When you talk to shipowners, you should know a very simple thing: ships are military equipment, and ships are civilian equipment. However, for construction, metals are used today as the main material. The largest tonnage falls on flat rolled steel used for the manufacture of hulls and superstructures. But a full-fledged merchant ship or warship is a complex mechanism that uses both special steels and non-ferrous metals.
Non-ferrous metals in shipbuilding
Copper, aluminum, titanium and alloys (brass, bronze, duralumin) are present in any boat or vessel. Non-ferrous metals are commonly used in various equipment and apparatus on ships and ships. They are used in much smaller quantities than steel. The rest of the materials (about 7.2 thousand tons) are ferrous metals: steel and cast iron, as well as a small amount of stainless steel.
Stainless steel in shipbuilding
Why is stainless steel so little used in ship design? It has a huge advantage for the shipbuilding industry: high corrosion resistance. Moreover, this metal contains at least 12% chromium, which, forming a stable oxide film on the metal surface, protects it from oxidation. In addition, stainless steel is welded using conventional methods, but with special methods, to obtain strong and corrosion-resistant parts. But apart from chromium, stainless steel also has a high nickel content, which is expensive and has a big impact on the final cost of the product.
Therefore, it will be practically impossible to build a ship's hull from stainless steel, since it would be, say, "gold". However, in shipbuilding, various special steels are used as an alternative to non-ferrous metals for making coatings for propeller shafts, turbine blades, etc. In addition, stainless steel is also available as painted steel. This is a two-layer material in which stainless steel (or other alloy) is applied in a thin layer over structural or low-alloy steel using a special technology. This provides protection against corrosion and prevents excessive cost increases.