Weld Studs (CD and Drawn-Arc) manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to ISO 13918. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose A4 Stainless Steel for Weld Studs (CD and Drawn-Arc)
Specified for marine, coastal and chemical applications. For weld studs (cd and drawn-arc), 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 Weld Studs (CD and Drawn-Arc) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Weld Studs (CD and Drawn-Arc), 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
The galvanic couple here runs the wrong way: aluminum is the less noble metal, so it corrodes and the fastener does not. What governs the rate is the ratio of areas — a large anode and a small cathode is a tolerable combination, the reverse concentrates the attack into thin material around the hole. An isolating washer plus sealant breaks the circuit; where that is impractical, match the fastener to the substrate.
Sizes of Weld Studs (CD and Drawn-Arc) Available in A4 Stainless Steel
| Thread size | Length L before weld (mm) | Weld process | Burn-off (mm) | Minimum sheet thickness (mm) | Flange diameter (mm) | Material | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 8 | CD (type PT) | 0.5 | 0.6 | — | Mild steel / A2 | ISO 13918 |
| M4 | 10 | CD (type PT) | 0.5 | 0.7 | — | Mild steel / A2 | ISO 13918 |
| M5 | 16 | CD (type PT) | 0.5 | 0.8 | — | Mild steel / A2 | ISO 13918 |
| M6 | 20 | CD (type PT) | 0.5 | 1.0 | — | Mild steel / A2 | ISO 13918 |
| M8 | 25 | Drawn-arc (type PD) | 4.0 | 2.0 | 13.0 | Mild steel | ISO 13918 |
| M10 | 30 | Drawn-arc (type PD) | 4.0 | 2.5 | 16.0 | Mild steel | ISO 13918 |
| M12 | 40 | Drawn-arc (type PD) | 5.0 | 3.0 | 19.0 | Mild steel | ISO 13918 |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this bolt in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. A non-standard bolt is quoted from the drawing; where one already exists in the catalog, the special is usually a variation on its tooling. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
