Bolt Loosening Prevention Measures and Durability
- What are the common anti - loosening measures for bolts?
Using spring washers is a common anti - loosening method. The spring washer produces elastic deformation when the bolt is tightened, continuously applying pressure to the bolt to prevent loosening. Double nut anti - loosening prevents the nut from loosening through the friction generated by the mutual extrusion of two nuts after tightening, which is suitable for parts with large vibration. Coating thread locking adhesive, after curing, can firmly bond the bolt and nut to form permanent anti - loosening. Special tools or heating are needed for disassembly. In addition, there is the 配合 of cotter pins and slotted nuts for anti - loosening. The cotter pin passes through the pin holes of the nut and bolt to restrict the rotation of the nut, with reliable anti - loosening effect.
- What are the differences in applicable scenarios of different anti - loosening measures?
Spring washer anti - loosening has a simple structure and low cost, and is suitable for ordinary track parts with small vibration, such as connecting bolts between sleepers and fasteners. Double nut anti - loosening has a good anti - loosening effect and can bear a certain vibration load, often used in areas with relatively large vibration such as turnouts. Thread locking adhesive anti - loosening is suitable for parts with high anti - loosening requirements and infrequent disassembly, such as fishplate connecting bolts. The 配合 of cotter pins and slotted nuts for anti - loosening is suitable for key parts with extremely high safety requirements, such as track connecting bolts on bridges, to ensure no loosening under long - term vibration.
- What impact does the surface treatment of bolts have on durability?
Galvanizing the surface of bolts can form a protective film, isolating air and moisture, preventing bolts from rusting, and improving durability in humid environments. Ordinary galvanized bolts can be used for 3 - 5 years in dry environments. Bolts treated with Dacromet have better corrosion resistance, and their service life in corrosive environments such as coastal areas and chemical industry is 2 - 3 times that of ordinary galvanized bolts. Phosphating treatment can improve the wear resistance and lubricity of the bolt surface, reduce wear during installation, and indirectly prolong the service life of bolts.
- How to evaluate the durability of bolts?
Evaluate the corrosion resistance of bolts through salt spray test. Place the bolts in a salt spray test chamber to simulate marine or industrial corrosion environments, observe the time when the bolts rust, and the longer the time, the better the durability. Conduct fatigue tests, apply alternating loads to the bolts, record the number of cycles when the bolts break, and the more cycles, the stronger the durability. In the actual line, spot - check the status of bolts regularly, check for rust, deformation, loosening, etc., and evaluate their actual durability according to the degree of damage.
- What maintenance measures can extend the durability of bolts?
Clean the bolts regularly to remove surface dirt and rust, and keep the surface dry and clean. For bolts not coated with anti - loosening adhesive, check and retighten them regularly to ensure that the torque meets the requirements. In corrosive environments, secondary anti - corrosion treatment can be carried out on bolts, such as painting anti - rust paint. When slight rust is found on the bolts, derust and touch up the anti - corrosion layer in time; for seriously damaged bolts, replace them in time to avoid affecting the connection performance.