Detection, 3-D positioning, and sizing of small pore defects using digital radiography and tracking

This article presents an algorithm that handles the detection, positioning, and sizing of submillimeter-sized pores in welds using radiographic inspection and tracking. The possibility to detect, position, and size pores which have a low contrast-to-noise ratio increases the value of the nondestructive evaluation of welds by facilitating fatigue life predictions with lower uncertainty. In this article, a multiple hypothesis tracker with an extended Kalman filter is used to track an unknown number of pore indications in a sequence of radiographs as an object is rotated. Each pore is not required to be detected in all radiographs. In addition, in the tracking step, three-dimensional (3-D) positions of pore defects are calculated. To optimize, set up, and pre-evaluate the algorithm, the article explores a design of experimental approach in combination with synthetic radiographs of titanium laser welds containing pore defects. The pre-evaluation on synthetic radiographs at industrially reasonable contrast-to-noise ratios indicate less than 1% false detection rates at high detection rates and less than 0.1 mm of positioning errors for more than 90% of the pores. A comparison between experimental results of the presented algorithm and a computerized tomography reference measurement shows qualitatively good agreement in the 3-D positions of approximately 0.1-mm diameter pores in 5-mm-thick Ti-6242

Integrity and quality assessment applied on laser welded titanium components

Laser welding of thin titanium components, a critical component of many gas turbine engines, has demonstrated a tendency of generating pores in clusters with a prescribed orientation. These pores, also known as chain porosities, are often of harmless sizes (of 50–100 micrometer) as individuals. Though the cluster as such, depending on the distances and orientations in between the pores, may have an impact on the structural integrity. A recently developed algorithm for 3-D positioning of small pore defects in planar geometries using digital X-ray inspection aims at providing 3-D positions of the defects. This could then be used in-line to assess the welding quality in the manufacturing process. This presentation describes the development of a methodology that aims to incorporate non-destructive evaluation with, in this case, structural integrity

Integrity and quality assessment applied on laser welded titanium components

Laser welding of thin titanium components, a critical component of many gas turbine engines, has demonstrated a tendency of generating pores in clusters with a prescribed orientation. These pores, also known as chain porosities, are often of harmless sizes (of 50-100 micrometer) as individuals. Though the cluster as such, depending on the distances and orientations in between the pores, may have an impact on the structural integrity. A recently developed algorithm for 3-D positioning of small pore defects in planar geometries using digital X-ray inspection aims at providing 3-D positions of the defects. This could then be used in-line to assess the welding quality in the manufacturing process. This presentation describes the development of a methodology that aims to incorporate non-destructive evaluation with, in this case, structural integrity. \ua9 Owned by the authors, published by EDP Sciences, 2014

Integrity and quality assessment applied on laser welded titanium components

Laser welding of thin titanium components, a critical component of many gas turbine engines, has demonstrated a tendency of generating pores in clusters with a prescribed orientation. These pores, also known as chain porosities, are often of harmless sizes (of 50-100 micrometer) as individuals. Though the cluster as such, depending on the distances and orientations in between the pores, may have an impact on the structural integrity. A recently developed algorithm for 3-D positioning of small pore defects in planar geometries using digital X-ray inspection aims at providing 3-D positions of the defects. This could then be used in-line to assess the welding quality in the manufacturing process. This presentation describes the development of a methodology that aims to incorporate non-destructive evaluation with, in this case, structural integrity. © Owned by the authors, published by EDP Sciences, 2014