Hydraulic cranes absolutely rely on the integrity of their high-pressure fluid systems for safe operation. A crane can become out of level when an outrigger cylinder leaks over time, possibly leading to a tip over. A boom can collapse if a hydraulic hose ruptures. It is not possible to absolutely prevent hydraulic cylinders from developing leaks or prevent hoses from rupturing during the life of a typical crane, therefore crane manufacturers provide load holding valves at key components to prevent these dangerous incidents. In fact, ASME B30.5, Mobile and Locomotive Cranes, requires load holding valves or equivalent devices at outrigger cylinders, boom support cylinders, and boom telescoping cylinders. Read More
Stress corrosion cracking involves the slow growth of small, often microscopic, cracks through a metal part in a corrosive environment. The cracking can continue to the point that the part fails suddenly and unexpectedly even though it still appears new and in good condition.
My first experience with stress corrosion cracking happened in the Charleston harbor when the stainless steel rudder suddenly separated from a sailboat during moderate winds. What had been a pleasant evening sail turned instantly into being in a difficult to control boat in the middle of the busy shipping channel. The rudder remained attached only Read More