How Long Does It Take to Pass a Salt Spray Test on Polished Hardware Parts?

The passing time for a salt spray test on polished hardware parts is typically 48 hours or more. Specific standards depend on the product material, surface treatment process, and usage environment. Generally, it is required that there be no red rust, coating blistering, or substrate corrosion after the test.

Different industries and application scenarios have different requirements for salt spray test durations. Below are common classifications and corresponding standards:

Ordinary Hardware Parts

Test Time: ≥48 hours (Neutral Salt Spray NSS)

Judgment Criteria: Slight white rust is allowed on the surface, but there must be no red rust spots, plating peeling, or substrate corrosion. Suitable for general uses such as interior decorative parts and furniture hardware.

Electroplated/Spray-Painted Polished Parts

Test Time: ≥72 hours

Judgment Criteria: No discoloration, blistering, or peeling of the plating; corrosion points with a diameter ≤0.5mm and no more than 3. Commonly used for products with high requirements for decorativeness and corrosion resistance, such as bathroom fixtures and door handles.

Stainless steel polished parts (e.g., 304, 316)

Testing time: ≥96 hours

Judgment criteria: No visible red rust, extremely slight pitting is allowed (area ≤0.1%), meeting grade 8 or higher in GB/T 10125 standard.

Outdoor or highly corrosive environment parts

Testing time: ≥500 hours (painted parts), ≥1000 hours (outdoor complete units)

Judgment criteria: No blistering or peeling of the coating, no corrosion of the substrate, and no discolored spots (such as red rust) on the surface.

High-end fields such as automotive, medical, and aerospace

Testing time: 240 to 1000 hours, some military-grade products require up to 2000 hours

Judgment criteria: In addition to no corrosion on the appearance, functional stability requirements must be met, such as contact resistance change ≤50mΩ (connectors).