Incoloy 825 Fasteners

Incoloy 825 Fasteners Supplier in Mumbai, India - UNS N08825 / ASTM B425 / Werkstoff 2.4858

Nicorex Alloys is an ISO 9001 and ISO 14001 certified leading supplier of Incoloy 825 fasteners based in Mumbai, India. Bolts, screws, and studs are manufactured to ASTM F468, nuts to ASTM F467, with bar stock produced to ASTM B425 and forgings to ASTM B564.

Incoloy 825 is an iron‑based Ni‑Fe‑Cr‑Mo‑Cu alloy engineered for aggressive acid environments. Its carefully balanced chemistry (38-46% nickel, 19.5-23.5% chromium, minimum 22% iron, 2.5-3.5% molybdenum, and 1.5-3.0% copper) delivers broad-spectrum corrosion resistance in sulfuric, phosphoric, nitric, and organic acids at a significantly lower cost. Titanium additions (0.6-1.2%) stabilise carbon in the weld heat‑affected zone, protecting against intergranular corrosion in welded assemblies. A key advantage of Incoloy 825 is its ability to withstand multiple acid types simultaneously while remaining economically attractive. Copper and molybdenum work together to improve resistance to reducing acids, while the 38-46% nickel content effectively prevents chloride stress corrosion cracking. Because Incoloy alloys are iron‑based (≥22% Fe), they use less nickel than Inconel alloys (≥50% Ni), cutting raw material cost without sacrificing essential corrosion performance in demanding acid service.

In accordance with UNS N08825 and Werkstoff 2.4858 designations. Typical mechanical properties include 586 MPa (85 ksi) minimum tensile strength, 241 MPa (35 ksi) minimum yield strength, and 30% minimum elongation. The range covers Incoloy 825 hex bolts, stud bolts, socket head cap screws (SHCS), nuts, lock nuts, washers, threaded rods, U‑bolts, anchor bolts, set screws, and eye bolts from M6 to M100 (1/4” to 4”) with UNC, UNF, and metric threads. All fasteners can be supplied to NACE MR0175 / ISO 15156 requirements.

Incoloy 825 Fastener Specifications

The following specifications define the required properties, dimensions, and manufacturing requirements for Incoloy 825 fasteners and bar products:

Standard	ASTM B425 / ASME SB-425
Forms	Bolts, Nuts, Screws, Washers, Studs, Threaded Rods, Hex Bolts, Socket Head Cap Screws, Hex Nuts, Lock Nuts, Stud Bolts
Size	M6 – M100 (Metric); 1/4″ – 4″ (Imperial)
Length	3 mm – 200 mm; Custom lengths available
Diameter	M6 – M100 (Metric); 1/4″ – 4″ (Imperial)
Thread Types	UNC, UNF, Metric Coarse, Metric Fine, BSW, BSF
Surface Finishes	Bright Finish, Pickled, Passivated, Hot-Dip Galvanised, Electropolished
Available Conditions	Solution Annealed

Chemical Composition of Incoloy 825 Fasteners

Chemical composition requirements for Incoloy 825 fasteners, defined in accordance with ASTM F468 and ASTM B425 material standards:

Element	Nickel (Ni)	Chromium (Cr)	Iron (Fe)	Molybdenum (Mo)	Copper (Cu)	Titanium (Ti)	Carbon (C)	Manganese (Mn)	Silicon (Si)
Composition (%)	38.0-46.0	19.5-23.5	22.0 min (Balance)	2.5-3.5	1.5-3.0	0.6-1.2	0.05 max	1.0 max	0.5 max

1.5-3.0% copper provides sulfuric and phosphoric acid resistance (same principle as Hastelloy C2000, but at lower Ni content and much lower cost). 0.6-1.2% titanium stabilises carbon to prevent sensitisation in the weld HAZ. This is critical for bolt positions adjacent to welds, where intergranular corrosion would otherwise occur. The 38-46% Ni prevents chloride SCC at a fraction of the cost of Inconel.

Mechanical Properties of Incoloy 825 Fasteners

Mechanical properties of Incoloy 825 fasteners in solution-annealed condition at 1177°C with water quench, as specified by ASTM B425:

Property	Tensile Strength (min)	Yield Strength 0.2% (min)	Elongation (min)	Hardness (max)
Value	586 MPa (85 ksi)	241 MPa (35 ksi)	30%	90 HRB

The value proposition of 825 is acid corrosion resistance at lower material cost, not raw strength. Mechanical properties are comparable to Inconel 600 in the annealed condition, but 825 costs roughly half as much per kilogram.

Incoloy 825 Fastener Equivalent Grades

Incoloy 825 has multiple equivalent designations across global standards, ensuring easy material identification and specification in international projects.

