Unifit Fastener is an ISO 9001:2015 certified Inconel fasteners manufacturer in India, producing Inconel bolts, nuts, stud bolts, washers, screws and threaded rods in grades 600, 601, 625, 718 and X-750. Sizes run from M3 to M100 and 1/8" to 4", in lengths to 5,000 mm, threaded to ASME B1.1 Class 2A/3A or ISO metric 6g. Every batch ships with an EN 10204 3.1 mill test certificate and heat-number traceability, with third-party inspection available on request. Supplied to refinery, gas turbine, offshore and aerospace subcontract buyers across India, the GCC, Europe and North America.
Inconel fasteners are load-bearing components machined or cold-forged from nickel-chromium superalloys. The nickel matrix resists chloride stress-corrosion cracking that fails 316 stainless; the chromium content builds a stable oxide film that survives cyclic heating where carbon steel scales and loses section. In practical terms, an Inconel fastener is specified when one of four things is true: the joint runs above roughly 550°C, the medium contains chlorides or reducing acids, the assembly is subject to thermal cycling that would relax a lower-alloy bolt, or a single fastener failure carries unacceptable consequence. Service limits are grade-specific — the selection table below maps each grade to its working envelope.
Unifit runs cold forging for sizes to M24 and CNC turning with thread rolling above that, so thread grain flow stays continuous rather than cut — which is what holds fatigue life in a bolt that will see thermal cycling. Age-hardenable grades (718, X-750) are solution-treated and precipitation-hardened in-house to AMS 5662 or AMS 5667 as specified. Standard portfolio covers hex bolts, heavy hex bolts, socket head cap screws, stud bolts, threaded rods, hex nuts, heavy hex nuts, nyloc nuts, flat washers, spring washers and dowel pins, plus drawing-to-part custom fasteners against customer specification.
With over two decades of manufacturing expertise, Unifit Fastener serves global procurement teams in aerospace, oil & gas, chemical processing, nuclear energy, and marine engineering — delivering on tight tolerances, complex specifications, and competitive lead times.
Need Alloy 625? View Inconel 625 Fasteners (UNS N06625)
Request QuoteWe manufacture a comprehensive selection of Inconel fastener types to meet diverse mechanical, structural, and industrial bolting requirements. All product types are available in grades 600, 601, 625, 718, and X-750.
Hex bolts, socket head bolts, eye bolts, flange bolts, J-bolts, U-bolts, and anchor bolts for high-load applications.
Hex nuts, heavy hex nuts, square nuts, coupling nuts, jam nuts, dome nuts, nylock nuts, and wing nuts.
Fully threaded, tap-end, and double-end studs for high-strength bolting in flanged pipe assemblies and pressure vessels.
Flat washers, spring lock washers, ogee washers, self-locking washers, and fender washers for load distribution.
Hex cap screws, socket cap screws, button head screws, machine screws, set screws, and self-drilling screws.
Right and left-hand threaded rods in cold drawn, polished, and mill finish. Heat-treated options available.
Precision dowel pins for alignment and shoulder bolts for high-reliability assemblies requiring controlled shank dimensions.
Engineered-to-specification fasteners manufactured per client drawings for specialized critical applications.
