SURFACE REFORMING OF METALLIC MATERIAL BY UNDERWATER HIGH-SPEED TWO-PHASE JET

摘要

PURPOSE: To reform the surface of a metallic material where a tensile stress resides so as to generate a contraction stress, by blowing in the air current near the upstream side of an exhaust nozzle to inject an under-water high pressure jet, and injecting a mixture of a liquid and a gas. ;CONSTITUTION: By reducing the diameter 3a of a nozzle to inject a high pressure water 8 under the water, and blowing in a compressed air 9 in the form of minute bubbles at the upstream of the nozzle, the generation of the cavitation of the water jet injected from the nozzle is expedited by a strong disturbing operation by the blown-in bubbles. That is, by utilizing the complex breakdown pressure generated by the blown-in bubbles and the cavitation (the blown-in bubbles exercise the role of cushioning to moderate the shock pressure of the temperature), the residual stress on the surface of an under-water is structure material is converted from the tensile stress side to the contraction stress side.;COPYRIGHT: (C)1994,JPO&Japio