A4 Stainless Steel Flanged Button Head Socket Screws are supplied to our own published dimensions — this is a trade-series article rather than one covered by a dimensional standard, so confirm the figures against the part you are replacing. The grade provides superior, including marine and chloride environments and is largely non-magnetic; the practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.
Why Choose A4 Stainless Steel for Flanged Button Head Socket Screws
Specified for marine, coastal and chemical applications. For flanged button head socket 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 |
Galvanic & Galling Considerations
Two important notes for stainless flanged button head socket 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 Flanged Button Head Socket Screws, the alternative stainless grade is A2 (304). A2 (304) covers general indoor and outdoor service. A4 (316) adds molybdenum, which is what buys the chloride resistance for marine and de-icing-salt exposure. Where strength matters more than corrosion, plated alloy steel in class 8.8 or 10.9 is the swap to make.
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 Flanged Button Head Socket Screws Available in A4 Stainless Steel
| Thread size | Pitch (mm) | Flange diameter dc (mm) | Head height k (mm) | Hex socket s (mm) | Bearing area vs plain button | Common length range (mm) | Property class |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 7.6 | 1.65 | 2.0 | approx. 1.9x | 5~25 | 10.9 |
| M4 | 0.7 | 9.4 | 2.20 | 2.5 | approx. 1.9x | 6~30 | 10.9 |
| M5 | 0.8 | 11.8 | 2.75 | 3.0 | approx. 2.0x | 8~40 | 10.9 |
| M6 | 1.0 | 14.2 | 3.30 | 4.0 | approx. 2.0x | 10~50 | 10.9 |
| M8 | 1.25 | 18.0 | 4.40 | 5.0 | approx. 2.0x | 12~60 | 10.9 |
| M10 | 1.5 | 22.0 | 5.50 | 6.0 | approx. 2.1x | 16~60 | 10.9 |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Lengths and thread lengths outside the standard table are the commonest request, followed by a drive the standard does not offer and a head marked with your own part number. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
