Magnetic inspection of fatigue degradation of a high-carbon pearlitic steel

The effect of high-cycle fatigue loading of U10 steel specimens with a fine-lamellar pearlite structure that were a annealed for a short time on the character of variations of the tangential component of the magnetic induction vector of specimens in a residual-magnetization state has been studied. It was found that fatigue loading up to major fatigue-crack formation leads to an increase in the tangential component of the magnetic induction vector and to nonuniformity of the magnetic induction distribution along the length of a specimen. This is due to the spheroidization of cementite plates, which occurs in U10 steel specimens under a fatigue load. Major fatigue-crack formation is accompanied by the appearance of a clearly pronounced peak in the distribution of the tangential component of the magnetic induction vector. The magnetic measurement technique that was used allows us to record both structural changes and cracks that result from the fatigue degradation of high-carbon-pearlitic steel.