Effect of Corrosion on the Fatigue Strength of the Medium Carbon Steel (CK 50) after a Shot Peening Technique

The surface modification is an important technique for maintaining the relatively favorable mechanical properties of surface properties and corrosion resistance. Surface shot peening technique (SPT) is applied on the medium carbon steel (CK 50) to increase its hardness under the influence of fatigue-corrosion. The fatigue strength of the medium carbon steel (CK 50) was estimated for several cases, which are samples as received and samples after shot peening and samples after submerging them with a saline solution (36% MgCl2) according to (ASTM G36), for 30 days (corrosion media) and shot peening after the immersion process. All tests were conducted by means of rotating bending tests under constant stress amplitude and stress ratio (R = -1), and at room temperature. After testing, the fatigue strength increased percentage (15%) with the shot peening and the fatigue strength decreased by (16%) after submerging it with saline solution (corrosion media) and the fatigue strength increased by (13%) for the samples with the shot peening after submerging them with a saline solution.