A4 Stainless Steel Shoulder Bolts pairs the standard ISO 7379 with a A4 Stainless Steel base material. The sections below cover why engineers select this grade for shoulder bolts, its corrosion and temperature behavior, and the sizes available.
Why Choose A4 Stainless Steel for Shoulder Bolts
Specified for marine, coastal and chemical applications. For shoulder bolts, 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 Shoulder Bolts in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Shoulder Bolts, 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.
Sizes of Shoulder Bolts Available in A4 Stainless Steel
| Shoulder diameter (mm) | Thread size | Pitch (mm) | Shoulder length range (mm) | Head diameter dk (mm) | Head height k (mm) | Reference standard |
|---|---|---|---|---|---|---|
| 4.0 | M3 | 0.5 | 8~50 | 8.0 | 4.3 | ISO 7379 / DIN 9841 |
| 5.0 | M4 | 0.7 | 8~63 | 9.5 | 5.3 | ISO 7379 / DIN 9841 |
| 6.0 | M5 | 0.8 | 10~63 | 11.0 | 6.5 | ISO 7379 / DIN 9841 |
| 8.0 | M6 | 1.0 | 10~80 | 13.0 | 8.0 | ISO 7379 / DIN 9841 |
| 10.0 | M8 | 1.25 | 12~100 | 16.0 | 10.0 | ISO 7379 / DIN 9841 |
| 12.0 | M10 | 1.5 | 16~100 | 18.0 | 12.0 | ISO 7379 / DIN 9841 |
| 16.0 | M12 | 1.75 | 20~125 | 24.0 | 16.0 | ISO 7379 / DIN 9841 |
| 20.0 | M16 | 2.0 | 25~160 | 30.0 | 20.0 | ISO 7379 / DIN 9841 |
| 25.0 | M20 | 2.5 | 32~200 | 36.0 | 25.0 | ISO 7379 / DIN 9841 |
| 30.0 | M24 | 3.0 | 40~200 | 45.0 | 30.0 | ISO 7379 / DIN 9841 |