Incoloy 800H and 800HT fasteners from Unifit Fastener deliver controlled carbon content (0.05–0.10% for 800H) and elevated Al+Ti sums (≥0.85% for 800HT) that sustain creep-rupture strength in reformer tubing flanges, pyrolysis furnace headers, and nuclear pressure vessel closure assemblies where standard stainless fasteners fail within months. Our precision-engineered nickel-iron-chromium alloy fasteners are purpose-built for industries where standard fasteners fail — delivering outstanding resistance to oxidation, carburization, and stress-corrosion cracking at temperatures reaching 1100°C.
Whether you need hex bolts, stud bolts, heavy hex nuts, socket cap screws, or flat washers in UNS N08800, UNS N08810, or UNS N08811 grades, Unifit Fastener maintains ready stock in metric and imperial sizes compliant with ASTM B408, ASME SB408, DIN, BS, and all international standards. Backed by rigorous in-house testing — radiography, PMI, IGC, hardness, and tensile tests — and full material traceability documentation, we serve clients across the oil & gas, petrochemical, power generation, aerospace, and heat treatment sectors globally. Request a competitive quote today and experience the Unifit advantage.
Request QuoteWhat Are Incoloy 800 Fasteners?
Incoloy 800 is a nickel-iron-chromium alloy (Ni: 30–35%, Fe: 39.5% min, Cr: 19–23%) known for its exceptional stability in high-temperature and corrosive environments. Incoloy 800 fasteners maintain their austenitic structure after prolonged thermal exposure, making them ideal for critical applications in furnaces, heat exchangers, petrochemical reactors, and nuclear power plants.
The 800H and 800HT sub-grades offer enhanced creep resistance:
- Incoloy 800H (UNS N08810): Controlled carbon content (0.05–0.10%) for superior creep-rupture strength above 600°C
- Incoloy 800HT (UNS N08811): Higher aluminum + titanium content (≥ 0.85%) for peak high-temperature strength and long-term stability
Incoloy 800-series alloys work-harden at approximately 2–3× the rate of 304 stainless steel, requiring carbide tooling, low cutting speeds (30–60 m/min for turning), and flood coolant to maintain dimensional tolerance. Unifit Fastener's CNC forming programme is configured specifically for these parameters, delivering M3–M100 fasteners to ±0.01 mm thread tolerance without the microstructural damage that causes premature fatigue failure.
Table of Content
- Incoloy 800 Fasteners Specifications
- Chemical Composition of Incoloy 800/800H/800HT Fasteners
- Mechanical Properties of Incoloy 800/800H/800HT Fasteners
- Equivalent Grades of Incoloy 800/800H/800HT Fasteners
- UNS N08810 Bolt Weight Reference Chart
- DIN 1.4876 Stud Bolt Tightening Torque Guide
- Incoloy 800 Nut Weight Chart
- Types Of Incoloy 800 Fasteners
- Incoloy 800/800HT Bolts
- Incoloy 800/800HT Nuts
- Incoloy 800/800HT Washers
- Incoloy 800/800HT Screws
- Incoloy 800/800HT Stud Bolt
- Industries & Applications of Incoloy 800 Fasteners
- Why Choose Unifit Fastener
- Quality Assurance & Testing
- Incoloy 800 vs 800H vs 800HT
- Incoloy 800/800HT Fasteners Price List
- Export Destinations For Incoloy 800/800HT Fasteners
Incoloy 800 Fasteners Specifications
| Parameter | Details |
| Specifications | ASTM B408 / ASME SB408 / ASME SB 564 |
| Standards | DIN, ASTM, BS, JIS, ISO, GOST — All International Standards |
| UNS Numbers | N08800 (800) | N08810 (800H) | N08811 (800HT) |
| Werkstoff Nr. | 1.4876 (800) | 1.4958 (800H) | 1.4959 (800HT) |
