Preparation Of PPS Coating For Steel And Study On Fatigue Properties

Because most metal component are easily destroyed by mechanical, physical and corrosive condition, the mechanical fatigue performance for anti-corrosion and high-temperature coating is studied in the paper. Polyphenylenesulphide(PPS) suspension dope was prepared using the method of mechanical mixing, and the PPS coating was prepared in metal surface through the process of high-temperature plastication. The appropriate parameters for heat treatment were determined.The fatigue experiments under stress-controlled cycling were conducted on Q235-A steel sample with PPS coating on its surface. The cyclic harden and soften characteristic were studied. It is shown that the symmetrical cyclic loading resulted in rupture of steel without necking, and had no obvious effects on the PPS coating. A fast cyclic soften phenomena happened on the initial period of the experiment both for Q235-A and PPS coating, then achieved cyclic stability after certain cycles. The cyclic soften rate increase with the loading stress level increased, and the cycle to achieve cyclic stability decreased. The S ? N curve of steel was linear on the log-log coordinates, and fatigue life increase with the stress amplitude decreased.A series of ratcheting experiments were performed on Q235-A steel sample with PPS coating on its surface. The effects of mean stress and stress amplitude on ratcheting strain were studied. It is shown that the unsymmetrical cyclic loading resulted in the fatigue of PPS coating, and had no obvious effect on steel. On the condition of constant stress amplitude, ratcheting strain and saturation ratcheting strain increase with the mean stress increased. On the condition of constant mean stress, ratcheting strain and saturation ratcheting strain increase with the stress amplitude increased,but mean stress has more effect on it than stress amplitude. Theσm ?Nfc curve for PPS was linear on the log-log coordinates under the condition that the stress amplitude was constant, and fatigue life increase with the mean stress decreased. TheΔσ/2?Nfc curve for PPS was also linear on the log-log coordinates, and fatigue life increase with the stress amplitude decreased.