Alternative wire material for suspension means used in goods handling and flow systems
Due to hygiene requirements or corrosive media the application of the ‘traditional suspension means’ of carbon steel ropes in rope drives for the nutrition industry (with special hygiene requirements) and in applications with acids or toxic environments (e.g. in wet pipe systems preparing vehicle bodywork for painting) are only suitable to a limited extent. Hence, alternative materials for suspension means like high strength fibre ropes, belts with steel or fibre cords as well as ropes with stainless steel wires (1.4401 or 1.4436/AS/316) are applied in goods handling and flow systems. For the use of alternative suspension means, safety relevant requirements such as sufficient service life as well as criteria for accurate and reliable discard have to be guaranteed for all kinds of suspension means, independent of the material. To date, due to the absence of experience and research, lifetime prediction of stainless steel ropes running over sheaves and drums as well as the dimensioning of rope drives with stainless steel ropes are normally based on the experiences with carbon steel ropes. However, the lifetime of stainless steel ropes under fluctuating tension and fluctuating bending stresses is in some cases smaller than with traditional suspension means by a factor of 3 to 8. This may result in both economic and safety problems. This paper reports experiences with stainless steel ropes in different applications and presents the results of bending fatigue tests with stainless steel ropes.
Author(s): W. Vogel, S. Schonherr and K.-H. Wehking