Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Incoloy 800H Centrifugally Cast Tubes
Incoloy 800H-envelope centrifugally cast tubes (UNS N08810, Werkstoff 1.4876) are supplied to ASTM A608 as the canonical primary form for ethylene cracker furnace tubes, hydrogen reformer outlet manifolds, ammonia reformer transfer lines and direct-reduced-iron (DRI) reformer tubes operating at tube-skin temperatures from 850 deg C to 1100 deg C. The centrifugal casting process spins molten heat-resistant CrNi-Fe-Mn-Al alloy in a rotating water-cooled mould to produce a dense, directionally solidified columnar-grain structure with wall thickness from 8 mm to 50 mm and OD from 60 mm to 250 mm. The cast tube envelope matches wrought 800H chemistry (30 to 35 Ni, 19 to 23 Cr, 0.05 to 0.10 C, 0.30 to 1.20 Al+Ti) and the as-cast grain coarsening delivers creep performance acceptable for the design tube-skin and design tube-metal temperatures specified in API 530 furnace design. Each cast tube ships with an EN 10204 type 3.1 mill certificate covering heat-number chemistry, ASTM A608 mechanical results from a sacrificial coupon, ultrasonic inspection per ASTM A609 and dimensional check; type 3.2 third-party witness is supplied on call-out for refinery, petrochemical and LNG procurement.
Request a Quote on Incoloy 800H Centrifugally Cast Tubes to ASTM A608
Cast Tube Dimensions per ASTM A608
| Property | Range |
|---|---|
| OD range | 60 mm to 250 mm |
| Wall thickness | 8 mm to 50 mm |
| Cast tube length | up to 4 m as single cast; longer assemblies built from welded sections |
| OD / ID tolerance | per ASTM A608 paragraph 6 (typically +/- 1.5 percent OD) |
| Wall tolerance | per ASTM A608 paragraph 6 (typically +/- 12.5 percent) |
| End preparation | Machined bevel per project drawing or B16.25 |
| Heat treatment | As-cast (no post-cast solution anneal - directional-grain structure is the design intent) |
Cast Tube Manufacturing Route
- Melt: Heat charged in argon-oxygen-decarburisation (AOD) or vacuum-induction furnace; chemistry adjusted to 800H envelope; ladle deoxidised with Al + Ti.
- Mould prep: Water-cooled steel mould lined with refractory wash to control mould-wall heat transfer.
- Centrifugal cast: Molten metal poured into the rotating mould at 1500 to 1900 rpm (size-dependent); centrifugal force pins metal against the mould wall and drives lighter inclusions inward where they are removed by ID boring.
- Cool + extract: Tube cools in mould then is extracted; outer surface dressed.
- ID + OD machining: Vertical lathe rough-machines ID and OD to remove the inclusion-rich inner skin and the rough outer skin. Finish-machined to drawing tolerance.
- NDT: 100 percent UT per ASTM A609 to confirm no recordable internal defect; PT per ASTM E165 on machined surface.
- Test bar: Sacrificial cast prolongation tested per ASTM A608 paragraph 8 - room-temperature tensile + yield + elongation per heat / lot.
- Marking: Heat number, ASTM A608 grade designation, drawing OD x wall, manufacturer mark per A608 paragraph 14.
Sizes Stocked and Lead Times
Centrifugally cast tubes are made-to-order against furnace OEM drawings. Stock holding is uneconomic because every project specifies a unique OD x wall x length combination tied to the radiant-section layout.
| Tube class | Typical OD x wall | Stock status | Lead time (after PO) |
|---|---|---|---|
| Ethylene cracker radiant tube | OD 100 to 180 mm x wall 8 to 14 mm | Cast on order | 14 to 18 weeks |
| Reformer outlet manifold | OD 180 to 250 mm x wall 25 to 50 mm | Cast on order | 16 to 20 weeks |
| DRI reformer transfer line | OD 150 to 220 mm x wall 12 to 25 mm | Cast on order | 14 to 18 weeks |
Cast Tube Inspection and Marking
- Ultrasonic per ASTM A609 - 100 percent of OD + ID after machining. Recordable indication limit per A609 acceptance grade B or C (project-specified).
