Ferritic Stainless Steel Grades, Properties, Standards & Supply

Shaanxi Shangyou Stainless Steel Co., Ltd. supplies ferritic stainless steels for automotive exhaust systems, household appliances, kitchen equipment, heat exchangers, hot-water systems, architectural components and industrial fabrication.

Ferritic stainless steels are primarily iron-chromium alloys. Compared with conventional austenitic stainless steels, they typically contain little or no nickel, have a ferritic microstructure and are ferromagnetic. Modern ferritic grades range from economical chromium grades such as 409 and 430 to stabilized 439 and 441 and molybdenum-alloyed 444 for more demanding corrosion conditions.

Ferritic stainless steel should therefore not be treated as one material. The correct grade depends on:

• Corrosion Environment
• Welding Requirement
• Temperature
• Formability
• Surface Requirement
• Product Form
• Service Life

Ferritic stainless steel is a stainless steel family whose structure is predominantly ferritic.

Chromium is the main alloying element responsible for stainless corrosion resistance. Depending on the grade, titanium, niobium and molybdenum may be added to improve weldability, stabilization, high-temperature performance or localized corrosion resistance.

Common commercial ferritic stainless steels can be divided into several practical groups:

World Stainless similarly distinguishes lower-chromium, standard chromium, stabilized and higher-alloy ferritic families rather than treating all 400-series stainless steels as identical.

A common purchasing mistake is to assume:

400 Series Stainless Steel = Ferritic Stainless Steel

This is incorrect.

The 400 series contains both ferritic and martensitic stainless steels.

For example:

430 → Ferritic

while:

410 / 420 / 440C → commonly purchased as Martensitic Stainless Steel

Therefore, material selection should be based on the actual grade, UNS designation, composition, delivery condition and specification—not only the first digit of the AISI designation.

Exact UNS/EN cross-references should always be checked against the applicable product specification because some commercial stabilized ferritic variants can have different UNS designations depending on chemistry and product route. Outokumpu, for example, lists EN 1.4509 variants under more than one UNS designation.

409 is a stabilized lower-chromium ferritic stainless steel family widely associated with automotive exhaust systems and applications where oxidation resistance, weldability and cost efficiency are more important than a bright decorative appearance.

Typical applications include:

• Automotive exhaust pipes
• Mufflers
• Catalytic-converter components
• Heat shields
• Industrial exhaust equipment

409 should not normally be positioned as a decorative substitute for 430 or 304 where a clean, bright appearance is the primary requirement.

For automotive applications, superficial discoloration can be acceptable even when functional service performance remains satisfactory.

Type 430 / UNS S43000 / EN 1.4016

430 is one of the best-known ferritic stainless steels and contains approximately 16% chromium. It combines corrosion resistance in mildly corrosive environments with useful forming properties and is particularly common in indoor applications.

Typical applications include:

• Kitchen equipment
• Household appliances
• Sinks
• Decorative panels
• Cutlery components
• Indoor architectural trim
• Equipment covers

430 should not automatically be promoted as the best ferritic grade for heavily welded fabrication.

Outokumpu specifically notes decreased intergranular corrosion resistance when conventional 430 is welded and does not recommend that particular product for welded applications. Where welding is a major design requirement, stabilized grades such as 439 or 441 should be evaluated instead.

439 is a medium-chromium stabilized ferritic stainless steel.

Titanium stabilization improves resistance to sensitization-related issues during welding, making 439 more suitable than conventional unstabilized 430 for many welded components.

Outokumpu identifies 439 / EN 1.4510 as suitable for applications including:

• Automotive exhaust systems
• Sugar-industry equipment
• Household appliances

and notes that its titanium alloying supports welding without creating the same intergranular-corrosion susceptibility associated with conventional 430.

439 should therefore be considered where the project requires:

• Formability
• Welding
• Moderate Corrosion Resistance
• Thermal Cycling

441 / EN 1.4509 is a stabilized ferritic stainless steel developed for applications requiring a combination of:

• Good corrosion resistance
• High-temperature strength
• Formability
• Weldability

Commercial variants may use niobium stabilization or combined niobium and titanium stabilization. Typical applications include exhaust systems, tubes, heat exchangers, restaurant equipment and indoor components.

