Abstract:For achieving the stress evaluation of laser cladding specimen based on metal magnetic memory testing technology,Fatigue tests of laser cladding specimen are carried out.Meanwhile,the magnetic signal is measured through the fatigue tests.The normal component of magnetic signal Hp(y),the tangential component of magnetic signal Hp(x),changing with fatigue cycle time are investigated.The magnetic memory signal characteristics of different fatigue cycles were observed.Analyze the changing law of the degree of gradient deviation of normal component,R,with the increase of fatigue cycle.The results indicate that,As N increases,the Hp(y) curve rotates clockwise,The R value increases slowly at first and then rapidly.The damage degree of laser cladding specimen was divided into three grades by using R value as the reference quantity.The safety thresholds of laser cladding specimen were determined to be 2.82 and 9.4.When R value reaches the threshold of 9.4,the specimen is in critical fracture state,and timely intervention should be made to ensure its safe service.The mechanism of stress evaluation of laser cladding specimen is discussed from viewpoint of the magnetoelastic effect and magneto-mechanical effect of crack propagation effect.