The original material we chose is hot dip galvanized carbon steel, because the thickness of the zinc layer is convenient to control, so that we can customize it according to the service life required by the user. The service life is divided into 3-5 years, 5-8 years, 8-12 years, 10-15 years, 15-20 years, 20-25 years, 30-40 years. At the beginning of the design, we repeated the salt spray test to get this data. The above years are rust years. The length of the years of use is mainly It is related to the thickness of the zinc layer of the material.