Incoloy Washers
RAYCHIN SPECIALTY METALS FASTENERS: BOLTS, NUTS, SCREWS, WASHERS, STUDS, THREADED RODS, U-BOLT, J-BOLTS
STANDARD AND CUSTOMIZED, SMALL BATCH AND LARGE BATCH, IMPERIAL AND METRIC
Incoloy Fasteners is widely used for its resistance to seawater, brine, sour gas and high chloride environments at elevated temperatures, which make it a popular choice in the oil and gas and power industries.
A Ni-Cr alloy with very good high temperature stability
Oxidization and carburization resistant up to 1400°F / 760°C
Good corrosion resistance, which increases with the various grades
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RAYCHIN LIMITED
Specialist in Incoloy Washers · Flat Washers · Heavy Washers · Spring Washers · CustomIncoloy Washers: Nickel-Iron-Chromium Superalloy Washers for Extreme Environments
RAYCHIN LIMITED is a recognized expert in Incoloy washers — from Incoloy flat washers, Incoloy heavy washers, Incoloy spring washers to custom non-standard configurations across all major Incoloy grades. Incoloy alloys are nickel-iron-chromium superalloys designed for high-temperature and corrosive service. The family includes Incoloy 800 series (800, 800H, 800HT) optimized for high-temperature strength and oxidation resistance up to 1150°C, and Incoloy 825/925 grades with molybdenum and copper additions for exceptional resistance to reducing acids and sour gas environments. The high nickel content ensures resistance to chloride stress corrosion cracking, while chromium provides oxidation resistance. Washers are essential components that distribute the load of threaded fasteners, prevent galling, and provide proper bearing surfaces. Our portfolio includes washers manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards. Engineered for the most demanding environments where high-temperature strength and corrosion resistance are critical. Incoloy washers are supplied in solution annealed condition (or aged for 925) with full traceability and third-party certifications.
Complete Range of Incoloy Washers – Types & Configurations
Flat Washers (DIN 125 / DIN 9021 / ISO 7089 / ASME B18.22.1)
Incoloy flat washers manufactured to DIN 125, DIN 9021, ISO 7089, ISO 7090 (chamfered), and ASME B18.22.1 standards. Available in narrow series (Type A) for general applications and wide series (Type B) for increased bearing area. Precision stamped or machined from solution annealed Incoloy, these washers provide uniform load distribution under bolt heads and nuts. Ideal for high-temperature corrosive applications up to 1150°C for grade 800 series, and up to 540°C for acid service with grade 825. Available in sizes from #0 to 4" (M1.6 to M100) with various thickness options. Supplied with deburred edges and passivated finish per ASTM A967.
Heavy Washers (DIN 434 / DIN 435 / ASME B18.22.1)
Incoloy heavy washers manufactured to ASME B18.22.1 (Type B heavy series), DIN 434, DIN 435, and ASTM F436 standards. Extra thickness provides increased bearing area and load distribution for heavy-duty bolting applications in corrosive environments. Essential for high-temperature flange connections where bolt preload must be maintained. Available in grades 800 series for high-temperature service and 825/925 for acid service. Sizes from 1/4" to 4" (M6 to M100). Suitable for pressure vessel closures, heat exchanger tube sheets, and API 6A wellhead equipment. NACE MR0175 compliant for sour service applications.
Spring Washers (DIN 6796 / DIN 127 / ASME B18.21.1)
Incoloy spring washers including Belleville disc springs, wave washers, and split lock washers manufactured to DIN 6796, DIN 127, and ASME B18.21.1 standards. These washers provide controlled spring force to maintain clamp load during thermal cycling and vibration. Incoloy's excellent high-temperature properties make it ideal for spring washers operating up to 1150°C for grade 800 series. Available in various load ratings and deflection characteristics. Ideal for gas turbine assemblies, furnace components, and high-temperature valve applications where bolt relaxation must be compensated.
