09MnD Low-Temperature Pipe Steel
09MnD Low-Temperature Pipe Steel - Q/TDGG0040 Standard Data & Cross-Reference
Comprehensive material data for 09MnD low-temperature pipe steel per enterprise standard Q/TDGG0040, including chemical composition, mechanical properties, physical properties, international equivalents, and application guidance.
Hot-finished or cold-drawn seamless; normalizing or normalizing + tempering; welding procedures possible for pipe fittings
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09MnD Low-Temperature Pipe Steel Introduction
09MnD is a low-alloy structural steel specifically designed for low-temperature service in welded pipes and seamless tubes. It is supplied under the Chinese enterprise standard Q/TDGG0040, which is closely aligned with GB/T 18984 for cryogenic seamless steel pipes. The steel provides excellent notch toughness at temperatures down to -45 °C and good weldability.
- Typical applications include cryogenic pressure piping, liquefied gas transmission, and low-temperature heat exchangers.
- Delivered in normalized or normalized and tempered condition to ensure fine-grain structure and consistent low-temperature properties.
- Controlled chemical composition with manganese as the main strengthening element and aluminum for grain refinement.
09MnD Low-Temperature Pipe Steel Chemical Composition
Chemical limits according to GB/T 18984-2016 (basis for Q/TDGG0040). The composition is designed to ensure adequate low-temperature toughness through controlled manganese content and fine-grain practice with aluminum addition. Residual elements are restricted to maintain weldability and ductility.
| Element | Specified Value (wt%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.12 | Ladle analysis |
| Silicon (Si) | 0.17 – 0.37 | |
| Manganese (Mn) | 1.15 – 1.50 | Key strength and toughness element |
| Phosphorus (P) | ≤0.020 | Max |
| Sulfur (S) | ≤0.010 | Max, for low-temperature ductility |
| Aluminum (Al) | ≥0.015 | Grain refining addition |
| Chromium (Cr) | ≤0.30 | Residual element |
| Nickel (Ni) | ≤0.30 | Residual element |
| Copper (Cu) | ≤0.20 | Residual element |
| Total residuals (Cr+Ni+Cu) | ≤0.60 |
09MnD Low-Temperature Pipe Steel Thermal and Electrical Physical Properties
Physical properties for 09MnD steel are typical for low-alloy carbon-manganese steels. These values are not part of the mandatory test requirements but are provided based on standardized literature data for similar grades. They may vary slightly depending on exact heat treatment and product form.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Elastic modulus (E) | 206 | GPa | 20 °C, dynamic method |
| Shear modulus (G) | 79.3 | GPa | Calculated from E and ν |
| Poisson ratio (ν) | 0.30 | - | Room temperature |
| Coefficient of thermal expansion (α) | 10.5 – 12.5 | ×10⁻⁶/K | Average between -45 °C and 20 °C |
| Thermal conductivity (λ) | 45 | W/(m·K) | at 20 °C |
| Specific heat capacity (c) | 460 | J/(kg·K) | at 20 °C |
| Electrical resistivity (ρe) | 0.23 | μΩ·m | at 20 °C |
09MnD Low-Temperature Pipe Steel Mechanical Properties
Mechanical requirements at room temperature and low-temperature impact toughness, as specified in GB/T 18984-2016 for 09MnD pipes. Tensile testing is performed in the longitudinal direction. Impact values are averaged over three specimens; single minimum allowed.
| Property | Specified Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength (ReH) | ≥275 | MPa | Wall thickness ≤16 mm |
| Yield strength (ReH) | ≥265 | MPa | Wall thickness >16 mm to 40 mm |
| Tensile strength (Rm) | 440 – 570 | MPa | Room temperature |
| Elongation after fracture (A) | ≥24 | % | Gauge length L0 = 5.65√S0; longitudinal |
| Impact energy (KV2) | ≥27 (average) | J | -45 °C, Charpy V-notch, transverse specimen |
| Impact energy (KV2) | ≥19 (single min.) | J | -45 °C, Charpy V-notch, transverse specimen |
09MnD Low-Temperature Pipe Steel Fully Equivalent Material Standards & Possible Substitute Grades
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 18984-2016 | 09MnD | Directly equivalent to the Q/TDGG0040 basis; chemical and mechanical requirements match. |
| USA | ASTM A333 / A333M | Grade 6 | Widely used low-temperature seamless pipe; similar Mn content, -45 °C impact test; minor differences in residual limits. |
| Europe | EN 10216-4 | P265NL | Low-temperature non-alloy steel; specified impact at -50 °C, comparable strength; verify production route and Ni content. |
09MnD Low-Temperature Pipe Steel Application Introduction
09MnD steel under Q/TDGG0040 is tailored for cryogenic piping systems and related equipment. Its balanced combination of strength, low-temperature toughness, and weldability makes it suitable for a broad range of industrial applications.
- The steel is commonly fabricated into seamless pipes and used for transporting liquefied gases such as LNG, liquid ethylene, and ammonia at temperatures down to -45 °C.
- Normalized delivery ensures consistent properties across wall thicknesses, and the material can be readily welded with pre- and post-heat treatment when required.
- Machining, bending, and forming operations are possible following standard practices for low-alloy grades.
Product Applications: Seamless steel pipes for cryogenic fluid transmission, Heat exchanger tubes for low-temperature service, Pressure vessel nozzles and connecting piping, Cryogenic storage tank pipework, Liquefied gas loading/unloading arms
Processed into products: Elbow fittings (long and short radius), Tee and reducer pipe fittings, Flanges (weld neck, slip-on, blind) in low-temperature carbon steel, Return bends for heat exchangers, Spool pieces and transition joints in cryogenic piping assemblies
Application industries: Oil & gas (onshore and offshore cryogenic storage and transport), Petrochemical (ethylene cracking units, low-temperature separation), Industrial gas (air separation units, LNG liquefaction plants), Refrigeration and cold storage, Power generation (cryogenic cooling circuits)
09MnD Low-Temperature Pipe Steel Similar / Alternative Materials for Low-Temperature Pipe Service
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 18984 | 16MnD | Higher Mn (1.60-1.90) for -60 °C service; may replace 09MnD where lower temperature capability is needed. |
| USA | ASTM A333 | Grade 3 | Contains 3.5% Ni for -101 °C; overqualified but can substitute if toughness margins require improvement. |
| Europe | EN 10216-3 | P355NL2 | Higher strength, impact at -50 °C; suitable for heavier wall low-temperature applications. |
Notes:
The Q/TDGG0040 enterprise standard may contain additional requirements such as tighter sulfur/phosphorus limits, ultrasonic testing, or specific flattening/bend tests for pipes. Users should confirm the exact specification scope with the manufacturer. This data sheet is provided as a general reference based on the publicly available GB/T 18984-2016 standard and typical physical properties for 09MnD type materials.
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