Bolt inspection

Bolt inspection is divided into manual and machine inspection. Manual inspection is the most basic and widely used method. To minimize the outflow of defective products, manufacturing personnel typically visually inspect packaged or shipped products to eliminate defective items (defects include chipped edges, mixed materials, rust, etc.).

The other method is fully automated machine inspection, primarily magnetic particle testing. Magnetic particle testing utilizes the interaction between the leakage magnetic field at bolt defects and magnetic particles. It addresses the difference in magnetic permeability between the bolt's potential defects (such as cracks, inclusions, mixed materials, etc.) and the steel's magnetic permeability. After magnetization, the magnetic field at these material discontinuities will be distorted, creating a leakage magnetic field on the workpiece surface at the point of magnetic flux leakage. This attracts magnetic particles, forming magnetic powder deposits-magnetic traces-at the defects. Under appropriate lighting conditions, the location and shape of the defects become apparent. Observing and interpreting these magnetic powder deposits helps to eliminate defective products.