Bolts and nuts are a type of fasteners commonly used in mechanical connections, and their role is to hold two or more parts together. The bolt is responsible for applying the tensile force, while the nut provides the fastening force by matching it to the bolt thread. The following factors should be considered when selecting bolts and nuts: Load requirements: First determine the type and size of the load to be borne by the parts to be connected. Select the appropriate bolts and nuts according to the load situation to ensure the connection is strong and safe. Environmental conditions: Consider the conditions that may exist in the working environment, such as high temperature, low temperature, humidity, corrosive gases, etc. Choose materials and surface treatments that can adapt to environmental conditions to extend service life and prevent corrosion. Connection mode: Select bolts and nuts according to the connection mode requirements. The connection method includes the size and shape of the bolt holes, and the design requirements of the connecting parts. Ensure that bolts and nuts fit perfectly and provide a solid connection. Material selection: The material selection of bolts and nuts should consider factors such as load requirements, environmental conditions and reliability. Common materials include carbon steel, alloy steel, stainless steel and so on. Select the right strength grade and corrosion resistance material to meet the needs of use. Specification selection: According to the design requirements of the connector, select the appropriate bolt diameter, pitch and length specifications. Ensure that the selected specifications meet the design standards and provide adequate fastening force. All in all, choosing the right bolts and nuts is an important part of achieving a safe and reliable mechanical connection. The above factors should be comprehensively considered according to the specific needs, and the appropriate specifications and materials should be selected to ensure the quality and reliability of the connection. At the same time, proper installation and maintenance are also key to ensuring connection performance.