The sulfur dioxide test is an accelerated corrosion test method used to evaluate the protection—corrosion resistance of decorative coatings. This is a special equipment with a sealing performance of sulfur dioxide testing machine, equipped with temperature adjustment, heating and gas introduction device. Distilled water is placed at the bottom of the box in order to maintain a certain humidity. Put the tested sample in the box, adjust it to the temperature and humidity required by the test, pass in sulfur dioxide gas, and observe the change of the sample after a certain period. The specific test conditions and methods are as follows. The volume of the sulfur dioxide testing machine is 300L, and 2L of distilled water with a conductivity of less than 500uS / m is placed at the bottom of the box. Then put the tested sample on the partition plate in the middle of the box, close the door of the box, pass 0.2L of sulfur dioxide gas into the box, and start timing. Turn on the heater to increase the temperature in the sulfur dioxide testing machine to 40 ℃ ± 3 ℃ within 1.5h and keep it. The test takes 24h as a cycle. In each cycle, it can be continuously kept in the box for 24h, or it can be first in the box for 8h, and then exposed for 16h in the room. The indoor temperature should be 23 ℃ ± 5 ℃, and the relative humidity should be 75%. If the following cycle is to be carried out, the distilled water and sulfur dioxide gas must be replaced. The evaluation criteria are the first appearance after the test; the appearance after removing corrosion products; the number and distribution of corrosion defects; and the time elapsed before the first corrosion point appears. Fruit Mask Machine,Automatic Fruit Mask Machine,Fruit Face Mask Machine,Smart Fruit Mask Machine Foshan Liqia Hardware Products Co., Ltd. , https://www.liqiamei.com