GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport: Properties & Equivalent Grades
Technical data sheet for Q295B fluid seamless pipe defined in GB/T 8163-2018, including chemical composition, mechanical and physical properties, international equivalents, and application guidelines.
Hot rolling, cold drawing, normalizing, quenching & tempering (delivery condition usually hot-rolled or as-rolled/N)
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GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Introduction
Q295B is a low-alloy high-strength structural steel grade specified in GB/T 8163-2018 for seamless steel pipes used in fluid transport. It offers a minimum yield strength of 295 MPa and excellent weldability, making it suitable for conveying water, oil, gas, and steam under moderate pressure. The material is supplied in hot-rolled or heat-treated condition and can be easily fabricated into piping components. With controlled sulfur and phosphorus content (B quality level), it provides good toughness at ambient temperature and is widely used in civil engineering, machinery, and energy industries.
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Chemical Composition
Chemical composition according to GB/T 8163-2018 for steel grade Q295B. All values are maximum unless a range is given. Aluminium is present as a deoxidizer; other residual elements are controlled to ensure weldability and mechanical properties.
| Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.16 | |
| Silicon (Si) | ≤ 0.55 | |
| Manganese (Mn) | 0.80 – 1.50 | |
| Phosphorus (P) | ≤ 0.030 | B quality requires lower P than A quality |
| Sulfur (S) | ≤ 0.030 | B quality requires lower S than A quality |
| Niobium (Nb) | ≤ 0.07 | Residual element |
| Vanadium (V) | ≤ 0.15 | Residual element |
| Titanium (Ti) | ≤ 0.20 | Residual element |
| Chromium (Cr) | ≤ 0.30 | Residual element |
| Nickel (Ni) | ≤ 0.30 | Residual element |
| Copper (Cu) | ≤ 0.30 | Residual element |
| Nitrogen (N) | ≤ 0.012 | |
| Molybdenum (Mo) | ≤ 0.10 | Residual element |
| Aluminium (Als) | ≥ 0.015 | Acid-soluble aluminium, or total Al agreed |
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Thermal and Electrical Physical Properties
Physical properties are typical for a low-alloy carbon-manganese steel at ambient temperature and are not specified in GB/T 8163-2018. These values serve as engineering references.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Elastic Modulus (E) | 200 – 210 | GPa | At room temperature |
| Shear Modulus (G) | 80 | GPa | At room temperature |
| Poisson's Ratio (ν) | 0.3 | – | At room temperature |
| Thermal Expansion Coefficient (α) | 12 × 10⁻⁶ | K⁻¹ | 20 – 100 °C |
| Thermal Conductivity (λ) | 50 | W/(m·K) | At 20 °C |
| Specific Heat Capacity | 460 | J/(kg·K) | At 20 – 100 °C |
| Electrical Resistivity (ρ_e) | 0.20 × 10⁻⁶ | Ω·m | At room temperature |
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Mechanical Properties
Mechanical properties per GB/T 8163-2018 for Q295B seamless pipe at room temperature. Tensile test conducted on longitudinal or transverse specimens. Impact test applies only to thickness ≥ 6 mm for B quality.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 295 | MPa | Wall thickness ≤ 16 mm |
| Yield Strength (ReH) | ≥ 275 | MPa | Wall thickness > 16 mm, ≤ 30 mm |
| Tensile Strength (Rm) | 390 – 570 | MPa | All thicknesses |
| Elongation after fracture (A) | ≥ 23 | % | Longitudinal direction |
| Elongation after fracture (A) | ≥ 21 | % | Transverse direction |
| Elongation after fracture (A) | ≥ 20 | % | For pipes with OD ≤ 42 mm (longitudinal) |
| Impact Energy (KV2) | ≥ 34 | J | At 20 °C, longitudinal, thickness ≥ 6 mm, average of 3 tests (min single 27 J) |
| Bend Test (Mandrel diameter) | 3a | – | 180° bend, a = wall thickness ≤ 16 mm |
| Bend Test (Mandrel diameter) | 4a | – | 180° bend, a > 16 mm |
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Completely Equivalent Material Standards & Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| ISO | ISO 4950/1 | FeE295 | Same yield strength (295 MPa), similar C-Mn composition; may be considered equivalent with agreement on fine-tuning. |
| USA | ASTM A572/A572M | Grade 42 | Minimum yield 290 MPa; slightly different composition, but often used interchangeably for structural pipes. |
| EU | EN 10025-2 | S275J0 | Yield strength ≥ 275 MPa, tensile 370–530 MPa; closest EN grade for general construction, but check impact temperature. |
| China | GB/T 1591-2018 | Q345B | Higher strength (yield ≥ 345 MPa), fully replaceable when higher strength is acceptable, but requires re-validation of design. |
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Application Introduction
Q295B seamless fluid pipe is a versatile low-alloy steel that can be used across many industries. Its combination of strength, formability, and weldability allows it to be processed into finished components through cutting, bending, welding, and machining. Typical applications include:
Product Applications: Transportation pipes for fluid media, Pressure piping systems in boilers and heat exchangers, Structural hollow sections for buildings and bridges, Line pipes for underground and subsea pipelines, Heat recovery steam generator components
Processed into products: Pipe bends (elbows), tees, and reducers, Flanges and pipe fittings, Welded structural columns and beams, Roller and conveyor hollow shafts, Casings for pumps and valves, Automotive roll cages and chassis members
Application industries: Oil and gas transportation pipelines, Water supply and drainage systems, Steam and heat transmission networks, Mechanical engineering and machine building, Construction and civil engineering structures, Automotive frame and chassis parts (as tube sections)
GB/T 8163 Q295B Seamless Steel Pipe for Fluid Transport Similar/Alternative Materials Recommendation
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G 3445 | STKM 18A | Mechanical tube with yield ≥ 295 MPa; composition may include microalloys. Suitable for similar fluid applications. |
| International | ISO 3183 | L290 (Grade B) | Pipeline standard; yield 290 MPa, used in petroleum and natural gas industry. Similar strength level. |
| USA | API 5L | Grade X42 | Line pipe steel; minimum yield 290 MPa, widely used in oil & gas transport. Composition requirements different but acceptable for many fluid services. |
| EU | EN 10210-1 | S355J2H | Hollow sections; yield 355 MPa, higher strength alternative for structural applications, but overmatching if 295 MPa is sufficient. |
Notes:
For applications requiring positive impact toughness at low temperatures, choose quality levels C, D, or E (e.g., Q295C, Q295D) according to GB/T 8163. Heat treatment (normalizing) can be applied to improve uniformity and toughness. When using international equivalents, verify full chemical and mechanical property compatibility with the specific design code.
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