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Help CenterSeamless Steel Pipe Supplier OD 5mm – 256mm | WT 0.8mm – 25mm | Carbon & Alloy Steel ASTM A106 / API 5L / EN 10216 / GB/T 8163 / GB/T 5310
Product Spotlights
OD 5mm – 256mm | WT 0.8mm – 25mm | Carbon & Alloy Steel
ASTM A106 / API 5L / EN 10216 / GB/T 8163 / GB/T 5310
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Seamless Steel Pipe
OD 5mm – 256mm | WT 0.8mm – 25mm | Carbon & Alloy Steel
ASTM A106 / API 5L / EN 10216 / GB/T 8163 / GB/T 5310
Product Overview
Our seamless steel pipe is manufactured by hot rolling or cold drawing processes, ensuring no weld seam and superior pressure integrity. With outer diameters from 5mm to 256mm and wall thicknesses from 0.8mm to 25mm, our seamless pipes are suitable for high pressure, high temperature, and critical service applications across multiple industries.
Key Features:
Seamless construction – No weld seam – zero leak risk
Wide size range – OD 5-256mm – one-stop sourcing
Multiple materials – Carbon steel & alloy steel (Cr-Mo)
Broad standard coverage – ASTM, ASME, API, EN, DIN, GB
Heat treated – Normalized, quenched & tempered, as-rolled
100% hydrostatic tested – Guaranteed integrity
Full traceability – EN 10204 Type 3.1 MTC with heat number
✅ Seamless construction – No weld seam – superior pressure integrity
✅ High pressure capability – Suitable for up to 10,000+ PSI
✅ High temperature service – Up to 850°F (carbon), 1,200°F (alloy)
✅ Low temperature service – Down to -195°C (A333 Gr.8)
✅ Factory direct | Global shipping
Key Specifications
| Parameter | Details |
|---|---|
| OD Range | 5mm – 256mm (0.197″ – 10.079″) |
| WT Range | 0.8mm – 25mm |
| Length | 4m – 12m (fixed or random) |
| Manufacturing | Hot rolled or Cold drawn |
| Material | Carbon Steel, Alloy Steel (Cr-Mo) |
| Surface Finish | Black / Bare / Oiled / Painted |
| End Finish | Plain / Beveled / Threaded |
| Delivery Condition | As-rolled / Normalized / Quenched & Tempered / Cold drawn |
Standards & Grades
| Standard | Grades | Application |
|---|---|---|
| ASTM A106 | Gr.B, Gr.C | High temperature service |
| ASTM A53 | Gr.B | General pressure piping |
| API 5L | Gr.B, X42, X52, X60, X65, X70 | Oil & gas pipelines |
| ASTM A179 | A179 | Heat exchanger & condenser |
| ASTM A192 | A192 | High pressure boiler |
| ASTM A210 | A-1, C | Boiler & superheater |
| ASTM A333 | Gr.1, Gr.3, Gr.6, Gr.8 | Low temperature service |
| ASTM A335 | P11, P22, P91 | High temperature alloy pipe |
| ASTM A519 | 1010, 1020, 1026, 1045 | Mechanical tubing |
| EN 10216-1 | P195, P235, P265 | Pressure purposes (room temp) |
| EN 10216-2 | P235GH, P265GH, 16Mo3, 13CrMo4-5 | Pressure purposes (elevated temp) |
| EN 10297-1 | E235, E355, 42CrMo4 | Mechanical engineering |
| EN 10305-1 | E235, E355 | Precision tubes |
| DIN 2391 | ST35, ST45, ST52 | Precision tubes (legacy) |
| DIN 17175 | St35.8, St45.8, 15Mo3, 13CrMo44 | Heat resistant boiler (legacy) |
| GB/T 8163 | 10#, 20#, Q345 | Fluid transport |
| GB/T 5310 | 20G, 15CrMoG, 12Cr1MoVG | High pressure boiler |
| GB/T 3087 | 10#, 20# | Low & medium pressure boiler |
| GB/T 8162 | 10#, 20#, 45#, Q345 | Structural purposes |
| GB/T 6479 | 20, 16Mn, 15CrMo | High pressure fertilizer (legacy) |
| GB/T 9948 | 20, 15CrMo, 1Cr5Mo | Petrochemical cracking |
| GB/T 18984 | 16MnDG, 09Mn2VDG, 06Ni3MoDG | Low temperature pipe |
Chemical Composition (Typical – Carbon Steel)
| Grade | C | Si | Mn | P max | S max |
|---|---|---|---|---|---|
| 20# / A106 Gr.B | 0.17-0.23 | 0.17-0.37 | 0.35-0.65 | 0.035 | 0.035 |
| 20G | 0.17-0.24 | 0.17-0.37 | 0.35-0.65 | 0.030 | 0.030 |
| Q345 | ≤0.20 | ≤0.55 | 1.00-1.60 | 0.030 | 0.030 |
Chemical Composition (Typical – Alloy Steel)
| Grade | C | Cr | Mo | Other |
|---|---|---|---|---|
| P22 (A335) | 0.05-0.15 | 1.90-2.60 | 0.87-1.13 | — |
| P91 (A335) | 0.08-0.12 | 8.00-9.50 | 0.85-1.05 | V 0.18-0.25 |
