The application scenarios for automotive structural fasteners in the 1000-10,000 piece range are mainly concentrated in the vehicle assembly stage, covering core modules such as the body, chassis, powertrain, and new energy vehicle's three-electric system.
According to industry data, the average number of fasteners used per vehicle is 3000-5000 pieces, while some new energy vehicle models, due to battery pack structure and lightweight design, can use more than 10,000 pieces. Specific application scenarios are as follows:
1. Body-in-White (BIW) and Body Structure
Number of Applications: Approximately 1000–2000 pieces
Main Types: Self-tapping screws, spot-welded studs, self-piercing rivets, flow drill screws
Function: Connecting doors, hoods, longitudinal beams, crossbeams, etc., ensuring body rigidity and collision safety
Technological Trend: Steel-aluminum hybrid materials are driving the development of riveting and adhesive bonding composite processes.
2. Chassis and Suspension System
Number of Applications: Approximately 500–800 pieces
Main Types: Grade 12.9 high-strength bolts, all-metal locknuts, pre-applied adhesive bolts
Function: Fixing control arms, shock absorbers, and steering knuckles, coping with long-term vibration and impact loads
Special Requirements: Anti-loosening, fatigue-resistant, corrosion-resistant; often used in conjunction with thread-locking adhesive.
3. Powertrain System (Traditional Gasoline Vehicles)
Number of Applications: Approximately 600–1000 pieces
Main Types: High-strength internal hex bolts, plastic-zone tightening bolts, shoulder bolts
Function: Connects the cylinder head, crankshaft, and camshaft, ensuring engine sealing and stable operation.
Process Requirements: Must be tightened using a "cross-step tightening" method; torque error ≤5%.
4. New Energy Vehicle Three-Electric System
Number of Applications: 800–1500 new pieces (especially battery packs)
Main Types:
Battery Pack Dedicated Bolts: High-strength, anti-galvanic corrosion coating, insulating washers
Electrical Connection Bolts: Silver-plated, low contact resistance, preventing fretting corrosion
Motor/Electrical Control Fasteners: Possesses electromagnetic shielding characteristics, resistant to high-frequency vibration
Trend: NIO, Li Auto, and other automakers are procuring lightweight welded fasteners in large quantities to achieve a balance between high strength and weight reduction.
