Incoloy Hex Cap Screws
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
Request a Quote from RAYCHIN
We're here to help!
RAYCHIN LIMITED
Specialist in Incoloy Hex Cap Screws · Hex Head · Heavy Hex · CustomIncoloy Hex Cap Screws: Nickel-Iron-Chromium Superalloy Hex Head Screws for Extreme Environments
RAYCHIN LIMITED is a recognized expert in Incoloy hex cap screws — from Incoloy hex head cap screws, Incoloy heavy hex cap screws, Incoloy hexagon head screws 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. Hex cap screws, also known as hex head cap screws or hexagon head bolts, feature a six-sided head designed for wrenching and are available in both partial thread and full thread configurations. Our portfolio includes hex cap screws 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 hex cap screws are supplied in solution annealed condition (or aged for 925) with full traceability and third-party certifications.
Complete Range of Incoloy Hex Cap Screws – Types & Configurations
Hex Head Cap Screws – Partial Thread (DIN 931 / ISO 4014 / ASME B18.2.1)
Incoloy hex head cap screws with partial thread manufactured to DIN 931, ISO 4014, and ASME B18.2.1 standards. Features a hex head with a partially threaded shank, providing unthreaded length for shear strength and alignment. 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 M6 to M48 (metric) and 1/4" to 2" (inch) in various lengths. Precision rolled threads for superior strength and corrosion resistance. Supplied in solution annealed condition per ASTM standards.
Hex Head Cap Screws – Full Thread (DIN 933 / ISO 4017 / ASME B18.2.1)
Incoloy hex head cap screws with full thread manufactured to DIN 933, ISO 4017, and ASME B18.2.1 standards. Features a hex head with threads extending the entire shank length, providing maximum thread engagement. Ideal for applications where the full length of the screw must be threaded or where grip length adjustment is required. Precision rolled UNC, UNF, and metric threads for superior fatigue resistance. Available in sizes from M6 to M48 (metric) and 1/4" to 2" (inch) in various lengths. Available in all Incoloy grades. Supplied with passivated finish per ASTM A967.
Heavy Hex Cap Screws (DIN 6914 / ASME B18.2.1)
Incoloy heavy hex cap screws manufactured to DIN 6914, ASME B18.2.1 (heavy hex series), and ASTM A325/A490 dimensional standards. Features a larger head configuration providing increased bearing area for high-pressure flange connections and pressure vessel applications. Essential for API 6A and ASME B16.5 bolting assemblies in high-temperature and corrosive environments. The heavier head distributes load more effectively and resists dilation at elevated temperatures. Available in all Incoloy grades. Sizes from 1/2" to 2" (M12 to M48). Supplied with matching Incoloy heavy hex nuts.
Incoloy Grade Selection Guide for Hex Cap Screws
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 Hex Cap Screw Design & Standards
Dimensional Standards
Our Incoloy hex cap screws meet or exceed the following specifications:
Available in UNC, UNF, UNJF-3A, and metric coarse/fine thread configurations.
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
- Silver Plating: Per AMS 2410 for high-temperature anti-seize
Key Benefits of Incoloy Hex Cap Screws
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 hex cap screws 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 hex cap screws 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.
External Drive Design
Hex head design allows for high torque application with standard wrenches and sockets. Suitable for applications requiring frequent assembly and disassembly. Available in both standard and heavy hex configurations for increased wrenching area.
Chloride SCC Immunity
With high nickel content (30-46%), Incoloy hex cap screws have excellent resistance to chloride stress corrosion cracking, making them ideal for marine environments and brackish water applications.
Partial & Full Thread Options
Available in both partial thread (for shear applications) and full thread (for maximum thread engagement) configurations to suit specific application requirements.
Manufacturing Standards for Incoloy Hex Cap Screws
RAYCHIN LIMITED manufactures Incoloy hex cap screws 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 Hex Cap Screws
To serve clients worldwide, RAYCHIN LIMITED manufactures Incoloy hex cap screws 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 hex cap screws 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 Hex Cap Screws
Incoloy hex cap screws 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 Hex Cap Screws
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 hex cap screws 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 hex cap screws 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 hex cap screws 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 hex cap screws 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 hex cap screws are fully heat treated and tested to ensure optimal performance.
Special focus: Incoloy Hex Cap Screws for Critical Applications
For the most demanding applications requiring exceptional high-temperature strength or acid resistance, RAYCHIN offers Incoloy hex cap screws manufactured to ASTM, ASME, NACE, and customer-specific specifications. Our capabilities include:
- Chemical Processing: Hex cap screws for reactor manway covers, heavy hex cap screws for pressure vessel flanges, instrument connections handling acids.
- Oil & Gas / Sour Service: NACE MR0175 compliant Incoloy 825 and 925 hex cap screws for wellhead equipment, valve assemblies, subsea connections.
- Heat Exchangers & Boilers: Incoloy 800 series hex cap screws for high-temperature heat exchanger heads, boiler access panels.
- Petrochemical Processing: Incoloy 800H and 800HT hex cap screws for ethylene furnace components, reformer tube supports.
- Power Generation: Incoloy 800 series hex cap screws for superheater supports, boiler component hardware.
- Nuclear Industry: Incoloy 800 hex cap screws for steam generator components, reactor system hardware.
- Marine Engineering: Incoloy 825 hex cap screws for seawater piping flanges, offshore platform hardware.
- Aerospace & Gas Turbines: Incoloy 800 series hex cap screws for combustion chamber hardware, turbine casing fasteners.
- Standards: DIN 931, DIN 933, DIN 6914 (metric); ISO 4014, ISO 4017; ASME B18.2.1 (inch); NAS1802 (aerospace).
- Thread Classes: 2A, 3A, UNJF-3A, 6g, 6H.
- Sizes: M6 through M48, 1/4" through 2".
- Certifications: EN 10204 3.1/3.2 material certifications, NACE MR0175, API 20F, PED 2014/68/EU.
All Incoloy hex cap screws are supplied with full traceability and third-party NDT upon request. Supplied with matching Incoloy nuts for complete bolting sets. Material certifications included.
Why RAYCHIN LIMITED – The Incoloy Hex Cap Screw 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 hex cap screws 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 hex cap screws meet applicable ASTM, ASME, NACE MR0175, and API standards.
Precision head forming & thread rolling
In-house CNC cold heading, hot forging, and precision thread rolling capabilities ensure consistent head dimensions and thread geometry. Precision rolled threads provide superior fatigue life and dimensional accuracy. Accurate hex heads for positive wrench engagement. 100% thread and dimensional inspection available. Controlled underhead fillet for improved fatigue resistance in high-temperature cyclic applications.
Custom solutions
Need a special head style, unusual thread configuration, or custom material certification for your extreme environment application? Our engineering team works with you to produce custom Incoloy hex cap screws to your drawing. We provide specialized surface treatments, passivation, and NACE MR0175 compliant processing per customer requirements.
Contact the Incoloy hex cap screw experts today
Request a quote for Incoloy hex cap screws, hex head cap screws, heavy hex cap screws & 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.
sales@ray-chin.com | +86 534 2166 566Our team speaks English, German, Mandarin, and Japanese – ready for your global procurement.
Request A Quote! We'll respond as soon as possible(within 12 hours)
Get a Quote