A4 Stainless Steel Helical Thread Inserts are stocked to DIN 8140. The grade provides superior, including marine and chloride environments and is largely non-magnetic; the practical service range is approx. -200 °C to +400 °C. Property data, grade comparison and the full size table follow.
Why Choose A4 Stainless Steel for Helical Thread Inserts
Specified for marine, coastal and chemical applications. For helical thread inserts, this matters when superior, including marine and chloride environments is the primary requirement.
Mechanical & Physical Properties
| Grade designation | A4-80 (316) |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C |
| 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 Helical Thread Inserts in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless helical thread inserts: (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.
Sizes of Helical Thread Inserts Available in A4 Stainless Steel
| Thread size | Pitch (mm) | Length (mm) | Drill / tap size (mm) | Free coil diameter (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 4.5 | 3.1 (STI tap) | 3.45 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M3 | 0.5 | 6.0 | 3.1 (STI tap) | 3.45 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M4 | 0.7 | 6.0 | 4.2 (STI tap) | 4.57 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M4 | 0.7 | 8.0 | 4.2 (STI tap) | 4.57 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M5 | 0.8 | 7.5 | 5.3 (STI tap) | 5.67 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M5 | 0.8 | 10.0 | 5.3 (STI tap) | 5.67 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M6 | 1.0 | 9.0 | 6.3 (STI tap) | 6.80 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M6 | 1.0 | 12.0 | 6.3 (STI tap) | 6.80 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M8 | 1.25 | 12.0 | 8.4 (STI tap) | 9.01 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M8 | 1.25 | 16.0 | 8.4 (STI tap) | 9.01 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M10 | 1.5 | 15.0 | 10.5 (STI tap) | 11.26 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M10 | 1.5 | 20.0 | 10.5 (STI tap) | 11.26 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M12 | 1.75 | 18.0 | 12.6 (STI tap) | 13.51 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M12 | 1.75 | 24.0 | 12.6 (STI tap) | 13.51 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M16 | 2.0 | 24.0 | 16.5 (STI tap) | 17.71 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M20 | 2.5 | 30.0 | 20.5 (STI tap) | 22.07 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |