Decking Screws, Stainless manufactured in A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) are dimensioned to Trade series (decking screw). 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 Decking Screws, Stainless
The most common stainless group for indoor and general outdoor fasteners. For decking screws, stainless, 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 Decking Screws, Stainless 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 Decking Screws, Stainless, the alternative stainless grade is A4 (316). 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
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 Decking Screws, Stainless Available in A2 Stainless Steel
| Nominal diameter (mm) | Head type | Drive | Thread form | Material | Suitable timber | Common length range (mm) | Pilot hole (mm) |
|---|---|---|---|---|---|---|---|
| 4.0 | Countersunk trim | TX20 | Twin thread + reverse thread | A2 stainless | Softwood, treated pine | 40~60 | 2.5 |
| 4.5 | Countersunk trim | TX20 | Twin thread + reverse thread | A2 stainless | Softwood, treated pine | 50~70 | 3.0 |
| 5.0 | Countersunk trim | TX25 | Twin thread + reverse thread | A4 stainless | Oak, hardwood, coastal | 50~90 | 3.2 |
| 5.5 | Countersunk trim | TX25 | Twin thread + reverse thread | A4 stainless | Oak, hardwood, coastal | 70~120 | 3.5 |
