Pin-in-Torx Security Screws manufactured in A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) are dimensioned to ISO 14583. 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 Pin-in-Torx Security Screws
The most common stainless group for indoor and general outdoor fasteners. For pin-in-torx security screws, 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-in-Torx Security Screws 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-in-Torx Security Screws, the alternative stainless grade is A4 (316). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Pin-in-Torx Security Screws Available in A2 Stainless Steel
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Drive | Security bit | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.6 | 2.4 | Pin-in-Torx | TR10 | 6~30 | ISO 14583 |
| M4 | 0.7 | 8.0 | 3.1 | Pin-in-Torx | TR20 | 8~40 | ISO 14583 |
| M5 | 0.8 | 9.5 | 3.7 | Pin-in-Torx | TR25 | 8~50 | ISO 14583 |
| M6 | 1.0 | 12.0 | 4.6 | Pin-in-Torx | TR30 | 10~60 | ISO 14583 |
| M8 | 1.25 | 16.0 | 6.0 | Pin-in-Torx | TR40 | 12~60 | ISO 14583 |
