Hastelloy Fasteners
Giriraj Impex is a manufacturer, stockist, supplier and exporter of Hastelloy fasteners in alloys C276 (UNS N10276) and C22 (UNS N06022). We manufacture Hastelloy stud bolts, hex bolts, heavy hex nuts, washers, screws and threaded rods from ASTM B574 / ASME SB574 bar, in imperial and metric sizes, with mill test certificates.
Hastelloy fasteners are used where bolting is exposed to the same aggressive media as the equipment it holds together – hot acids, chlorides, wet chlorine and sour fluids – in chemical plants, pollution-control systems, offshore installations and marine equipment, where stainless steel bolts would corrode or crack.
Specifications
| Item | Details |
|---|---|
| Material | ASTM B574 / ASME SB574 bar – C276 (N10276), C22 (N06022); other Hastelloy grades on request |
| Products | Stud bolts, threaded rods, hex bolts, heavy hex bolts, heavy hex nuts, hex nuts, washers, screws, U-bolts |
| Dimensions | ASME B18.2.1, B18.2.2, B16.5 stud lengths; ISO and DIN for metric fasteners |
| Threads | UNC, UNF and 8UN (imperial); ISO metric coarse and fine |
| Condition | Solution annealed; cold worked or strain hardened for higher strength on request |
| Finish | Plain, bright; anti-galling lubricant or coating on request |
| Documents | Mill test certificate (MTC); third-party inspection on request |
Chemical composition
| Alloy | Ni | Cr | Mo | Fe | W | Co | C | Si | Mn | V |
|---|---|---|---|---|---|---|---|---|---|---|
| C276 (N10276) | Balance | 14.5–16.5 | 15.0–17.0 | 4.0–7.0 | 3.0–4.5 | 2.5 | 0.010 | 0.08 | 1.00 | 0.35 |
| C22 (N06022) | Balance | 20.0–22.5 | 12.5–14.5 | 2.0–6.0 | 2.5–3.5 | 2.5 | 0.015 | 0.08 | 0.50 | 0.35 |
Phosphorus and sulphur limits as given in the standards.
Fasteners keep the composition of the B574 bar from which they are made, as shown on the mill test certificate. Background on the alloys is on the Hastelloy page.
Strength of Hastelloy bolting
In the solution annealed condition, Hastelloy C276 and C22 have a minimum tensile strength of about 690 MPa (100 ksi) and a minimum yield strength of about 280 to 310 MPa (41 to 45 ksi). That yield strength is well below that of alloy steel B7 studs, so a flanged joint bolted with annealed Hastelloy studs cannot be tightened to the same preload. Designers allow for this in the joint design, use more or larger bolts, or specify cold-worked bar with higher yield strength. Please state the required mechanical properties if strain-hardened material is needed.
Why use Hastelloy fasteners
Bolting is often the weak point of a corrosion-resistant system. If a Hastelloy flange or vessel is bolted with stainless or carbon steel studs, any leak or condensation can attack the bolts, and galvanic coupling between different metals can speed up corrosion. Hastelloy C276 bolts resist pitting, crevice corrosion and chloride stress corrosion cracking, as well as reducing acids. C22 adds resistance to oxidising acids and mixed media. Both are used for bolting in contact with seawater, acid splash, chlorine and sour gas.
How we manufacture Hastelloy fasteners
We manufacture Hastelloy fasteners from certified B574 bar. Studs and threaded rods are cut to length, and threads are rolled or cut; rolled threads are preferred where fatigue strength matters. Bolts are hot forged or machined from bar, and nuts are machined from hexagonal or round bar. Nickel alloys work-harden quickly, so machining uses rigid set-ups, sharp tools and steady feeds. Each fastener is marked with the grade and heat number, inspected for thread gauging and dimensions, and supplied with the mill test certificate of the bar.
Galling and installation
Like other nickel alloys and stainless steels, Hastelloy threads can gall – the threads seize under load as the surfaces cold-weld together. Galling is reduced by applying a suitable anti-seize lubricant compatible with the process, tightening at a steady, moderate speed, and avoiding reuse of damaged threads. Using a slightly different condition or alloy for nuts and studs also helps. Tightening torque should be calculated from the lubricant and material, not taken from tables for carbon steel bolting.
Ordering Hastelloy fasteners
Please give the alloy, fastener type, diameter and thread, length, number of nuts per stud, washers, condition or required strength, quantity and any testing or inspection requirement. For flange bolting, give the flange size, class and facing and we can calculate the stud lengths.
Applications and related products
Hastelloy fasteners are used for flanged joints and equipment in chemical and pharmaceutical plants, flue-gas desulphurisation and scrubbers, acid and chlorine handling, offshore and subsea systems, seawater equipment and sour gas service. Matching products include Hastelloy flanges, Hastelloy pipe fittings, Hastelloy pipes and tubes, Hastelloy sheets and plates and Hastelloy round bars. Fasteners in other materials are on the fasteners page.
Frequently Asked Questions
Hastelloy C276 and C22 fasteners are made from bar to ASTM B574 (ASME SB574), with dimensions to ASME B18.2.1 and B18.2.2 or the relevant ISO and DIN standards.
Hastelloy resists pitting, crevice corrosion, chloride stress corrosion cracking and reducing acids far better than stainless steel, so the bolting lasts as long as the Hastelloy equipment.
No. Annealed Hastelloy has a much lower yield strength than B7 alloy steel, so joints are designed for a lower bolt preload or cold-worked material is specified.
Use a compatible anti-seize lubricant, tighten at a steady moderate speed and avoid reusing damaged threads. Rolled threads also reduce galling.
Yes. Hastelloy fasteners are supplied in imperial and ISO metric sizes, to ASME, ISO and DIN dimensions.
C276 is the most common grade for fasteners. C22 is used where oxidising conditions are present or the equipment itself is C22.
Request a Quote for Hastelloy Fasteners
Tell us the product, grade, size, standard, quantity and delivery location, and our sales team will reply with a quotation.
Hastelloy® is a trademark of Haynes International.