Hastelloy B Fasteners — Thread Stress Areas, Hex Dimensions and Material Data (UNS N10001 / WNr 2.4800)
Thread stress areas across the UNC/UNF/8UN inch ladder, hex width and thickness geometry from 1/4 to 2-1/2, and the material identification and property lines for Hastelloy B fasteners — transcribed row-for-row from the collected tables.
Last updated: 2026-11
Specifications
Hastelloy B is the nickel-molybdenum alloy (about 28% Mo, balance nickel, iron held deliberately low) built for one dominant enemy: hydrochloric acid. Where stainless loses its chromium-oxide passivity to reducing acids, Hastelloy B's high molybdenum content keeps corrosion rates low in unoxidizing environments — hot HCl of nearly any concentration, wet hydrogen chloride gas, sulfuric, phosphoric and acetic acid streams — which is why B-class bolts, studs and nuts show up on acid service equipment, vessel internals and reactor hardware rather than on general plant. The page carries the three tables a fastener call needs: the thread stress-area ladder (1/4 through 1-1/2 in UNC, UNF and 8UN — stress area 0.0318 in² on 1/4-20 up to 1.4050 in² on 1-1/2-6, the figure that converts the alloy's 690 MPa tensile strength into a bolt load), the hex geometry from 1/4 to 2-1/2 (widths across flats and corners with max/min pairs, thickness), and the identification and property lines — UNS N10001, Werkstoff 2.4800, density 9.24 g/cm³, melting range 1330–1380 °C, and a 690 MPa tensile / 310 MPa yield / 40% elongation band. Reading notes carried from the source: the rows print in unsorted order, the 3/8 row prints as "3/18", the 3/8 thickness pair appears swapped and the 1-1/2 row's last cell carries print corruption — all reproduced verbatim and flagged on the tables, never silently repaired. One boundary this page carries loudly: Hastelloy B's corrosion advantage stops at oxidizing species — ferric ions, dissolved oxygen, free chlorine strip the alloy of its advantage, and B-2/B-3 grades exist for post-weld corrosion performance; grade selection is an RFQ conversation with the medium chemistry attached.
| Material designation | Hastelloy B — UNS N10001, Werkstoff Nr. 2.4800; density 9.24 g/cm³, melting range 1330–1380 °C, CTE 10.0 µm/m-°C (20–100 °C), thermal conductivity 11.7 W/m-K |
|---|---|
| Mechanical (as printed) | Tensile 690 MPa min, yield 310 MPa min, elongation 40% — the alloy property band; finished-part requirements per the invoked fastener standard |
| Thread stress areas (in²) | UNC/UNF/8UN ladder 1/4 through 1-1/2: 0.0318/0.0364 (1/4-20/-28) up to 1.4050/1.5810 (1-1/2-6/-12), 8UN from 1-1/8 — converts to bolt load via the tensile figure |
| Hex geometry (in) | Widths across flats/corners and thickness max/min, 1/4 through 2-1/2 as printed (source rows unsorted, flagged) |
| Corrosion envelope | Reducing acids (hot HCl, wet HCl gas, H2SO4/H3PO4/acetic streams); NOT rated for oxidizing species (ferric ions, dissolved O2, chlorine) — grade and condition per RFQ with medium chemistry |
| Not tabulated | Creep/fatigue data, heat-treatment condition, B-2/B-3 deltas, welding guidance — per RFQ |
| Size (inch) | Coarse: Stress Area (in²) | Coarse: TPI | Fine: Stress Area (in²) | Fine: TPI | 8-Thread: Stress Area (in²) | 8-Thread: TPI |
|---|---|---|---|---|---|---|
| 1/2 | 0.1419 | 13 | 0.1599 | 20 | ||
| 9/16 | 0.1820 | 12 | 0.2030 | 18 | ||
| 5/8 | 0.2260 | 11 | 0.2560 | 18 | ||
| 1/4 | 0.0318 | 20 | 0.0364 | 28 | -- | -- |
| 5/16 | 0.0524 | 18 | 0.0580 | 24 | -- | -- |
| 3/18 | 0.0775 | 16 | 0.0878 | 24 | -- | -- |
| 7/16 | 0.1063 | 14 | 0.1187 | 20 | ||
| 3/4 | 0.3340 | 10 | 0.3730 | 16 | ||
| 7/8 | 0.4620 | 9 | 0.5090 | 14 | ||
| 1 | 0.6060 | 8 | 0.6630 | 12 | ||
| 1 1/8 | 0.7630 | 7 | 0.8560 | 12 | 0.790 | 8 |
| 1 1/4 | 0.9690 | 7 | 1.0730 | 12 | 1.000 | 8 |
| 1 3/8 | 1.1550 | 6 | 1.3150 | 12 | 1.233 | 8 |
| 1 1/2 | 1.4050 | 6 | 1.5810 | 12 | 1.492 | 8 |
- Row 7 (7/16): Source prints the 3/8 row as "3/18" — a typo for 3/8 (its TPI 16/24 matches 3/8); reproduced verbatim, flagged.