Incoloy Grade Selection Guide for Washers
Incoloy 800 (UNS N08800 / 1.4876)
High-Temperature General Purpose: Nickel-iron-chromium alloy with excellent oxidation and carburization resistance up to 815°C. Good creep strength and resistance to sigma phase embrittlement. Ideal for heat exchangers, furnace components, and petrochemical applications. Minimum tensile strength: 585 MPa, yield strength: 240 MPa.
Incoloy 800H (UNS N08810 / 1.4958)
Enhanced High-Temperature Strength: Higher carbon content (0.05-0.10%) provides improved creep and rupture strength. Excellent performance up to 1150°C. Preferred for applications requiring long-term high-temperature stability such as ethylene furnace tubes and steam generators. Maintains structural integrity at extreme temperatures.
Incoloy 800HT (UNS N08811 / 1.4959)
Optimized High-Temperature Performance: Controlled chemistry with aluminum and titanium additions for enhanced creep resistance. Maximum service temperature up to 1150°C. Superior performance in cyclic temperature applications. Ideal for industrial furnace components, radiant tubes, and high-temperature structural fasteners.
Incoloy 825 (UNS N08825 / 2.4858)
Acid & Chloride Resistance: Nickel-iron-chromium alloy with molybdenum (2.5-3.5%) and copper (1.5-3%) additions. Exceptional resistance to sulfuric and phosphoric acids. Resists 40% H₂SO₄ at 100°C with <0.05mm/year corrosion rate. Ideal for chemical processing, acid storage, and marine applications. Maximum service temperature: 540°C in acid service.
Incoloy 925 (UNS N09925)
Sour Service Specialist: Precipitation-hardenable alloy with titanium additions (1.9-2.4%) providing significantly higher strength through aging. Excellent resistance to sulfide stress cracking in H₂S environments. Yield strength 760-965 MPa in aged condition. Ideal for oil & gas downhole tools, sour gas well equipment, and high-strength corrosion-resistant fasteners. Qualified per NACE MR0175.
Incoloy Washer Design & Standards
Dimensional Standards
Our Incoloy washers meet or exceed the following specifications:
Available in inch and metric sizes from #0 to 4" (M1.6 to M100).
Material Specifications by Grade
- Incoloy 800: ASTM B408 / ASME SB408, ASTM B163, ASTM B407
- Incoloy 800H: ASTM B408 / ASME SB408, ASTM B163, ASTM B407
- Incoloy 800HT: ASTM B408 / ASME SB408, ASTM B163, ASTM B407
- Incoloy 825: ASTM B424 / ASME SB424, ASTM B423, NACE MR0175
- Incoloy 925: ASTM B805, API 6A, NACE MR0175
Surface Finish Options
- Passivated: Per ASTM A967 for maximum corrosion resistance
- Electropolished: For clean room and pharmaceutical applications
- PTFE Coated: For anti-galling and lubricity
- As-Formed: Clean, deburred edges
Key Benefits of Incoloy Washers
Exceptional High-Temperature Strength (800 Series)
Incoloy 800H and 800HT maintain useful strength up to 1150°C. At 900°C, tensile strength remains 130-180 MPa, significantly higher than 316H. Excellent creep rupture strength at 1000°C with 20-25 MPa for 1000 hours.
Superior Acid Resistance (825)
Incoloy 825 washers resist 40% H₂SO₄ at 100°C with <0.05mm/year corrosion rate. Excellent performance in phosphoric acid service, including wet process phosphoric acid containing fluoride impurities.
Sour Service Excellence (925)
Incoloy 925 washers offer yield strength up to 760 MPa in aged condition with exceptional resistance to sulfide stress cracking. Qualified per NACE MR0175 for H₂S environments up to 425°C. Ideal for wellhead equipment, valve assemblies, and downhole tools.
Load Distribution
Proper washer selection prevents galling, distributes bolt preload evenly, and protects the surface finish of mating components. Essential for maintaining joint integrity in high-temperature and corrosive environments.