| T91 (A213) | 0.08-0.12 | 8.00-9.50 | 0.85-1.05 | V 0.18-0.25 |
Mechanical Properties
| Grade | Tensile (MPa) | Yield (MPa) | Elongation (%) |
|---|---|---|---|
| 20# / A106 Gr.B | 410-550 | ≥245 | ≥20 |
| 20G | 410-550 | ≥245 | ≥24 |
| Q345 | 470-630 | ≥345 | ≥20 |
| P22 | ≥415 | ≥205 | ≥30 |
| P91 | ≥585 | ≥415 | ≥20 |
| A333 Gr.6 | ≥415 | ≥240 | ≥30 |
| X65 | 531-758 | ≥448 | ≥22 |
| E355 (NBK) | 490-640 | ≥355 | ≥22 |
Available Sizes – Seamless Steel Pipe
| OD (mm) | OD (inch) | WT Range (mm) | Typical Applications |
|---|---|---|---|
| 5 – 20 | 0.197″ – 0.787″ | 0.8 – 2.5 | Instrumentation, small bore |
| 20 – 50 | 0.787″ – 1.968″ | 1.5 – 5.0 | General fluid, hydraulic lines |
| 50 – 100 | 1.968″ – 3.937″ | 2.0 – 8.0 | Boiler tubes, gathering lines |
| 100 – 200 | 3.937″ – 7.874″ | 3.0 – 15.0 | Steam lines, transmission |
| 200 – 256 | 7.874″ – 10.079″ | 4.0 – 25.0 | Large diameter pipelines |
💡 Most popular sizes: 21.3mm, 26.9mm, 33.7mm, 42.4mm, 48.3mm, 60.3mm, 76mm, 88.9mm, 114.3mm, 168.3mm, 219.1mm OD
Grade Selection Guide by Application
| Application | Recommended Grade | Standard | Key Property |
|---|---|---|---|
| General fluid transport | 20#, A106 Gr.B | GB/T 8163, ASTM A106 | Economical |
| High pressure boiler | 20G, A192 | GB/T 5310, ASTM A192 | High pressure |
| Superheater / reheater | T11, T22, T91 | ASTM A213 | High temperature |
| Oil & gas pipeline | X52, X65, X70 | API 5L | High strength |
| High temperature alloy | P11, P22, P91 | ASTM A335 | Creep strength |
| Low temperature (-45°C) | A333 Gr.6 | ASTM A333 | Impact tested |
| Low temperature (-195°C) | A333 Gr.8 (9% Ni) | ASTM A333 | Cryogenic |
| Heat exchanger / condenser | A179 | ASTM A179 | Heat transfer |
| Hydraulic cylinder | E355, ST52 | EN 10305, DIN 2391 | Precision |
| Structural support | Q345, S355J2H | GB/T 8162, EN 10210 | High strength |
| Petrochemical cracking | 15CrMo, 1Cr5Mo | GB/T 9948 | High temp + corrosion |
Applications by Industry
| Industry | Application | Recommended Grade |
|---|---|---|
| Oil & Gas | Gathering, transmission, distribution | API 5L X42-X70 |
| Power Generation | Boiler tubes, superheaters, steam lines | A106 Gr.B, A192, A213 T91 |
| Petrochemical | Process piping, heat exchangers, furnaces | A106 Gr.B, A335 P11/P22 |
| Construction | Structural frames, scaffolding | Q345, S355J2H |
| Hydraulic Systems | Cylinder barrels, hydraulic lines | E355, ST52 |
| Shipbuilding | Hull structures, marine piping | ABS Grade, API 5L |
| Water Treatment | Water supply, sewage lines | 20#, A53 Gr.B |
| Low Temperature | LNG, refrigeration, arctic pipelines | A333 Gr.6, Gr.8 |
| Automotive | Shock absorber tubes, steering components | E355, ST52 |
| Heat Exchanger | Shell and tube heat exchangers | A179, A213 |
| General Engineering | Machinery parts, supports, shafts | 20#, 45#, Q345 |
Quality Assurance & Testing
| Test | Method | Coverage | Critical For |
|---|---|---|---|
| Hydrostatic Test | Water pressure | 100% | All seamless pipes |
| Ultrasonic Testing (UT) | ASTM E213 | By agreement | Internal defects |
| Eddy Current (ET) | ASTM E309 | By agreement | Surface defects |
| Tensile Test | ASTM E8 | Per lot | Strength verification |
| Charpy Impact Test | ASTM E23 | Per lot | Low temp & alloy grades |
| Hardness Test | Rockwell/Brinell | Per lot | Grade control |
| Flattening Test | ASME/API | Per lot | Ductility |
| Flaring Test | ASME/API | Per lot | Tube end expansion |
| Dimensional Inspection | Micrometer | 100% | Size verification |
| Visual Examination | Direct | 100% | Surface quality |
Mill Test Certificate
EN 10204 Type 3.1 MTC – Standard
EN 10204 Type 3.2 – Available upon request (third-party: SGS, BV, TUV, DNV)
Traceability: Full traceability from melt to finished pipe
Heat treatment records – Normalizing, Q&T temperatures
