A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. When spring (roll) pin are specified in this grade, the dimensions remain per ISO / DIN; the material determines corrosion behavior (superior, including marine and chloride environments) and the service temperature range (approx. -200 °C to +400 °C, subject to the property class and the joint). Both are covered below with the size table.
Why Choose A4 Stainless Steel for Spring (Roll) Pin — ISO / DIN (Series 103)
Specified for marine, coastal and chemical applications. For spring (roll) pin — iso / din (series 103), 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
For stainless spring (roll) pin — iso / din (series 103) the compatibility question is galvanic rather than galling: joined to aluminum or galvanized steel in wet service, stainless drives corrosion of the less-noble metal. Isolate with a coating, sleeve or non-conductive washer where the joint sees moisture. Note also that stainless is softer than hardened carbon steel, so where the part carries a wear or shear duty, check the load against the grade before substituting.
Comparable Grades
For Spring (Roll) Pin — ISO / DIN (Series 103), the alternative stainless grade is A2 (304). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Spring (Roll) Pin — ISO / DIN (Series 103) Available in A4 Stainless Steel
| Nominal diameter (mm) | Length L (mm) | Recommended hole (mm) | Material | Reference standard |
|---|---|---|---|---|
| 2 | 12 | 2.0 | Spring steel | ISO 8748 / DIN 1481 |
| 3 | 16 | 3.0 | Spring steel | ISO 8748 / DIN 1481 |
| 4 | 20 | 4.0 | Spring steel | ISO 8748 / DIN 1481 |
| 5 | 25 | 5.0 | Spring steel | ISO 8748 / DIN 1481 |
| 6 | 32 | 6.0 | Spring steel | ISO 8748 / DIN 1481 |
| 8 | 40 | 8.0 | Spring steel | ISO 8748 / DIN 1481 |
| 10 | 50 | 10.0 | Spring steel | ISO 8748 / DIN 1481 |
| 12 | 63 | 12.0 | Spring steel | ISO 8748 / DIN 1481 |
| 16 | 80 | 16.0 | Spring steel | ISO 8748 / DIN 1481 |
