(1) The reason for the medium. Although some anchor bolts are not in direct contact with the medium, for various reasons, the corrosive medium is likely to be transferred to the anchor bolts, which will cause the anchor bolts to corrode.

(2) Environmental reasons. If in a humid environment, the bolts of carbon steel materials will be corroded.

(3) Reasons for bolt data. In the design, although the anchor bolts are selected according to the regulations, they often only consider the strength of the bolts and do not take into account that under special conditions, the anchor bolts will be corroded during use. Therefore, corrosion-resistant materials such as stainless steel are not used.