In the field of automotive manufacturing, although combination screws are small, they are related to the safety and performance of the entire vehicle. They are distributed in key parts such as the engine, chassis and interior, playing an important role in fastening and connecting. This article will sort out the type characteristics, industry standards and selection suggestions of automotive combination screws for you, helping you make more suitable choices in design and assembly.
I. Common Types of Screws and Applicable Scenarios
1. Cross head combination screw
The disc head design comes with a flat washer and a cross groove structure for easy installation.
Low cost and fast assembly, suitable for non-load-bearing scenarios such as interior decoration and wire harness fixation.
2. Hexagon socket combination screws
The cylindrical head is equipped with hexagonal holes, which are compatible with professional wrenches and provide precise torque control.
It has strong torsional resistance and good sealing performance, and is often used in high-strength connection parts such as engine mounts and chassis.
The head is equipped with an integrally formed flange surface, and the surface has anti-slip tooth patterns.
It has a large contact area and excellent anti-loosening performance, making it suitable for high-frequency vibration environments such as wheel hubs and braking systems.
4. Nylon locking combination screws
The threaded end is embedded with a nylon ring to prevent loosening through friction.
It has good anti-vibration performance and is suitable for car door hinges, seat rails, etc., but it is not resistant to high temperatures and corrosive media.
Ⅱ.Key Performance and Standard Specifications
1. Strength grade
For common parts, grade 8.8 (tensile strength ≥ 800MPa) is commonly used.
Key components such as the chassis and engine should be of grade 10.9 or 12.9 (tensile strength ≥ 1000-1200MPa).
2. Rust prevention treatment
Electro-galvanizing: Low cost, suitable for dry environments;
Dacromet: Strong corrosion resistance, salt spray test ≥ 240 hours, suitable for chassis and engine compartment.
Hot-dip galvanized/stainless steel: used in highly corrosive or high-load environments.
3. Torque standard
It must comply with standards such as ISO 7380, DIN 7984 or GB/T 9074;
Insufficient torque can cause loosening, while excessive torque may damage the threads. It is essential to use a torque wrench for assembly in accordance with the specifications.
4. Anti-loosening performance
Verified through vibration tests, the nylon locking screws need to meet DIN 980 requirements, and the flange surface screws rely on tooth patterns for effective meshing.
Ⅲ. Selection and Usage Suggestions
Select the type according to the force conditions
Load-bearing parts (suspension, engine) : Select hex socket, flange surface or high-strength screws;
Non-load-bearing parts (interior, wiring harnesses) : Economical cross-head screws are available as an option.
Adapt to the usage environment
High-temperature area: Avoid nylon locking screws. It is recommended to use metal locking or flange type.
Damp/Corrosive environment: Dakro treatment or stainless steel material is recommended.
Key points of procurement and assembly
When purchasing, check the material, strength and salt spray test report.
When assembling, use a torque wrench and strictly follow the standard torque value.
Ⅳ.Future Development Trends
Material upgrade: Lightweight materials such as titanium alloys and high-strength aluminum alloys will be gradually promoted.
Structural innovation: Smart screws such as self-locking and embedded sensing are on the rise;
Standardization: Internationalization and green manufacturing standards will be further popularized.
About Us
Yuhuang Fasteners has passed the IATF16949 quality management system certification and is dedicated to the research and development and manufacturing of automotive combination screws, providing one-stop services from selection support, sample testing to batch delivery. If you have any product selection, technical parameter or customization requirements, please feel free to contact us at any time. We will provide you with professional answers and quotation plans.
Consult the customized plan immediately and get the exclusive quotation!
Dongguan Yuhuang Electronic Technology Co., Ltd
Email:yhfasteners@dgmingxing.cn
WhatsApp/WeChat/Phone: +8613528527985
Post time: Oct-24-2025
