Sonia D., Faiza B., Rafik H.

DEFECTS DETECTION IN WELDS USING ULTRASONIC ANALYSIS S. Djili1, F. Boukazouha2, R. Halimi3 Caracterisation and Instrumentation Laboratory, Scientific Center of Research on Welding and Non Destructive Testing, Algiers, Algeria, 1 sonia_djili@yahoo.fr; 2 faiza_bb2002@yahoo.fr; 3 halimir@yahoo.fr The development of welding requires certain processes which lead to imperfections; moreover the welding undergoes, during its life, thermal and mechanical stresses or deteriorations due to the oxidation effects, which weaken it and could reveal defects. It is important, for the safety of the environment (danger of escapes in industrial installation, exp: petrochemical industry, chemical industry, transport of gas, refineries....) to be able to control welds, in a non-destructive way. In our work, two welded carbon steel of 3.8 cm of thickness have been made using two different processes of welding: manual arc process with low energy and automatic welding with high energy. The method used to control and characterize welds is the non destructive testing by ultrasound. The experiments were carried out by immersion and using two 2.25 MHz and 5 MHz piezoelectric transducers. After studying the influence of the welding parameters on the characteristics of the ultrasonic beam in the welded zone, volume defects with cylindrical form, were introduced into the welded zone and the base metal. Longitudinal waves mode with various angles of propagation (L0 and L45) have been generated in order to detect and characterise these defects. Conclusions are made.