Residual Stress Test And Investigation Of Duplex Roll

In accordance with the demand for the development of modern iron and steel industry, we test and investigate the residual stress in centrifugal casting duplex roll. Because of the combination layer between work layer and core is the special part of the roll, we test its mechanical and physical property and observe its microstructure firstly. From the result of testing property and observing microstructure we know that the combination layer of centrifugal casting duplex roll is very thin, only one millimeter about. The combination layer has no evident effect to duplex roll.We mainly adopt magnetism method, X radial method and stress ring method to test the residual stress of duplex roll. By comparing of the three methods, we can conclude that magnetism method is a suitable method to test centrifugal casting duplex roll. Through testing to duplex roll by ring stress method, we can got the mathematical model of testing residual stress by concluding theoretically. The expression of the mathematical model is as follows.From the analysis of the different testing results we can conclude that the residual stress existed in duplex roll is a stretch stress field. It develops and forms gradually through every tache in process. The inline shearing stress of the centrifugal casting duplex rollσ_θz is decided by special technical process of the horizontal centrifugal casting. It is formed through the one time crystalline structure remained in the roll which is cockle style because of the rotation of the membrane equipment. These residual stress data got by different methods reveal that reasonable thermal treatment process not only can make the structure property of the roll improved, but also can make the stress distribution altered. The testing results of the different material rolls got by magnetism reveal that the eliminating rate of mostly different material rolls can reach eighty percent. The effect is very notable. Through reasonable thermal treatment process, the ring stress of the roll surfaceσ_θθ changes into compressive stress. That improves the ability of resisting fatigue and prolongs its longevity.Whether got from new roll or old roll, the stress ring which specs and size is reasonable can reflect the distribution of the macroscopic residual stress in roll actually. It is the testing method which has least disturbing factors.