The 10 levels of salt spray testing and their corresponding degrees of corrosion are as follows:
Level 10: Defect free area, appearance rating A, no change in surface appearance of the sample, indicating excellent corrosion resistance of the material.
Level 9: The defect area accounts for no more than 0.1%, with an appearance rating of B. The sample surface has slight to moderate discoloration, such as very few rust spots or slight discoloration.
Level 8: The proportion of defect area is between 0.1% and 0.25%, with an appearance rating of C. The surface of the sample is severely discolored or has very slight corrosion, with an increase in rust spots and an expansion of the discolored area.
Grade 7: Defect area accounts for 0.25% to 0.5%, appearance rating D, severe loss of gloss on the surface of the sample, and extremely mild corrosion products or pitting corrosion.
Level 6: Defect area accounts for 0.5% to 1.0%, with an appearance rating of E. The surface of the sample is severely dull, or there is a thin layer of corrosion products or pitting on the local surface of the sample.
Level 5: Defect area accounts for 1.0% to 2.5%, appearance rating F, there are corrosion products or pitting corrosion on the surface of the sample, and one of them is distributed throughout the surface of the sample.
Level 4: Defect area accounts for 2.5% to 5%, appearance rating G, and there is a thick layer of corrosion products or pitting corrosion on the surface of the sample.
Level 3: Defect area accounts for 5% to 10%, with an appearance rating of H. The surface of the sample has a very thick layer of corrosion products or pitting, with deep pitting.
Level 2: Defect area accounts for 10% to 25%, appearance rating I, and the sample shows corrosion of the base metal.
Level 1: The defect area accounts for 25% to 50%, which is a severe corrosion phenomenon. The material is almost covered by rust or completely loses its original shape and structure.
The 10 levels and their corresponding times:
--- 24 hours: This is the most basic level of salt spray testing, where materials or equipment are continuously exposed to a salt spray environment for 24 hours to evaluate their basic corrosion resistance performance
--- 48 hours: At this level, the time for salt spray testing is extended to 48 hours to more comprehensively evaluate the corrosion resistance of materials or equipment in salt spray environments
--- 72 hours: extended from 48 hours of testing to 72 hours, further enhancing the rigor of salt spray testing
--- 96 hours: The testing time is extended to 96 hours, usually used for stricter corrosion resistance testing of some important components or equipment
--- 120 hours: lasting for 5 days (120 hours), used to evaluate materials or equipment that require higher standards of corrosion resistance performance
--- 144 hours: extended from 120 hours of testing to 144 hours, usually used for stricter corrosion resistance testing of some key components or equipment
--- 168 hours: The testing time is extended to 168 hours (7 days) to evaluate materials or equipment that require very high corrosion resistance performance
--- 192 hours: Duration of 8 days (192 hours), usually used for more rigorous corrosion resistance testing of some key components or equipment
--- 216 hours: extended from 192 hours of testing to 216 hours for testing materials or equipment that require the highest standard of corrosion resistance performance
--- 240 hours: The highest level of salt spray testing, lasting for 10 days, is typically used to conduct the most rigorous corrosion resistance performance testing on some extremely important components or equipment
Through the above 10 levels of salt spray testing, the corrosion resistance of materials and equipment in salt spray environments can be better evaluated, providing reference and guidance for their practical application. When conducting salt spray testing, it is necessary to choose the appropriate testing level based on the specific situation to ensure the accuracy and reliability of the evaluation results. Salt spray testing is an important environmental testing method that is of great significance for ensuring the quality and performance of materials and equipment.
