A4 Stainless Steel Concealed-Head Self-Clinching Studs and Standoffs combine the dimensional form of Trade series (concealed-head clinch hardware) with the material properties of grade ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80: superior, including marine and chloride environments, largely non-magnetic, service range approx. -200 °C to +400 °C, subject to the property class and the joint. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose A4 Stainless Steel for Concealed-Head Self-Clinching Studs and Standoffs
Specified for marine, coastal and chemical applications. For concealed-head self-clinching studs and standoffs, 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 concealed-head self-clinching studs and standoffs: (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 Concealed-Head Self-Clinching Studs and Standoffs, 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
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 Concealed-Head Self-Clinching Studs and Standoffs Available in A4 Stainless Steel
| Thread size | Form | Maximum tightening torque (Nu00b7m) | Test sheet options | Installation |
|---|---|---|---|---|
| M3 | concealed-head standoff or stud | 0.55 | cold-rolled steel / 5052-H34 aluminum | self-clinching in sheet metal |
| M4 | concealed-head standoff or stud | 2.0 | cold-rolled steel / 5052-H34 aluminum | self-clinching in sheet metal |
| M5 | concealed-head standoff or stud | 3.6 | cold-rolled steel / 5052-H34 aluminum | self-clinching in sheet metal |
| M6 | concealed-head standoff or stud | 7.2 | cold-rolled steel / 5052-H34 aluminum | self-clinching in sheet metal |
