Grades

Stainless Steel Types and Grades: Properties & Applications

Stainless steel is available in different types and grades, each offering a different combination of properties and suitable applications. The right material depends on the requirements of the product, manufacturing process and intended use.

The major stainless steel types include austenitic, ferritic, martensitic, duplex and precipitation-hardened (PH) stainless steel. The table below provides an overview of these major types, their commonly used grades, key properties, and typical applications.

Stainless Steel Types and Grades

TYPE	GRADES	PROPERTIES	APPLICATION
AUSTENITIC STAINLESS STEEL (200/300 SERIES)	20O SERIES (201,202,205)	200 series is mainly based on Manganese and nitrogen which are partially substituted for nickel, improving cost-effectiveness while resulting in a 30% higher yield strength than grade 304. Due to a high manganese content, this grade is more economical than the 300 series. This type offers good ductility, weldability, and hardening rate, as well as fair corrosion resistance.	Washing machines, cutlery, automotive industry, and food and beverage industry.
AUSTENITIC STAINLESS STEEL (200/300 SERIES)	30O SERIES (301,302,303,304,316,304L,316L,309,310,314,321,347 etc.)	300 Series stainless steels are predominantly austenitic chromium-nickel alloys. The presence of molybdenum improves corrosion resistance in acidic mediums. It has considerable strength, heat resistance, corrosion resistance, and performs well at sub-zero temperature. 300 series have excellent weldability and formability.	Food processing industry, kitchenware and appliances, heat-exchangers, chemical containers, water filtration systems, and architectural panelling, Automotive exhaust systems
FERRITIC STAINLESS STEEL	405,409,430,446 etc.	Ferritic stainless steels are plain chromium steels with a body-centred cubic (BCC) crystal structure (ferrite) at all temperatures. They typically contain 11–18% chromium and very little or no nickel. Carbon content is low (often ≤0.05–0.10%) to avoid forming austenite or martensite. Key features include moderate corrosion resistance (better than plain carbon steel but generally less than austenitic grades) and good resistance to stress corrosion cracking.	Consumer products and automotive applications
MARTENSITIC STAINLESS STEEL	403,410,420,431,440A,440B,440C etc.	They are chromium steels with higher carbon (typically 0.1% up to 1% C) that can be hardened by quenching and tempering, similar to carbon steels. They generally contain 11–18% chromium and no or low nickel (usually ≤2% Ni). The higher carbon allows them to form martensite (a hard, body-centred tetragonal phase)	Knife blades, cutting tools, surgical instruments, turbine blades, valve parts, springs, shafts and fasteners. bearings, wear-resistant surfaces
DUPLEX STAINLESS STEEL	2202,2205,2304,2507 etc.	Duplex stainless steels have a mixed microstructure of approximately 50% austenite and 50% ferrite, hence the name “duplex.” Chemically, they are designed with chromium content in the 18–28% range, moderate nickel (4–8%), plus significant molybdenum (2.5–4%) and nitrogen (~0.1–0.3%)	Oil & gas production equipment, offshore platforms, heat exchangers, pressure vessels, and piping that handles brackish or chloride-bearing waters, desalination plants, seawater systems, pulp and paper industry
PRECIPITATION HARDENED (PH) STAINLESS STEEL	17-4PH, 15-5PH, 13-8Mo, A-286 etc.	Precipitation-hardening stainless steels are a special category that can be strengthened to very high levels by a precipitation heat treatment (age hardening). They achieve this by forming fine intermetallic compounds in the steel matrix upon aging. PH steels often have a martensitic or semi-austenitic structure that can be altered through heat treating. This series shows high strength and moderate corrosion resistance.	Aerospace industry, power generation, firearm components, marine applications

Austenitic Stainless Steel

Austenitic stainless steel includes the 200 and 300 series and is widely used across industrial and commercial applications. These grades are generally known for a combination of corrosion resistance, weldability and formability. Common grades listed for this category include 201, 202, 205, 301, 302, 303, 304, 316, 304L, 316L, 309, 310, 314, 321 and 347. Typical applications include food processing equipment, kitchenware, appliances, heat exchangers, chemical containers, water filtration systems and automotive applications.

Ferritic Stainless Steel

Ferritic stainless steel is a chromium-based stainless steel category. Common grades include 405, 409, 430 and 446. These grades are used in applications such as consumer products and automotive components.

Martensitic Stainless Steel

Martensitic stainless steels contain higher carbon levels and can be hardened through suitable heat treatment. Common grades include 403, 410, 420, 431, 440A, 440B and 440C. They are used in applications where hardness and strength are important, including knife blades, cutting tools, surgical instruments, turbine components, valve parts, shafts, springs and fasteners.

Duplex Stainless Steel

Duplex stainless steel has a mixed austenitic-ferritic structure. Common grades listed include 2202, 2205, 2304 and 2507. Duplex grades are used in demanding applications such as oil and gas equipment, offshore platforms, heat exchangers, pressure vessels, piping, desalination plants and seawater systems.

Precipitation-Hardened Stainless Steel

Precipitation-hardened stainless steels, commonly called PH stainless steels, are designed to achieve high strength through precipitation or age-hardening treatment. Common grades include 17-4PH, 15-5PH, 13-8Mo and A-286. Typical applications include aerospace, power generation and marine applications.

Stainless Steel Types at a Glance

The five major types can be understood at a glance:

Austenitic: Includes many widely used 200 and 300 series grades.
Ferritic: Chromium-based grades used in consumer and automotive applications.
Martensitic: Heat-treatable grades used where hardness and strength are important.
Duplex: Combines austenitic and ferritic structures for demanding applications.
Precipitation-Hardened: High-strength stainless steels strengthened through precipitation or age hardening.

The exact grade should be selected according to the material specification and requirements of the finished component.

Stainless Steel Grades and Product Forms

Stainless steel grades are supplied in different product forms depending on the manufacturing process and end-use requirements. Maruti Inox manufactures and supplies stainless steel products including bars, bright bars, hot rolled bars, forged round bars, continuous cast billets, forging quality ingots and stainless steel angles.

For semi-finished products, the selected grade and product form should be suitable for the downstream process, such as rolling, forging or fabrication.

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Frequently Asked Questions

What are the main types of stainless steel?

The main stainless steel types are austenitic, ferritic, martensitic, duplex and precipitation-hardened stainless steel.

What is the difference between a stainless steel type and a grade?

A stainless steel type is a broader material category, while a grade identifies a specific stainless steel material within that category. For example, 304 is an austenitic stainless steel grade.

What are the common austenitic stainless steel grades?

Common grades listed in the Maruti Inox reference table include 201, 202, 205, 301, 302, 303, 304, 316, 304L, 316L, 309, 310, 314, 321 and 347.

What are the common ferritic stainless steel grades?

The listed ferritic grades include 405, 409, 430 and 446.

What are the common martensitic stainless steel grades?

The listed martensitic grades include 403, 410, 420, 431, 440A, 440B and 440C.

What are common duplex stainless steel grades?

The listed duplex grades include 2202, 2205, 2304 and 2507.

What are common precipitation-hardened stainless steel grades?

The listed PH grades include 17-4PH, 15-5PH, 13-8Mo and A-286.