ASTM A312 TP347 seamless tubes for pyrolysis furnace
Steel standard:ASTM A312
Steel Grade:TP347
Process ::Hot rolled/hot expansion/cold drawn/cold rolled
Surface: Pickling 2B surface treatment
Wall Thickness:0.89-60mm
Cross-Section Shape:Round
Outside Diameter:6mm~630mm (1/8"~24")
Thickness:1mm-60mm (Sch5~Schxxs)
Proctor: Plastic cap
Package: Bundles
Inspection: With Hydraulic Testing, Ultrasonic testing or X-ray Test
Certificate ISO9001;2015
Send E-mail:info@gneestainless.com
Tel:+8615824687445
Description
Gnee Steel (Tianjin) Co., Ltd. is one of the most professional manufacturers and suppliers of astm a312 tp347 seamless tubes for pyrolysis furnace in China. With abundant experience, we warmly welcome you to wholesale customized astm a312 tp347 seamless tubes for pyrolysis furnace from our factory. For price consultation, contact us.
Are you searching for seamless tubing that offers exceptional high-temperature stability, is capable of withstanding the rigors of long-term operation in pyrolysis furnaces, and remains free from creep failure or intergranular corrosion? GNEE is a seasoned supplier with extensive experience in exporting stainless steel tubing for petrochemical projects, holding certifications such as TRCU and PED. We offer high-quality ASTM A312 TP347 seamless steel tubes, specifically engineered for use in pyrolysis furnaces.
All ASTM A312 TP347 seamless tubes are supplied in a solution-annealed condition (heat-treated at 1050–1100°C followed by rapid cooling) to eliminate internal stresses. The material composition-featuring C ≤ 0.08%, Cr 17.0–19.0%, Ni 9.0–13.0%, and Nb ≥ 8×C-effectively suppresses the precipitation of chromium carbides, thereby ensuring long-term structural stability under continuous high-temperature service conditions.
Our ASTM A312 TP347 high-temperature stainless steel tubes undergo cold rolling, pickling, and passivation processes. The outer diameter tolerance is strictly controlled within ±0.05 mm, and the inner wall roughness is maintained at Ra ≤ 0.8 μm; this results in a smooth, uniform inner surface that effectively minimizes media fouling and heat transfer losses. With a creep rupture strength of ≥ 15 MPa at 850°C and a tensile strength of ≥ 515 MPa at room temperature, these tubes are fully capable of meeting the rigorous demands associated with long-term cyclic thermal stresses.
ASTM A312 TP347 Seamless Tubes Specification
| Feature | (TP347 / TP347H) |
| Grade Comparison | TP347: Standard stabilized grade / TP347H: High-carbon version for superior creep strength |
| Manufacturing Process | Seamless (Cold Drawn or Hot Rolled), Bead-removed for smooth internal flow |
| Standard Compliance | ASTM A312 / ASME SA312 (Standard Spec for Seamless Austenitic SS Pipe) |
| Service Temperature | Recommended for 400°C to 815°C (750°F to 1500°F) |
Chemical Composition (Mass %)
| Element | TP347 (%) | TP347H (%) |
| Carbon (C) | 0.08 max | 0.04 – 0.10 |
| Niobium (Nb) |
10×C min, 1.10 max |
8×C min, 1.10 max |
| Chromium (Cr) | 17.0 – 19.0 | 17.0 – 19.0 |
| Nickel (Ni) | 9.0 – 13.0 | 9.0 – 13.0 |
| Manganese (Mn) | 2.00 max | 2.00 max |
Mechanical & Physical Properties
| Property | Value (at Room Temp) |
| Tensile Strength |
≥515 MPa (75 ksi) |
| Yield Strength (0.2%) |
≥205 MPa (30 ksi) |
| Elongation (in 2 in.) |
≥35% |
| Grain Size | ASTM No. 7 or coarser (for 347H) |
ASTM A999 Dimensional Tolerances
Essential for accurate fit-up and welding using ASME B16.25 bevels.
| Dimension | Tolerance | Notes for Procurement |
| Outside Diameter (OD) |
±0.4mm to ±1.5mm |
Varies by pipe size (NPS). |
| Wall Thickness (WT) |
−12.5% to +15% |
Minimum wall thickness must be guaranteed for pressure. |
| Straightness |
≤1.5mm/m≤1.5mm/m |
Vital for long furnace tubes to prevent vibration. |
| Inside Diameter (ID) | Controlled for flow | Minimizes "coking" (carbon buildup) in the furnace. |
Which welding filler metal should be selected for TP347 piping?
ER347 or E347 series welding consumables. This filler metal must contain Niobium to ensure that the weld possesses intergranular corrosion resistance equivalent to that of the base metal pipe. For the root pass, the TIG (GTAW) welding process is recommended to achieve a clean, fully penetrated weld.
Can GNEE provide tubes with ASME B16.25 Beveling?
Yes. For pyrolysis furnace projects, we provide precision-machined ends according to ASME B16.25 (typically a 37.5° single bevel). This allows for immediate on-site welding, ensuring perfect alignment (root gap) and high-quality radiographic (X-ray) results.
ASTM A312 TP347 Seamless Tubes Supplier
GNEE operates specialized production lines for stainless steel seamless tubes: the monthly production capacity for TP347/347H specialty stainless steel seamless tubes is approximately 300 to 500 tons.
Lead times depend on the order volume and whether specialized stabilizing heat treatment (Stabilizing Annealing) is required.
Ex-stock Specifications:
7 – 10 days. This timeframe primarily covers surface finishing, end processing, customs clearance, and packaging.
30 – 45 days. This timeframe encompasses: billet preparation -> cold drawing/cold rolling -> solution treatment -> stabilizing heat treatment (a critical process for TP347) -> inspection -> packaging.
Mandatory Testing & Quality Control (NDT)
Pyrolysis tubes are "Critical Path" items; these tests are non-negotiable for GNEE supply.
| Test Type | Technical Standard | Purpose |
| Hydrostatic Test | ASTM A999 / ASME B31.3 | Ensures pressure-tight integrity. |
| Ultrasonic Testing (UT) | ASTM E213 | Detects internal longitudinal & transverse flaws. |
| Eddy Current Test (ET) | ASTM E426 | Detects surface and near-surface defects. |
| IGC Test (Practice E) | ASTM A262 | Verifies resistance to Intergranular Corrosion. |
| Stabilizing Heat Treatment | 850°C - 900°C | Done after solution annealing to maximize Nb-carbide formation. |
Packaging Method
End Protection:
All tube ends are fitted with plastic caps to prevent the ingress of foreign objects.
For tubes featuring pre-machined ASME B16.25 bevels, reinforced rubber sleeves are utilized to protect the weld bevels from deformation caused by impact.
Hexagonal Bundling: Applicable to small-to-medium diameter tubes; securely bundled using steel straps.
Premium Wooden Case Packing (Recommended): For high-precision TP347H tubes used in pyrolysis furnaces, the use of fumigation-free wooden crates or steel-frame crates is recommended to ensure that no bending or deformation occurs during long-distance sea transport.
Each tube features clear stenciled markings (indicating Grade, Standard, Size, and Heat No.). The outer packaging is affixed with stainless steel shipping tags.
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