Cage Nuts (Snap-In Rack Nuts) manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to Trade series (EIA-310 rack practice). The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose A4 Stainless Steel for Cage Nuts (Snap-In Rack Nuts)
Specified for marine, coastal and chemical applications. For cage nuts (snap-in rack nuts), this matters when superior, including marine and chloride environments is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Superior, including marine and chloride environments |
Corrosion Behavior in Service
A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Cage Nuts (Snap-In Rack Nuts) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Cage Nuts (Snap-In Rack Nuts), the alternative stainless grade is A2 (304). A2 (304) covers general indoor and outdoor service. A4 (316) adds molybdenum, which is what buys the chloride resistance for marine and de-icing-salt exposure. Where strength matters more than corrosion, plated alloy steel in class 8.8 or 10.9 is the swap to make.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so with an electrolyte present — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. Area ratio decides how bad it gets: a small stainless fastener in a large aluminum section is normally acceptable, a large stainless fastener in thin aluminum is not. Where the joint gets wet, isolate the metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Cage Nuts (Snap-In Rack Nuts) Available in A4 Stainless Steel
| Thread size | Square panel hole (mm) | Rail thickness (mm) | Cage width (mm) | Cage height (mm) | Retained nut | Material | Finish |
|---|---|---|---|---|---|---|---|
| M5 | 9.5 | 0.8~2.0 | 15.9 | 15.9 | Floating square | Spring steel | Zinc plated |
| M6 | 9.5 | 0.8~2.0 | 15.9 | 15.9 | Floating square | Spring steel | Zinc plated |
| M6 | 9.5 | 2.0~3.0 | 15.9 | 15.9 | Floating square | Spring steel | Black passivated |
| 10-32 | 9.5 | 0.8~2.0 | 15.9 | 15.9 | Floating square | Spring steel | Zinc plated |
| 12-24 | 9.5 | 0.8~2.0 | 15.9 | 15.9 | Floating square | Spring steel | Zinc plated |
| M8 | 12.0 | 1.0~2.5 | 19.0 | 19.0 | Floating square | Spring steel | Zinc plated |
