A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. Specified on hollow wall anchors (molly bolts) it determines the corrosion behaviour (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); the dimensions are ours rather than a standard's, and are listed in full below.
Why Choose A4 Stainless Steel for Hollow Wall Anchors (Molly Bolts)
Specified for marine, coastal and chemical applications. For hollow wall anchors (molly bolts), 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 Hollow Wall Anchors (Molly Bolts) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Galvanic & Galling Considerations
Two important notes for stainless hollow wall anchors (molly bolts): (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.
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 Hollow Wall Anchors (Molly Bolts) Available in A4 Stainless Steel
| Screw size | Drill hole diameter (mm) | Wall thickness range (mm) | Anchor length (mm) | Flange diameter (mm) | Setting | Material | Screw retained |
|---|---|---|---|---|---|---|---|
| M4 | 8 | 3~13 | 32 | 11.0 | Screw-set / setting tool | Zinc plated steel | Yes — removable |
| M5 | 10 | 5~20 | 38 | 13.0 | Screw-set / setting tool | Zinc plated steel | Yes — removable |
| M5 | 10 | 13~30 | 52 | 13.0 | Screw-set / setting tool | Zinc plated steel | Yes — removable |
| M6 | 12 | 5~25 | 45 | 16.0 | Screw-set / setting tool | Zinc plated steel | Yes — removable |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this anchor & concrete fixing in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Embedment depth, thread size, body length and corrosion protection are the variables; capacity remains a concrete design value, not a property of the anchor alone. Made by hot forging or thread rolling.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