- Liquid penetrant per ASTM E165 on full machined surface (OD + ID + bevels).
- Tensile + yield + elongation per ASTM A608 paragraph 8 on a sacrificial prolongation per heat / lot.
- Hardness per ASTM E18 on machined OD.
- Dimensional: OD, ID, wall, length, bevel angle, straightness, ovality per ASTM A608 paragraph 6.
- Marking: per ASTM A608 paragraph 14 - heat number, grade designation, drawing OD x wall, manufacturer mark; permanent low-stress die-stamp on each tube.
Typical Cast Tube Service Conditions
Centrifugally cast 800H-envelope tubes operate at the most extreme tube-skin temperatures of any 800H product form. The directionally solidified columnar-grain structure is the design intent for long-term creep service at tube-skin temperatures above 900 deg C, where wrought 800H seamless tube would not deliver the required design life.
| End-use cast tube | Tube-skin temperature | Companion application |
|---|---|---|
| Ethylene cracker radiant tube | 950 to 1100 deg C | Ethylene cracker tubes |
| Steam-methane reformer outlet manifold | 850 to 950 deg C | Reformer pigtails |
| DRI reformer transfer line | 900 to 1050 deg C | Radiant tubes |
Companion Forms and Furnace Tie-In
Cast 800H tubes are spooled with wrought 800H forgings for the header connections and B16.9 fittings for the return-bend pigtails. Welds between centrifugal-cast and wrought sections follow a qualified procedure per ASME Section IX with ERNiCrFe-2 filler (see weldability procedures). For wrought-tube applications below 815 deg C tube-skin, see seamless tube; for parent-alloy specifications see chemical composition and mechanical properties.
Centrifugally Cast Tubes FAQ
Q. Why is centrifugal casting preferred over wrought tube for ethylene cracker service?
At tube-skin temperatures above 900 deg C, the columnar-grain directional-solidification structure of a centrifugally cast tube delivers substantially longer creep-rupture life than a wrought tube with equiaxed solution-annealed grain. The cast tube also avoids the cost of hot-piercing and cold-drawing the thick-wall 800H section, which is mill-expensive in the wall range typical of cracker radiant tubes (8 to 14 mm wall on OD 100 to 180 mm).
Q. Is the cast tube solution-annealed after machining?
No. The directional-grain as-cast structure IS the design intent. A post-cast solution anneal would coarsen and recrystallise the directional grains and reduce creep performance. ASTM A608 specifies the as-cast condition as the standard supply state.
Q. What ASTM A608 grade designation maps to the 800H envelope?
ASTM A608 covers heat-resistant centrifugally cast iron-chromium-nickel alloys by designation rather than UNS number. The 800H wrought-equivalent envelope is normally specified to the project drawing chemistry (typically HK40, HP-modified or 32-21 grades depending on the furnace OEM standard). HP-Nb or HP-micro-alloyed grades extend the temperature window above 1050 deg C.
Q. Do you supply weld-overlay (cladding) on the cast tube ID?
Yes on call-out. Erosion-resistant or carburisation-resistant weld overlay on the cast tube ID is applied by ESW or PTA welding before final machining, with the overlay chemistry per project drawing (typical: Inconel 625 or 800HT for carburisation resistance, Stellite for erosion).
Q. How is the tube-skin temperature monitored in service?
Optical pyrometers (single-colour or two-colour) read tube-skin temperature through the furnace peep-hole; thermocouples welded directly to the tube OD provide spot measurement at critical locations. The tube-skin temperature drives the creep-life calculation per API 530 furnace design and dictates the inspection interval (typical reformer pigtail re-inspection every 12 to 18 months by replication and creep-life calculation).
Request a Quote on Incoloy 800H Centrifugally Cast Tubes
Send the furnace drawing, ASTM A608 grade or chemistry envelope, OD x wall, length, quantity, NDT class (A609 grade B or C), bevel detail and any ID overlay or pre-bend add-ons to our sales desk.
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