Evaluation of discontinuities in a36 steel repairs with friction hydro pillar processing using different axial forces

Abstract

Friction welding techniques are widely used in several industrial sectors. A non-destructive inspection is mandatory in postprocessing for repair quality evaluation. The present study examines through conventional ultrasonic technique Friction Hydro Pillar Processing (FHPP) repairs on ASTM A36 low carbon steel plates. The repairs were made using four different axial forces, 200, 250, 300 and 350 kN with constant rotational speed of 1 000 rpm. The features of the echogram signals obtained made possible to identify and distinguish microcracks, lack of bound, clustered inclusions and isolated inclusions, forming three critical regions within the weld. It was seen that high processing forces increases probability to generate microcracks from discontinuities. These ultrasonic results were related and validated with micrographic analysis and it was possible to make a relationship between echograms features and micrographs to differentiate the discontinuities founded within the repairs. This information could be used as a guideline for operating procedure to locate discontinuities. © 2013 ISIJ.