Material page for key-locking threaded inserts in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80). The sizes below are the ones we supply; there is no published dimensional standard for this article, so the table rather than a standard number is what to quote. Corrosion behaviour is superior, including marine and chloride environments and the service range is approx. -200 °C to +400 °C, subject to the property class and the joint.
Why Choose A4 Stainless Steel for Key-Locking Threaded Inserts
Specified for marine, coastal and chemical applications. For key-locking threaded inserts, 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 Key-Locking Threaded Inserts in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Key-Locking Threaded Inserts, 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 Key-Locking Threaded Inserts Available in A4 Stainless Steel
| Internal thread | External thread | Length L (mm) | Tapped hole required | Keys | Locking method | Material | Typical use |
|---|---|---|---|---|---|---|---|
| M4 | M8x1.0 | 8.0 | M8x1.0 | 4 | Driven keys broach parent | Carbon steel / 303 stainless | High-vibration repair |
| M5 | M10x1.25 | 10.0 | M10x1.25 | 4 | Driven keys broach parent | Carbon steel / 303 stainless | High-vibration repair |
| M6 | M12x1.25 | 12.0 | M12x1.25 | 4 | Driven keys broach parent | Carbon steel / 303 stainless | High-vibration repair |
| M8 | M14x1.25 | 14.0 | M14x1.25 | 4 | Driven keys broach parent | Carbon steel / 303 stainless | Aerospace, motorsport |
| M10 | M16x1.5 | 16.0 | M16x1.5 | 4 | Driven keys broach parent | Carbon steel / 303 stainless | Aerospace, motorsport |
| M12 | M20x1.5 | 20.0 | M20x1.5 | 4 | Driven keys broach parent | Carbon steel / 303 stainless | Aerospace, motorsport |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this threaded insert in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Thread size, body length, knurl or key form and installation method are all variable against the parent material. Made by tapping or knurling.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
