Description

Our silicon nitride (Si₃N₄) ceramic locating pins are designed for accurate positioning of nuts and sheet-metal components during projection welding and resistance welding.

Compared with conventional metal locating pins, silicon nitride ceramics provide excellent electrical insulation, high hardness, low thermal expansion, high thermal-shock resistance, and strong wear resistance. These characteristics make Si₃N₄ ceramic welding pins particularly suitable for demanding automotive body welding and nut welding applications where the locating pin is exposed to repeated welding cycles, heat, spatter, and mechanical wear.

Silicon nitride ceramic centering pins are already used in projection welding applications for positioning sheet metal and nuts. Their electrical insulation prevents unwanted current flow through the locating pin, while their smooth ceramic surface helps reduce welding-spatter adhesion.

Key Features
High-hardness Si₃N₄ silicon nitride ceramic
Excellent wear resistance for repeated welding cycles
High electrical insulation
Excellent thermal shock resistance
High-temperature resistance
Low thermal expansion and good dimensional stability
Smooth surface helps reduce welding spatter adhesion
Suitable for nut and sheet-metal positioning
Available in customized dimensions and geometries
Suitable for automotive body and resistance welding applications

Material	Silicon Nitride (Si₃N₄)
Density	Approx. 3.2–3.21 g/cm³
Vickers Hardness	Approx. HV 1,500–1,650
Flexural Strength	Approx. 800–850 MPa
Compressive Strength	Up to approx. 3,000 MPa
Fracture Toughness	Approx. 6–7 MPa·√m
Thermal Conductivity	Approx. 21–30 W/m·K
Coefficient of Thermal Expansion	Approx. 2.5–3.3 × 10⁻⁶/K
Electrical Resistivity	Approx. 10¹⁴ Ω·cm
Maximum Operating Temperature	Up to approx. 1,300°C depending on material grade and conditions
Electrical Insulation	Excellent
Thermal Shock Resistance	Excellent

Why Use Silicon Nitride Ceramic Locating Pins?

1. High Wear Resistance

During nut projection welding, locating pins are repeatedly exposed to mechanical contact, heat and welding spatter. The high hardness and wear resistance of Si₃N₄ help maintain the locating geometry over extended production cycles.

This is particularly important where positioning accuracy directly affects nut alignment and weld quality.

2. Excellent Electrical Insulation

Silicon nitride is electrically insulating, making it suitable for locating and centering components positioned close to the welding current path.

This helps prevent unwanted current flow through the locating pin and reduces the risk of electrical interference with the welding process.

3. High Thermal Shock Resistance

Projection welding generates rapid and repeated temperature changes. Silicon nitride has a combination of low thermal expansion and high thermal-shock resistance, allowing it to withstand repeated thermal cycling better than many conventional ceramic materials.

4. High Temperature Stability

Welding pins can be exposed to significant temperatures during repeated welding cycles. Representative welding-grade Si₃N₄ materials can operate at temperatures up to approximately 1,300°C in oxidizing atmospheres, depending on material grade and operating conditions.

5. Reduced Welding Spatter Adhesion

A properly finished silicon nitride ceramic surface helps reduce the adhesion of welding spatter compared with many metallic locating pins. This can reduce cleaning and maintenance requirements and help maintain stable positioning.