A286 Vented 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
A286 / Alloy 660 for excellent high temperature oxidation resistance
Excellent high temperature oxidation resistance to 1300°F / 700°C
Maintains high strength at elevated temperatures
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RAYCHIN LIMITED
Specialist in A286 Vented Screws · Center Vented · Socket Head · Hex Head · CustomA286 Vented Screws: Center Vented Screws for High-Temperature Vacuum Systems & Custom Configurations
RAYCHIN LIMITED is a recognized expert in A286 vented screws — from A286 center vented screws, A286 vacuum vented screws, A286 socket head vented screws, A286 hex head vented screws to custom non-standard vented screw configurations. A286 (UNS S66286) is an iron-nickel-chromium superalloy strengthened by precipitation hardening. Also designated as Alloy 660, it maintains exceptional strength and oxidation resistance up to 700°C (1292°F), making it the preferred material for high-temperature vented screw applications in gas turbines, aerospace, and semiconductor processing equipment. The venting feature provides an outlet for the complete evacuation of trapped air and gas contaminants from blind-tapped screw holes, bottoms, sides and shoulders. With a Pitting Resistance Equivalent (PRE) and high nickel content, A286 offers excellent resistance to oxidation and corrosion in demanding environments. Our portfolio includes vented screws manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards. Engineered for extreme environments where high-temperature strength, vacuum performance, and corrosion resistance are critical. A286 vented screws are available in solution annealed and aged conditions with precision-drilled center bores and full traceability.
Complete Range of A286 Vented Screws
Center Vented Screws – Socket Head
A286 center vented socket head cap screws featuring a precision-drilled axial bore from the head through the threaded shank. Manufactured to DIN 912 / ISO 4762 with venting modification. Ideal for high vacuum and ultra-high vacuum applications requiring both high-temperature resistance up to 700°C and trapped gas evacuation. Available in sizes from #2 to 1" (M2 to M24) with custom vent diameters. The precipitation-hardened A286 structure ensures exceptional strength at elevated temperatures while eliminating virtual leaks and enabling faster pump-down times in gas turbine and aerospace vacuum systems.
Center Vented Screws – Hex Head
A286 center vented hex head cap screws with precision axial vent hole. Manufactured to DIN 931 / DIN 933 and ISO 4014 / ISO 4017 with venting modification. Designed for high-pressure and high-temperature vacuum applications requiring external wrenching. The center bore provides an outlet for trapped air and gas contaminants to be pumped away from blind holes, bottoms, sides, and shoulders. Ideal for gas turbine casings, rocket engine components, and high-temperature research chambers requiring both oxidation resistance and vacuum compatibility.
Vented Washers & Venting Systems
Complementary A286 vented washers featuring two bored canals on opposite sides of the flat face. These washers provide an escape route for gases trapped beneath the screw head or between mating surfaces. When used with A286 vented screws, they ensure complete venting of all cavities in high-temperature vacuum systems. The volume of gas can be trapped in the space and beneath the fastener head along the screw shaft; our vented washers eliminate this issue. Available in all standard washer sizes with custom vent configurations. The A286 superalloy composition provides the same exceptional high-temperature strength and oxidation resistance as the mating screws.
High-Temperature Furnace Vented Screws
A286 vented screws designed for high-temperature furnace applications where both gas evacuation and oxidation resistance are critical. Used in thermal processing equipment, high-temperature furnaces, and heat treatment fixtures operating up to 700°C. The venting feature provides an outlet for the complete evacuation of trapped air and gas contaminants from blind-tapped screw holes, bottoms, sides and shoulders. Excellent resistance to oxidation and thermal fatigue under cyclic heating conditions.
Semiconductor & Research Vented Screws
A286 vented screws for semiconductor wafer processing equipment, particle accelerators, and research chambers operating at elevated temperatures. Available with UNJF-3A threads per MIL-S-8879 and custom vent diameters. Full traceability with material certification and third-party testing available. Enables faster, more efficient pump-down of HV & UHV systems. Eliminates virtual leaks and relieves pressure from blocked gases. Provides means to vent contaminants found in screw voids, promoting higher system throughput and improved yield in high-temperature processing environments.