| Grade | UNS Number | Composition Highlights | Max Temp (°C) | Key Applications | Quick Link |
|---|---|---|---|---|---|
| Inconel 600 | N06600 | High Nickel, Chromium | 1095°C | Chemical processing, furnace components, food industry | Inconel 600 Fasteners |
| Inconel 601 | N06601 | Added Aluminum for oxidation resistance | 1250°C | Heat-treating equipment, gas-turbine components | Inconel 601 Fasteners |
| Inconel 625 | N06625 | Nickel-Chromium-Moly-Niobium | 980°C | Most Popular: Subsea, marine hardware, chemical plants | Inconel 625 Fasteners |
| Inconel 718 | N07718 | Precipitation Hardened (Fe-Nb-Mo) | 700°C | Aerospace turbines, high-strength cryogenic tanks | Inconel 718 Fastener |
| Inconel X-750 | N07750 | Age-hardenable (Al-Ti added) | 815°C | High-temperature springs, gas turbines, nuclear reactors | Inconel X-750 Fasteners |













| Product Type | Available Grades | Size Range | Standards | Common Uses |
|---|---|---|---|---|
| Hex Bolts & Heavy Hex | 600, 601, 625, 718 | M6 – M100 | ASME B18.2.1, DIN 931, DIN 933 | Structural assemblies, engine mounts, heavy machinery |
| Socket Head Cap Screws | 625, 718, X-750 | M3 – M48 | ASME B18.3, DIN 912 | Precision aerospace parts, high-pressure valves |
| Stud Bolts (Full/Double End) | 600, 625, 718 | M10 – M150 | ASME B16.5, ASTM A193/A194 | Flange connections in high-temp/high-pressure piping |
| Hex & Lock Nuts | 600, 601, 625, 718, X-750 | M3 – M150 | ASTM A194, DIN 934, DIN 985 | Securing stud bolts and machine bolts in corrosive environments |
| Washers (Flat & Spring) | 625, 718, X-750 | M3 – M100 | DIN 125, DIN 127, ASME B18.22.1 | Load distribution and vibration resistance in gas turbines |
| Threaded Rods | 600, 625, 718 | 1m – 3m | ASME B18.31.2, DIN 975/976 | Hanging supports in chemical tanks, custom anchoring |
| Machine Screws | 600, 625 | M1.6 – M10 | ASME B18.6.3, DIN 7985 | Small electronic housing in marine/medical settings |
| Grade | UNS Number | Composition Highlights | Max Temp (°C) | Key Applications | Quick Link |
|---|---|---|---|---|---|
| Inconel 600 | N06600 | High Nickel, Chromium | 1095°C | Chemical processing, furnace components, food industry | Inconel 600 Fasteners |
| Inconel 601 | N06601 | Added Aluminum for oxidation resistance | 1250°C | Heat-treating equipment, gas-turbine components | Inconel 601 Fasteners |
| Inconel 625 | N06625 | Nickel-Chromium-Moly-Niobium | 980°C | Most Popular: Subsea, marine hardware, chemical plants | Inconel 625 Fasteners |
| Inconel 718 | N07718 | Precipitation Hardened (Fe-Nb-Mo) | 700°C | Aerospace turbines, high-strength cryogenic tanks | Inconel 718 Fastener |
| Inconel X-750 | N07750 | Age-hardenable (Al-Ti added) | 815°C | High-temperature springs, gas turbines, nuclear reactors | Inconel X-750 Fasteners |
| Manufacturing Standards | ASTM / ASME SB160, SB164, SB425, SB166, SB446, SB472 & SB574 |
|---|---|
| Diameter Range | Metric sizes from M10 to M100 |
| Available Length | Supplied in custom lengths up to 1000 mm |
