ESSC & DUPLEX 2019

In the areas of protection against falling rocks and the protection of fish in aquaculture, there are good opportunities for the use of stainless steels to ensure a sustainable use of materials. As a result of increasing needs and shrinking resources, aquaculture is gaining progressively significance in the recent years. Ecological issues such as negative effects on the ecological system due to the high fish density in the farms, the use of textile/polymer material for the nets and copper as antifouling strategy etc. are very present, particularly regarding the increasing number of fish going to be produced in farms in the future. Current trends focus on larger farms operated offshore. To make these farms working safe and economical, reliability has to be improved and maintenance costs need to be reduced. Also, alternatives with higher mechanical strength compared to current textile net materials as well as common metal wires might be necessary. The first part of this work shows the development and application of a new material system from high strength duplex stainless steel wires as net material with environmentally compatible antifouling properties for off-shore fish farm cages. Therefore, current net materials from textiles (polyamide) shall be partially replaced by high strength duplex stainless steel in order to have a more environmentally compatible system which meets the more severe mechanical loads (waves, storms, predators (sharks)). With a new antifouling strategy current issues like reduced ecological damage (e.g. due to copper disposal), lower maintenance costs (e.g. cleaning) and reduced durability shall be resolved. High strength steel wires are also widely used in geological protection systems, for example rockfall protection or slope stabilisation. Here normally hot-dip galvanised carbon steel is used. But in highly corrosive environments like coastal areas, volcanic areas or mines for example, other solutions with a high corrosion resistance are necessary. Protection systems made of high strength duplex stainless steel wires enable a significantly longer service life of the protection systems in thus a higher level of security.