Custom & Specialty A286 Vented Screws
Need a special head style, unusual thread combination, or custom vent diameter for your high-temperature vacuum application? RAYCHIN engineers work with you to produce custom A286 vented screws to your drawing. Options include cross-drilled vents, multiple vent holes, and specialized vent geometries. Expert heat treatment (solution annealed at 982°C followed by precipitation hardening at 718°C for 16 hours) precisely controlled for each batch. Manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN, KS standards. Also suitable for cryogenic applications with toughness down to -196°C.
Key Benefits of A286 Vented Screws
Faster Pump-Down
Enables faster, more efficient pump-down of HV and UHV systems by providing escape routes for trapped gases.
Virtual Leak Elimination
Eliminates virtual leaks by venting gases trapped in blind-tapped holes, bottoms, sides, and shoulders.
Pressure Equalization
Allows for constant pressure and temperature equalization across vacuum system components.
High Temperature Resistance
Exceptional high-temperature strength and oxidation resistance up to 700°C (1292°F).
Cryogenic Toughness
Maintains excellent toughness at cryogenic temperatures down to -196°C.
Economic Alternative
Provides a cost-effective balance of high-temperature strength and corrosion resistance – approximately 60-70% the cost of nickel-based alloys like Inconel 718.
Manufacturing Standards for A286 Vented Screws
RAYCHIN LIMITED manufactures A286 vented 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 A286 Vented Screws
To serve clients worldwide, RAYCHIN LIMITED manufactures A286 vented screws from material conforming to the following national and international specifications. This ensures full compliance for projects in the Americas, Europe, Asia, and the Middle East.
UNS S66286 Alloy 660 ASTM A453 AMS 5732 AMS 5737 NACE MR0175 1.4980
Chemical Composition (Weight %) – A286 Superalloy (UNS S66286 / 1.4980)
Our A286 vented screws are produced from melts that strictly conform to the limits below per ASTM A453 / AMS 5731. The high nickel and chromium content provide excellent oxidation resistance, while titanium and aluminum enable precipitation hardening through gamma-prime (γ') phase formation. Molybdenum and vanadium contribute to solid solution strengthening, and boron enhances creep resistance.
Expert note: The combination of titanium and aluminum promotes the formation of Ni₃(Al,Ti) gamma-prime precipitates during aging, which provide A286 with its exceptional high-temperature strength. The addition of boron (0.001-0.010%) significantly improves creep resistance by strengthening grain boundaries. With nickel content of 24-27%, A286 offers excellent resistance to chloride stress corrosion cracking and maintains a stable austenitic structure from cryogenic temperatures up to 700°C.
Complete Mechanical Properties of A286 Vented Screws (per ASTM A453)
A286 vented screws are supplied in the solution annealed and precipitation hardened condition (982°C solution treat + 718°C age for 16 hours). ASTM A453 defines multiple classes for different strength levels and size ranges. The data below represent minimum requirements per ASTM A453/A453M. Screws are proof load tested to ensure compatibility with mating nuts.
Tensile Requirements by Class – ASTM A453 Grade 660
Hardness Requirements
Stress Rupture Properties (650°C / 1200°F)
A critical requirement for high-temperature fasteners is stress rupture resistance. Per ASTM A453, Class A, B, and C materials must meet the following:
Research confirms that A286 maintains anti-tensile strength not less than 885 MPa at 500°C with stress retention greater than 88.35%, making it the optimal choice for high-temperature fastener applications.
Temperature-Dependent Yield Strength
The following table shows typical yield strength (0.2% offset) at elevated temperatures for A286 in the fully heat-treated condition.
At 500°C, A286 maintains excellent stress retention, with studies showing stress retention rates exceeding 88.35% at this temperature.
