"Environmental testing" is the test of exposing products or materials to natural or artificial environments under specified conditions, so as to evaluate their performance under the conditions of storage, transportation and use that may actually be encountered.
There are three types of high and low temperature test chamber environmental tests: natural exposure test, field test and artificial simulation test. The first two types of tests are expensive and time-consuming, and the repeatability and regularity of the tests are also poor, but the problems found in the tests can more realistically reflect the actual state of use, so these two tests are artificial simulations the basis of the test. Artificial simulated environment test is widely used in quality inspection. In order to make test results comparable and reproducible, basic environmental test methods for products are now standardized.
Common methods of environmental testing are as follows:
1. High and low temperature test of high and low temperature test box: used to assess or determine the adaptability of products for storage and (or) use under high and low temperature environmental conditions.
2. The temperature shock test of the high and low temperature test chamber: determine the adaptability of the product and the bearing capacity of the structure under one or continuous temperature changes.
3. Damp heat test of high and low temperature test chamber: it is mainly used to determine the adaptability of the product to damp heat (whether or not condensation occurs), especially the changes in the electrical properties and mechanical properties of the product. It can also be used to check the resistance of the test sample to certain some corrosive capabilities.
① Constant damp heat test: generally used for products whose moisture-affected mechanism is mainly adsorption or absorption, and only penetrates (or diffuses) without respiration. performance and mechanical properties, or whether sealing and insulating materials can provide sufficient protection.
② Alternating damp heat test: This is an accelerated environmental test used to determine the suitability of the product for use and storage in a humid and hot environment with cyclic temperature changes and usually when condensation occurs on its surface. It uses the respiration of the product with the change of temperature and humidity to change the humidity inside the product. The tested product is successively tested in four stages of heating, high temperature, cooling and low temperature in the high and low temperature test chamber to form a cycle. Carry out several cycles of tests as specified in the technical conditions.
③ Damp heat test at room temperature: The product is generally tested under the conditions of conventional temperature and high relative humidity.
4. Anti-corrosion test of high and low temperature test chamber: to check the resistance of the product to the corrosion of salt water or industrial atmosphere. It is widely used in electrical and electronic, light industry, metal materials and other products. Corrosion test is divided into atmospheric exposure corrosion test and artificial accelerated corrosion test.
In order to shorten the test period, artificial accelerated corrosion tests are often used, among which neutral salt spray and other tests are widely used. Salt spray test is mainly used to measure the corrosion resistance of protective decorative coatings in salt spray environment, and to evaluate the quality of various coatings.