Product Specifications
| Model / Specification | M4 – M16 |
| Material | Carbon Steel |
| Thread size d |
M4 | M5 | M6 | M8 | M10 | M12 | (M14) | M16 | |
| P | Pitch (coarse) | 0.7 | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 |
| Pitch (fine) | / | / | / | 1 | 1 | 1.5 | 1.5 | 1.5 | |
| Pitch (fine) | / | / | / | / | 1.25 | 1.25 | / | / | |
| b | Max. | 0.8 | 1.0 | 1.2 | 1.5 | 1.8 | 2.0 | 2.5 | 2.5 |
| Min. | 0.5 | 0.7 | 0.9 | 1.2 | 1.4 | 1.6 | 2.1 | 2.1 | |
| b1 | Max. | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 2 | / | / |
| Min. | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.5 | / | / | |
| d3 | Max. | 5.18 | 6.18 | 7.72 | 10.22 | 12.77 | 13.77 | 17.07 | 19.13 |
| Min. | 5 | 6 | 7.5 | 10 | 12.5 | 13.5 | 16.8 | 18.8 | |
| da | Max. | 4.6 | 5.75 | 6.75 | 8.75 | 10.8 | 13 | 15.1 | 17.3 |
| Min. | 4 | 5 | 6 | 8 | 10 | 12 | 14 | 16 | |
| e | Min. | 8.63 | 9.93 | 12.53 | 16.34 | 20.24 | 22.84 | 26.21 | 30.11 |
| h | Max. | 0.7 | 0.9 | 0.9 | 1.1 | 1.3 | 1.5 | 1.5 | 1.7 |
| Min. | 0.5 | 0.7 | 0.7 | 0.9 | 1.1 | 1.3 | 1.3 | 1.5 | |
| h1 | Max. | 1 | 1 | 1 | 1 | 1 | 1.2 | / | / |
| Min. | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 1 | / | / | |
| m | Max. | 3.5 | 4.2 | 5 | 6.5 | 8 | 9.5 | 11 | 13 |
| Min. | 3.2 | 3.9 | 4.7 | 6.14 | 7.64 | 9.14 | 10.3 | 12.3 | |
| s | Max. | 7 | 8 | 10 | 13 | 16 | 18 | 21 | 24 |
| Min. | 6.64 | 7.64 | 9.64 | 12.57 | 15.57 | 17.57 | 20.16 | 23.16 | |
| n | Min. | 0.3 | 0.3 | 0.3 | 0.5 | 0.5 | 0.5 | / | / |
| Max. | 0.5 | 0.5 | 0.5 | 1 | 1 | 1 | / | / | |
| Proof load (N) | 6800 | 11000 | 15500 | 28300 | 44800 | 65300 | 89700 | 123000 | |
| Wt./1000 pcs (steel) ≈ kg | Type A | 1.09 | 1.48 | 2.18 | 4.55 | 8.13 | 11.79 | 16.35 | 22.24 |
| Type B | 0.79 | 1.18 | 2.37 | 5.16 | 9.77 | 13.95 | / | / | |
Welded Square Nut — Product Introduction
The welded square nut is a sheet-metal welding fastener conforming to the GB/T 13680-1992 standard. Its shape is square with four projection-weld lugs at the corners. It is pre-fixed to steel plates or sheet-metal parts through projection welding or spot welding, and then mated with bolts to form a detachable threaded connection. It is mainly used in cases where direct tapping on thin sheets is impractical or where higher threaded connection strength is required. Thread sizes typically cover M4 to M16.
I. Product Features
- Square anti-rotation structure: The square profile provides anti-rotation engagement with the plate after welding, preventing the nut from rotating when the bolt is tightened.
- Four-corner projection weld lugs: Projection weld points or bosses are provided at the four corners; during welding, current concentrates at these points, forming stable and reliable weld spots to ensure connection strength.
- Excellent weldability: The standard specifies that the carbon content of the material shall not exceed 0.25%. Commonly used low-carbon steels (such as Q195, 15A, SWRCH10K, etc.) are suitable for projection welding and spot welding processes.
- Thin and compact design: The overall height is relatively low, making it suitable for thin-sheet structures and space-restricted locations; the surface after welding is relatively flat.
- Complete thread specifications: The standard covers M4 to M16, with common types such as Type A and Type B. Specifics should follow standard drawings or supply requirements.
- Diverse materials and surface treatments: Carbon steel, stainless steel (304/316), and other options are available; carbon steel parts are typically zinc-plated and passivated, left plain, or treated as required.
II. Product Advantages
- Improved thin-sheet connection strength: Eliminates the need for direct tapping on thin sheets; the threaded strength is borne by the welded nut, resulting in a more reliable connection.
- Anti-rotation and anti-loosening: The square body and weld spots work together to effectively prevent nut rotation and loosening, making it suitable for vibrating conditions.
- High assembly efficiency: Can be pre-welded onto sheet-metal parts, followed by quick bolt assembly — ideal for automation and流水线 production.
- Detachable connection: Bolts can be repeatedly assembled and disassembled without damaging the plate threads, facilitating maintenance and replacement.
- Consistent positioning: Projection weld lugs ensure consistent batch welding positions, improving assembly accuracy and product uniformity.
- Lower cost: The simple, highly standardized structure makes comprehensive costs easier to control compared to some clinch/rivet solutions.
III. Application Scope
- Automotive industry: Body sheet metal, chassis, seat frames, brackets, fuel tanks, braking systems, and other thin-sheet connection locations.
- Home appliances and electronics: Air conditioners, refrigerators, washing machines, and other sheet-metal housings, control boxes, and internal brackets.
- Cabinets and enclosures: Electrical control cabinets, communication enclosures, distribution boxes, server chassis, and network equipment housings.
- Rail transit and construction machinery: Cover panels, protective covers, thin-sheet structural parts, interior trim, and more.
- General sheet-metal manufacturing: Thin-sheet connection applications requiring welded nuts in metal furniture, shelving, elevator components, agricultural machinery, architectural decoration, and similar fields.
