A2 Stainless Steel (A2-70 (304)) is the most common stainless grade for indoor and general outdoor fasteners. When phillips countersunk screws are specified in this grade, the dimensions remain per ISO 7046 / DIN 965; the material determines corrosion behavior (good general corrosion resistance) and the service temperature range (approx. -200 °C to +400 °C). Both are covered below with the size table.
Why Choose A2 Stainless Steel for Phillips Countersunk Screws
The most common stainless grade for indoor and general outdoor fasteners. For phillips countersunk screws, this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | A2-70 (304) |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C |
| Corrosion characteristic | Good general corrosion resistance |
Galvanic & Galling Considerations
Two important notes for stainless phillips countersunk screws: (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.
Comparable Grades
For Phillips Countersunk 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.
Sizes of Phillips Countersunk Screws Available in A2 Stainless Steel
| Size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Cross recess | Countersink angle (deg) | Reference standard |
|---|---|---|---|---|---|---|
| M1.6 | 0.35 | 3.0 | 0.96 | PH0 | 90 | ISO 7046 / DIN 965 |
| M2 | 0.4 | 3.8 | 1.2 | PH1 | 90 | ISO 7046 / DIN 965 |
| M2.5 | 0.45 | 4.7 | 1.5 | PH1 | 90 | ISO 7046 / DIN 965 |
| M3 | 0.5 | 5.6 | 1.65 | PH1 | 90 | ISO 7046 / DIN 965 |
| M3.5 | 0.6 | 6.5 | 1.93 | PH2 | 90 | ISO 7046 / DIN 965 |
| M4 | 0.7 | 7.5 | 2.2 | PH2 | 90 | ISO 7046 / DIN 965 |
| M5 | 0.8 | 9.2 | 2.5 | PH2 | 90 | ISO 7046 / DIN 965 |
| M6 | 1.0 | 11.0 | 3.0 | PH3 | 90 | ISO 7046 / DIN 965 |
| M8 | 1.25 | 14.5 | 4.0 | PH3 | 90 | ISO 7046 / DIN 965 |
| M10 | 1.5 | 18.0 | 5.0 | PH4 | 90 | ISO 7046 / DIN 965 |