Iron is alloyed with different amounts of chromium to produce 3 classes of stainless steel. These are martensitic, ferritic, and austenitic steels. These three are classed separately because each has a different microstructure.
304 Stainless SteelType 304 stainless is austenitic. It is non-magnetic. Special treatments change that. The treatments may be to produce fasteners or other items that require it.
Magnetic & Non-MagneticBoth ferritic and martensitic stainless steels are easy to magnetize. Austenitic steels such as cold worked 304 undergo partial conversion of their austenite microstructure to martensite.
Because stainless type 304 is cheap yet has many fine properties, it is chosen for objects requiring cold working. They may be magnetized. Yet some are non-magnetic.
Videos on Steel ManufacturingThis U.S. Steel video gives a brief steel making demo – start to finish – from blasting for ore to finished product.
- Virginia Tech: Laboratory for Scientific Visual Analysis: Ni-Cr-Fe
- Fastenal Company: Magnetism in Stainless Steel Fasteners