Why don magnets work on some stainless steels?
Thomas Devine, a materials science and engineering professor at the University of California, Berkeley, provides this answer. Stainless steels are iron-based alloys primarily known for their generally excellent corrosion resistance, which is largely due to the steel’s chromium concentration. There are several different types of stainless steels. The two main types are austenitic and ferritic, each of which exhibits a different atomic arrangement. Due to this difference, ferritic stainless steels are generally magnetic while austenitic stainless steels usually are not. A ferritic stainless steel owes its magnetism to two factors: its high concentration of iron and its fundamental structure. The metallic atoms in an austenitic stainless steel are arranged on a face-centered cubic (fcc) lattice. The unit cell of an fcc crystal consists of a cube with an atom at each of the cube’s eight corners and an atom at the center of each of the six faces. In a ferritic stainless steel, however, the
