Aerospace
ApplicationNote
Rev.: 2002-01

Inspection Of
Titanium Castings Using
Ultrasound Phased Array

General description of the application

Some aircrafts structural part such as engine mount and frame are now built with titanium casting. This material is very difficult to inspect because of its large grain structure. The usual inspection methods are X-ray and ultrasounds, however they present some limitations.
The use of ultrasound phased arrays brought a break­through in the inspection of casting by providing a much better detectability than the conventional methods.
Typical inspection requirement
• Finding and characterizing inclusions
• Covering casting part volume completely
• Flexible enough to fit various shapes
• Portable to perform inspections in-service or in-production

Defects detected
• Ceramic shell as small as 0.031 in. at a 1-in depth
• Tungsten carbide as small as 0.031 in at a 1-in. depth

Description of the solution
• Phased array probe steering the beam from –30°to 30°LW
• Merged top and side views
• 10 and 5 MHz linear phased array probe

Description of the inspection system
• Focus 32:32 or more
• Dynamic Depth Focusing option
• Linear phased array probe
• Manual or automated X-Y scanner

Parts to inspect
• Engine mount
• Frame
• Thickness: 1 to 6 inches

Method of inspection
The phased array probe steers the beam continuously between –30°to 30°LW with an angular resolution of 1 degree. It allows the detection of orientated inclusions. Dynamic Depth Focusing is applied to keep the beam focused over the depth range. The probe scans a X-Y surface and data is merged together to create a top-side view of the casting part. Analysis is performed.
Advantages
• Better detectability than X-ray (The smallest defect detected by X-ray is 0.065 in; by UT phased arrays, it is 0.031 in.)
• Versatility
• Fast and easy to use


Detection of ceramic schells. Merged top- and side-views display.


Manual X-Y scanner and phased array probe.


FOCUS phased array acquisition unit.

Other Aerospace Applications

Composite Airplane Parts
R/D Tech has delivered complete systems for the inspection of composite material panels. These systems can inspect many different types of parts, looking for typical defects found in composite material (for example disbonding).
In order to scan complex shapes, a multiaxis robot is often used. The scan pattern can be acquired from CATIA CAD files or automatically learned (teach mode). Once the shape is memorized, the part is automatically scanned with ultrasound at speeds of up to 330 mm/s. Inspections can be performed in pulse-echo or through-transmission modes.
Corrosion Mapping of Aircraft Fuselage Using Eddy Current Arrays
Corrosion degradation is a major source of concern for the aircraft industry. As aircraft are flying longer than what their design intended, the development of a reliable and fast inspection technique is necessary.
This technique uses eddy current arrays to detect and measure internal corrosion beyond the first layer of the aircraft fuselage. The system allows accurate corrosion sizing as well as fast inspection.

The FSW technique was developed as a method to join materials that are difficult to fusion weld, such as aluminum alloys. The quality of the weld is very high; however, the process may generate small, tight defects that are hard to detect.
The best method to inspect FSW is to use the ultrasonic phased array technique. Because of the weld shape, raster scanning is impossible; but with phased arrays, inspection of the entire weld volume is done in a single-pass scan. Phased arrays also permit lateral scanning to detect transverse defects. Inspection angle optimization maximizes the probability of detection. The increased number of zones covered by phased arrays provides accurate flaw sizing and location. High speed, accuracy, and versatility make phased arrays the choice technique for FSW inspection.

Products used for this application

TomoScan FOCUS
With more than 350 units sold, the R/D Tech Tomoscan FOCUS acquisition unit is the benchmark for automated UT inspections. It comes in many configurations.