Nas523 Pdf «2027»
NAS523 Rivet Code
The is a standardized identification system used in the aviation industry to concisely provide detailed specifications for rivets on engineering drawings and technical diagrams. Instead of writing out full part numbers, a single four-quadrant "crosshair" symbol is used to indicate the rivet's type, diameter, manufacturer’s head location, and length. 1. Understanding the NAS523 Symbol Structure
- Solution composition & bath control – limits for hexavalent chromium, pH, temperature, immersion time.
- Rinse water quality – resistivity, contamination limits.
- Drying procedures – time, temperature, avoidance of overheating.
- Water Absorption Test: Non-metallic washers must not absorb more than a specific percentage of moisture (e.g., 1.5% after 24 hours).
- Compression Set: After being compressed at a specific temperature, the washer must return to a defined percentage of its original thickness.
- Torque Retention: The captive assembly must retain a specific break-loose torque after vibration cycles.
Northwest (NW - Upper Left):
Contains the fastener part number (e.g., AN or MS) and a letter code for the material alloy . For example, "BJ" identifies a standard MS20470AD rivet made from 2117-T3 aluminum alloy. nas523 pdf
Step 4: Storage & Shelf Life
Diameter Rule:
The rivet diameter should be at least three times the thickness of the thickest sheet being joined. NAS523 Rivet Code The is a standardized identification
Southwest (SW)
: Provides specific installation instructions, such as dimpling or countersinking requirements. Solution composition & bath control – limits for
