Failure Analysis of Sheathed Coils for Ground Wire Connection
During the manufacturing process of through ground wire,a cable manufacturing factory found that the sheath coil was cracked.The reasons for the cracking of through ground wire sheath coils were analyzed using methods such as macroscopic morphology analysis,chemical composition analysis,metallographic microscopy analysis,and residual stress analysis.The results show that during the online annealing of the ground wire,there is instability in the power supply of the annealing furnace,and the power supply suddenly increases,causing grain growth in the sheathed coil and even local point melting to produce crack sources.With the combined effect of thermal stress,deformation stress of the sheathed coil,and stress release of the cable core,cracks in the sheathed coil expand and even fracture.
through ground wireH68 sheathed coilcrackingonline annealingstress releasecurrent voltage surge
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