Steel powder is an aggregate of iron particles with sizes of about 20–200 microns. Metal Parts that are difficult cutting or machining from steel blocks, or even poorly-soluble materials, can be made of steel powder to be molded into complex forms (powder metallurgy process*). This process is suitable for producing small parts of complex forms, e.g. gears in an automobile or machinery. This process using metal molds fits for mass production.

*Note: Powder metallurgy is a process to compress metal powders into metal molds and then sinter them with high temperatures to make parts of complex forms.