Material page for tri-wing pan-head machine screws in A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70). The sizes below are the ones we supply; there is no published dimensional standard for this article, so the table rather than a standard number is what to quote. Corrosion behaviour is good general corrosion resistance and the service range is approx. -200 °C to +400 °C, subject to the property class and the joint.
Why Choose A2 Stainless Steel for Tri-Wing Pan-Head Machine Screws
The most common stainless group for indoor and general outdoor fasteners. For tri-wing pan-head machine 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 Tri-Wing Pan-Head Machine 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 Tri-Wing Pan-Head Machine Screws, the alternative stainless grade is A4 (316). 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
Stainless steel is more noble than aluminum, so with an electrolyte present — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. Area ratio decides how bad it gets: a small stainless fastener in a large aluminum section is normally acceptable, a large stainless fastener in thin aluminum is not. Where the joint gets wet, isolate the metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Tri-Wing Pan-Head Machine Screws Available in A2 Stainless Steel
| Thread size | Head diameter (mm) | Head height (mm) | Drive | Length range (mm) | Material / finish |
|---|---|---|---|---|---|
| M3 | 5.6 | 1.8 | W2 | 6~25 | A2 stainless / blackened / Nylok-coated |
| M4 | 8.17 | 2.92 | W4 | 6~30 | A2 stainless / blackened / Nylok-coated |
| M5 | 9.47 | 3.37 | W5 | 10~50 | A2 stainless / blackened / Nylok-coated |
| M6 | 12.49 | 4.44 | W6 | 10~50 | A2 stainless / blackened / Nylok-coated |
| M8 | 15.62 | 5.53 | W7 | 10~50 | A2 stainless / blackened / Nylok-coated |
Dimensions are independent of the material: every size above is available in A2 Stainless Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
A2 Stainless Steel is one of the grades the catalog describes. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
