Ultrasonic Evaluation of Remelted Zone Thickness in Aluminum Alloy Castings

摘要

Aluminum alloy castings for automobiles are partially strengthened by remelting their surfaces to a depth of several mm with a TIG welding machine. In the present work, a method was studied to evaluate the thickness and the width of the remelted zone nondestructively, by applying a phenomenon that the intensity of back scattering of ultrasonic wave depends on the size and distribution of the crystal grain in materials. By applying this method, the thickness and width of the remelted zone were evaluated for a plate made of Al-Cu-Si alloy castings with a thickness of about 18 mm nondestructively. They were in good agreement with the thickness and width of the remelted zone obtained by destructive testing: sectioning, etching and measurement of specimens.