Thermal Expansion Advantage of A286 Vented Screws
A286 is specifically designed for bolting austenitic stainless steel components operating at elevated temperatures. Its thermal expansion coefficient closely matches that of 304/316 stainless steels, preventing loss of preload during thermal cycling – a critical feature for vented screws used in high-temperature vacuum assemblies where maintaining sealing force is essential.
This expansion match is critical for maintaining seal integrity in high-temperature vacuum applications such as gas turbine casings, rocket engine components, and furnace systems. Standard alloy steel fasteners expand less than the surrounding components, leading to loss of preload and potential vacuum leaks. A286 eliminates this mismatch.
API 6A & NACE MR0175 Compliance
A286 vented screws are widely used in oil and gas applications requiring sour service resistance. Per API 6A and API 20F, A286 Grade 660 Class D is approved for H₂S service with maximum hardness of 35 HRC.
Heat Treatment & Microstructural Stability
Optimal mechanical properties in A286 vented screws are achieved through a two-step heat treatment:
- Solution Annealing: 980°C (1800°F) for 1 hour, oil quench or water quench. This dissolves carbides and prepares the matrix for precipitation hardening.
- Aging (Precipitation Hardening): 718°C (1325°F) for 16 hours, air cool. This forms coherent γ' (gamma-prime) precipitates [Ni₃(Al,Ti)] that provide high-temperature strength.
Metallurgical studies show that aging at 730°C accelerates precipitation kinetics but can lead to overaging and formation of η (eta) phase (Ni₃Ti), which degrades mechanical properties. Our controlled aging at 718°C ensures optimal γ' formation while avoiding η phase precipitation, maximizing creep resistance and long-term stability up to 700°C.
Physical Properties of A286
Corrosion Resistance of A286 Vented Screws
While A286 is primarily selected for high-temperature strength, it also offers good corrosion resistance in many environments due to its high chromium (14-16%) and nickel (24-27%) content. The alloy exhibits excellent oxidation resistance up to 700°C continuous service and 815°C intermittent service.
Oxidation and Scaling Resistance
The chromium content provides excellent resistance to oxidation and scaling. A286 vented screws form a protective Cr₂O₃ scale that prevents further oxidation at elevated temperatures. They provide excellent oxidation resistance up to 1500°F (815°C) in conditions typically found in gas turbine exhaust streams and high-temperature vacuum systems.
Corrosion in Other Environments
Critical Corrosion Considerations for Vented Screws
- Oxidation Resistance: Excellent oxidation resistance up to 1500°F (815°C) in gas turbine and exhaust environments. Suitable for continuous service up to 700°C.
- NACE MR0175 Compliance: A286 is qualified for sour service (sulfide stress cracking resistance) in oilfield equipment per NACE MR0175/ISO 15156. Class D with maximum hardness 35 HRC is preferred for sour applications.
- Temperature Limitations: Maximum service temperature for continuous service is 700°C (1300°F). For intermittent service, temperatures up to 815°C are acceptable.
- Galvanic Corrosion: When paired with lower-grade materials, galvanic corrosion should be considered. A286 is cathodic to most stainless steels but compatible with nickel-based alloys.
- Non-Magnetic Property: A286 is essentially non-magnetic, making it suitable for applications requiring non-magnetic fasteners such as MRI equipment and sensitive instrumentation.
- Vent Design: Center vent holes provide pressure equalization and virtual leak elimination without compromising the corrosion resistance of the base material.
High-Temperature & Vacuum Engineering Note: For critical applications in aggressive environments, RAYCHIN LIMITED can provide passivation, specialized coatings (Xylan, PTFE, silver plating per AMS 2410), or recommend optimal heat treatment conditions. Third-party corrosion testing per ASTM G31, G48, or G61 available upon request. NACE MR0175 compliant A286 vented screws available in Class D condition with certified hardness ≤ 35 HRC. A286 offers a cost-effective balance of high-temperature strength and corrosion resistance – approximately 60-70% the cost of nickel-based alloys like Inconel 718.
