Nondestructive measurement of the grain size of laser cladding coatings using a laser ultrasonic method

Abstract

Due to the processing characteristics of laser cladding, the beads and joints of the laser cladding coatings have different grain sizes. We used the laser ultrasonic (LU) method to measure the distribution of the grain sizes of laser cladding coatings nondestructively. The surface acoustic wave amplitude was influenced by the grain size; hence, the amplitude varied for beads and joints because of their different attenuations. The spatial resolution of LU is higher than that of the traditional ultrasonic testing method, leading to a fringe distribution of the C-scan results in the scanning area. The LU results were verified through metallographic experiments. It was concluded that the LU method can be used to determine the grain sizes of coatings.

Study on Detecting Method of Internal Defects by Laser Ultrasonics in Lap Joint Welding of Galvanized Steel Sheet and Finite Element Analysis of Its Detectability

“…With these features, it has been used for defect measurement [8,9] including the detection of internal defects [10][11][12][13]. In addition, there have been many research reports on plate thickness measurement [14] and material evaluation [15,16].…”