Wire harness connector salt spray test according to standard
The necessity of salt spray testing for wiring harness connectors.
Whether for harness accessories such as connectors, terminals, buckles, or harness assemblies, DV testing cannot bypass salt spray testing.
When a car or truck is walking, the location of the wire harness connector may come into contact with water splashing on the tires, especially after snow in the northern winter, when salt is used to speed up the melting of snow on the road. These connectors usually require salt spray testing to verify corrosion resistance.
The standard for wire harness salt spray test validation is to check the reliability of contact resistance, not the appearance. These connectors are often used with sealing rings to improve salt spray resistance.
Wire harness connector salt spray test according to standard
IEC 60068-2-11:1981 Environmental testing of electrical and electronic products — Part 2: Test Methods — Ka: W fog test method
IEC 60068-2-52:2017 Environmental tests – Part 2: Test Methods – Kb: Salt spray, alternating (sodium chloride) solution
GB/T 2423.18-2012 “Environmental testing — Part 2: Test methods — Kb: Salt spray, alternating petulant sodium) solution”
Which connectors need to be salt – oligonucleated?
Salt spray environment is mainly used for military, special vehicles and marine applications. Generally, salt spray tests are carried out in a salt spray chamber with 5% salt solution and the exposure time is 48-96 hours.
Salt spray is highly corrosive to many materials and has been proven to cause the failure of many connector coating systems, both precious and non-precious metal coatings. If the salt spray is used, connectors intended for use in the application environment will fail during the test.
The purpose of salt spray testing is to evaluate the performance of a product, not to damage it. Salt spray tests are suitable for connectors in Marine environments. The properties of the salt spray tests are appearance detection, weight detection and resistance measurement.
Which products do not need to be tested for salt spray？
For protected areas of vehicles (e.g. carriages), there is no need to conduct salt spray testing in such environments. In these applications, for noble metal plating applications, the common failure mechanisms are pore corrosion and corrosion screw change, which are evaluated by MFG (HCI, SO2, H2S, etc. Mixed gas flow) tests.
For the contact interface of non-precious metal coatings, the primary failure mechanism is fretting corrosion, which was assessed by vibration and high-frequency temperature and humidity cycling tests.
Connector terminal tinning product salt spray test
Many enterprises use salt spray for incoming inspection of connector terminal tinned products, and to monitor their appearance.
The connectors tested may not be exposed to salt or Marine environments at all, and the products are likely to be installed in a protected environment where the use of salt spray testing does not demonstrate consistency with the actual application.
There is a layer of oxide film on the surface of tin plating products, and the main failure mechanism is fretting corrosion after coordination. In this case, the salt spray test has no relationship with its failure mechanism.
Even if the oxide layer on the surface turns black after the salt spray test, in practical use, the matching terminal can easily remove the oxide layer and contact the pure tin inside to form a gold connection.
Salt spray tests have no acceleration factor, and salt spray past 48 hours is not indicative of how many years the product will last under certain conditions.
Environmental reliability testing equipment is widely used in the level from raw materials, components, to the level of a circuit board/module, water heater products such as electronics, electrical appliances, power of constant temperature, constant humidity and temperature changes.
It also applies to salt fog test, the mixed gas test, ozone ageing test, UV ultraviolet accelerated ageing test, lamp ageing test, sulfur dioxide corrosion test, high Air low-pressure test, IPX1 ~ 8 waterproof rank test, dust/sand dust test, drop test, combustion test, a half-sine wave/trapezoidal acceleration shock test, sine/random vibration test, collision simulation test, drop test, the tensile strength test, fatigue test, the test and highly accelerated life test screening machinery, mechanical stress and environment, climate environmental testing and the integrated environment Pilot project.