| Alloy Grades Offered | Inconel 600 (UNS N06600), Inconel 601 (UNS N06601), Inconel 625 (UNS N06625), Incoloy 800 (UNS N08800), Incoloy 800H/HT (UNS N08810), Incoloy 825 (UNS N08825) |
| Compliance Standards | Manufactured as per IS, BS & ASTM specifications |
| Product Range | Hex Bolts, Heavy Hex Nuts, Stud Bolts, Threaded Bars, Eye Bolts, Anchor Bolts, Socket Head Screws, Cotter Pins, Industrial Washers, Foundation Fasteners, Precision Fasteners & related components |
| Grade | UNS | ASTM / ASME | DIN / W.Nr. | JIS | EN / ISO Equivalent |
|---|---|---|---|---|---|
| Inconel 600 | N06600 | SB-166 / B166 | 2.4816 | NCF 600 | NiCr15Fe |
| Inconel 601 | N06601 | SB-166 / B166 | 2.4851 | NCF 601 | NiCr23Fe |
| Inconel 625 | N06625 | SB-446 / B446 | 2.4856 | NCF 625 | NiCr22Mo9Nb |
| Inconel 718 | N07718 | SB-637 / B637 | 2.4668 | NCF 718 | NiCr19Fe19Nb5Mo3 |
| Inconel X-750 | N07750 | SB-637 / B637 | 2.4669 | — | — |
| Incoloy 800 | N08800 | SB-408 / B408 | 1.4876 | NCF 800 | X10NiCrAlTi32-21 |
| Incoloy 825 | N08825 | SB-425 / B425 | 2.4858 | NCF 825 | NiCr21Mo |
| Metric Size | Length Range (mm) | Thread Pitch | Common Pressure Class |
|---|---|---|---|
| M6 | 20 – 100 | 1.0 | Class 150 |
| M8 | 25 – 150 | 1.25 | Class 150–300 |
| M10 | 30 – 200 | 1.5 | Class 300 |
| M12 | 40 – 250 | 1.75 | Class 300–600 |
| M16 | 50 – 300 | 2.0 | Class 600 |
| M20 | 60 – 350 | 2.5 | Class 900 |
| M24 | 80 – 400 | 3.0 | Class 1500 |
| M30 | 100 – 500 | 3.5 | Class 2500 |
Understanding the elemental makeup of each Inconel grade helps engineers specify the right fastener for the service environment. The nickel-chromium matrix provides the base corrosion resistance, while secondary elements like molybdenum, niobium, and titanium govern strength and thermal stability.
| Element | Inconel 600 | Inconel 625 | Inconel 718 | Inconel X-750 |
|---|---|---|---|---|
| Nickel (Ni) | 72.0 min | 58.0 min | 50.0–55.0 | 70.0 min |
| Chromium (Cr) | 14.0–17.0 | 20.0–23.0 | 17.0–21.0 | 14.0–17.0 |
| Iron (Fe) | 6.0–10.0 | 5.0 max | Balance | 5.0–9.0 |
| Molybdenum (Mo) | — | 8.0–10.0 | 2.8–3.3 | — |
| Niobium (Nb + Ta) | — | 3.15–4.15 | 4.75–5.50 | 0.70–1.20 |
| Titanium (Ti) | — | 0.40 max | 0.65–1.15 | 2.25–2.75 |
| Aluminum (Al) | — | 0.40 max | 0.20–0.80 | 0.40–1.00 |
| Carbon (C) | 0.15 max | 0.10 max | 0.08 max | 0.08 max |
| Cobalt (Co) | — | 1.0 max | 1.0 max | — |
| Property | Inconel 600 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Density (g/cm³) | 8.47 | 8.44 | 8.19 |
| Melting Point | 1413°C (2580°F) | 1350°C (2460°F) | 1260°C (2300°F) |
| Tensile Strength (MPa) | 655 min | 930 min | 1,275 min |
| Yield Strength 0.2% (MPa) | 310 | 517 | 1,034 |
| Elongation (%) | 40 | 42.5 | 12 |
| Hardness (Brinell) | ≤ 179 HB | ≤ 240 HB | ≤ 444 HB |
Not all Inconel grades are interchangeable. Each grade is engineered for a specific balance of strength, corrosion resistance, and weldability. Use this table to select the optimal grade for your service conditions.