441 is particularly relevant to buyers comparing materials for:

• Automotive hot-end components
• Heat exchanger components
• Industrial tubes
• Appliance components
• Hot equipment fabrication

Type 444 / UNS S44400 / EN 1.4521

444 represents a major step up from conventional 430-type ferritic grades.

It is a molybdenum-alloyed, nickel-free ferritic stainless steel designed for stronger corrosion performance. Outokumpu lists it for applications including hot-water tanks and drinking-water piping and notes its high resistance to stress corrosion cracking.

Typical applications include:

• Hot-water tanks
• Heat exchangers
• Water-heating equipment
• Drinking-water systems
• Food-processing equipment
• Selected chloride-containing environments

444 should be evaluated when the project requires improved localized corrosion resistance without automatically moving to conventional 316L.

However:

444 is not a universal replacement for 316L.

Final selection depends on fabrication route, temperature, corrosive medium, structural design and applicable product standard.

Ferritic and austenitic stainless steels behave differently enough that they should not be selected only by comparing chromium percentages.

The lower thermal expansion and higher thermal conductivity of ferritic grades can reduce distortion and buckling during welding compared with austenitic or duplex stainless steels.

Ferritic stainless steel corrosion resistance depends strongly on:

• Chromium Content
• Molybdenum Content
• Stabilization
• Surface Condition
• Temperature
• Chloride Concentration
• Crevice Geometry

There is therefore no single statement such as:

Ferritic stainless steel has excellent corrosion resistance.

that is technically useful for engineering procurement.

430 performs well in many mildly corrosive indoor environments and is widely used for appliances, kitchen equipment and decorative components.

Lower-chromium grades such as 409 are generally selected where functional corrosion and oxidation performance is sufficient and superficial discoloration can be accepted.

Molybdenum improves localized corrosion resistance.

This is why 444 occupies a different engineering position from 430.

World Stainless notes that molybdenum-containing ferritic grades can provide substantially higher pitting resistance than standard ferritic grades.

Grade selection for chloride service should therefore consider:

• Chloride concentration
• Temperature
• Crevices
• Deposits
• Surface finish
• Water chemistry

rather than choosing only by grade family.

Resistance to chloride-induced stress corrosion cracking is one of the most important reasons engineers evaluate ferritic stainless steels.

Outokumpu notes that ferritic grades can be more suitable than conventional austenitic grades where high resistance to chloride SCC is required.

This does not mean ferritic stainless steel is immune to every form of corrosion.

A material can perform well against SCC while still being limited by:

• Pitting
• Crevice corrosion
• Uniform corrosion
• Galvanic corrosion
• Weld corrosion

depending on the environment.

Ferritic stainless steels are particularly useful in applications involving repeated heating and cooling.

Compared with conventional austenitic stainless steel, ferritic grades generally have:

• Lower thermal expansion

and

• Higher thermal conductivity

which can help reduce thermal distortion in exhaust systems, heat exchangers and welded sheet constructions.

This partly explains the extensive use of stabilized ferritic grades in automotive exhaust and thermal equipment.

Conventional ferritic stainless steels such as 430 are not hardened through the quenching-and-tempering route used for martensitic stainless steels.

Heat treatment is instead used primarily to control:

• Microstructure
• Ductility
• Residual stress
• Grain structure
• Fabrication condition

The correct annealing condition depends on:

• Grade
• Product form
• Thickness
• Manufacturing route
• Applicable specification

Ferritic and martensitic stainless steels should therefore never share the same generic “heat treatment” paragraph on a product website.

Weldability varies significantly among ferritic grades.

Best suited to applications where extensive welding is not the main requirement.

Titanium stabilization improves welded performance.

Nb/Ti stabilization supports fabrication and elevated-temperature service.

Stabilization combined with Mo alloying supports both corrosion performance and welded industrial applications.