Chloride SCC Immunity
With high nickel content (30-46%), Incoloy washers have excellent resistance to chloride stress corrosion cracking, making them ideal for marine environments and brackish water applications.
Multiple Configurations
Available in flat, heavy, spring, and custom configurations to suit specific application requirements. Custom sizes and thicknesses available for unique applications. Precision stamped or machined for exact dimensions.
Manufacturing Standards for Incoloy Washers
RAYCHIN LIMITED manufactures Incoloy washers to the following national and international standards, ensuring full compliance for projects worldwide. Both standard and non-standard custom configurations are available.
International Standards & Global Designations for Incoloy Washers
To serve clients worldwide, RAYCHIN LIMITED manufactures Incoloy washers from material conforming to the following national and international specifications.
UNS N08800 1.4876 UNS N08825 2.4858 UNS N09925 NACE MR0175 API 6A
Chemical Composition (Weight %) – Incoloy Alloys
Our Incoloy washers are produced from melts that strictly conform to the limits below per ASTM standards. The nickel-iron-chromium matrix provides the exceptional high-temperature strength and corrosion resistance characteristic of these alloys.
Incoloy 800 / 800H / 800HT (UNS N08800 / N08810 / N08811)
Incoloy 825 (UNS N08825 / 2.4858)
Incoloy 925 (UNS N09925)
Expert note: The high nickel content provides resistance to chloride stress corrosion cracking. Chromium offers oxidation resistance at elevated temperatures. In 825/925 grades, molybdenum and copper additions provide exceptional resistance to reducing acids like sulfuric and phosphoric acids. Titanium in 925 enables precipitation hardening, achieving yield strengths over 760 MPa. The aluminum and titanium in 800 series contribute to creep resistance at high temperatures.
Complete Mechanical Properties of Incoloy Washers
Incoloy washers are supplied in the solution annealed condition (800 series, 825) or precipitation hardened condition (925). The data below represent minimum requirements per ASTM standards unless otherwise noted.
Mechanical Properties by Grade
Physical Properties by Grade
Elevated Temperature Properties – Incoloy 800H
Elevated Temperature Mechanical Properties by Grade
Exceptional Corrosion Resistance of Incoloy Washers
Incoloy alloys offer outstanding resistance to a wide range of corrosive environments, tailored by grade composition.
High-Temperature Oxidation & Carburization Resistance (800 Series)
Incoloy 800 series washers form a stable, adherent Cr₂O₃ oxide layer that provides excellent protection up to 1150°C. Chromium content (19-23%) ensures scaling resistance, while the nickel-rich matrix resists carburization and sigma phase embrittlement. Performance is significantly better than 316L stainless steel at elevated temperatures.
Sulfuric & Phosphoric Acid Resistance (825)
Incoloy 825 washers resist 40% H₂SO₄ at 100°C with corrosion rates <0.05mm/year. The molybdenum and copper additions provide exceptional resistance to reducing acids. Excellent performance in phosphoric acid service, including wet process phosphoric acid containing fluoride impurities.
Sour Service & Chloride SCC Resistance (825, 925)
With high nickel content (>38%), Incoloy washers have excellent resistance to chloride stress corrosion cracking. Incoloy 825 and 925 are qualified per NACE MR0175/ISO 15156 for H₂S environments. Incoloy 925 offers premium resistance to sulfide stress cracking at strength levels up to 760 MPa yield.
Resistance to Specific Environments
Heat Treatment & Microstructural Stability
Incoloy washers are supplied in appropriate heat treated conditions for optimum properties:
- Incoloy 800/825: Solution annealed at 980-1035°C followed by rapid cooling.
- Incoloy 800H/HT: Higher temperature solution anneal (1050-1100°C) for enhanced creep properties.
- Incoloy 925: Supplied in solution annealed or aged condition. Aging at 620-760°C after solution treatment produces precipitation hardening, achieving 760-965 MPa yield strength.
