In Neuß, Germany, an SKF four-row taper roller bearing made history when it was retired recently after nearly 18 years and 67,000 hours in service. The huge bearing, almost a metre in diameter and weighing about 4,500 kilograms, had served as a back-up roller bearing in an aluminium hot rolling mill at Aluminium-Norf GmbH since 1970.
Normally, the lifetime of such a bearing is about 15,000 hours. The company decided to remove the bearing not because there were problems, but for safety reasons. This type of bearing deals with forces in the range of 40,000 kN.