Impact test report – For low temperature and alloy grades
NDT reports – UT/ECT results (if specified)
Processing Services
| Service | Description |
|---|---|
| Cutting | Precision cutting to exact length (±1mm) |
| Beveling | For welding preparation (30°-37.5°) |
| Threading | NPT, BSP, or custom threads (NPS ≤4″) |
| Bending | Cold or hot bending |
| Heat treatment | Normalizing, annealing, stress relieving |
| Surface coating | Oiling, painting, galvanized, 3LPE, FBE |
| Honing | Internal surface finish for hydraulic cylinders |
Packaging & Shipping
| Item | Details |
|---|---|
| Packaging | Hexagonal bundles (small OD) or steel crates (large OD) |
| Protection | Anti-rust oil + plastic end caps |
| Marking | Stencil/spray with Grade, size, heat number, standard |
| Documentation | MTC + test reports |
| Lead time | 7-15 days (stock sizes), 20-30 days (custom) |
| Port | Tianjin / Shanghai / Guangzhou |
Why Choose Our Seamless Steel Pipe?
| Advantage | Description |
|---|---|
| Wide size range | OD 5-256mm – one-stop sourcing |
| Seamless construction | No weld seam – superior pressure integrity |
| Multiple standards | ASTM, ASME, API, EN, DIN, GB – all in one place |
| Full grade range | Carbon steel to chrome-moly alloy |
| Heat treated | Normalized or quenched & tempered |
| 100% hydrostatic tested | Guaranteed pressure integrity |
| Full traceability | EN 10204 3.1 MTC with heat number |
| In-house processing | Cutting, beveling, threading, coating |
| Competitive pricing | Factory direct – no middlemen |
| Global export | Shipped to over 30 countries |
Contact for Quote
Please provide the following details:
Standard : ASTM / API / EN / GB / Other _______
Grade : _______
OD (mm) : _______
WT (mm) : _______
Length (m) : _______
Quantity : _______ (pieces / meters / tons)
Application : _______
End Finish : Plain / Beveled / Threaded
Heat Treatment : As-rolled / Normalized / Q&T
Inspection : Standard / Third-party (SGS/BV/TUV/DNV)
📧 Email: yjhtrade@gmail.com
📞 WhatsApp: +86 15106174543
🌐 Website: /
Reply within 24 hours.
FAQ – Seamless Steel Pipe
Q1: What is the difference between seamless and welded steel pipe?
A: Seamless – no weld seam, higher pressure rating, higher cost. Welded – has a longitudinal weld seam, lower cost, suitable for general applications.
Q2: What is the maximum size available for seamless pipe?
A: 256mm OD standard. Larger sizes up to 610mm available upon request.
Q3: Which seamless grade is best for high temperature service?
A: ASTM A106 Gr.B/C for carbon steel, ASTM A335 P11/P22/P91 for alloy steel.
Q4: Which seamless grade is best for low temperature service?
A: ASTM A333 Gr.6 for -45°C, Gr.8 (9% Nickel) for -195°C LNG service.
Q5: Which seamless grade is best for oil & gas pipelines?
A: API 5L X52, X65, X70 – PSL2 for sour service.
Q6: Which seamless grade is best for boiler tubes?
A: ASTM A192 for high pressure, GB/T 5310 20G for Chinese standard.
Q7: Is seamless steel pipe weldable?
A: Yes – carbon steel grades have excellent weldability. Alloy grades require preheat and PWHT.
Q8: Do you provide third-party inspection?
A: Yes. SGS, BV, TUV, DNV, or any customer-specified agency.
Q9: Do you offer free samples?
A: 30cm sample available for common sizes. Shipping fee applies.
Related Products
Seamless Steel Pipe – High pressure applications (this product)
ERW Steel Pipe – Cost-effective general purpose
Precision Steel Tube – Hydraulic cylinder applications
Alloy Steel Pipe – High temperature service (P11, P22, P91)
Low Temperature Pipe – Cryogenic service (A333 Gr.6, Gr.8)
Boiler Tube – High pressure boiler applications
Line Pipe – Oil & gas transmission
Heat Exchanger Tube – Condenser and heat transfer
Tags: Seamless Steel Pipe Seamless Pipe ASTM A106 API 5L Carbon Steel Seamless Pipe Alloy Steel Seamless Pipe GB/T 8163 GB/T 5310
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