ULTRASONIC METHOD FOR CONTROLLING RAIL HEAD Russian patent published in 2002 - IPC

FIELD: quality control; measurement technology. SUBSTANCE: method involves mounting a pair of inclined acoustic transducers on the rolling surface of rail head turned at equal acute angles relative to the longitudinal rail axis to lateral surfaces of the rail head. The transducers travel along the rail in emitting and receiving ultrasonic oscillations within the given time intervals. The received oscillation parameters being processed, defect is considered to be available. The second pair of transducers having the same parameters is mounted on the longitudinal axis. Angles of ultrasonic oscillation entrance into rail metal and turn angles of the first pair of transducers are selected by taking into account the condition of ultrasonic beams axes intersection reflecting from the areas radius transition of lateral and lower rail head surfaces on the longitudinal axis of rolling surface. Distance between the transducer pairs with ultrasonic oscillation entrance angles and turn angles of the second pair of transducers are selected with signal reception condition taken into account for defects like transverse cracks in lateral portions of rail head. Availability and orientation of defect is evaluated by applying cooperative analyses of signals received by the transducers. Echo signals coming from potential defects are selected in four time zones. The first one is used for receiving echo signals from defects in lateral surface of the rail head when irradiating them with direct ultrasonic beam. The second zone is used for receiving echo signals mirror-reflected from defects in lateral surface of the rail head with the second pair of transducers. The third zone is used for receiving echo signals from defects in lateral surface of the rail head when irradiating them with ultrasonic beam once- reflected from the areas of radius transition of lateral and lower rail head surfaces. The fourth zone is used for receiving signals emitted by one transducer and received by an another one after being reflected from angular reflector formed by transverse crack and rolling surface or horizontal crack. Crack position in the rail head and its orientation are evaluated by concurrent analysis of the received signals. EFFECT: enhanced accuracy and reliability of ultrasonic control. 2 dwg, 2 dwg