| Size Range (Bolts/Screws) | M3 – M100 | 3/8" to 4" | Custom Sizes Available |
| Nut Size Range | M3 – M56 | 3/8" to 2" | Custom Sizes Available |
| Washer Size Range | M1 – M64 | #4 to 3" | Custom Sizes Available |
| Length | 10 mm to 1000 mm | Custom Lengths on Request |
| Thread Types | UNC, UNF, METRIC, BSW, BSF, ACME, NPT, NPTF |
| Forms Available | Hex, Square, Round, Hex Flange, T-Head, Triangular, Flat |
| Head Types | Hex, Slotted, Phillips, Six-Lobe, Socket, Pan, Truss, Button |
| Surface Coating | Phosphating, Oxidation, HDG, Zinc, Black Oxide, Cadmium, Teflon |
| Manufacturing Process | Hot Forging (M24–M100), Cold Forming (M2–M24), CNC Machining |
| MTC Certificate | EN 10204 3.1 / 3.2 | Third-Party Inspection Available |
| HS Code | 72192212 |
Chemical Composition of Incoloy 800/800H/800HT Fasteners
| Grade | Ni | Fe | Cr | Cu | Mn | Si | Al | Ti | C |
| Incoloy 800 | 30.0–35.0 | 39.5 min | 19.0–23.0 | 0.75 max | 1.5 max | 1.0 max | 0.15–0.60 | 0.15–0.60 | 0.10 max |
| Incoloy 800H | 30.0–35.0 | 39.5 min | 19.0–23.0 | 0.75 max | 1.5 max | 1.0 max | 0.15–0.60 | 0.15–0.60 | 0.05–0.10 |
| Incoloy 800HT | 30.0–35.0 | 39.5 min | 19.0–23.0 | 0.75 max | 1.5 max | 1.0 max | 0.85–1.20 | 0.25–0.60 | 0.06–0.10 |
Mechanical Properties of Incoloy 800/800H/800HT Fasteners
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%) |
| 800 / 800H / 800HT | 7.94 g/cm³ | 1385°C (2525°F) | Psi 75,000 / MPa 520 | Psi 30,000 / MPa 205 |
| Elongation | 30% minimum | |||
Incoloy 800/800H/800HT Fasteners — Equivalent Grades
| Grade | Werkstoff Nr. | UNS | JIS | BS | GOST | AFNOR | EN |
| Incoloy 800 | 1.4876 | N08800 | NCF 800 | NA 15 | ЭИ670 | Z8NC32-21 | X10NiCrAlTi32-20 |
| Incoloy 800H | 1.4958 | N08810 | NCF 800H | NA 15(H) | ЭИ670 | Z8NC33-21 | X5NiCrAlTi31-20 |
| Incoloy 800HT | 1.4959 | N08811 | NCF 800HT | NA 15(HT) | ЭИ670 | — | X8NiCrAlTi32-21 |
UNS N08810 Bolt Weight Reference Chart
Approximate Weight of 100 Hex Bolts (kg) as per IS 1363 / ISO Metric Threads
| Bolt Length (mm) | M6 | M8 | M10 | M12 | M16 | M20 |
| 20 | 0.81 | 1.71 | 3.41 | 4.89 | – | – |
| 30 | 1.01 | 2.07 | 3.91 | 5.57 | 10.71 | 18.66 |
| 50 | 1.45 | 2.87 | 5.16 | 7.30 | 13.62 | 22.73 |
| 80 | 2.11 | 4.07 | 7.01 | 10.00 | 18.25 | 30.30 |
| 100 | – | 4.87 | 8.25 | 11.82 | 21.46 | 35.71 |
| 150 | – | – | 11.31 | 16.34 | 29.41 | 48.54 |
| 200 | – | – | 14.33 | 20.83 | 37.59 | 60.98 |
| 300 | – | – | 20.33 | 29.94 | 53.76 | 87.72 |
Note: Weights are indicative values for estimating shipment mass and procurement planning. Actual weight may vary depending on thread length, manufacturing tolerances, and material density.
DIN 1.4876 Stud Bolt Tightening Torque Guide
Recommended Assembly Torque for ASME B16.5 Class 150 & Class 300 Flanges
| Flange Size (NPS) | Stud Size | Final Torque (ft-lbs) | Tightening Pattern |
| 1/2" – 1" | 1/2" | 30 – 60 | 4-Bolt Cross Pattern |
| 1-1/2" – 4" | 5/8" | 120 | 4 or 8-Bolt Star Pattern |
| 5" – 8" | 3/4" | 200 | 8-Bolt Star Pattern |
| 10" – 12" | 7/8" | 320 | 12-Bolt Sequence |
| 14" – 16" | 1" | 490 | 16-Bolt Sequence |
| 18" – 20" | 1-1/8" | 710 | 16–20 Bolt Sequence |
| 24" | 1-1/4" | 1000 | 20-Bolt Sequence |
Recommended Tightening Procedure
| Step | Torque Applied |
| First Pass | 30% of Final Torque |
| Second Pass | 60% of Final Torque |
| Final Pass | 100% of Required Torque |
Engineering Note: Torque values are reference guidelines only. Final tightening loads should be validated according to gasket type, lubrication condition, flange class, and applicable project specifications.
