Effects of Heat Treatment for Steel End Fitting on Pull-Out Force of Automobile Cable

In order to improve the pull-out force of automobile cable, the 35 steel ending fittings were heated at 250 ℃ for different times. The microstructure of the steel ending fitting and the zinc coating on its surface was analyzed by optical microscopy (OM) and scanning electron microscopy (SEM). And the test for pull-out force was examined. Results indicate that with the holding time prolonging at 250 ℃, the pearlite in the microstructure changed from lamellar to spheroidal gradually, which decreased the hardness and enhanced the plastic deformation capacity of the steel end fitting, and then increased the minimum pull-out force. The pull-out force of auto cable could reach the safety requirement after 6 h heat treatment of the steel end fitting at 250 ℃.