Stainless steel is a corrosion-resistant alloy, characterized by a chromium-rich oxide layer, and is categorized into ferritic, austenitic, martensitic, duplex, and precipitation hardening types, each with distinct properties and applications. Ferritic stainless steels are magnetic and cost-effective but challenging to weld, while austenitic steels are the most widely used due to their excellent workability. Stainless steel finds applications in architecture, automotive, construction, medical fields, and more.