Iron encounter some chemical products will produce chemical reactions, and stainless steel is not easy to produce chemical reactions. Their biggest difference is: iron will rust, and stainless steel is the opposite. So in life we now use more stainless steel knife.

Note that stainless steel knives are not easy to rust, but it is difficult to restore the sharpness of kitchen knives after the edge of the knife is rolled. But iron knife is different, as long as a little grinding after rolling mouth can make the knife edge sharp, use as before.