| Grade | UNS Number | Best For | Limitations | Typical Uses |
|---|---|---|---|---|
| Inconel 600 | N06600 | Excellent oxidation & carburization resistance; good strength up to 650°C | Susceptible to stress corrosion cracking in chloride environments | Heat exchangers, chemical plant equipment, nuclear fuel rod tubing |
| Inconel 625 | N06625 | Outstanding pitting & crevice corrosion resistance; excellent weldability | Lower strength than 718 at elevated temperatures | Marine, subsea, offshore, chemical processing, heat exchangers |
| Inconel 718 | N07718 | Superior tensile and fatigue strength; age-hardenable; widest service range | More complex heat treatment required; higher cost | Gas turbines, aerospace bolting, high-pressure downhole tooling |
| Inconel X-750 | N07750 | High creep rupture strength; excellent spring properties at temperature | Moderate corrosion resistance only | Turbine blades, springs, high-temp structural bolting |
| Incoloy 825 | N08825 | Resistance to sulfuric and phosphoric acids; good formability | Lower strength vs. 625 | Chemical processing, phosphoric acid plants, oil & gas |
| Product Type | Approx Price Range |
|---|---|
| Inconel Hex Bolts | $8 – $45 per piece |
| Inconel Stud Bolts | $10 – $60 per piece |
| Inconel Nuts | $5 – $25 per piece |
| Inconel Washers | $1 – $10 per piece |
| Inconel Threaded Rods | $20 – $120 per meter |
| Inconel Anchor Bolts | $15 – $80 per piece |
| Fastener Type | Standard Size Range |
|---|---|
| Bolts & Screws | M3 to M100 |
| Nuts | M3 to M100 |
| Stud Bolts | M6 to M100 |
| Threaded Rods | 100 mm to 3000 mm length |
| Washers | Custom & standard metric sizes |
| Anchor Fasteners | M10 to M72 |
| Product Type | Available Grades | Size Range | Standards | Common Uses |
|---|---|---|---|---|
| Hex Bolts & Heavy Hex | 600, 601, 625, 718 | M6 – M100 | ASME B18.2.1, DIN 931, DIN 933 | Structural assemblies, engine mounts, heavy machinery |
| Socket Head Cap Screws | 625, 718, X-750 | M3 – M48 | ASME B18.3, DIN 912 | Precision aerospace parts, high-pressure valves |
| Stud Bolts (Full/Double End) | 600, 625, 718 | M10 – M150 | ASME B16.5, ASTM A193/A194 | Flange connections in high-temp/high-pressure piping |
| Hex & Lock Nuts | 600, 601, 625, 718, X-750 | M3 – M150 | ASTM A194, DIN 934, DIN 985 | Securing stud bolts and machine bolts in corrosive environments |
| Washers (Flat & Spring) | 625, 718, X-750 | M3 – M100 | DIN 125, DIN 127, ASME B18.22.1 | Load distribution and vibration resistance in gas turbines |
| Threaded Rods | 600, 625, 718 | 1m – 3m | ASME B18.31.2, DIN 975/976 | Hanging supports in chemical tanks, custom anchoring |
| Machine Screws | 600, 625 | M1.6 – M10 | ASME B18.6.3, DIN 7985 | Small electronic housing in marine/medical settings |
| Manufacturing Standards | ASTM / ASME SB160, SB164, SB425, SB166, SB446, SB472 & SB574 |
|---|---|
| Diameter Range | Metric sizes from M10 to M100 |
| Available Length | Supplied in custom lengths up to 1000 mm |
