How to check the quality of fishplate bolt?

Fish plate bolt is a common railway equipment, and it also plays an important role in railway equipment. According to railway equipment manufacturers, rail bolts are mainly used in track laying in the metallurgical industry, coking industry, and steel industry. The connection between the rail and the rail joint is very important. How to check the quality of bolts?

Bolt inspection is divided into manual and machine. Manual detection is a very common method of consistent detection. In order to minimize the outflow of defective products, the general production company personnel inspect the packaged or shipped products by visual inspection to eliminate defective products. The other method is automatic machine inspection, mainly magnetic particle inspection. Magnetic particle inspection uses the interaction between the leakage magnetic field at the bolt defect and the magnetic powder to deal with the difference between the magnetic permeability of the fish plate bolt (such as cracks, slag inclusions, mixing, etc.) and the magnetic permeability of steel. These materials are discontinuous after magnetization. The magnetic field will be turbulent, forming part of the magnetic flux leakage, and a leakage magnetic field will be generated on the surface of the workpiece, thereby attracting the accumulation of magnetic powder at the defect of the magnetic powder-magnetic marks. Under proper lighting conditions, the defect position and shape will appear. The accumulation of these magnetic powders is observed and explained, and the purpose of rejecting defective products has been achieved.

Fish plate bolt will also have various problems during use. The reasons for the problems are mainly concentrated in the following aspects!

1. The material problems of fishplate bolts, processing defects and heat treatment process problems can also cause the connecting rod bolts to break during engine operation.

2. When assembling, the tightening torque is too large, the force is not uniform, and the tightening torque is too large, which exceeds the yield limit of the fish plate bolt material, causing the connecting rod bolt to yield and deform, which is caused by excessive extension under the action of impact load, long and broken.