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
ASTM B408 Incoloy 800H Rod & Bar (UNS N08810 / N08811)
ASTM B408 is the cover specification for nickel-iron-chromium alloy rod and bar in UNS N08800 (Incoloy 800), UNS N08810 (Incoloy 800H) and UNS N08811 (Incoloy 800HT). It defines chemistry limits, room-temperature mechanical floors, dimensional tolerances and surface condition for hot-worked, cold-worked, annealed and machined product forms used in fastener manufacture, machined components, forging stock and stud bar for high-temperature pressure-vessel service. The most recent revision is ASTM B408-23 and the ASME adoption is SB-408, published in ASME Section II Part B for use under Section VIII Division 1. TorqBolt supplies ASTM B408 Incoloy 800H rod and bar in OD 8 mm to 250 mm, in hot-rolled, cold-drawn, peeled-and-polished or machined finish, with EN 10204 type 3.1 mill test certificate by default and type 3.2 with Lloyds Register / DNV / BV / SGS / TUV witness on call-out.
Full Scope of ASTM B408
ASTM B408 covers wrought rod and bar in the UNS N08800 / N08810 / N08811 family produced by hot-rolling, hot-forging or hot-extrusion of ingot or billet, with subsequent solution-anneal in the high-temperature 1149 deg C minimum cycle followed by rapid cool for the H and HT grades. Cold-drawing, peeling, polishing and machining are permitted secondary operations to deliver the size, finish and straightness specified by the purchase order. ASTM B408 does NOT cover wire (covered by ASTM B473), nor does it cover forgings (covered by ASTM B564). The scope is rod (cross-section less than approximately 25 mm) and bar (cross-section above approximately 25 mm).
ASTM B408 Revision History
| Revision | Year | Notable change |
|---|---|---|
| B408-23 | 2023 | Current revision; chemistry windows held |
| B408-19 | 2019 | Prior revision |
| B408-13 | 2013 | Aligned grain-size reporting with B407 / B409 |
ASTM B408 Chemistry Limits
ASTM B408 chemistry windows are identical to ASTM B407 for the same UNS designations. The chemistry table is reproduced below for convenience; cross-verify the limits against ASTM B408-23 cover sheet and the Special Metals Alloy 800H / 800HT technical bulletin before mill release.
| Element | N08800 | N08810 (800H) | N08811 (800HT) |
|---|---|---|---|
| Carbon (C) | 0.10 max | 0.05 to 0.10 | 0.06 to 0.10 |
| Manganese (Mn) | 1.50 max | 1.50 max | 1.50 max |
| Sulfur (S) | 0.015 max | 0.015 max | 0.015 max |
| Silicon (Si) | 1.00 max | 1.00 max | 1.00 max |
| Copper (Cu) | 0.75 max | 0.75 max | 0.75 max |
| Nickel (Ni) | 30.0 to 35.0 | 30.0 to 35.0 | 30.0 to 35.0 |
| Chromium (Cr) | 19.0 to 23.0 | 19.0 to 23.0 | 19.0 to 23.0 |
| Aluminium (Al) | 0.15 to 0.60 | 0.15 to 0.60 | 0.25 to 0.60 |
| Titanium (Ti) | 0.15 to 0.60 | 0.15 to 0.60 | 0.25 to 0.60 |
| Al + Ti combined | 0.30 to 1.20 | 0.30 to 1.20 | 0.85 to 1.20 |
| Iron (Fe) | balance | balance | balance |
ASTM B408 Room-Temperature Mechanical Floors
| Property | N08800 hot-finished | N08810 / N08811 hot-finished | Cold-finished |
|---|---|---|---|
| Tensile strength (Rm) | >= 520 MPa (75 ksi) | >= 450 MPa (65 ksi) | >= 550 MPa (80 ksi) |
| 0.2 percent proof stress (Rp0.2) | >= 205 MPa (30 ksi) | >= 170 MPa (25 ksi) | >= 240 MPa (35 ksi) |
| Elongation A5 | >= 30 percent | >= 30 percent | >= 25 percent |
| Hardness HB max | 192 | 184 | 200 |
| ASTM grain size (H / HT only) | n/a | 5 or coarser | 5 or coarser |
Bar Diameter and Length Tolerances
ASTM B408 references ASTM B880 for dimensional tolerances. Hot-finished round bar OD tolerance is plus 0.41 mm minus 0.41 mm up to 25 mm OD, plus 0.81 mm minus 0.41 mm from 25 to 75 mm OD, and tightens with cold-drawn finish. Standard length is 3 to 6 metres random; cut-to-length is supplied at the order line on call-out. Straightness is 1.5 mm per metre maximum for hot-finished, 0.5 mm per metre maximum for cold-drawn and peeled.