- Row 1 (1/2): Source rows are unsorted (1/2, 9/16, 5/8, 1/4, …); re-sort by size if a ladder read is wanted.
| Nominal Size | Flats: 1st printed (in) | Flats: Max | Flats: Min | Corners: Max | Corners: Min | Thickness: Max | Thickness: Min |
|---|---|---|---|---|---|---|---|
| 1/4 | .2500 | .428 | .438 | .488 | .505 | .212 | .226 |
| 9/16 | .5625 | .861 | .875 | .982 | 1.010 | .473 | .496 |
| 1/2 | .5000 | .736 | .750 | .840 | .866 | .427 | .448 |
| 5/8 | .6250 | .922 | .938 | 1.051 | 1.083 | .535 | .559 |
| 3/8 | .3750 | .551 | .562 | .628 | .650 | .479 | .337 |
| 5/16 | .3125 | .489 | .500 | .557 | .577 | .258 | .273 |
| 7/16 | .4375 | .675 | .688 | .768 | .794 | .365 | .385 |
| 7/8 | .8750 | 1.269 | 1.312 | 1.447 | 1.516 | .724 | .776 |
| 3/4 | .7500 | 1.088 | 1.125 | 1.240 | 1.299 | .617 | .665 |
| 1 | 1.0000 | 1.450 | 1.500 | 1.653 | 1.732 | .831 | .887 |
| 1-3/8 | 1.3750 | 1.994 | 2.062 | 2.273 | 2.382 | 1.138 | 1.206 |
| 1-1/8 | 1.1250 | 1.631 | 1.688 | 1.859 | 1.949 | .939 | .999 |
| 2-1/2 | 2.5000 | 3.625 | 3.750 | 4.133 | 4.330 | 2.105 | 2.209 |
| 2-1/4 | 2.2500 | 3.263 | 3.375 | 3.719 | 3.897 | 1.890 | 1.986 |
| 2-3/4 | 2.7500 | 3.988 | 4.125 | 4.546 | 4.763 | 2.319 | 2.431 |
| 1-1/2 | 1.500 | 2.175 | 2.250 | 2.480 | 2.598 | 1.245 | 1.ASTM A194 GR. 8 |
| 1-3/4 | 1.7500 | 2.538 | 2.625 | 2.893 | 3.031 | 1.460 | 1.540 |
| 1-5/8 | 1.6250 | 2.356 | 2.438 | 2.686 | 2.815 | 1.353 | 1.429 |
| 2 | 2.0000 | 2.900 | 3.000 | 3.306 | 3.464 | 1.675 | 1.763 |
- Row 1 (1/4): Column semantics: the source header merges "Width in Flats / Width in Corners / Thickness" with Minimum/Maximum sub-labels; the printed rows carry 7 values per nominal in a fixed order (reproduced verbatim). The 1/4 row’s first value (.2500) is the nominal itself.
- Row 6 (5/16): The 3/8 row prints thickness figures .479/.337 in an order that breaks the rest of the column’s rising pattern (likely a print swap) — as printed; verify against the governing standard for critical design.
- Row 16 (1-1/2): The 1-1/2 row’s last cell prints "1.ASTM A194 GR. 8" — source print corruption (should be the thickness figure, ~1.245/1.245 band per neighbours); reproduced verbatim, flagged, never repaired silently.
| Property / Designation | Value |
|---|---|
| CTE, linear (20–100 °C) | 10.0 µm/m-°C (5.56 µin/in-°F, 68–212 °F) |
| Thermal conductivity (20–100 °C) | 11.7 W/m-K (81.2 BTU-in/hr-ft²-°F, 68–212 °F) |
| Density | 9.24 g/cm³ |
| Melting range | 1330-1380°C |
| Tensile strength | 690 Mpa |
| Yield strength | 310 Mpa |
| Elongation | 40 % |
| Werkstoff Nr. / UNS | 2.4800 / N10001 |
- Row 7 (Elongation): The designation row’s header cells ("Russia"/"North America" under WERKSTOFF NR./UNS) mislabel the columns — Werkstoff 2.4800 is the European (German) designation and UNS N10001 the North American; figures reproduced verbatim.
Materials
- Hastelloy B (Ni–Mo alloy); fastener stock condition and any requested B-2/B-3 substitution are RFQ items — state the service medium and temperature band
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (Hastelloy B Fasteners — Thread Stress Areas, Hex Dimensions and Material Data (UNS N10001 / WNr 2.4800)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantities and lead times for this family are confirmed at quotation — send your sizes, grades and quantities on the RFQ and the quote will carry a firm schedule. Sample availability is confirmed with the quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
When does Hastelloy B beat the stainless and titanium options on a fastener call — and when does it lose badly?
Follow the acid chemistry, not the price list. Hastelloy B is the strong pick in reducing environments — hot hydrochloric acid across nearly any concentration is its signature case, along with wet HCl gas and a range of sulfuric, phosphoric and acetic streams where 316 stainless corrodes at rates that destroy threads and titanium sits outside its own passivity window. The high molybdenum content (~28%) carries the corrosion resistance, and the 690 MPa tensile with 40% elongation means the bolt retains ductile margin while doing it — the thread stress-area table on this page exists precisely so that strength can be turned into a per-size bolt load. B loses badly in oxidizing conditions: any ferric ion (Fe³⁺) contamination, dissolved oxygen, free chlorine or nitric species destroys the molybdenum advantage and the alloy can corrode faster than the stainless it replaced — a common failure when HCl service picks up air ingress upstream. That is why grade selection runs through the medium chemistry: dissolved-oxygen content, ferric contamination risk and temperature band decide B versus B-2/B-3 versus C-family alloys, and finished fasteners additionally need the welding and heat-treatment condition stated (as-welded B can lose corrosion performance in the HAZ). Bring the service chemistry to the RFQ; the property lines here are the design inputs, not the selection logic.
Commercial terms for Hastelloy B fasteners?
Commercial terms are confirmed at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support