LUMEX™ Ultraviolet Light Porosity Testing Equipment

Application Background

Almex’s specially designed LUMEX™ Ultraviolet Light (UV) Porosity Testing Equipment and Process are configured to detect extremely fine porosity that may exist inside a DC cast billet or slab cross-section. Depending on the Hydrogen content of the melt and the depth of the sump during casting, as well as on other chemical and heat transfer characteristics involved during casting, an extremely varying and complex distribution of porosity can exist in the material. It is important to examine this porosity over the entire cross section of the cast product and not just in the isolated areas which pertain to metallographic microscopic examination. The spread of the porosity and the size of the pores can indicate if the porosity is purely due to Hydrogen, due to shrinkage, or due to both. Ultraviolet Testing Equipment is regularly used at facilities that are approved by airframe builders around the world.

Besides the processes utilized by LUMEX™ UV Testing Equipment, no other method (including ABB® Alscan™ nor Ultrasonic Testing) can expose the combined effects of Hydrogen porosity and shrinkage porosity simultaneously.

Operating Principle

Ultraviolet light, sometimes referred to as UV or black light, is used in conjunction with penetrant testing; also known as dye penetrant testing or liquid penetrant testing. The process is based upon the capillary action of liquids or dye penetrants wherein the low surface tension fluid penetrates into the discontinuities of the specimen being tested. Fluorescent penetrant is used so that inspection can be performed under UV light and captured using specialized ultraviolet photography and inspection equipment. The Lumex UV Testing Equipment utilizes specialized penetrants so that detections of porosity as small as 10 microns in size can be achieved. Almex’s special LUMEX process technology is embedded into the sample preparation and data interpretation results to make pass/reject decisions which affect metal quality.

International Standards Compliance

LUMEX Ultraviolet Porosity Testing Equipment and Process are designed to meet the rigorous demands of international engineering standards with respect to the equipment used as well as the test procedures and methods. Each laboratory apparatus is supplied in compliance with Standard 1714, 165, and 443 by the American Society of Testing and Materials (ASTM International).

Detection Capabilities

Impurity Detected Capability
Casting porosity larger than 10 microns
Primary Inter-metallic Phase larger than 20 microns
Hydrogen Gas Porosity larger than 10 microns