NAS1252-10L - Aerospace Flat Washer

NAS1252-10L – Aerospace Flat Washer

Available now on the Airparts.aero Marketplace.

Overview

The NAS1252-10L is a National Aerospace Standard, high-strength, high-temperature flat washer engineered for the most demanding applications in aerospace and turbine engine technology. This is not a standard washer; it is a precision-manufactured component fabricated from A-286 corrosion-resistant steel (CRES), an iron-nickel-chromium based superalloy. The "L" designation specifies this high-performance material. The NAS1252-10L is designed to be used under the head of high-strength bolts or nuts, providing uniform load distribution and preventing surface damage at extreme temperatures where standard steel or stainless steel washers would fail.

Key Features

• A-286 CRES Superalloy Construction: Fabricated from A-286, a precipitation-hardenable superalloy. This material is renowned for its ability to maintain high tensile strength, creep resistance, and corrosion resistance at extremely elevated temperatures.
• Extreme Temperature Capability: Engineered to perform reliably in continuous operating temperatures up to 1200°F (649°C), making it essential for use in turbine engine hot sections, exhaust systems, and other high-temperature aerospace applications.
• Uniform Load Distribution: Provides a smooth, hard, and flat bearing surface that evenly distributes the high clamping force of a fastener. This is critical for protecting the surfaces of softer materials and preventing the loss of bolt preload.
• High Strength & Hardness: Heat-treated to achieve a high tensile strength and surface hardness, ensuring it will not deform, cup, or yield under the high torque and clamping loads associated with structural and high-performance bolts.
• NAS Certified Standard: Manufactured in strict accordance with the NAS1252 standard, guaranteeing full material traceability, dimensional accuracy, and quality control for use in flight-critical assemblies.

Technical Specifications

• Standard: NAS1252 (Washer, Flat, High Strength)
• Full Part Number: NAS1252-10L
• Material (L): A-286 Corrosion-Resistant Steel (CRES)
• Finish: Passivated
• Nominal Screw/Bolt Size: #10 (0.190 inches)
• Dimensions:
  • Inside Diameter (I.D.): 0.203 inches
  • Outside Diameter (O.D.): 0.438 inches
  • Thickness: 0.032 inches
    
• Maximum Operating Temperature: 1200°F (649°C)

Aircraft Compatibility

The NAS1252-10L is a high-performance hardware component specified for use in the most demanding areas of modern aircraft, from business jets and commercial airliners to military platforms.

• Common Applications:
  • Turbine Engine Assemblies: Used extensively in the assembly of turbine engine hot sections, including combustor cases, turbine sections, and exhaust plenums.
  • Exhaust Systems: The standard washer for securing exhaust system components, heat shields, and ducting on both turbine and high-performance piston aircraft.
  • Firewall Forward: Used in any firewall-forward application where high temperatures and high-strength fasteners are present.
  • High-Performance Airframes: Specified for use in structural joints that experience high temperatures due to aerodynamic heating or system proximity.

Applications

The NAS1252-10L is the specified solution when standard washers are not sufficient:

• High-Temperature Bolted Joints: Essential for maintaining the integrity of a bolted joint in environments that would anneal, soften, or degrade standard steel washers.
• Maintaining Bolt Preload: Provides a stable, non-deforming surface that prevents the loss of bolt preload due to material creep at high temperatures.

Why Choose NAS1252-10L?

In a high-temperature bolted joint, the washer is just as critical as the nut and bolt. Using a standard washer with a high-temperature bolt (like one made from A-286) will result in the washer yielding and deforming under heat and load. This leads to a loss of clamping force, which can cause joint failure. The NAS1252-10L is made from the same class of materials as the high-temperature fasteners it is designed to be paired with, ensuring the entire joint maintains its integrity. For any high-temperature, flight-critical application, there is no substitute for certified NAS hardware.

Order Your NAS1252-10L Washers Now

Ensure the integrity of your aircraft's most critical high-temperature connections with certified aerospace hardware. Visit Airparts.aero to order your NAS1252-10L high-strength washers today.

The selection of A-286 (UNS S66286) for the NAS1252-10L is a deliberate engineering choice for high-temperature performance. A-286 is an age-hardenable superalloy that derives its strength from the precipitation of secondary phases, particularly gamma prime (Ni3(Al,Ti)), within its austenitic matrix. This microstructure gives it remarkable stability and resistance to "creep"—the tendency of a material to slowly deform over time when subjected to high stress at high temperatures. This ensures that a bolted joint using a NAS1252-10L washer will maintain its critical preload and clamping force even after thousands of hours of service in the hostile environment of a turbine engine hot section.

Note: This is a flight-critical structural component. Always verify the correct washer part number from the applicable aircraft or engine maintenance manual. Ensure all components of a bolted joint (bolt, washer, and nut) are of the correct, matching material specification for the intended application.