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FULLERKREG DIN 928 square weld nuts in marine-grade stainless steel A4 (SUS316) deliver superior corrosion resistance compared to standard A2 grade, making them the preferred choice for marine, offshore, chemical processing, coastal outdoor, and food & pharmaceutical equipment. The molybdenum addition in SUS316 significantly enhances resistance to chloride-induced pitting and crevice corrosion — critical in welded assemblies where the heat-affected zone is particularly vulnerable. Four precision weld projections on the bearing face concentrate heat during resistance welding for consistent, high-strength weld joints. The square body provides excellent anti-rotation resistance in the parent material.
| Standard | Type | Material | Grade | Surface Treatment | Thread | RoHS |
|---|---|---|---|---|---|---|
| DIN 928 | Square Weld Nut (Projection Welding) | Stainless Steel | A4 / SUS316 | Pickled & Passivated | Metric (M3–M12) | Compliant |
All dimensions in millimeters (mm). Weight per 1000 pcs in kg. Unit weight (g/pc) calculated from standard data. Refer to diagram: A = body width across flats, C = body thickness, D = thread diameter, H = projection height, E = projection diameter, F = projection pitch circle diameter.
| Thread (D) | Body Width (A) mm | Body Thickness (C) mm | Projection Height (H) mm | Projection Ø (E) mm | Proj. PCD (F) mm | Weight / 1000 pcs (kg) | Unit Weight (g/pc) |
|---|---|---|---|---|---|---|---|
| M3 | 9 | 3 | 0.8 | 1.5 | 5.5 | 1.44 | 1.44 |
| M4 | 11 | 3.5 | 0.9 | 1.8 | 7 | 2.68 | 2.68 |
| M5 | 13 | 4 | 1.0 | 2.0 | 8.5 | 4.33 | 4.33 |
| M6 | 16 | 4.5 | 1.1 | 2.3 | 10.5 | 7.52 | 7.52 |
| M8 | 20 | 5 | 1.2 | 2.8 | 13.5 | 14.94 | 14.94 |
| M10 | 25 | 6 | 1.4 | 3.2 | 17 | 28.84 | 28.84 |
| M12 | 30 | 7 | 1.6 | 3.8 | 20.5 | 51.50 | 51.50 |
Note: Dimensional data per DIN 928 standard. Weights based on SUS316 density (8.00 g/cm³), approximately 3% higher than A2/SUS304. Actual weights may vary slightly by batch.
| Property | A2 / SUS304 | A4 / SUS316 |
|---|---|---|
| Molybdenum Content | None | 2–3% |
| Chloride / Saltwater Resistance | Moderate | Excellent |
| Pitting Resistance at Weld Zone | Standard | Enhanced (Mo addition) |
| Marine / Offshore Use | Not recommended | ✅ Recommended |
| Chemical Processing | Limited | ✅ Superior |
| Food & Pharma Compliance | Good | Superior (preferred grade) |
| Property | Value | Standard |
|---|---|---|
| Material Grade | A4 / SUS316 / 1.4401 | ISO 3506 |
| Tensile Strength (min) | 500 MPa | ISO 3506-2 |
| Proof Load Stress | A4-50 class | ISO 3506-2 |
| Hardness (max) | 220 HV | ISO 3506-2 |
| Chromium Content | 16–18% | ASTM A276 |
| Nickel Content | 10–14% | ASTM A276 |
| Molybdenum Content | 2–3% | ASTM A276 |
| Magnetic | Non-magnetic (annealed) | – |
| Parameter | Guidance |
|---|---|
| Welding Method | Resistance projection welding (spot welding machine) |
| Parent Material | Stainless steel, mild steel, or duplex sheet (0.8–3.0 mm) |
| Projection Function | 4 projections concentrate current for consistent weld nugget formation |
| Electrode Force | Adjust per sheet thickness; higher force for thicker panels |
| Post-weld Treatment | Passivation strongly recommended to restore A4 corrosion resistance at weld HAZ |
| Thread Protection | Use thread protector plug during welding to prevent spatter in thread |
| Marine Environment Note | Ensure full passivation of weld zone; unpassivated HAZ may exhibit reduced chloride resistance |
| Application Scenario | Recommended Size | Reason |
|---|---|---|
| Marine & offshore structures | M5 – M12 | A4 SUS316 resists saltwater chloride attack at weld zone |
| Chemical processing equipment | M5 – M12 | Molybdenum addition enhances acid and chloride resistance |
| Coastal outdoor installations | M4 – M10 | Superior pitting resistance in humid salt air environments |
| Food & pharmaceutical machinery | M4 – M8 | SUS316 preferred grade for hygienic welded assemblies |
| Swimming pool & water treatment | M5 – M10 | Chlorinated water resistance superior to A2 |
| HVAC in corrosive environments | M4 – M8 | Flush weld on thin sheet, A4 for aggressive atmospheres |
DIN 928 specifies square weld nuts with metric threads and four weld projections, issued by the Deutsches Institut für Normung (DIN). The standard defines body dimensions, projection geometry, and thread tolerances for resistance welding applications. FULLERKREG manufactures these nuts in A4 / SUS316 marine stainless steel with strict conformance to DIN 928 dimensional tolerances, pickled and passivated to maximize corrosion protection — especially critical at the heat-affected weld zone.
DIN 928 A4 Marine Stainless Steel Square Weld Nuts – actual product photos
| [Photo 1] | [Photo 2] | [Photo 3] | [Photo 4] |
🏭 Direct Manufacturer – Factory-direct pricing with full dimensional traceability
📐 DIN Precision – Strict conformance to DIN 928 tolerances, projection geometry verified by QC
🌊 True Marine Grade A4 – SUS316 with molybdenum for superior chloride and saltwater resistance
⚡ Weld-Ready Projections – 4 precision projections ensure consistent resistance weld quality
✅ RoHS Compliant – All products meet EU RoHS environmental directives
📦 Bulk Wholesale Ready – MOQ flexible, available in bags, boxes, or bulk cartons
🌍 Global Shipping – Reliable export logistics to Europe, North America, Southeast Asia
💬 Technical Support – Engineering team available for welding parameters and substitution queries
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