M6 automotive screws are made of zinc-nickel alloy, black, high salt spray with washers, which are high-performance fasteners designed for harsh environments. The following is a detailed description of its product customization requirements.
1. Core requirements
Material and process
Base material: carbon steel or stainless steel 304 or 316, must be selected.
Surface treatment: zinc-nickel alloy electroplating, black passivation treatment.
Salt spray test: neutral salt spray test ≥ 720 hours, a third-party test report is required.
Specifications
Thread specification: M6 × length, by ISO 898-1 standard (performance level 8.8 or higher).
Washer combination: spring washer + flat washer (the material must be consistent with the screw, and the surface treatment is the same as the requirements).
Head type: hexagonal head or flange head; the drive mode must be marked.
2. Key details
Dimensions and tolerances
Thread tolerance: 6g (external thread) / 6H (internal thread).
Washer size: inner diameter 6.5mm±0.1mm, outer diameter 12mm±0.2mm, thickness 1mm±0.05mm.
Surface characteristics
Black passivation film thickness: ≥3μm, uniform color (no white exposure, color difference).
Lubrication requirements: optional coating of MoS₂ or PTFE lubrication layer (need to be specified).
Mechanical properties: tensile strength ≥800MPa (carbon steel); ≥500MPa (stainless steel).
Torque test: After matching the washer, the tightening torque is ≥10Nm (test data must be provided).
3. Additional requirements
Packaging and labeling
Packaging method: blister tray + anti-rust paper/vacuum packaging (1000 pieces/box).
Labeling requirements: laser marking (including material, batch number, salt spray level).
Certification and documents must comply with: RoHS, REACH, and IATF 16949 (automotive industry certification).
Provide: material certification, salt spray report, and full-size inspection report.
Customization options: non-standard length/washer combination.
Special anti-loosening design (such as nylon pads, serrated washers).
IV. Recommended parameters (for reference)
Item Parameter example
Screw length: M6×20mm (adjustable)
Head height: 5.5mm (hexagonal head)
Zinc-nickel plating thickness: 8-12μm
Washer hardness: 300HV (spring washer)
The above content can be adjusted according to actual needs. It is recommended to clarify the drawing confirmation and sample verification process with the supplier and sign a technical agreement to ensure compliance.
The screw meets the core needs of the automotive industry for high strength, high corrosion resistance, and convenient assembly through the triple guarantee of "plating + structure + material", and is a cost-effective solution for harsh environments.
