Martensitic stainless steels, the first stainless steels commercially developed (For cutlery) have a relatively high carbon content (0.1 - 1.2%) compared to other grades of stainless steels. They are plain chromium steels containing between 12 and 18% chromium. The stainless steel is of moderate corrosion resistance which can be hardened by heat treatment resulting in high strength and hardness. It has poor weldability and is magnetic. It is commonly used for knife blades, surgical instruments, shafts, spindles and pins

These are plain chromium stainless steels with varying chromium content between 11% and 18%, but with low carbon content. They have a moderate to good corrosion resistance, are not hardenable by heat treatment and always used in the annealed conditions. They are magnetic. The formability is not as good as the austeinitics. These are commonly used in computer floppy disk hubs (430), automotive trim (430), automotive exhausts (409), material handling equipment (3CR12) and in hot water tanks (444).

Most commonly used austenitic stainless steel contain 18% chromium and 8% nickel. They have an excellent corrosion resistance, weldability, formability fabricability, ductility, cleanability and hygiene characteristics. Along with good high and excellent low temperature properties, these are non magnetic (if annealed) and are hardenable by cold work only.

This is the most widely used stainless steel. The common uses are in computer floppy disk shutters (304), computer keyboard key springs (301), kitchen sinks (304D), pharmaceuticals, petrochemical industry, food processing equipment, architectural applications and chemical plants.

The highly popular low nickel stainless proprietary grades are used for kitchen products

These are stainless steels containing relatively high chromium (between 18 and 28%) and moderate amounts of nickel (between 4.5 and 8%). The nickel content is insufficient to generate a fully austenitic structure and the resulting combination of ferritic and austenitic structures is called duplex. Most duplex steels contain molybdenum in a range of 2.5 - 4%. These have a high resistance to stress corrosion, cracking and chloride ion attacks. They have a higher tensile and yield strength than austenitic of ferritic steels as well as good weldability and formability. They are commonly used in marine applications, desalination plants, heat exchangers and petrochemical plants

These grades are used in the chemical, textile, paper, pharmaceutical and photographic industries because of its excellent resistance to chemical corrosion. It also finds use where the combination of corrosion resistance and its extremely high strength at elevated temperatures is necessary.

These types are extremely popular in the food and dairy industries and for use in pharmaceutical equipment. It is exceedingly useful in applications where good mechanical properties and corrosion resistance are essential. It is highly desirable for products such as instrumentation where non-magnetism is fundamental. These grades are available in a wide range of forms and finishes.

Type 347 is mainly used where corrosion resistance and sustained operations at temperatures between 800OF and 1600OF is of the utmost importance. It is also a superior grade for use on heavy welded objects which can not be reannealed. It finds its principal applications in aircraft and missile engines, high temperature equipment in chemical industry, manifolds, furnace and blower parts etc.

Type 321 is used principally for applications involving welding or sustained elevated temperature operations where reannealing is not practical. It is used extensively in the aircraft and missile industries for engine parts, heat exchangers, exhaust stacks, rocket engines, manifolds etc.

Because of its high strength and versatility in heat treatment applicability and because of its good mechanical and machining properties, type 410 finds usage in a wide range of applications. It is used for low-cost cutlery, food industry machine parts, pump shafts, valve parts, compressor shrouds and abrasive applications. It is not generally recommended for high-stress usage above 1200OF