Salt spray

Salt spray machine is a laboratory equipment that is precisely designed according to the relevant standard to evaluate the ability of rust-resistant components against corrosion due to weather conditions. Double-walled with fiberglass insulation.

Temperature range: Ambient up to +55 ° C
Temperature fluctuation: +/- 0.5 ° C
Temperature control: Integrated microcomputer controller PID + S, S, R
Spray method: Continuous / Cycle (optional)
Related standards: JIS Z 2371 , ASTM B117-16, IS: 5528, IS: 6910 (R2003)

Internal dimensions of the tank:

Volume: 108 liters (WxDxH) – 600 * 400 * 450 mm
Volume: 270 liters (WxDxH) – 900 * 600 * 500 mm
Volume: 600 liters (WxDxH) – 1200 * 1000 * 500 mm
Volume: 960 L ( WxDxH) – 2300 * 1300 * 1400 mm

• First, small panels (usually 3.5 inches or 4.6 inches) are prepared with the test coating. The edges and back of the panels are usually protected with tape. The front of the panel is then “scraped” with a sharp tool to scratch the metal layer from the cover.
• After preparing the panel, it is placed inside the test chamber. The compartment has shelves that hold the panels in the position specified by ASTM B-117 -15 to 30 degrees behind the vertical.
• The chamber is then closed and the 5% salt solution enters the cabinet through the fumigator at a constant speed and temperature. The salt mist is sprinkled upwards so that the drops come down and sit on the plates.
• After this step, periodic inspections of the test panels as well as monitoring of the salt spray cabinet are performed to ensure its proper operation during the test period. During these brief evaluations of the panels, it is determined whether the test is progressing as expected or whether the coating on the test plates will deteriorate quickly.

Although each lab has slightly different settings, the basics of testing are as follows. Heresite is lucky to have a cabinet with a digital readout that shows the total working hours of the test cabinet.

It also alerts us to a variety of important issues, such as low salt levels. These features are important because some salt spray tests run for a very long time.

For example, Heresite P-413 was tested against ASTM B-117 for +6000 hours. This is a 250 day direct (or a little over 8 months) continuous salt spray.

 ISO 12944-9 uses the salt spray test. P-413, ES-606 and WB-506 Heresite are all tested according to this standard.

Although both ASTM B-117 and ISO 12944-9 are used to measure corrosion protection, there are significant differences between the two tests.

 Unlike the B-117, which is just a static salt spray test, ISO 12944-9 is a cyclic test, in which boards are tested for 72 hours of UV light, followed by 72 hours of salt spray, then 24 hours of freezing (for a total of 168 hours per week of intense weather cycles to which HVAC-R units are often exposed in the real world.

For this reason, the SSPC (Association of Protective Coatings) has concluded that “combined corrosion / weathering is a significant improvement in the traditional salt spray test (ASTM B117) in terms of rapid reproduction of atmospheric corrosion.”

 You can read the studies to see more about the differences between the two tests and why we test according to ISO 12944-9. The ASTM-B117 salt spray test has nothing to do with real environments.

Once the required level for ASTM B-117 or ISO 12944-9 is reached, the laboratory evaluates the panel in terms of blister, rust and creep creep from the scribe. The results are recorded and shared on our technical data sheet.

Source :

https://www.heresite.com/what-is-salt-spray-testing-and-how-does-the-process-work/