Fracture Reasons of 1Cr13 Stainless Steel Connecting Rod Ball Joint of Knife Switch in Coastal Humid and Hot Climate Environment

In the humid and hot coastal climate, the connecting rod ball joint of the bus bar knife drive rod in a 220 kV substation was completely broken, and the knife could not be operated. In order to identify the cause of the failure, the connecting rod ball joint was analyzed using stereomicroscopy, optical microscopy, direct reading spectrometer, scanning electron microscope, energy spectrum analyzer and other equipment. The results showed that there was corrosive element Cl on the fractured spherical joint section of connecting rod due to the influence of oceanic climate. Overall, the direct cause of the fracture of the connecting rod ball joint was that in the humid and hot coastal environment, Cl ions damaged the passivation film on the surface of 1Cr13 stainless steel, thereby inducing electrochemical corrosion of the stainless steel. After corrosion developed to a certain extent, it interacted with wear and ultimately led to fracture.