We understand that steel tendons play a crucial role in the shipping industry. These components, although often overlooked, are central to stabilizing loads, absorbing heavy impacts and protecting valuable cargo from damage.
Liquefied natural gas (LNG) carrier with 4 LNG tanks sails along the sea. Credit: Shutterstock
The importance of material selection for steel tendons
The choice of material is crucial to ensure the longevity of steel tendons in marine environments. Not all steel types are equal; their composition affects how well they perform under demanding conditions. Properties such as elasticity, yield strength and resistance to mechanical fatigue are necessary for the tendons to perform reliably under continuous loading. Cyclic loading, i.e. constant compression and decompression, can lead to material fatigue, reducing the ability of steel to return to its original shape. In addition, temperature variations cause expansion and contraction, which can weaken the structural integrity of the tendon.
The consequences of a tendon failure in a ship can be severe. A broken or weakened tendon in a cargo hold can result in the cargo shifting uncontrollably, leading to potential damage, financial losses and even safety risks. In engine assembly, failing tendons can cause excessive vibrations, leading to mechanical inefficiencies and increased maintenance costs.
Our solution: 9RU10 - A high-performance stainless steel
To meet these challenges, we have developed 9RU10, a high performance, hard enable stainless steel specifically designed for demanding applications where strength, elasticity and fatigue resistance are important. Unlike conventional spring steels, 9RU10 undergoes a specialized heat treatment process that improves the precipitation of particles within its microstructure, significantly improving its resistance under repeated stress.
According to Mikael Hansson, Product Specialist at Alleima:
“All our spring steels are carefully evaluated for fatigue resistance through extensive testing in our advanced R&D facility. During production, we keep strict control over the mechanical properties, which are very important for the fatigue resistance of the material.”
The ability to customize the mechanical properties of our spring steel is another significant advantage in shipbuilding. “We can tailor the mechanical properties to suit the customer's needs for individual applications,” adds Hansson. This flexibility allows shipbuilders to optimize performance, ensuring that each component, be it a suspension system, an engine mount or a load stabilizer, meets the specific requirements of its function.
Looking ahead: Sustainability in focus
Sustainability is becoming an increasingly important factor in material choices across industries, and marine technology is no exception. In 2024, our 9RU10 steel had an average of 82% recycled content, and we are committed to the Science Based Targets initiative (SBTi) with short- and long-term plans to achieve CO₂ reduction targets by 2030 and reach netzero emissions by 2050.
As global trade continues to expand, the need for safe and efficient freight transportation remains strong. While steel tracks may not receive the same attention as advanced navigation systems or state-of-the-art propulsion technologies, their contribution to maritime logistics is undeniable. By ensuring cargo stability, minimizing damage and supporting critical ship functions, they play a quiet but essential role in keeping the world's goods moving safely across the oceans.