Boron steel consists of small amounts of boron being added to the steel. The added boron mainly affects the hardness of the alloy, which improves its suitability for certain industrial applications, which are typically related to construction.
Steel is a common alloy made of iron and copper. Various other elements are added to steel to alter its properties, including boron. The most common addition to steel is chromium. The chromium forms a very thin layer around the steel when it forms a chromium oxide compound. This layer protects the material from rust and other staining, which is why the new material is called stainless steel.