Spiral Retaining Rings manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to Trade series (spiral wound retaining ring). 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 Spiral Retaining Rings
Specified for marine, coastal and chemical applications. For spiral retaining rings, 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 Spiral Retaining Rings in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Spiral Retaining Rings, the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.
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 Spiral Retaining Rings Available in A4 Stainless Steel
| Groove diameter (mm) | Free outer diameter (mm) | Thickness t (mm) | Groove width (mm) | Shoulder contact | Thrust capacity (kN) | Material | Fitting |
|---|---|---|---|---|---|---|---|
| 10 | 11.4 | 0.6 | 0.7 | 360u00b0 | 3.4 | Carbon spring steel | By hand, no pliers |
| 16 | 18.2 | 0.8 | 0.9 | 360u00b0 | 7.2 | Carbon spring steel | By hand, no pliers |
| 20 | 22.7 | 1.0 | 1.1 | 360u00b0 | 11.5 | Carbon spring steel | By hand, no pliers |
| 25 | 28.3 | 1.2 | 1.3 | 360u00b0 | 17.8 | Carbon spring steel | By hand, no pliers |
| 30 | 34.0 | 1.2 | 1.3 | 360u00b0 | 22.0 | Carbon spring steel | By hand, no pliers |
| 40 | 45.2 | 1.5 | 1.6 | 360u00b0 | 36.5 | Carbon spring steel | By hand, no pliers |
| 50 | 56.5 | 1.5 | 1.6 | 360u00b0 | 46.0 | Carbon spring steel | By hand, no pliers |
