Recovery of Life for Aging Material by Addition of Grain Boundary Strength Element

Abstract

The surface of welded joint specimens for service material are applied by Boron element, they are taken Heat Treatment at 630℃×1000Hour. We have creep rupture tests them at 630℃×58.8MPa, as a result, Residual Life extends 1.9 times, and one of Simulated Coarse, Fine Heat Affected Zone Specimens are 2.5〜4.5 times at 630℃×78.4MPa on creep rupture tests, and it is confirmed that Boron is segregated on the Grain Boundary and trespass to center section of specimen by diffusion, therefore, We consider that recovery of life by applying Boron is possible on the stress above 58.8 MPa.