemical composition, mechanical properties, heat treatment processes, and non-metallic inclusion control, ensuring long-term safe operation under the extreme working conditions of nuclear power plants and supercritical units.

Material composition: The standard primarily covers two core grades – 16ГС (16GS) low-alloy structural steel and 15Х1М1Ф (15Kh1M1F) low-alloy heat-resistant steel.

II. Material 16ГС (16GS) in Detail – Low-Alloy High-Strength Structural Steel

16ГС (Latin transliteration: 16GS) is a low-alloy high-strength structural steel under the Russian standard system, widely used in boiler, pressure vessel, and welded structural component manufacturing.

International equivalent grades:

Standard System	Equivalent Grade	Remarks
China (GB)	Q345D (formerly 16Mn)	Low-alloy high-strength structural steel
General international	Low-alloy Mn-Si system structural steel	—

Chemical composition (wt%): It is a low-carbon, high-manganese steel with carbon ≤0.20%, manganese 1.30–1.70%, and silicon 0.50–0.80%, offering excellent weldability and low-temperature toughness.

Mechanical properties:

Tensile strength: 470–640 MPa

Yield strength: 305–345 MPa (depending on thickness)

Low-temperature impact toughness: meets -40°C impact requirements

Typical applications:

Boiler piping systems in nuclear and thermal power plants

Structural components for steam boilers and pressure vessels

Welded pressure equipment and metal structures

Material characteristics: 16ГС features excellent weldability, good low-temperature toughness, and relatively high strength, making it a key material for boiler piping in nuclear and thermal power applications.

III. Material 15Х1М1Ф (15Kh1M1F) in Detail – A Benchmark Low-Alloy Heat-Resistant Steel

15Х1М1Ф (Latin transliteration: 15Kh1M1F) is a low-alloy heat-resistant steel under the Russian standard system, primarily positioned for nuclear and supercritical thermal power high-temperature, high-pressure service. This pearlitic heat-strengthened steel incorporates alloying elements such as chromium (Cr), molybdenum (Mo), and vanadium (V) to significantly enhance creep strength at elevated temperatures, oxidation resistance, and long-term service stability.

Material designation breakdown: 15 indicates carbon content of about 0.15%, Х stands for chromium (Cr), 1 for chromium content of about 1%, М for molybdenum (Mo), 1 for molybdenum content of about 1%, and Ф for vanadium (V).

International equivalent grades:

Standard System	Equivalent Grade	Remarks
China (GB/T 3077)	15Cr1Mo1V	Low-alloy heat-resistant steel, core material for domestic thermal power units
Germany (DIN/EN)	15CrMoV5-9 / 1.8521	—

Chemical composition (wt%) – Typical requirements per ТУ 3-923-75:

Element	Content Range	Role/Explanation
C (Carbon)	0.10 – 0.16	Balances strength and toughness
Si (Silicon)	0.17 – 0.37	Improves oxidation resistance
Mn (Manganese)	0.40 – 0.70	Enhances strength and hardenability
Cr (Chromium)	1.00 – 1.40	Forms a dense oxide film, providing corrosion and heat resistance
Mo (Molybdenum)	0.90 – 1.10	Boosts high-temperature strength and creep resistance
V (Vanadium)	0.20 – 0.25	Refines grain structure and improves thermal strength
Ni (Nickel)	≤ 0.25	Improves toughness
S (Sulphur)	≤ 0.025	—
P (Phosphorus)	≤ 0.025	—

15Х1М1Ф is chemically very close to China’s 15Cr1Mo1V, which has been widely used in over 20 imported 300 MW and above thermal power units for main steam pipes, reheat steam pipes, and headers. Its technical maturity and engineering reliability have been fully validated.

Mechanical properties:

Tensile strength: ≥ 500 MPa

Yield strength: ≥ 320 MPa

Elongation (δ5): ≥ 18% (longitudinal) / ≥ 16% (transverse)

Impact toughness (KCU): ≥ 500 kJ/m² (longitudinal) / ≥ 400 kJ/m² (transverse)

Key performance features:

Thermal strength: The combined addition of Mo and V significantly improves creep rupture strength at elevated temperatures.

