ASTM B407 Incoloy 800 Tube Buyer's Guide: 800/800H/800HT Seamless Pipe for High-Temperature Service

Why B407 Incoloy 800 Tube Matters in High-Temperature Service

If you have ever been handed a piping class sheet that calls for “Incoloy 800 seamless tube, ASTM B407, 800H grade” and wondered whether that means the same thing as the basic 800, you are not alone. The Incoloy 800 family — 800, 800H, and 800HT — is one of the most specified iron-nickel-chromium alloy systems for service between roughly 600 °C and 1100 °C, where austenitic stainless steels start to lose creep strength and nickel-rich alloys such as Inconel 600 / 625 become over-specified for the duty. ASTM B407 is the standard that most EPCs, refineries, and ethylene plant designers turn to when they need a heat-resistant tube that can hold its microstructure for years at temperature.

For procurement teams, the practical question is rarely “is Incoloy 800 good?” — the metallurgy has been proven for decades. The real questions are: which of the three grades (800, 800H, 800HT) is actually called out, what is the right dimensional envelope, what inspection documents should be on the table, and how do you avoid the common traps that show up when a 200-ton ethylene revamp or a utility boiler retrofit is being sourced? This guide is written for that buyer, the piping engineer, and the QA inspector who has to sign off on the material test report before a single tube enters a welding shop.

At b407 incoloy 800 tube inventory held at the Lishui facility, EZ Steel Industrial carries the full B407 grade set in seamless form — N08800, N08810, and N08811 — in outside diameters from 1/2" to 6" and wall thicknesses to schedule 160, with mill-direct pricing, full EN 10204 3.1 / 3.2 documentation, and bundled supply of complementary pipe fittings and pipe flanges when the package is being built at the same source.

What ASTM B407 / ASME SB-407 Actually Covers

ASTM B407 — and its ASME twin, SB-407 — is the standard specification for “Nickel-Iron-Chromium Alloy Seamless Pipe and Tube.” It covers the Incoloy 800 series (UNS N08800, N08810, N08811) plus the related N08800 modifications in the form of cold-worked seamless pipe and tube intended for general corrosion-resistant service and, more importantly for most readers, for high-temperature applications where creep and stress rupture are the design drivers.

Forms and Sizes Within B407

B407 actually describes several product forms, and the right one depends on your piping class:

• Cold-worked seamless pipe and tube — the most common form for boiler, superheater, and heat-exchanger service. Outside diameters typically 1/8" to 6" with wall thicknesses down to 0.5 mm.
• Hot-finished seamless pipe and tube — used for larger OD or heavier-wall applications such as furnace tubes and process piping headers.
• Hot-worked billet and bar stock — when the eventual product is flanges, fittings, or machined components produced from B407-certified starting stock.

Companion Standards You Will See on the Same Drawing

B407 rarely travels alone on a piping class. Expect to see the following standards cross-referenced when the tube is being specified into a working piping system:

• ASTM B163 — Seamless nickel and nickel alloy condenser and heat-exchanger tubes. When the application is a condenser or feedwater heater, B163 is usually the callout, with B407 chemistry behind it.
• ASTM B167 — Nickel-chromium-iron alloy (N06600 / N06690 / N06693) seamless pipe and tube. Higher nickel content, used where reducing-service corrosion is the concern.
• ASTM B829 — General requirements for nickel and nickel alloys, referenced by B407 for testing, inspection, and certification rules.
• ASME SB-407 — The ASME Boiler and Pressure Vessel Code version of the same specification, required when the tube is going into a Section I (power boiler) or Section VIII (pressure vessel) code stamp.

800 vs. 800H vs. 800HT: The Differences That Actually Matter

The three Incoloy 800 variants share the same basic Fe-Ni-Cr chemistry and the same nominal 20% chromium / 30% nickel / balance iron composition. What separates them is the carbon content and the grain size control — and that is what drives the high-temperature performance difference.

In short: 800 is the “general purpose” grade; 800H is the grade most procurement teams actually mean when they write B407 on a data sheet for high-temperature service; 800HT is the most tightly specified variant, with the additional Al+Ti and Ti/C controls that give it superior creep resistance at the top of the operating envelope. If the MTR says “Incoloy 800” without an H or HT suffix, the buyer should confirm whether the application is creep-limited — if it is, that plain 800 callout is almost certainly a mistake.

