Hex Washer Flange Self-Drilling Screws manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to Trade series (hex washer flange self-drilling screws). 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 A4 Stainless Steel for Hex Washer Flange Self-Drilling Screws
Specified for marine, coastal and chemical applications. For hex washer flange self-drilling screws, 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 Hex Washer Flange Self-Drilling Screws in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Hex Washer Flange Self-Drilling Screws, the alternative stainless grade is A2 (304). Choose A2 (304) for general use and A4 (316) wherever chlorides are present; the molybdenum in A4 is the whole difference. Remember that stainless is the corrosion answer, not the strength answer — for load, look at class 8.8 or 10.9 instead.
Using Stainless Fasteners in Aluminum
The galvanic couple here runs the wrong way: aluminum is the less noble metal, so it corrodes and the fastener does not. What governs the rate is the ratio of areas — a large anode and a small cathode is a tolerable combination, the reverse concentrates the attack into thin material around the hole. An isolating washer plus sealant breaks the circuit; where that is impractical, match the fastener to the substrate.
Sizes of Hex Washer Flange Self-Drilling Screws Available in A4 Stainless Steel
| Head form | Bearing surface | Point | Substrate | Typical use |
|---|---|---|---|---|
| hex washer head | integral flange | integrated drill point | metal sheet | metal roofing and cladding |
| hex washer head | integral flange | integrated drill point | thin structural members | solar mounting brackets |
| hex washer head | integral flange | integrated drill point | structural steel to sheet | structural assemblies |
