Steel corrosion not only causes huge economic losses, but also has a significant impact on the safety and durability of buildings. The direct economic loss caused by steel corrosion in China is as high as hundreds of billions of yuan every year, including tens of billions of yuan in the oil and chemical industry alone. Meanwhile, in recent years, engineering accidents caused by steel corrosion are frequent at home and abroad, resulting in huge casualties. Therefore, steel corrosion has brought great loss and harm to the development of national economy, which must be paid great attention to by various industries.

Steel exposed to the air will inevitably rust, and the corrosion rate of steel is related to its environment, mainly controlled by air humidity. When the relative humidity in the air is below 60%, the water on the surface of steel is not enough to form water film, and the corrosion of steel develops slowly. When the relative humidity of air is between 60% and 90%, the corrosion speed of steel is obviously accelerated. When the relative humidity of air is above 90%, the corrosion rate of steel will decrease. The corrosion of the steel structure also has a great relationship with its location. If the steel is in the position where dust and water are easy to accumulate, the moisture in the dust is not easy to dry, so it is easier to produce rust than other positions. In addition, outdoor steel is more likely to rust than indoor steel due to the long-term effect of dry and wet alternating and medium.

Meanwhile, in recent years, engineering accidents caused by steel corrosion are frequent at home and abroad, resulting in huge casualties [3]. Therefore, steel corrosion has brought great loss and harm to the development of national economy, which must be paid great attention to by various industries.

Steel exposed to the air will inevitably rust, and the corrosion rate of steel is related to its environment, mainly controlled by air humidity. When the relative humidity in the air is below 60%, the water on the surface of steel is not enough to form water film, and the corrosion of steel develops slowly. When the relative humidity of air is between 60% and 90%, the corrosion speed of steel is obviously accelerated. When the relative humidity of air is above 90%, the corrosion rate of steel will decrease. The corrosion of the steel structure also has a great relationship with its location. If the steel is in the position where dust and water are easy to accumulate, the moisture in the dust is not easy to dry, so it is easier to produce rust than other positions. In addition, outdoor steel is more likely to rust than indoor steel due to the long-term effect of dry and wet alternating and medium.