Chemical Composition — What the MTR Should Show

The ASTM B407 composition limits for the 800 family are essentially the same across the three grades, with the H and HT grades adding the tighter carbon, Al+Ti, and grain-size requirements. The heat analysis limits in the current revision of B407 are:

The thing to look for on a mill test certificate is the actual heat number, the actual carbon result (not just “conforms”), and the grain size reported as an ASTM E112 number. A 800H or 800HT MTR that does not show a grain size — or that lists “finer than ASTM 5” as the only grain-size call-out — is one that is hiding a non-conformance.

Mechanical Properties Buyers Should Check

B407 specifies both room-temperature mechanical properties and, for 800H and 800HT, high-temperature stress-rupture values that the buyer should not be afraid to ask for. Typical room-temperature values on the certificate:

• Tensile strength: 520 MPa (75 ksi) minimum, typical 550 – 700 MPa
• Yield strength (0.2% offset): 205 MPa (30 ksi) minimum, typical 240 – 310 MPa
• Elongation in 2": 30% minimum, typical 35 – 45%
• Hardness: typically 130 – 180 HB (Brinell), 70 – 95 HRB

For 800H and 800HT the more useful numbers are the stress-rupture values at 980 °C / 1000 h, which is the basis for ASME Section I and Section VIII allowable-stress tables. If a tube is being installed under code stamp, the MTR should be traceable to a B407-certified heat with rupture data available — either on the certificate or by lot reference to the producer's published data book.

Where B407 Incoloy 800 Tube Is Actually Used

The 800 family earned its reputation in three groups of applications. Understanding which one a given inquiry falls into is the fastest way to confirm the grade selection.

1. Ethylene and Steam Cracking Furnace Tubes

Incoloy 800H is one of the workhorse alloys for ethylene cracking furnace tubes, where tube-metal temperatures can run 900 °C to 1050 °C on the fire side. The 800H chemistry is designed to resist carburization on the process side while holding creep strength on the load-bearing side. For this duty, B407 tube is usually paired with B408 (bar) and B409 (plate) fittings and supports, all from the same heat for traceability.

2. Utility Boiler Superheaters and Reheaters

In conventional and once-through utility boilers, 800H is widely used for final-stage superheater and reheater tubing where austenitic stainless T22/T91 begins to lose strength. The same tubes are also used in heat-recovery steam generators (HRSGs) for combined-cycle plants. In these applications, the tube is often bent into u bend tube configurations, and the B407-certified tube is then bent, solution-annealed, and hydrostatically tested at the bend fabricator.

3. Hydroprocessing and High-Pressure Hydrogen

Hydrocracker reactors and high-pressure hydrogen service use 800HT where the combination of elevated temperature, high pressure, and hydrogen partial pressure makes 800H marginal. The tighter Al+Ti and Ti/C ratio in 800HT is what makes the difference in long-term creep-rupture performance under hydrogen.

4. Heat Exchangers, Condensers, and Process Heating

For the lower end of the temperature range, plain 800 (N08800) is still used in heat efficiency tubes, feedwater heaters, and chemical process heat exchangers, especially where resistance to nitrate, nitrite, and caustic corrosion is the design driver. For these duties, B163 is often the more specific callout, with B407 chemistry underneath.

Dimensional, Tolerance, and Inspection Checklist

A practical inspection checklist for a B407 Incoloy 800 tube shipment looks like this. Use it on every PO, especially when a new mill is being qualified or a new grade (800H or 800HT) is being introduced for the first time:

Common Pitfalls When Sourcing B407 Incoloy 800 Tube

A few traps that show up repeatedly on B407 inquiries, especially from new buyers or new project teams:

Pitfall 1: Specifying 800 Instead of 800H

The single most common error. A data sheet written years ago by a piping engineer who intended 800H ends up with a 800 callout because the MOC list was not updated. By the time the QA inspector catches it, half the heat has been annealed at the wrong temperature. The fix is to put 800H or 800HT on the purchase order line item, not just “Incoloy 800 B407” in the materials section.

Pitfall 2: Confusing B407 with B163

Both standards cover the same alloy family. B163 is the condenser / heat-exchanger tube standard, and the dimensional envelope, testing, and marking rules are slightly different. A B407 callout on a condenser duty usually means the supplier will provide a heavier-wall tube with different NDT coverage than the specifier actually needed.

