Acoustic emission data classification of 18 percent Ni maraging steel 250 specimens during tensile deformation

Abstract

ABSTRACT Acoustic emission (AE) evaluation is an important Nondestructive Testing technique. The technique is a whole field passive technique that detects defects that are growing during the application of force on the structure. At a certain threshold, AE starts emanating from the structure while the structure is stressed by tensile deformation. 18% Ni Maraging steel 250 grade material is widely used in the aerospace industry and exhibits fracture behaviour. In the current study, tensile specimens are used and acoustic emission (AE) parameters are recorded. Four types of specimens Type A, Type B, Type C and Type D specimens are designated as heat -affected zone, parent metal, defect-free weldment and weld with notch defect, respectively. These specimens are tensile deformed in order to obtain AE parameters at 60% of failure load (FL), 60–75% of FL, 75–90% of FL and 90% to FL. AE parameters – amplitude, ring down counts, duration, rise time, energy, RA value, DA value, hit rate, count rate and energy rate – are tabulated for various FLs. These parameters have vital importance in critical assessment of the structural integrity of 18% Ni Maraging steel 250 structures.