Применение и теория НК

Контроль коррозии

Just about anything made of metal is potentially subject to corrosion. A particularly important problem in the petrochemical and power generation industries is measurement of remaining wall thickness in pipes, tubes, or tanks that may be corroded on the inside surface. Such corrosion is often not detectable by visual inspection without cutting or disassembling the pipe or tank. Structural steel beams, particularly bridge supports and steel pilings, are also subject to corrosion that reduces the original thickness of the metal. If undetected over a period of time, corrosion will weaken walls and possibly lead to dangerous structural failures. In the aerospace industry, corrosion may occur on the inside of aluminum aircraft skins and in other critical areas. Ultrasonic testing is a widely accepted nondestructive method for performing this inspection, and ultrasonic testing of corroded metal is usually done with dual element transducers. Hand-held ultrasonic corrosion gages can readily measure thickness of pipes and tanks as well as structural metals like supports and beams, while eddy current instruments are appropriate for thinner metal fabrications like aircraft skins and thin-walled tubing.