Pitfall 3: Forgetting the Companion Components

A furnace tube package is not just tubes. It also includes pipe fittings (return bends, elbows, tees), pipe flanges for the headers, and often a gasket, stud bolt & nut set for the header flanges. Sourcing the tube from one supplier and the fittings from another doubles the MTC review work and increases the risk of chemistry mismatches at the welds.

Pitfall 4: Treating Incoloy 800 Like a Stainless Steel

Incoloy 800 is an iron-nickel-chromium alloy, not a stainless steel. It work-hardens faster than 304 or 321, it requires more aggressive tooling, and its thermal expansion is closer to carbon steel than to austenitic stainless. Quoting, scheduling, and welding-procedure qualification all need to reflect that, otherwise the field cost will overrun the material savings.

Why Source from a Mill-Direct Manufacturer

For B407 Incoloy 800 tube, the mill-direct channel offers three concrete advantages that the typical trading house cannot match:

1. Heat Lot Consistency Across the Whole Package

When the tube, the return bends, the elbows, and the header flanges are all produced from the same parent heat, the MTC work drops to a single document review and the welding procedure qualification becomes straightforward. At EZ Steel Industrial, the Incoloy 800 program runs through the Lishui facility, where the same heat can be drawn into tube, formed into return bends, and forged into flange blanks without a single re-melt.

2. Documentation That the EPC Actually Wants

Mill-direct means EN 10204 3.1 or 3.2 certificates issued by the producing mill — not a trader-issued certificate of conformity. For code-stamp work and for the EPC's own quality plan, that distinction matters: a 3.1 certificate carries independent test data, a 3.2 certificate is independently witnessed, and a trader's certificate is neither.

3. Project-Level Bundling

An ethylene cracking furnace package, a utility boiler bank, or a refinery reactor charge can be drawn from a single source, on a single production schedule, and shipped in just-in-time waves that match the erection sequence. EZ Steel Industrial's three-plant network — Cangzhou, Yangzhou, and Lishui — supports exactly that kind of bundled supply for the 800 family.

How to Build a B407 Inquiry That Gets the Right Quote

A well-written inquiry for B407 Incoloy 800 tube should include at least the following line items, in this order. Sending a partial data sheet is the most common reason quotes come back with the wrong grade, the wrong MTC, or the wrong price.

1. Standard and grade: ASTM B407 / ASME SB-407, 800 / 800H / 800HT.
2. UNS number: N08800 / N08810 / N08811.
3. Form: cold-worked seamless tube / hot-finished seamless pipe.
4. Size: OD x wall x length, with quantity per size.
5. Tolerance: standard ASTM or tighter (for bent service).
6. Heat treatment: solution annealed at 1145 °C min for 800H/HT.
7. Testing and inspection: hydrostatic, eddy current / ultrasonic, PMI, grain size, rupture data.
8. Certification: EN 10204 3.1 or 3.2, ISO 9001 mill QMS, PED if European destination.
9. Marking and packaging: per tube or per bundle, export packaging, end caps, desiccant.
10. Logistics: FOB / CIF / DDP, port of discharge, target delivery window.
11. Companion items: return bends, fittings, flanges, gaskets, stud bolts, valves — if the package is being built at the same source.

Conclusion and Next Steps

ASTM B407 Incoloy 800 tube — in its 800, 800H, and 800HT variants — remains one of the most reliable high-temperature alloy systems available to the process industries. The specification is mature, the supply chain is established, and the metallurgical track record across ethylene, refining, and power generation is well documented. The buyer's job is to make sure the right grade is on the purchase order, the MTC is from a real mill, the documentation matches the code-stamp requirements, and the companion items are part of the same source rather than a separate purchase.

For EPCs, refineries, ethylene operators, and boiler fabricators that want a mill-direct quote on B407 Incoloy 800 tube, EZ Steel Industrial maintains inventory at the Lishui facility in UNS N08800, N08810, and N08811 seamless tube, with the corresponding pipe fittings, pipe flanges, and gasket, stud bolt & nut sets held for project-level supply. Send the line-item data sheet and the project schedule and a quotation can be turned around within the same week.