Is stainless steel harder than pure iron? By weight, steel contains about 2.14% carbon. Although that’s a relatively small amount of carbon, it results in significant physical changes. Steel, for example, is both harder and stronger than pure iron. In comparison, steel is a man-made alloy that’s made by mixing iron and carbon together.
Why is stainless steel harder than pure iron? The smaller or bigger atoms distort the layers of atoms in the pure metal. This means that a greater force is required for the layers to slide over each other. The alloy is harder and stronger than the pure metal.