When developing a welding procedure, consider:

• Base Grade
• Thickness
• Heat Input
• Joint Design
• Filler Metal
• Shielding Gas
• Grain Growth
• Intergranular Corrosion
• Final Service Temperature

Ferritic stainless steel should not simply inherit a 304/316 welding procedure without material-specific qualification.

Ferritic stainless steel can provide useful forming performance, and modern stabilized grades have significantly expanded the range of fabricated ferritic products.

Outokumpu notes that some ferritic products can provide forming characteristics comparable with deep-drawing quality carbon steels.

Typical processing includes:

• Roll Forming
• Press Forming
• Bending
• Stamping
• Tube Forming
• Slitting
• Cut-to-Length

The minimum bend radius and allowable forming reduction should be confirmed according to grade, thickness and delivery condition.

The grade and the product standard must be treated separately.

ASTM A240/A240M covers chromium, chromium-nickel and chromium-manganese-nickel stainless steel plate, sheet and strip for pressure-vessel and general applications.

As of August 2026, the active edition is:

ASTM A240/A240M-26.

Typical ferritic grades within its scope can include applicable 409, 430, 439, 441 and 444 variants, subject to the actual specification tables and purchase requirements.

ASTM A268/A268M specifically covers seamless and welded ferritic and martensitic stainless steel tubing for general corrosion-resisting and high-temperature service.

The active edition is:

ASTM A268/A268M-24.

The standard includes ferritic grades such as TP439 and S44400 among its listed materials.

ASTM A276/A276M covers applicable hot-finished and cold-finished stainless steel bars and commonly used shapes such as:

• Rounds
• Squares
• Hexagons
• Angles
• Tees
• Channels

The active edition is ASTM A276/A276M-25.

Always confirm that the requested ferritic grade is actually included in the applicable edition before stating compliance.

Common commercial grades:

• 430
• 409
• 439
• 441
• 444

Available surfaces may include:

• 2B
• BA
• No.4
• Brushed
• Polished
• Mill Finish

depending on grade and production route.

Typical applications:

• Automotive stamping
• Appliance manufacturing
• Kitchen equipment
• Industrial fabrication
• Tube production

Available processing:

• Slitting
• Cut-to-Length
• Leveling
• Edge Conditioning
• Surface Finishing

Suitable for:

• Precision components
• Appliance parts
• Automotive components
• Heat-management parts
• Formed products

Custom slit widths and coil weights can be arranged according to production requirements.

Available according to grade and standard in:

• Welded Tube
• Seamless Tube where applicable
• Heat Exchanger Tube
• Automotive Tube
• Industrial Tube

For ASTM projects, confirm whether ASTM A268 or another application-specific specification is required.

Depending on grade and production availability:

• Round Bar
• Flat Bar
• Custom Profiles
• Angles
• Fabricated Sections

Special ferritic bar and profile grades are commonly more restricted than conventional 304/316 products and should not automatically be described as regular stock.

Actual finish availability depends strongly on grade, thickness, width and production route.

This is an initial selection guide.

Final material selection should consider:

• Temperature
• Medium
• Chloride Level
• pH
• Welding
• Product Form
• Design Life

Recommended grades to evaluate:

• 409
• 439
• 441

Applications:

• Exhaust pipes
• Mufflers
• Catalytic-converter housings
• Heat shields
• Hot-end components

Typical grades:

• 430
• 439
• 441

Applications:

• Dishwashers
• Washing machines
• Ovens
• Kitchen equipment
• Appliance panels

Grades to evaluate:

• 441
• 444

Selection depends on:

• Water chemistry
• Temperature
• Pressure
• Tube geometry
• Welding
• Chlorides

Typical candidates:

• 439
• 444

444 is especially relevant where stronger localized corrosion resistance is required.

Depending on the environment:

• 430
• 441
• 444

can be evaluated for equipment components where their corrosion resistance, appearance and fabrication characteristics meet the hygiene and service requirements.

Available inspection should be specified according to the material standard and purchase order.