Standard System	UNS	Werkstoff Number	DIN	EN	JIS	GOST	AFNOR	ISO
Equivalent Grade	N08825	2.4858	NiCr21Mo	NiCr21Mo	NCF 825	Not Specified	NC21FeDu	Not Specified

Physical Properties of Incoloy 825

The following section summarises Incoloy 825’s key physical characteristics and performance parameters measured under standard conditions:

Property	Density	Melting Range	Thermal Conductivity (25°C)	Thermal Expansion (20-100°C)	Modulus of Elasticity
Value	8.14 g/cm³ (0.294 lb/in³)	1370-1400°C (2500-2550°F)	11.1 W/m·K	14.0 µm/m·°C	196 GPa (29,900 ksi)

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Types of Incoloy 825 Fasteners Available

Incoloy 825 fasteners are available in a complete range of bolts, nuts, washers, rods, and speciality shapes for critical applications.

Incoloy 825 Hex Bolts / Heavy Hex Bolts

825 Stud Bolts - Double-end, fully threaded

Alloy 825 Socket Head Cap Screws

UN08825 Hex Nuts / Heavy Hex Nuts (ASTM F467)

Incoloy 825 Lock Nuts

825 Flat Washers / Spring Washers

Alloy 825 Threaded Rods

UN08825 U-Bolts / Anchor Bolts

Incoloy 825 Set Screws / Eye Bolts

Surface Finish and Coating Options

Plain: Standard
Passivated: Citric or nitric acid passivation per ASTM A967
PTFE Coated: Anti-galling
Manganese Phosphate: Thread lubricity
Anti-Seize: Nickel-based recommended

Industries and Applications for Incoloy 825 Fasteners

Incoloy 825 fasteners deliver reliable, cost-effective corrosion resistance for demanding chemical, fertiliser, oil & gas, nuclear, and marine applications.

Chemical Processing and Acid Plants: Sulfuric acid tank flange bolting, acid cooler studs, H₂SO₄ pump casing bolts, pickling system equipment. Incoloy 825 resists sulfuric acid at concentrations and temperatures where 316L corrodes, at half the cost of C276.
Fertiliser Production: Wet-process phosphoric acid reactor bolting, DAP/MAP plant equipment, ammonium sulfate crystalliser studs. 825 is the industry standard for phosphoric acid production, resisting H₃PO₄ with fluoride, chloride, and siliceous contaminants.
Oil & Gas: Reliable sour gas gathering flange bolts and wellhead bonnet studs meeting NACE MR0175.
Nuclear: High-integrity bolting solutions for spent nuclear fuel reprocessing and critical containment equipment.
Marine & Offshore: Corrosion-resistant fasteners for seawater heat exchangers and desalination systems in harsh marine environments.
Pollution Control: Durable FGD scrubber bolting engineered for dilute acid service in emission control systems.

How to Order Incoloy 825 Fasteners from Nicorex Alloys

To order Incoloy 825 Fasteners, follow these 7 important details:

Fastener Types - Hex Bolts, Stud Bolts, Heavy Hex Nuts, Threaded Rods, etc.
Size & Thread Specifications - Metric / Inch / UNC / UNF
Thread Tolerance & Fit Class - 6g / 6H / 2A / 2B
Material Grade - Incoloy 825 / UNS N08825 / W.Nr. 2.4858
Standards - ASTM B425, ASTM B564, ASME B18.2.1, DIN 931/933/934
Additional Requirements - NACE, IGC, PMI, and anti-galling treatment
Documentation & Packaging - Full documentation and export packaging details

Quotation within 24 hours.

Frequently Asked Questions

What is the Price of Incoloy 825 Fasteners per Kg in India?

Incoloy 825 fasteners usually cost about ₹2,000 to ₹4,500 per kg. This is cheaper than Inconel 625 and Hastelloy C276, which are typically ₹3,500 to ₹7,000 per kg. Because it is more affordable, Incoloy 825 is commonly selected for acid‑service bolting in cost‑sensitive projects.

What is the difference between Incoloy 825 and Inconel 625 for Fasteners?

Inconel 625 is a nickel‑based alloy (Ni‑Cr‑Mo‑Nb) with about 58% nickel. It is more expensive and is mainly used for strong resistance to chloride attack in marine environments. In general, use Incoloy 825 for acid plants, fertiliser production, and sour gas service, and use Inconel 625 for subsea equipment, seawater exposure, and very aggressive chloride pitting and crevice conditions.

What is the difference between Incoloy and Inconel?

Incoloy alloys are iron-based (≥22% Fe, 38-46% Ni) for acid corrosion resistance at moderate temperatures. Inconel alloys are nickel-based (≥50% Ni) for higher corrosion resistance and high-temperature service. Both are registered trademarks of Special Metals Corporation.

Is Incoloy 825 resistant to phosphoric acid?

Yes. 825 is the industry standard for wet-process phosphoric acid production. It resists H₃PO₄ with fluoride, chloride, and siliceous contaminants that corrode 316L rapidly.

Does ASTM F468 cover Incoloy 825 Fasteners?

Yes. UNS N08825 is listed in ASTM F468 for sizes 1/4” to 1-1/2”. Larger fasteners use ASTM B425 bar. Nuts are covered under ASTM F467.

Can Incoloy 825 replace 316L Stainless Steel Fasteners?

Yes, where 316L fails due to pitting, SCC, or acid attack. 825 provides far better sulfuric acid, phosphoric acid, and chloride SCC resistance. 825 costs roughly 2-3× more than 316L, so specify it only where 316L has demonstrated failure.