LISCA Ultraviolet (UV) Testing
LISCA is the “non-submergence” ultrasonic instrumentation developed by Almex for inspection of as-cast slabs and billets to detect internal defects within the cast metal. The equipment is based upon the “pulse-echo” principle and utilizes a probe of 12 mm diameter and works at 5 MHz frequency.
An ultrasonic signal interpreter both displays the feedback signal and can be programmed to provide an audible alarm upon detection of a defect. A set of custom made standards are furnished with the equipment for the billet diameters to be inspected. These standards provide the necessary calibration for accurate inspection of the entire range of billet diameters cast.
A 10 meter long billet table is provided with loading station to load billets onto the table by overhead crane. The table has a gradual slope with indexing station for loading the billets onto the inspection table and then discharging the inspected billets to a platform for offloading. A gantry is located at the inspection table which spans the width of the table and houses the probe on a traversing mechanism. Once the billet has been loaded, the probe is lowered to the recording position and travels along the length of the billet. Defects are identified by visual display on the LCD display and by audible alarm. The billet is marked in the region of the defect before the probe continues the detection cycle. Upon completion of a billet, the billet is automatically discharged onto the offloading platform for necessary in house identification marking and offloading. The next billet for inspection is indexed onto the inspection table and the procedure is repeated.
An optional bar code writer is available with the system which will automatically print and apply a detailed bar code to the inspected billet per customer specifications before the inspected billet is discharged from the inspection table. This system also provides both automatic marking of defective billets and the specific location of the identified defect. The defective billets are also indented with red ink spray at the top / bottom end face for easy recognition.
Equipment
The system will be provided with the following:
• Cubicle consisting of an industrial cabinet containing:
• Ultrasonic signal generator
• LCD ultrasonic interpreter and visual output
• Man machine interface (MMI)
• All necessary electrical and utility connections
• Storage for shop floor calibration standards (second set housed in QC lab)
• Storage for couplant media
• Storage for ultrasonic machine accessories
• (3) Ultrasonic transmitter / receiver probes. 1 duty, 2 spare.
• 10m long billet table, complete with loading station, inspection table and offloading platform suitable for machined billets of 8” to 12”in diameter and 6500 mm long.
• Gantry with necessary transducers and actuators for accurate positioning, traversing and installation of probe and associated detection equipment. All utilities will be supplied from an interface at the system cubicle.
• (10 liters) couplant media
Performance:
• Conforms to MIL Std. 2154 Class A detection.
• Standard plant inspection performance capable of detecting flaws up to 0.5 mm.
• Absolute capability of flaw detection up to 0.127 mm.
• Metallurgical Nature of Flaws Identified
• Hairline sub-surface cracks
• Center line star cracks
• Agglomerated porosity (gas plus shrinkage)
• Cluster of inclusions