Material specification page for quick-release pin receptacles in A4 Stainless Steel. Covers the grade designation (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to Trade series (quick-release pin receptacles).
Why Choose A4 Stainless Steel for Quick-Release Pin Receptacles
Specified for marine, coastal and chemical applications. For quick-release pin receptacles, 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 Quick-Release Pin Receptacles in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Quick-Release Pin Receptacles, the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.
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 Quick-Release Pin Receptacles Available in A4 Stainless Steel
| Pin diameter | Barrel OD (in or mm) | Overall length (in) | Usable reduction (in) | Mating thread | Mounting form | Material |
|---|---|---|---|---|---|---|
| 3/16 in | 3/8 in | 1/2 | 1/8 | 3/8-16 | thread-in | passivated 18-8 stainless steel |
| 1/4 in | 1/2 in | 1/2 | 1/8 | 1/2-13 | thread-in | passivated 18-8 stainless steel |
| 5/16 in | 5/8 in | 5/8 | 1/8 | 5/8-11 | thread-in | passivated 18-8 stainless steel |
| 3/8 in | 5/8 in | 11/16 | 3/16 | 5/8-11 | thread-in | passivated 18-8 stainless steel |
| 1/2 in | 3/4 in | 13/16 | 1/4 | 3/4-16 | thread-in | passivated 18-8 stainless steel |
| 5/8 in | 1 in | 15/16 | 1/4 | 1-14 | thread-in | passivated 18-8 stainless steel |
| 5 / 6 / 8 / 10 / 12 / 16 mm | M10u00d71.5 through M24u00d72 | thread-in or surface-mount | passivated 18-8 stainless steel |