• Heat Number
• Grade Verification
• Material Traceability

• Mill Chemical Analysis
• PMI where applicable

• Thickness
• Width
• Length
• OD
• Wall Thickness
• Flatness
• Straightness

• Tensile Strength
• Yield Strength
• Elongation
• Hardness

according to the applicable material specification.

For ASTM A268 tubing, applicable testing can include mechanical tests and hydrostatic or nondestructive electric testing according to the standard requirements.

Available documentation can include:

• EN 10204 3.1 MTC
• Chemical Composition
• Mechanical Properties
• Heat Number
• Product Dimensions
• Inspection Results
• PMI Report where specified
• Third-Party Inspection when requested

Do not assume every low-volume or non-standard item automatically includes the same documentation package. Document requirements should be confirmed before production.

Shaanxi Shangyou Stainless Steel Co., Ltd. can coordinate processing according to material and product form:

• Coil Slitting
• Cut-to-Length
• Leveling
• Laser Cutting
• Shearing
• Polishing
• Tube Cutting
• Saw Cutting
• Custom Fabrication
• Export Packing

Processing feasibility depends on grade, thickness, dimensions, tolerance and order quantity.

For an accurate quotation, please provide:

• Grade
  409 / 430 / 439 / 441 / 444
• Product Form
  Sheet / Coil / Strip / Tube / Bar / Profile
• Standard
• Dimensions
  Thickness × Width × Length
  or
  OD × Wall Thickness × Length
• Quantity
• Surface Finish
• Required Tolerance
• Welding / Processing Requirement
• Inspection Requirement
• MTC Requirement
• Destination Port

Do not select ferritic stainless steel only by price.

Send us:

• Application
• Operating Temperature
• Corrosive Medium
• Chloride Level
• Welding Requirement
• Required Product Form

and we can help narrow the appropriate grade and production route before quotation.

Shaanxi Shangyou Stainless Steel Co., Ltd.

Ferritic stainless steels are primarily iron-chromium stainless steels with a predominantly ferritic microstructure. Depending on the grade, molybdenum, titanium or niobium may also be added.

Important commercial ferritic grades include 409, 430, 439, 441 and 444. These grades serve substantially different corrosion, welding and temperature requirements.

Yes. Type 430 / UNS S43000 / EN 1.4016 is a classic approximately 16% chromium ferritic stainless steel.

409 is commonly supplied as a stabilized ferritic stainless steel family, particularly for automotive exhaust applications.

Yes. Ferritic stainless steels are ferromagnetic. ASTM A268 also describes the relevant straight-chromium ferritic grades in its scope as ferromagnetic.

Conventional ferritic grades such as 430 are not hardened using the quench-and-temper treatment used for martensitic grades.

430 is a general-purpose ferritic grade for mildly corrosive environments. 439 is stabilized with titanium and provides better suitability for many welded and thermal-cycle applications.

444 contains molybdenum and is designed for stronger localized corrosion resistance than conventional 430. It is commonly evaluated for hot-water and heat-exchanger applications.

441 is a stabilized ferritic grade used in applications including exhaust systems, heat exchangers, tubes, restaurant equipment and other applications requiring good thermal performance and fabrication characteristics.

It depends on the grade. Stabilized ferritic grades such as 439 and 441 are generally better suited to welded fabrication than conventional unstabilized 430.

Ferritic stainless steels generally offer strong resistance to chloride-induced stress corrosion cracking compared with conventional austenitic stainless steels, although other corrosion mechanisms must still be evaluated.

444 can be a technically attractive alternative to 316L in certain applications, particularly where localized corrosion resistance and chloride SCC performance are important. It should not be treated as a universal one-for-one replacement; fabrication, mechanical and service requirements must be checked.

ASTM A240/A240M covers applicable stainless steel plate, sheet and strip. As of August 2026, the current edition is ASTM A240/A240M-26.

ASTM A268/A268M-24 covers applicable seamless and welded ferritic and martensitic stainless steel tubing for general corrosion-resisting and high-temperature service.

MTC / EN 10204 3.1 can be specified for applicable materials and orders. Send the grade, product form, standard, dimensions and quantity so documentation availability can be confirmed before quotation.