| 摘要 |
PURPOSE:To improve the fatigue strength of a steel spring, by applying Ni-type electroless plating treatment to the surface of a steel spring and subjecting the above spring to shot peening treatment. CONSTITUTION:The surface of a steel spring is plated with Ni-base alloy, such as Ni-P alloy and Ni-B alloy, by an electroless plating method. Subsequently, the spring is annealed at 200-400 deg.C and then subjected to shot peening treatment to establish compressive residual stress in the spring, by which the occurrence of fine cracks at the spring surface can be prevented even after long use and the steel spring excellent in fatigue strength can be manufactured. |
