A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. When pin-in-torx security screws are specified in this grade, the dimensions remain per ISO 14583; the material determines corrosion behavior (superior, including marine and chloride environments) and the service temperature range (approx. -200 °C to +400 °C, subject to the property class and the joint). Both are covered below with the size table.
Why Choose A4 Stainless Steel for Pin-in-Torx Security Screws
Specified for marine, coastal and chemical applications. For pin-in-torx security 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 pin-in-torx security 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 Pin-in-Torx Security 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
Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.
Sizes of Pin-in-Torx Security Screws Available in A4 Stainless Steel
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Drive | Security bit | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.6 | 2.4 | Pin-in-Torx | TR10 | 6~30 | ISO 14583 |
| M4 | 0.7 | 8.0 | 3.1 | Pin-in-Torx | TR20 | 8~40 | ISO 14583 |
| M5 | 0.8 | 9.5 | 3.7 | Pin-in-Torx | TR25 | 8~50 | ISO 14583 |
| M6 | 1.0 | 12.0 | 4.6 | Pin-in-Torx | TR30 | 10~60 | ISO 14583 |
| M8 | 1.25 | 16.0 | 6.0 | Pin-in-Torx | TR40 | 12~60 | ISO 14583 |
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. 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.
