Which of the following is NOT one of the main categories of stainless steel?

Stainless steel is primarily categorized into three main types based on their microstructure and properties: austenitic, ferritic, and martensitic. Each of these categories has distinct characteristics and applications.

Austenitic stainless steels are known for their excellent corrosion resistance and high ductility, making them widely used in food processing, chemical industries, and medical applications. Ferritic stainless steels, on the other hand, are magnetic and contain a higher proportion of chromium, providing good corrosion resistance but moderate strength. Martensitic stainless steels are characterized by high strength and hardness due to their carbon content, making them ideal for applications requiring cutting tools and high-wear resistance components.

The term 'halogenated' does not pertain to a category of stainless steel. Halogens are a group of elements and do not represent a type or classification of stainless steel. Therefore, this option is not relevant to the context of stainless steel categorization.