Threaded Shaft Collars manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to Trade series (threaded-bore shaft collars). The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose A4 Stainless Steel for Threaded Shaft Collars
Specified for marine, coastal and chemical applications. For threaded shaft collars, 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 |
Corrosion Behavior in Service
A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Threaded Shaft Collars in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Threaded Shaft Collars, 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 Threaded Shaft Collars Available in A4 Stainless Steel
| Thread | Outside diameter (mm) | Width (mm) | Set by |
|---|---|---|---|
| M6 x 1.0 | 18 | 9 | clamp screw |
| M8 x 1.25 | 22 | 11 | clamp screw |
| M10 x 1.5 | 26 | 11 | clamp screw |
| M12 x 1.75 | 30 | 13 | clamp screw |
| M16 x 2.0 | 38 | 15 | clamp screw |
| M20 x 2.5 | 45 | 17 | clamp screw |