Incoloy 800 Nut Weight Chart
Approximate Unit Weight (grams per piece)
| Nominal Size | Heavy Hex Nut | Finished Hex Nut | Square Nut | Heavy Square Nut | Jam Nut |
| 1/2" | 6.54 | 3.75 | 5.78 | 7.87 | 2.62 |
| 5/8" | 11.90 | 7.33 | 10.80 | 14.30 | 4.93 |
| 3/4" | 19.30 | 11.90 | 15.40 | 23.50 | 7.70 |
| 7/8" | 29.70 | 19.00 | 24.50 | 36.20 | 12.00 |
| 1" | 42.50 | 28.30 | 36.30 | 51.50 | 17.60 |
| 1-1/8" | 59.20 | 40.30 | 52.50 | 72.40 | 24.70 |
| 1-1/4" | 78.60 | 54.30 | 70.60 | 95.50 | 36.10 |
| 1-3/8" | 102.00 | 73.00 | 94.50 | 125.00 | 47.90 |
| 1-1/2" | 131.00 | 94.30 | 122.00 | 161.00 | 60.90 |
| 2" | 299.00 | 224.00 | – | – | 140.00 |
Weight Calculation Formula
| Component | Formula |
| Bolt Weight | Volume × Material Density |
| Nut Weight | Nut Geometry Volume × Material Density |
| Shipment Weight | Unit Weight × Quantity Ordered |
Types of Incoloy 800 Fasteners Supplied by Unifit Fastener
EN 1.4876 Hex Head Bolts
DIN 1.4876 Flange Bolts
800 Inconel Square Head Bolts
Nickel 800 J-Bolts
UNS N08800 U-Bolts
WNR 1.4876 Hanger Bolts
Incoloy 800 Eye Bolts
Incoloy 1.4876 Shoulder Bolts
Incoloy 800 Stud Bolts
Nickel Alloy 800 Heavy Hex Nuts
Werkstoff NR. 1.4876 Wing Nuts
ASTM B408 UNS N08800 Coupling Nuts
Incoloy 800 Castle Nuts
Incoloy Alloy 800 Keps-K Lock Nuts
Incoloy 800 Cap Nuts
Incoloy Alloy 800 Hex Jam Nuts
Incoloy 800 Fender Washers
ASTM B408 Square Washers
ASME SB 408 Structural Washers
Nickel Alloy 800 Drywall Screws
Werkstoff NR. 1.4876 Threaded Cutting Screws
Incoloy Alloy 800 Socket Set Screws
Incoloy 800 Machine Screws
Incoloy Alloy 800 Self Drilling Screws
Incoloy 800 Eye Screws
Alloy Incoloy 800 Wood Screws
Alloy Incoloy 800 Stove Bolts
Alloy 800 Hex Lag Screws
Industries & Applications of Incoloy 800/800H/800HT Fasteners
Unifit Fastener's Incoloy 800/800H/800HT fasteners are engineered for demanding industrial environments where conventional stainless steel fasteners would fail. Key application areas include:
| Industry | Application |
| Oil & Gas | Refinery piping, pressure vessels, flanged joints |
| Petrochemical Processing | Heat exchanger fasteners, reactor internals |
| Power Generation | Boiler fittings, turbine components, steam lines |
| Nuclear Industry | Reactor vessel assemblies, coolant system fasteners |
| Aerospace | Furnace fixtures, high-temp structural fasteners |
| Pulp & Paper Industry | Digesters, bleaching equipment, evaporators |
| Heat Treatment | Furnace conveyor systems, heat treatment baskets |
| Chemical Processing | Acid vessels, chloride-rich process environments |
| Cement & Automotive | Kiln internals, exhaust system components |
Why Choose Unifit Fastener for Incoloy 800 Fasteners?
