1. Salt spray test standards

 

 

 

1. Standards are unified regulations on repetitive things and overviews.

 

 

 

2. The salt spray test standard is a clear and specific regulation of the 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 the salt spray test chamber.

 

 

 

3. The salt spray test standard for the same product should be selected based on the characteristics of the salt spray test, the corrosion rate of the metal, and the sensitivity to salt spray.

 

 

 

4. Here are several salt spray test standards:

 

 

 

1) GB/T2423.17-1993 "Basic Environmental Testing Procedures for Electrical and Electronic Products Test Ka: Salt Spray Test Method",

 

 

 

2) GB/T2423.18-2000 "Environmental testing of electrical and electronic products Part 2: Test test Kb: salt spray, alternating (sodium chloride solution)",

 

 

 

3) GB5938-86 "Corrosion resistance test methods for metal coatings and chemical treatment layers of light industrial products",

 

 

 

4) GB/T1771-91 "Determination of Neutral Salt Spray Resistance of Paints and Varnishes".

 

 

 

2. Salt spray test judgment

 

 

 

The purpose of the salt spray test is to assess the salt spray corrosion resistance of products or metal materials. The judgment of the salt spray test results is a judgment on the product quality. Whether its judgment results are correct and reasonable is a correct measure of the salt spray resistance of the product or metal. The key to corrosion quality.

 

 

 

1. The judgment methods of salt spray test results are:

 

Rating judgment method, weighing judgment method, corrosion product appearance judgment method, corrosion data statistical analysis method.

 

 

 

2. The rating judgment method divides the percentage of the corrosion area to the total area into several levels according to a certain method, and uses a certain level as the basis for qualification. It is suitable for evaluation of flat samples;

 

3. The weighing judgment method is a method of weighing the weight of the sample before and after the corrosion test, and calculating the weight lost by corrosion to evaluate the corrosion resistance quality of the sample. It is especially suitable for assessing the corrosion resistance quality of certain metals. ;

 

 

4. The corrosion product appearance determination method is a qualitative determination method. It determines whether the product has corrosion phenomena after the salt spray corrosion test. This method is mostly used in general product standards;

 

 

5. The corrosion data statistical analysis method provides a method for designing corrosion tests, analyzing corrosion data, and determining the confidence level of corrosion data. It is mainly used to analyze and count corrosion situations, rather than specifically used to determine the quality of a specific product.

 

 

 

3. Salt spray test classification

 

 

There are three types of salt spray tests: neutral salt spray test (NSS), acetic salt spray (AA SS) and copper accelerated acetate salt spray (CA SS, also known as copper chloride acetate salt spray) test, among which the most widely used test is The most common is the neutral salt spray test.

 

 

 

4. Basic methods of salt spray testing

 

 

 

It is a method of accelerating corrosion by spraying 5% sodium chloride aqueous solution in the test chamber at 35 degrees Celsius to simulate the seawater environment. The length of its resistance time determines the quality of the corrosion resistance.

 

 

 

1. The volume of the salt spray box should not be less than 012 m3, preferably not less than 014 m3.

 

 

 

2. The temperature inside the box is 35℃± 2℃

 

 

 

3. Spray pressure 70~170kPa

 

 

 

4. At least two salt spray collectors with a collection area of 80 cm2 each.

 

 

 

5. The tested surface should be 15 to 30° away from the vertical direction to allow the salt spray to settle freely on the tested surface. Direct spraying is not allowed. The test bracket is made of glass or plastic, and the test pieces cannot contact or drip with each other;

 

 

 

6. The temperature inside the box is 35℃±2℃, and each collector collects the solution.