Special focus: A286 Vented Screws for High-Temperature Vacuum Applications
For critical applications requiring both high-temperature oxidation resistance and vacuum performance, RAYCHIN offers A286 vented screws manufactured to ASTM, ASME, NACE, and customer-specific specifications. Our capabilities include:
- Aerospace Applications: Rocket engine components, thrust chamber assemblies, turbopump housings, combustion chambers, nozzle extensions, exhaust systems, satellite propulsion systems. Meets AMS 5732, AMS 5737, NAS, and MS specifications.
- Gas Turbines & Power Generation: Turbine casing bolting, combustion chamber liners, heat exchanger connections, steam turbine components, HRSG systems, flue gas systems requiring venting in high-temperature vacuum sections.
- Semiconductor & Research: HV and UHV systems requiring faster pump-down and virtual leak elimination at elevated temperatures. Wafer processing equipment, particle accelerators, research chambers, mass spectrometers, electron microscopes.
- Oil & Gas: Offshore platform equipment, subsea assemblies, wellhead components, refinery applications, sour service per NACE MR0175, high-temperature piping supports where trapped gases must be eliminated.
- Chemical Processing: High-temperature reactors, reformers, crackers, heat exchangers, thermowell assemblies, processing vessels where gas entrapment can affect performance.
- Heat Treating & Furnace Applications: Vacuum furnaces, heat treatment equipment, sintering furnaces, annealing covers, retort assemblies requiring oxidation resistance up to 700°C.
- Vent Configurations: Center axial vent holes (standard), cross-drilled vents, multiple vent holes, custom vent diameters from 0.5mm to 6mm
- Head Styles: Socket head cap screws (DIN 912/ISO 4762), hex head cap screws (DIN 931/933), button head, flat head
- Thread Specifications: UNC/UNF, metric coarse/fine, UNJF-3A per MIL-S-8879, MJ – all classes up to 3A/6g
- Surface Treatments: Electropolishing for reduced outgassing, passivation per ASTM A967, silver plating per AMS 2410, high-temperature anti-seize coatings, vacuum-compatible lubricants
- Special Processing: Ultrasonic cleaning, Class 100 cleanroom packaging, helium leak testing
- Class Selection: Class A (standard strength), Class B, Class D (higher yield strength, API sour service), Cold Worked (maximum strength)
- Custom: Special vent geometries, non-standard lengths, unique head configurations per customer drawings
All A286 vented screws are supplied with full traceability and third-party NDT upon request. Sizes available from M2 to M48 (#0 to 2") in all standard configurations. Material certifications (EN 10204 3.1/3.2) included.
Why RAYCHIN LIMITED – The A286 Vented Screw Authority
Metallurgical competence
Engineers on staff with deep expertise in precipitation hardening superalloys. We ensure proper solution annealing (982°C minimum) and precipitation hardening (718°C for 16 hours) for optimal high-temperature strength and creep resistance across all A286 vented screws. Every heat is verified by in-house testing and PMI verification. With 24-27% nickel and titanium-aluminum precipitation hardening, our vented screws provide exceptional strength up to 700°C while maintaining excellent corrosion resistance.
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 A286 vented screws meet applicable AMS, ASTM A453, and NACE MR0175 requirements.
Precision vent drilling
In-house precision drilling capabilities ensure concentric vent holes with tight tolerances (±0.05mm). Deep hole drilling available for lengths up to 200mm. 100% inspection of vent hole diameter and position. Ultrasonic cleaning available for vacuum applications. Provides means to vent contaminants found in screw voids, promoting higher system throughput and improved yield in high-temperature processing environments.
Custom solutions
Need a special vent configuration, unusual head style, or custom material certification for your high-temperature vacuum application? Our CNC turning and drilling departments handle short runs with agility. We also provide specialized coatings and vacuum compatibility testing per customer requirements. Available in Class A, Class B, Class D (API sour service), and cold worked conditions.
Contact the A286 vented screw experts today
Request a quote for A286 center vented screws, socket head vented screws, hex head vented screws, vented washers & custom configurations – any global standard (NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN, KS), any quantity. Inquire about high-temperature vacuum applications up to 700°C or NACE MR0175 sour service requirements.
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