- ISO 9001:2015 Certified manufacturer with full quality management system
- Ready stock in all standard sizes — enabling fast dispatch within 24–72 hours
- Complete material traceability: MTC (EN 10204 3.1/3.2), Mill Test Reports, CoA
- In-house testing: PMI, Hardness, Tensile, IGC, Radiography, Ultrasonic, Micro/Macro
- Competitive pricing with flexible MOQ — suitable for both small and bulk orders
- Export experience across 50+ countries including UAE, Saudi Arabia, USA, UK, Germany
- Custom manufacturing available — any size, thread type, coating, or head style
- Packaging in wooden boxes, pallets, or cartons to ensure damage-free delivery
Quality Assurance & Testing at Unifit Fastener
Every Incoloy 800 fastener leaving Unifit Fastener's facility passes through a comprehensive inspection protocol:
| Test Type | Purpose |
| PMI (Positive Material ID) | Verifies exact alloy composition before dispatch |
| Radiography Test | Detects internal defects and inclusions |
| Hardness Test | Ensures correct mechanical properties |
| Tensile / Yield Strength | Confirms structural integrity under load |
| IGC Test | Intergranular corrosion resistance verification |
| Ultrasonic Test | Non-destructive detection of sub-surface flaws |
| Pitting Resistance Test | Evaluates corrosion pit formation tendency |
| Chemical Analysis | Full elemental breakdown via spectro analysis |
Incoloy 800 vs 800H vs 800HT — Key Differences
| Property | Incoloy 800 | Incoloy 800H | Incoloy 800HT |
| UNS | N08800 | N08810 | N08811 |
| Carbon Range | 0.10 max | 0.05–0.10 | 0.06–0.10 |
| Al + Ti (min) | 0.30 | 0.30 | 0.85 |
| Best Feature | General corrosion resistance | Creep strength up to 800°C | Peak high-temp stability |
| Typical Use | Heat exchangers, chemical plants | Reformer tubes, furnaces | Nuclear, advanced furnaces |
Incoloy 800 800ht Fasteners Price List
Unifit Fastener offers highly competitive pricing. Below are approximate indicative price ranges for reference:
| Product Type | Approximate Price (USD) |
| Incoloy 800H/800HT Hex Bolt & Nut | $0.05 – $1.00 / Piece |
| Alloy 800 Hex Cap Screw / Bolt | $0.10 – $100.00 / Piece |
| UNS N08800 Stud Bolt c/w 2 Hex Nuts | $15.60 – $19.00 / Piece |
| Alloy 800 Stud Bolts with Hex Nut | $0.01 – $2.00 / Piece |
| UNS N08800 Big NUT Heavy Hex Nut | $14.80 – $15.60 / Piece |
| 12-Point Flange Bolt (1.4876) | $3.20 – $3.60 / Piece |
* Prices vary based on size, quantity, grade, and current nickel market rates. Contact Unifit Fastener for a firm quotation.
Our Related Products
Unifit Fastener manufactures, suppliers and exports of Incoloy 800 / 800HT Fasteners to various countries such as Thailand, Kazakhstan, Belgium, Hong Kong, Mexico, Mexico, Turkey, Ecuador, Egypt, Kenya, Romania, Poland, Bulgaria, Sri Lanka, Estonia, Australia, Iran, Chile, Lithuania, Belarus, Argentina, Pakistan, Iraq, Greece, Czech Republic, China, Saudi Arabia, Algeria, Chile, Malaysia, Lebanon, Japan, Netherlands, Portugal, Ukraine, Italy, Ghana, Taiwan, Austria, Trinidad & Tobago, France, Nigeria, Hungary, South Korea, Tunisia, Colombia, Oman, Bangladesh, Libya, Costa Rica, Russia, Spain, Morocco, Bahrain, Iran, Slovakia, Norway, Yemen, South Africa, Vietnam, Angola, Nigeria, United Kingdom, Denmark, Indonesia, Mongolia, Azerbaijan, Venezuela, Croatia, Gabon, United States, Finland, Israel, Philippines, Qatar, United Arab Emirates, Peru, Canada, Bhutan, Afghanistan, Sweden, New Zealand, Brazil, Poland, Serbia, Bolivia, Singapore, Jordan, Switzerland, Kuwait.
FAQs – Incoloy 800 / 800H / 800HT Fasteners
Incoloy 800 fasteners are used in applications requiring resistance to oxidation, carburization, and stress-corrosion cracking at elevated temperatures — including furnace components, heat exchangers, petrochemical reactors, power generation equipment, and nuclear power plants. They remain stable up to 1100°C.
All three are nickel-iron-chromium alloys with similar base composition. Incoloy 800H (UNS N08810) has a controlled carbon content of 0.05–0.10% for improved creep strength. Incoloy 800HT (UNS N08811) has additional aluminum and titanium (Al+Ti ≥ 0.85%) for peak high-temperature performance. Choose 800H/800HT when operating above 600°C for long durations.
Unifit Fastener stocks Incoloy 800 bolts in M3 to M100 metric and 3/8" to 4" imperial sizes. Nuts are available M3–M56, washers M1–M64, and lengths from 10 mm to 1000 mm. Custom sizes are manufactured on request.
Incoloy 800/800H/800HT fasteners have a tensile strength of 75,000 Psi (520 MPa), yield strength of 30,000 Psi (205 MPa), and elongation of 30% minimum, with a density of 7.94 g/cm³ and melting point of 1385°C (2525°F).
Yes. Unifit Fastener supports both small quantity and bulk orders with no minimum order quantity restrictions for standard sizes. Sample orders for trial and approval purposes are welcome. Contact our sales team to request samples with full MTCs.