Salt spray test and practical connection

The salt fog test and the actual salt fog test is a kind of environmental test which mainly uses the artificial simulated salt fog environmental conditions created by the salt fog test equipment to assess the corrosion resistance of products or metal materials It can be divided into two categories, one is natural environmental exposure test, the other is artificial accelerated simulated salt spray environmental test Artificial simulated salt spray environment test is to use a kind of test equipment with a certain volume space, salt spray test chamber, in its volume space with artificial methods, resulting in salt spray environment to assess the salt spray corrosion resistance quality of products Compared with the natural environment, the salt concentration of chloride in the salt spray environment can be several times or dozens of times of that in the general natural environment, which greatly improves the corrosion rate and shortens the time to get the result of salt spray test on the product If a product sample is tested in natural exposure environment, it may take one year to corrode it However, if it is tested in artificial simulated salt spray environment, it only takes 24 hours to get similar results The artificial simulated salt spray test includes neutral salt spray test, acetate spray test, copper salt accelerated acetate spray test and alternating salt spray test (1) neutral salt spray test (NSS test) is a kind of accelerated corrosion test method which has been widely used in Zui for a long time It uses 5% NaCl solution, and the pH of the solution is in neutral range (6~7) as a spray solution The test temperature is 35 ℃, and the sedimentation rate of salt spray is required to be between 1-2ml / 80cm2 H (2) the acetate spray test (ASS test) is developed on the basis of the neutral salt spray test It is to add some glacial acetic acid into 5% sodium chloride solution to reduce the pH value of the solution to about 3, the solution becomes acid, and the salt mist formed after Zui also changes from neutral salt mist to acid Its corrosion rate is about three times faster than NSS test (3) Cass (copper salt accelerated acetate spray test) is a kind of rapid salt spray corrosion test recently developed abroad The test temperature is 50 ℃, and a small amount of copper salt copper chloride is added into the salt solution, which strongly induces corrosion Its corrosion rate is about 8 times that of NSS test 2 The salt spray test standard and the judgment standard of the test results are the unified provisions for the repeatability and overview Salt spray test standard is a clear and specific regulation on salt spray test conditions, such as temperature, humidity, sodium chloride solution concentration and pH value In addition, it also puts forward technical requirements for the performance of salt spray test chamber The salt spray test standard for the same product shall be selected according to the characteristics of salt spray test, corrosion rate of metal and sensitivity to salt spray The following introduces several salt spray test standards, such as GB / t2423.17-1993 basic environmental test procedures for electric and electronic products Test Ka: salt spray test method, GB / t2423.18-2000 environmental test for electric and electronic products Part 2: Test Test Kb: salt spray, alternating (sodium chloride solution), gb5938-86 corrosion resistance test method for metal coating and chemical treatment layer of light industrial products, GB / t1771-91 paints and varnishes - Determination of resistance to neutral salt spray The purpose of salt spray test is to assess the salt spray corrosion resistance quality of products or metal materials, and the judgment of salt spray test results is the judgment of product quality Whether the judgment results are correct and reasonable is the key to correctly measure the salt spray corrosion resistance quality of products or metals The determination methods of salt spray test results include rating determination, weighing determination, corrosives occurrence determination and corrosion data statistical analysis Rating method is to divide the percentage of corrosion area to total area into several grades according to a certain method, and take a certain grade as the basis of qualification judgment, which is suitable for plate sample evaluation Weighing judgment method is a method of weighing the weight of samples before and after the corrosion test to calculate the weight of the corrosion loss to evaluate the corrosion quality of samples, which is especially suitable for the assessment of the corrosion quality of a certain metal The determination method of corrosives appearance is a kind of qualitative determination method It judges the samples by whether the products produce corrosion after salt spray corrosion test This method is mostly used in general product standards The statistical analysis method of corrosion data provides a method to design corrosion test, analyze corrosion data and determine the confidence degree of corrosion data It is mainly used for analysis and statistics of corrosion, rather than specific for the quality judgment of a specific product