| Alloy Grades Offered | Inconel 600 (UNS N06600), Inconel 601 (UNS N06601), Inconel 625 (UNS N06625), Incoloy 800 (UNS N08800), Incoloy 800H/HT (UNS N08810), Incoloy 825 (UNS N08825) |
| Compliance Standards | Manufactured as per IS, BS & ASTM specifications |
| Product Range | Hex Bolts, Heavy Hex Nuts, Stud Bolts, Threaded Bars, Eye Bolts, Anchor Bolts, Socket Head Screws, Cotter Pins, Industrial Washers, Foundation Fasteners, Precision Fasteners & related components |
| Grade | UNS | ASTM / ASME | DIN / W.Nr. | JIS | EN / ISO Equivalent |
|---|---|---|---|---|---|
| Inconel 600 | N06600 | SB-166 / B166 | 2.4816 | NCF 600 | NiCr15Fe |
| Inconel 601 | N06601 | SB-166 / B166 | 2.4851 | NCF 601 | NiCr23Fe |
| Inconel 625 | N06625 | SB-446 / B446 | 2.4856 | NCF 625 | NiCr22Mo9Nb |
| Inconel 718 | N07718 | SB-637 / B637 | 2.4668 | NCF 718 | NiCr19Fe19Nb5Mo3 |
| Inconel X-750 | N07750 | SB-637 / B637 | 2.4669 | — | — |
| Incoloy 800 | N08800 | SB-408 / B408 | 1.4876 | NCF 800 | X10NiCrAlTi32-21 |
| Incoloy 825 | N08825 | SB-425 / B425 | 2.4858 | NCF 825 | NiCr21Mo |
| Metric Size | Length Range (mm) | Thread Pitch | Common Pressure Class |
|---|---|---|---|
| M6 | 20 – 100 | 1.0 | Class 150 |
| M8 | 25 – 150 | 1.25 | Class 150–300 |
| M10 | 30 – 200 | 1.5 | Class 300 |
| M12 | 40 – 250 | 1.75 | Class 300–600 |
| M16 | 50 – 300 | 2.0 | Class 600 |
| M20 | 60 – 350 | 2.5 | Class 900 |
| M24 | 80 – 400 | 3.0 | Class 1500 |
| M30 | 100 – 500 | 3.5 | Class 2500 |
Understanding the elemental makeup of each Inconel grade helps engineers specify the right fastener for the service environment. The nickel-chromium matrix provides the base corrosion resistance, while secondary elements like molybdenum, niobium, and titanium govern strength and thermal stability.
| Element | Inconel 600 | Inconel 625 | Inconel 718 | Inconel X-750 |
|---|---|---|---|---|
| Nickel (Ni) | 72.0 min | 58.0 min | 50.0–55.0 | 70.0 min |
| Chromium (Cr) | 14.0–17.0 | 20.0–23.0 | 17.0–21.0 | 14.0–17.0 |
| Iron (Fe) | 6.0–10.0 | 5.0 max | Balance | 5.0–9.0 |
| Molybdenum (Mo) | — | 8.0–10.0 | 2.8–3.3 | — |
| Niobium (Nb + Ta) | — | 3.15–4.15 | 4.75–5.50 | 0.70–1.20 |
| Titanium (Ti) | — | 0.40 max | 0.65–1.15 | 2.25–2.75 |
| Aluminum (Al) | — | 0.40 max | 0.20–0.80 | 0.40–1.00 |
| Carbon (C) | 0.15 max | 0.10 max | 0.08 max | 0.08 max |
| Cobalt (Co) | — | 1.0 max | 1.0 max | — |
| Property | Inconel 600 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Density (g/cm³) | 8.47 | 8.44 | 8.19 |
| Melting Point | 1413°C (2580°F) | 1350°C (2460°F) | 1260°C (2300°F) |
| Tensile Strength (MPa) | 655 min | 930 min | 1,275 min |
| Yield Strength 0.2% (MPa) | 310 | 517 | 1,034 |
| Elongation (%) | 40 | 42.5 | 12 |
| Hardness (Brinell) | ≤ 179 HB | ≤ 240 HB | ≤ 444 HB |
Not all Inconel grades are interchangeable. Each grade is engineered for a specific balance of strength, corrosion resistance, and weldability. Use this table to select the optimal grade for your service conditions.