Surface Finishes Available
- Hot-rolled (HR): as-rolled, oxide scale, for forging stock
- Hot-rolled annealed (HRA): descaled, pickled, solution-annealed
- Cold-drawn (CW): bright-drawn, close tolerance, for fastener manufacture
- Cold-drawn annealed (CWA): drawn then annealed for machining
- Peeled and polished (PP): turned to size with low Ra surface for high-quality fasteners and machined components
- Centerless-ground: tightest tolerance and finest finish for precision machined components
Inspection Requirements
ASTM B408 requires visual inspection for surface defects and dimensional inspection per ASTM B880 on every bar. Ultrasonic test per ASTM A388 is required on bar above 100 mm OD intended for pressure-vessel forging stock. Macroetch to ASTM E381 is required on H and HT grade bar to confirm absence of pipe, segregation and porosity in the centre. ASTM grain size verification per ASTM E112 (intercept method) is mandatory for H and HT grades to certify the grain size 5 or coarser envelope.
ASME SB-408 Adoption
ASME Section II Part B publishes SB-408 as the boiler and pressure vessel code adoption of ASTM B408. SB-408 is the qualified source specification for Incoloy 800H / 800HT rod and bar used in ASME Section VIII Division 1 pressure vessels with maximum design temperature 815 deg C (1500 deg F). The corresponding ASME P-Number for welding-procedure qualification is P-No. 45.
Compliant TorqBolt Product Range
| Form | Size range | Page |
|---|---|---|
| Round bar | OD 8 mm to 250 mm | Round Bar |
| Stud bolt bar stock | M6 to M64 | Stud Bolts |
| Hex bolt bar stock | M6 to M64 | Hex Bolts |
| Heavy hex bolt bar stock | 1/4 inch to 4 inch | Heavy Hex Bolts |
| Machined components | per project drawing | Machined Components |
Cross-References and Companion Specifications
- ASTM B407: Seamless pipe and tube in the same UNS designations
- ASTM B409: Plate, sheet and strip
- ASTM B564: Forgings, flanges and rolled rings
- ASME Section VIII Division 1: Pressure-vessel code adoption
- ASTM B880: General requirements for nickel-alloy bar and wire (companion)
- ASTM B473: Wire in the same UNS designations
Frequently Asked Questions
Q. What products does ASTM B408 cover?
ASTM B408 is the cover specification for Ni-Fe-Cr alloy rod and bar in UNS N08800 (Incoloy 800), N08810 (Incoloy 800H) and N08811 (Incoloy 800HT). It defines chemistry limits, mechanical floors, dimensional tolerances and surface condition for hot-worked, cold-worked and machined product forms used in fasteners, machined components and forging stock.
Q. Is ASTM B408 adopted by ASME?
Yes. ASME Section II Part B publishes SB-408 as the boiler and pressure vessel code adoption of ASTM B408. SB-408 is the qualified source specification for ASME Section VIII bolting and structural bar in Incoloy 800H / 800HT.
Q. What finishes are available under ASTM B408?
Hot-worked (HR), hot-worked annealed (HRA), cold-worked (CW), cold-worked annealed (CWA), machined or ground (M) and centerless-turned. TorqBolt supplies the finish required by the bar end-use, with peeled and polished bar standard for fastener manufacturing.
Q. What is the maximum bar diameter ASTM B408 covers?
ASTM B408 places no specific upper bar diameter limit; mill practice and forging-press capacity govern. TorqBolt routinely supplies Incoloy 800H bar to 250 mm OD, with larger sections produced as forged bar to ASTM B564.
Q. Does ASTM B408 specify ASTM grain size?
Yes for grade UNS N08810 (Incoloy 800H) and UNS N08811 (Incoloy 800HT). ASTM B408 requires ASTM grain size 5 or coarser, certified on the heat by intercept method. This grain-size envelope is what qualifies the bar for sustained creep service above 600 deg C (1100 deg F).
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