TD1771 SERIES SALT SPRAY TEST CHAMBER IS MANUFACTURED BY HEBEI TIANQI XingZI TESTING EQUIPMENT Co., LTD. Applicable to CNS.4158, JIS H8502, IEC68-2, ASTM.B117, B/T10125, GB/T2423, CNS.4159, GB/T12967, GB/T1771 these test procedures.

Two, test procedures:

1. Scope of application: This standard specifies the contact resistance test method of salt water spray for all metal substrates after plating, organic or inorganic coating and other surface treatments.

2. Test method: This method is a corrosion test method by spraying sodium chloride solution on the coated film with a salt spray test chamber.

3. Preparation of test solution: dissolve sodium chloride (chemically pure and analytically pure) in distilled water (or water with total dissolved solids less than 200 ppm or less) and prepare it into a test solution with a concentration of 5±0.1%. After spraying the test solution at 35℃, the PH value of the collected solution should be 6.5~7.2. Before spraying, the test solution should not contain floating substances.

Note (1) Sodium chloride cannot contain impure copper nickel, the content of sodium iodide in the solid is less than 0.1%. Because the impure may contain corrosion inhibitors, the total impure content must be less than 0.3%.

(2) The specific gravity of the test liquid measured at 33~35℃ should be 1.0258~1.0402, and the specific gravity measured at 25℃ is 1.0292~1.0443. The concentration of the test solution can also be verified by silver nitrate drop determination or other methods.

(3) the test liquid shall be level with reagent hydrochloric acid or sodium hydroxide dilute solution to adjust PH value, and with a PH meter or other reliable way to measure it, because of the preparation of test fluid water containing carbon dioxide, carbon dioxide in water solubility with temperature change and influence the PH of the solution, we must be careful control of PH value, PH value can be adjusted in accordance with any of the following methods:

① The test solution was prepared at room temperature and sprayed at 35℃. The PH value was increased due to the rise of temperature, which caused part of carbon dioxide to escape from the solution. Therefore, when the test liquid is prepared at room temperature, the PH value should be adjusted within 6.5, so that the PH value of the collected liquid can be between 6.5 and 7.2.

(2) Before PH adjustment, the test solution should be boiled and then cooled to 35℃, or maintained at 35℃ for 48 hours. This adjustment of PH will not produce much change in the spray.

(3) First heat the water to more than 35℃ to remove the dissolved carbon dioxide, and then modulate the test liquid and adjust the PH value, so that at 35℃ spray, the adjusted PH value will not produce too much change.

(4) In order to avoid blocking of the spray nozzle, the test liquid should be filtered or carefully tilted into the brine bucket, or a glass screen should be installed at the front of the spray suction pipe for filtration. The glass nozzle should be replaced every 2000 hours of operation of the salt spray tester.

4. Equipment: The equipment required in this test is composed of spray nozzle, salt water bucket, test piece support, spray liquid collection container, test chamber, salt water [supply bucket, pressure bucket, compressed air supply equipment and exhaust equipment, etc. The devices are shown in Figure 1 and tested according to the following conditions.

4.1 Saltwater spray testing machine and its required pipeline shall be made of blunt material, which shall not affect the corrosion test of spray or be corroded itself.

4.2 The spray nozzle shall not spray the test liquid directly to the sample, and the solution gathered at the top of the spray chamber shall not drop on the test sheet.

4.3 The test liquid dropped from the test tablet shall not be returned to the brine bucket for further use in the test.

4.4 Compressed air cannot contain grease and dust, so air purifiers are required. The air pressure should be kept at 1.00±0.01kgf/cm2. Because compressed air will absorb heat when expanding, it should be preheated in advance to increase the temperature and humidity of compressed air, as shown in Appendix 2, so as to obtain uniform temperature spray.

4.5 The horizontal area of the spray absorber is 80cm2, and the diameter is about 10 cm, which is placed near the test sheet (the two places close to the nearest and farthest places of the nozzle).

4.6 Spray volume shall be calculated for the whole time, and an average of 1.0 to 2.0ml of saline solution shall be collected per hour on the taking vessel. The spray solution should be collected for at least 16 hours, and the average value of the spray is indicated.

4.7 In the test, the concentration of sodium chloride solution should be maintained at 40~60g/L. If the salt solution used in the test is not used up within a week, it is necessary to replace it. When the next test is over a week, it is necessary to clean the laboratory and drain the salt solution and water from the heated tank.

4.8 The temperature of the pressure tank shall be maintained at 47±1℃, and the temperature of the salt water tank shall be maintained at 35±1℃.

4.9 The relative humidity of the laboratory shall be maintained above 85%. Requirements for higher relative humidity can be determined by mutual agreement with the customer.

4.10 During the experimental work, if the experimental fog leaks out at the edge of the experimental cover, water should be added to the sealed water tank. If the test period is more than 1 month, the water in the hot water tank should be replaced.