| Grade | UNS Number | Best For | Limitations | Typical Uses |
|---|---|---|---|---|
| Inconel 600 | N06600 | Excellent oxidation & carburization resistance; good strength up to 650°C | Susceptible to stress corrosion cracking in chloride environments | Heat exchangers, chemical plant equipment, nuclear fuel rod tubing |
| Inconel 625 | N06625 | Outstanding pitting & crevice corrosion resistance; excellent weldability | Lower strength than 718 at elevated temperatures | Marine, subsea, offshore, chemical processing, heat exchangers |
| Inconel 718 | N07718 | Superior tensile and fatigue strength; age-hardenable; widest service range | More complex heat treatment required; higher cost | Gas turbines, aerospace bolting, high-pressure downhole tooling |
| Inconel X-750 | N07750 | High creep rupture strength; excellent spring properties at temperature | Moderate corrosion resistance only | Turbine blades, springs, high-temp structural bolting |
| Incoloy 825 | N08825 | Resistance to sulfuric and phosphoric acids; good formability | Lower strength vs. 625 | Chemical processing, phosphoric acid plants, oil & gas |
| Product Type | Approx Price Range |
|---|---|
| Inconel Hex Bolts | $8 – $45 per piece |
| Inconel Stud Bolts | $10 – $60 per piece |
| Inconel Nuts | $5 – $25 per piece |
| Inconel Washers | $1 – $10 per piece |
| Inconel Threaded Rods | $20 – $120 per meter |
| Inconel Anchor Bolts | $15 – $80 per piece |
Note:
Pricing depends on:
| Fastener Type | Standard Size Range |
|---|---|
| Bolts & Screws | M3 to M100 |
| Nuts | M3 to M100 |
| Stud Bolts | M6 to M100 |
| Threaded Rods | 100 mm to 3000 mm length |
| Washers | Custom & standard metric sizes |
| Anchor Fasteners | M10 to M72 |
Where high temperature properties are required, which are above 600 °C, then in those environments Inconel fasteners are used rather than stainless steel. Although stainless steel is excellent for general purposes, it is more likely to lose its strength when it is exposed to high temperatures. About oxidation resistance, Inconel is superior, and it does not lose mechanical integrity in extremely hot conditions. Stainless steel fasteners, however, are less expensive and hence can be used in less demanding applications. In the case of the normal industrial requirements, you can check Stainless Steel Fasteners.
Hastelloy fasteners are more suitable when working under conditions of high acids and other chemical conditions, particularly when resistance to acids is imperative. On the other hand, Inconel fasteners are highly temperature oxidation-resistant and stable. The decision is made between chemical resistance and high-temperature performance in the application. Hastelloy Fasteners may be recommended in the case of acid-related applications.
Monel is widely used in seawater and marine components and is effective under low to moderate temperatures. When high temperature strength and oxidation resistance are needed, then Inconel fasteners are the most suitable choice. In saltwater usage with reduced exposure to heat, the Monel Fasteners are commonly used.
Unifit Fastener manufactures Inconel fasteners in different product forms and configurations according to applicable product standards and customer requirements. Manufacturing can include standard and custom dimensions, thread configurations and product specifications, subject to technical feasibility.
Quality and inspection requirements are determined according to the selected Inconel grade, product type and order specification. Where specified and confirmed for the order, material documentation and inspection may include Mill Test Certificates (MTC), material traceability, Positive Material Identification (PMI), dimensional inspection, hardness and tensile testing, and third-party inspection.
Applicable ASTM, ASME, DIN, ISO and other standards are selected according to the specific grade and fastener form. Testing, certification and inspection requirements should be confirmed before order placement.
Fasteners come in different ranges, and the availability also depends on their popularity. The different size ranges and availability information are given below.
Unifit Fasteners has enjoyed a reputable history as an exotic alloy fastener supplier since 2014, with high-quality solutions for the needy industries. Having in-house machining and high quality, all the fasteners are tested by PMI. We offer the specialization of custom production per your specifications of drawings, thus a perfect fit and performance. Competitive pricing, quick delivery time, and worldwide shipping with a good export package are some of the reasons why we are a good partner. Technical support is given by experienced engineers, and such common grades as 625 and 718 are available in stock.
Secure Premium Inconel Fasteners NowYes, Inconel fasteners come with strength and reliability at low temperature so it's a preferable choice for cryogenic applications.
No, Inconel fasteners are generally non-magnetic.
To prevent galling, always use proper lubrication, anti-seize compounds, or controlled torque installation to prevent galling.
Making the custom inconel fasteners typically takes 2–8 weeks, depending on size, grade, and order quantity.
Yes, NACE MR0175-compliant fasteners are available for sour service applications.
Yes, with the use of proper welding techniques and a compatible filter, you can easily weld Inconel Fasteners.