Material specification page for countersunk head grooved pins in A4 Stainless Steel. Covers the grade designation (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to ISO 8747.
Why Choose A4 Stainless Steel for Countersunk Head Grooved Pins
Specified for marine, coastal and chemical applications. For countersunk head grooved pins, 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 Countersunk Head Grooved Pins in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Countersunk Head Grooved Pins, 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 Countersunk Head Grooved Pins Available in A4 Stainless Steel
| Nominal diameter d (mm) | d_1_max (mm) | d_1_min (mm) | d_k_max (mm) | d_k_min (mm) | d_2 (mm) | c (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|
| 1.4 mm | 1.4 | 1.35 | 2.7 | 2.3 | 1.5 | 0.42 | 3~6 | ISO 8747 |
| 1.6 mm | 1.6 | 1.55 | 3 | 2.6 | 1.7 | 0.48 | 3~8 | ISO 8747 |
| 2 mm | 2 | 1.95 | 3.7 | 3.3 | 2.15 | 0.6 | 4~10 | ISO 8747 |
| 2.5 mm | 2.5 | 2.425 | 4.6 | 4.2 | 2.7 | 0.75 | 4~12 | ISO 8747 |
| 3 mm | 3 | 2.925 | 5.45 | 4.95 | 3.2 | 0.9 | 5~16 | ISO 8747 |
| 4 mm | 4 | 3.9 | 7.25 | 6.75 | 4.25 | 1.2 | 6~20 | ISO 8747 |
| 5 mm | 5 | 4.9 | 9.1 | 8.5 | 5.25 | 1.5 | 8~25 | ISO 8747 |
| 6 mm | 6 | 5.9 | 10.8 | 10.2 | 6.3 | 1.8 | 8~30 | ISO 8747 |
| 8 mm | 8 | 7.85 | 14.4 | 13.6 | 8.3 | 2.4 | 10~40 | ISO 8747 |
| 10 mm | 10 | 9.85 | 16 | 14.9 | 10.35 | 3 | 12~40 | ISO 8747 |
| 12 mm | 12 | 11.8 | 19 | 17.7 | 12.35 | 3.6 | 16~40 | ISO 8747 |
| 16 mm | 16 | 15.8 | 26 | 23.7 | 16.4 | 4.8 | 20~40 | ISO 8747 |
| 20 mm | 20 | 19.8 | 31.5 | 30.7 | 20.5 | 6 | 25~40 | ISO 8747 |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this pin in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Diameter, length, tolerance class, hardness and end form are specifiable. Ground diameters are held after heat treatment rather than before. Made by cold heading or turning.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
