When the tire nut is installed on the wheel hub, after years of sun and rain, it is easy to rust. Especially in winter, the road will be spreaded salt, hydrochloric acid will accelerate wheel nut rust. Therefore, it is very important to choose a wheel nut with higher anti-rust performance.
Generally in a specific test chamber, the salt water containing sodium chloride and pH value of 6.5~7.2 is continuously sprayed through the spray device, and the liquid with salt and acid corrosion is settled to the wheel nut. After a certain period of time, the corrosion state of the surface is observed, so as to judge its anti-corrosion performance and grade of nut.
Comparison of two salt spray tests
Neutral Salt Spray test (NSS) | Copper Accelerated Acetate Spray test (CASS) | ||
Test environment | Laboratory temperature | room temperature | room temperature |
Pressure barrel temperature | 47±1℃ | 63±1℃ | |
Test chamber temperature | 35±2℃ | 50+1℃ | |
Saturator temperature | 40±1℃ | ||
Test chamber humidity | >85% | ||
Test condition | Nacl | 50g±5g/L | |
CuC12.2H20 | 0 | 0.26±0.02g/L | |
PH value | 6.5~7.2 | 3.2±0.1 | |
Volume of spray/Precipitation rate of salt spray | 1~2ml/80c㎡·h | ||
Air pressure | 1.00±0.01kgf/cm² | ||
Spray pressure | 70~170kPa | ||
Test method | Sample placement | Lean 15-30° | |
Exposure to state | Continued exposure | ||
Spray mode | Continuous spray |
The corrosion rate of CASS is approximately 8 times that of the NSS test
For example:
Pass CASS test 24 h,equal to Pass NSS test 192 h.
Pass CASS test 48 h,equal to Pass NSS test 384 h.
We promise that our chrome can pass the 72-hours neutral salt spray test, and actually bulk goods will not appear rust spots until 144 hours.
We promise that our chrome can pass the 24-hours CASS test, and actually bulk goods will not appear rust spots until CASS test 48 hours.
Bulk quality is always better than the promise, this is our HONISHEN standard.