Low-Profile Captive Pins manufactured in A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) are dimensioned to Trade series (captive tack pins). 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 A2 Stainless Steel for Low-Profile Captive Pins
The most common stainless group for indoor and general outdoor fasteners. For low-profile captive pins, this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Good general corrosion resistance |
Corrosion Behavior in Service
A2 (304) gives excellent atmospheric and most-water corrosion resistance and is the most common stainless for Low-Profile Captive Pins in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).
Comparable Grades
For Low-Profile Captive Pins, the alternative stainless grade is A4 (316). 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
Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.
Sizes of Low-Profile Captive Pins Available in A2 Stainless Steel
| Part form | Pin diameter (in) | Pin length (in) | Head diameter (in) | Head height (in) | Panel thickness (in) | Installation hole (in) | Material |
|---|---|---|---|---|---|---|---|
| T4-10-025 | 0.051 | 0.040 | 0.079 | 0.008 | 0.008~0.011; minimum 0.035 | 0.051 | 400-series stainless steel |
| TA-10-025 | 0.051 | 0.040 | 0.079 | 0.008 | 0.008~0.011; minimum 0.035 | 0.051 | aluminum |