Proper heat treatment ensures the balanced microstructure that provides the exceptional corrosion resistance and mechanical properties characteristic of Incoloy alloys. All washers are fully heat treated and tested to ensure optimal performance.
Special focus: Incoloy Washers for Critical Applications
For the most demanding applications requiring exceptional high-temperature strength or acid resistance, RAYCHIN offers Incoloy washers manufactured to ASTM, ASME, NACE, and customer-specific specifications. Our capabilities include:
- Chemical Processing: Flange washers for ASME B16.5 connections, manway cover washers, reactor closure washers, heat exchanger tube sheet washers handling acids.
- Oil & Gas / Sour Service: NACE MR0175 compliant washers for wellhead equipment, valve assemblies, subsea flanges, and API 6A closures.
- Heat Exchangers & Boilers: Incoloy 800 series washers for high-temperature heat exchanger flanges, boiler component hardware.
- Petrochemical Processing: Incoloy 800H and 800HT washers for ethylene furnace components, reformer tube supports.
- Power Generation: Incoloy 800 series washers for superheater supports, boiler component hardware, turbine casing studs.
- Nuclear Industry: Incoloy 800 washers for steam generator components, reactor system hardware.
- Marine Engineering: Incoloy 825 washers for seawater piping flanges, pump connections, valve assemblies, offshore platform hardware.
- Aerospace & Gas Turbines: Incoloy 800 series washers for combustion chamber hardware, turbine casing fasteners.
- Standards: DIN 125, DIN 9021, ISO 7089, ISO 7093 (metric); ASME B18.22.1 (inch); DIN 127, DIN 6796, ASME B18.21.1 (spring washers).
- Types: Flat washers, heavy washers, spring washers, Belleville washers, wave washers, split lock washers.
- Sizes: #0 through 4", M1.6 through M100.
- Thickness: Standard, heavy, and custom thicknesses available.
- Certifications: EN 10204 3.1/3.2 material certifications, NACE MR0175, API 20F, PED 2014/68/EU.
All Incoloy washers are supplied with full traceability and third-party NDT upon request. Supplied with matching Incoloy bolts, studs, and nuts for complete bolting sets. Material certifications included.
Why RAYCHIN LIMITED – The Incoloy Washer Authority
Metallurgical competence
Engineers on staff with deep expertise in nickel-iron-chromium superalloys. We ensure proper heat treatment for each grade—solution annealing for 800/825, optimized annealing for 800H/HT, and precise aging for 925—to achieve optimal properties. Every heat is verified by in-house PMI testing to confirm chemistry. Our washers provide the exact balance of high-temperature strength and corrosion resistance required for your application.
Global approvals & traceability
Our quality system is ISO 9001:2015 and AS9100D certified; we also comply with NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS. Full material traceability from melt to final packaging (EN 10204 3.1/3.2). Third-party inspections (ABS, DNV, Lloyds) available. All Incoloy washers meet applicable ASTM, ASME, NACE MR0175, and API standards.
Precision stamping & finishing
In-house precision stamping and CNC machining capabilities ensure consistent washer dimensions and superior surface finish. Burr-free edges and tight dimensional tolerances. 100% dimensional inspection available. Ultrasonic cleaning and passivation available for critical applications. Flatness and parallelism maintained to strict tolerances.
Custom solutions
Need a special size, unusual thickness, or custom configuration for your extreme environment application? Our engineering team works with you to produce custom Incoloy washers to your drawing. We provide specialized surface treatments, passivation, and NACE MR0175 compliant processing per customer requirements.
Contact the Incoloy washer experts today
Request a quote for Incoloy washers, flat washers, heavy washers, spring washers & custom configurations – any global standard (NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN, KS), any quantity. Inquire about Incoloy 800, 800H, 800HT, 825, or 925 grades for high-temperature or acid-resistant applications.
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