Material specification page for pin-and-collar lockbolt assemblies in A2 Stainless Steel. Covers the grade designation (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to Trade series (pin-and-collar lockbolt).
Why Choose A2 Stainless Steel for Pin-and-Collar Lockbolt Assemblies
The most common stainless group for indoor and general outdoor fasteners. For pin-and-collar lockbolt assemblies, 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 Pin-and-Collar Lockbolt Assemblies 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 Pin-and-Collar Lockbolt Assemblies, 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
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 Pin-and-Collar Lockbolt Assemblies Available in A2 Stainless Steel
| Nominal diameter (in) | Grip ranges (in) | Pin material | Collar material | Collar styles | Head style |
|---|---|---|---|---|---|
| 3/16 | 0.062~0.625 / 0.312~1.250 | carbon steel or 7075-T6 aluminum | carbon steel or 6061 aluminum | standard / medium-flange / wide-flange | button head |
| 1/4 | 0.062~0.625 / 0.312~1.250 | carbon steel or 7075-T6 aluminum | carbon steel or 6061 aluminum | standard / medium-flange / wide-flange | button head |
| 5/16 | 0.125~0.750 / 0.625~1.375 | carbon steel or 7075-T6 aluminum | carbon steel or 6061 aluminum | standard / medium-flange / wide-flange | button head |
| 3/8 | 0.125~0.875 / 0.812~1.625 | carbon steel or 7075-T6 aluminum | carbon steel or 6061 aluminum | standard / medium-flange / wide-flange | button head |
