Silicon nitride ceramic locating pin is a solid Si₃N₄ pin that guides and centers a weld nut or stud in a resistance or projection welding fixture. The pin enters the bore of the nut, keeps it concentric to the sheet metal hole, and withstands repeated mechanical loading, high weld forces, elevated temperatures and current pulses. The ceramic body provides electrical insulation, low spatter adhesion and dimensional stability, which helps maintain weld quality and reduce fixture maintenance.
Silicon Nitride Ceramic Locating Pin Benefits
1. Extended Service Life vs Steel and KCF Pins
Steel and KCF locating pins in high-volume nut welding stations often have to be changed several times per day because of wear, deformation and spatter build-up. Field reports and case studies on ceramic welding pins show that silicon nitride locating pins can run from weeks up to roughly a month under comparable conditions, which corresponds to an increase in service life on the order of 10–20 times for many cells.
2. Stable Alignment at Welding Temperature
In nut projection welding, the locating pin is exposed to repeated thermal cycles and mechanical forces. Silicon nitride maintains high flexural strength at elevated temperature, and its relatively low coefficient of thermal expansion helps keep the guide nose and shoulder in position as the fixture goes from cold start to steady-state weld temperature. This stability supports consistent nut location and weld nugget formation throughout the lifecycle of the pin.
3. Electrical Insulation and Reduced Spatter Build-Up
Silicon nitride ceramics have high electrical resistivity, so a silicon nitride ceramic locating pin does not carry welding current in a resistance or projection welding tool. This helps direct current through the projections of the nut and sheet instead of shunting through the pin, and it reduces local overheating of the guide section. The hard, smooth surface is also less prone to weld spatter adhesion than steel, which lowers the risk of nut jamming on the pin.
Silicon Nitride Locating Pin Properties
| Si3N4 Type | Gas pressure sintering Si3N4 | Hot pressing sintering Si3N4 | High thermal conductivity Si3N4 |
| Density (g/cm3) | 3.2 | 3.3 | 3.25 |
| Flexture strength (MPa) | 700 | 900 | 600~800 |
| Young Modulus (GPa) | 300 | 300 | 300~320 |
| Poisson's ratio | 0.25 | 0.28 | 0.25 |
| Compressive strength (MPa) | 2500 | 3000 | 2500 |
| Hardness (GPa) | 15 | 16 | 15 |
| Fracture toughness (MPa*m1/2) | 5~7 | 6~8 | 6~7 |
| Maximum working temperature (℃) | 1100 | 1300 | 1100 |
| Thermal conductivity (W/m*K) | 20 | 25 | 80~100 |
| Thermal expansion coefficient (/℃) | 3*10-6 | 3.1*10-6 | 3*10-6 |
| Thermal shock resistance (ΔT ℃) | 550 | 800 | / |
Si3N4 Ceramic Guide Pin Specifications
| Silicon Nitride Ceramic Locating Pin | |||
| Item No. | Specification | Diameter (mm) | Length (mm) |
| AT-SIN-DW1001 | M5 Round Head | 5.8 | 26.5 |
| AT-SIN-DW1002 | M6 Round Head | 6.8 | 25.9 |
| AT-SIN-DW1003 | M8 Round Head | 8.8 | 25.75 |
| AT-SIN-DW1004 | M10 Round Head | 10.8 | 28.8 |
| AT-SIN-DW1005 | M12 Round Head | 12.8 | 31.1 |
| AT-SIN-DW1006 | 7/16 Round Head | 12.8 | 30.65 |
| AT-SIN-DW1007 | M4 Pointed Head | 4.8 | 29 |
| AT-SIN-DW1008 | M5 Pointed Head | 5.8 | 30 |
| AT-SIN-DW1009 | M6 Pointed Head | 6.8 | 31.5 |
| AT-SIN-DW1010 | M8 Pointed Head | 8.8 | 31.5 |
| AT-SIN-DW1011 | M10 Pointed Head | 10.8 | 34.5 |
| AT-SIN-DW1012 | M12 7/16 Pointed Head | 12.8 | 35.8 |
Silicon Nitride Locating Pin Packaging
- Each silicon nitride ceramic locating pin is individually wrapped to prevent pin-to-pin contact.
