EFFECTS OF WATER JET PEENING AND HARDNING TREATMENT ON FATIGUE PROPERTIES OF SCR420

摘要

An experimental study of high pressure water jet peening treatment on chromium steal SCr420 H3V2L2 is conducted to study the effects of cavitation impacts of high-speed water on fatigue crack initiation and propagation of notched specimens. There are six different kinds of specimens. First three kinds are treated with; only annealing, only water quenching, and only oil quenching. Other three kinds are treated with above heat treatment and water jet peening, respectively. An axial tensile fatigue tests' condition is 260MPa maximum stress amplitude, 0 stress ratio and 10Hz frequency, while in-situ observation by SEM is employed. Although fatigue life of the specimens with annealing and water jet peening is shorter than that of only annealing, fatigue life of water and oil quenching with water jet peening specimens is obviously longer than those without water jet peening treatment. Water jet peening has increased residual stress inside the specimens on the latter case and raised their fatigue strength. In-situ observation on the crack tips approves above analysis.