Microstructural stability: After normalising and high-temperature tempering, a stable bainite/tempered sorbite structure is obtained.

Recommended operating temperature: Capable of long-term stable service at temperatures up to +585°C.

Nuclear suitability: Suitable for nuclear power plant (AC) equipment and piping systems.

Typical application areas:

Application	Specific Use	Service Conditions
Nuclear power	Main steam lines, high-pressure equipment piping	High temperature, high pressure, radiation environment
Thermal power	Supercritical/ultra-supercritical boiler superheater tubes, reheater tubes, main steam pipes	Temperatures ≤585°C, supercritical pressures
Boiler manufacturing	High-pressure boiler tubes, steam boiler piping	High steam parameters, long-term service
Pressure vessels	High-temperature pressure vessels	High-temperature pressure

IV. Technical Rigour of the ТУ 3-923-75 Standard

As a dedicated standard for nuclear and thermal power boiler tubes, ТУ 3-923-75 imposes extremely strict technical requirements:

Heat treatment process: The standard specifies precise heat treatment for 15Х1М1Ф, typically normalising + high-temperature tempering, to achieve a stable bainite/tempered sorbite structure. Accurate control of the heat treatment process directly determines the microstructural stability and mechanical property retention during long-term high-temperature service.

Tight chemical composition control: Strict limits on harmful impurities such as sulphur and phosphorus ensure material cleanliness and reliability over extended high-temperature operation.

Non-destructive testing: Every tube must undergo ultrasonic testing (UT) and eddy current testing (ET) to guarantee freedom from internal defects.

V. Quality Assurance and CBAM Compliance Support

Quality assurance:

Each batch comes with a complete MTC (Mill Test Certificate)

EN 10204 3.1/3.2 certificates available upon request

Third-party inspections by SGS, BV, TÜV supported

Full traceability from heat number to finished product

EU CBAM carbon tariff compliance support:

We provide product-specific carbon emission data based on actual site measurements

Assistance in preparing monitoring plans, emission reports, and other audit documentation

Helps you avoid the EU default value penalty mechanism and reduce carbon tariff costs

VI. Why Choose Sanonpipe?

Our Advantages	Details
Standard expertise	In-depth understanding of ТУ 3-923-75 and the Russian technical system, with accurate interpretation of nuclear and thermal power boiler tube requirements
Material assurance	Complete material certificates for 16ГС and 15Х1М1Ф, with simultaneous provision of Russian and Chinese equivalent grade documentation
Comprehensive size range	Available in outside diameters 10–630 mm and wall thicknesses 1–32 mm, covering mainstream requirements
Rapid delivery	Backed by a 20,000-tonne standing stock; emergency orders shipped within 7–15 days
Full-service support	From enquiry, technical clarification, and quotation to documentation and logistics – one-stop delivery
Zero-risk commitment	Over 240 internal quality control checkpoints and zero documentation discrepancies

 VII. Contact Us

Sanonpipe is dedicated to supplying high-quality seamless boiler tubes in compliance with ТУ 3-923-75 for the nuclear and thermal power sectors in Russia and the CIS region. Whether you need standard specifications or custom sizes, we offer professional technical support and flexible supply solutions.

Typical specification description examples:

Труба стальная бесшовная горячедеформированная 630×25 ТУ 3-923-75 / 16ГС
(Hot-rolled seamless steel tube 630×25, per ТУ 3-923-75, grade 16ГС)

Труба стальная бесшовная горячедеформированная 530×18 ТУ 3-923-75 / 15Х1М1Ф
(Hot-rolled seamless steel tube 530×18, per ТУ 3-923-75, grade 15Х1М1Ф)

Sanonpipe
+86 22 58658800
info@sanonpipe.com
www.sanonpipe.com

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