Tube cutter blades are usually made of stainless steel.
Stainless steel is a steel alloy, the main quality of which is that it is corrosion resistant. Corrosion resistance is important in tube cutters because, as a plumbing tool, they can often be exposed to water. As stainless steel is just a variation of steel, it still retains the strength and toughness quality of steel.
Stainless steel must be made up of at least 10.5% chromium to make it corrosion resistant. The chromium in the steel combines with oxygen in the air to make a chromium oxide layer on the steel.Even if the metal is cut or scratched and the layer is damaged, more oxide quickly recovers the exposed surface, protecting it from corrosion.
Other elements that are added to steel to create stainless steel include nickel, nitrogen and molybdenum. These also add to the material’s corrosion resistance, but this does not work without the minimum 10.5% of chromium.