Eddy current testing is used to detect sustained load cracking in aluminum alloy cylinders. Our computer controlled test probe will identify cracks, corrosion, gouges, pits, folds, valleys and tool stops in the cylinder neck threads. It shows the differences among them on five different colour coded graphs, including both linear and three-dimensional views, on a computer screen. The five year hydrotest combined with the eddy current test provides ample opportunity to discover sustained load cracks before they lead to leaks or rupture.
Sustained load cracking is a stress related and progressive slow creep failure mechanism occurring in the 6351 aluminum alloy. It is a metallurgical anomaly that may take 8-10 years for a crack to develop in high pressure cylinders. Coupled with sufficient internal stresses, any pre-existing flaw can reach a critical size leading to leakage or a catastrophic failure. If an attempt is made to fill a leaking cylinder, a rupture can occur that could lead to injury, death, or property damage.
Luxfer, Justice, Walter Kidde and Cliff Impact cylinders manufactured before 1990 are inspected for sustained load cracking. Catalina cylinders have never been manufactured with the 6351 alloy.
Majestic Hydrotest & Fire Extinguisher Services
120, 239 Mayland Place Northeast, Calgary, Alberta T2E7Z8, Canada