For pan head self-drilling screws (din 7504 n) in A4 Stainless Steel, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is summarized below together with every size supplied.
Why Choose A4 Stainless Steel for Pan Head Self-Drilling Screws (DIN 7504 N)
Specified for marine, coastal and chemical applications. For pan head self-drilling screws (din 7504 n), 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 Pan Head Self-Drilling Screws (DIN 7504 N) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless pan head self-drilling screws (din 7504 n): (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.
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 Pan Head Self-Drilling Screws (DIN 7504 N) Available in A4 Stainless Steel
| Head form | Point | Material and finish | Substrate | Pre-drilling |
|---|---|---|---|---|
| pan head | integrated drill tip | carbon steel, zinc plated | steel sheet and purlins | not required within the point capacity |
| pan head | integrated drill tip | carbon steel, zinc plated | metal roofing | not required within the point capacity |
| pan head | integrated drill tip | carbon steel, zinc plated | light steel structures | not required within the point capacity |
