Stainless steels for corrosive environments

Core

Our Core range contains austenitic and ferritic stainless steel products for medium corrosive environments. The range is suitable for a wide variety of applications that require good formability and weldability.

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Outokumpu Core grades

Core 304/4301

Core 304/4301 is a classic 18% chromium, 8% nickel austenitic stainless steel. It’s an all-purpose product with good corrosion resistance and is suitable for a wide variety of applications that require good formability and weldability. Core 304/4301 can be delivered with a variety of surface finishes.

Core 304/4301 is an austenitic stainless steel, which belongs to the standard CrNi stainless steel family. Core 304/4301 is the basic variant with normal carbon and nickel content.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products.

Core 304/4301 is commonly available from many stainless steel stockists in many product forms and dimensions. It can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Household appliances and consumer goods
  • Kitchen equipment
  • Indoor and outdoor cladding, handrails, and window frames
  • Food and beverage industry equipment
  • Storage tanks
  • Flanges and valves
Product forms
Chemical composition

Core 304L/4307

Core 304L/4307 is a low-carbon alternative to Core 304/4301. The lower carbon content minimizes carbide precipitation as a result of heat input, for example during welding, giving improved resistance against intergranular corrosion. It’s suitable for a wide variety of applications that require good formability and weldability, and can be delivered with a variety of surface finishes.

Core 304L/4307 is an austenitic stainless steel that belongs to the standard CrNi stainless steel family.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products.

Core 304L/4307 is commonly available from many stainless steel stockists in many product forms and dimensions. Core 304L/4307 is also available in the temper rolled condition with higher strength.

Typical applications
  • Food and beverage industry equipment
  • Chemical and pharmaceutical industry equipment
  • Heat exchangers
  • Storage tanks and containers
  • Pipes
  • Flanges and valves
Product forms
Chemical composition

Core 304LN/4311

Core 304LN/4311 is a low-carbon, higher nickel and nitrogen alloyed alternative to Core 304/4301 with improved strength and low-temperature toughness. Suitable for applications that require high tensile strength. is an austenitic stainless steel that belongs to the standard CrNi stainless steel family.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products. Due to its fully austenitic structure, Core 304LN/4311 is suitable for applications with low magnetic permeability requirements (µ < 1.005).

Typical applications
  • Railroad cars
  • Pressure vessels
  • Chemical plant equipment(mild to medium corrosive environments)
  • Flanges and valves
Product forms
Chemical composition

Core 304L/4306

Core 304L/4306 is a higher nickel alternative to Core 304L/4307 with improved formability and deep drawability. Core 304L/4306 is an austenitic stainless steel that belongs to the standard CrNi stainless steel family. Core 304L/4306 has the variant with 10.5 wt.% nickel for improved formability and low carbon content for improved resistance against intergranular corrosion after welding.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products.

Core 304L/4306 is commonly available from many stainless steel stockists in manyproduct forms and dimensions. It can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Chemical and pharmaceutical plant equipment (mild to medium corrosive environments)
  • Flanges and valves
Product forms
Chemical composition

Core 305/4303

Core 305/4303 is a high-nickel alternative to Core 304/4301 with reduced strain hardening and excellent cold forming properties. Ideal for parts that require high deformation degrees.

Core 305/4303 is an austenitic stainless steel that belongs to the standard CrNi stainless steel family. It has 12.5 wt.-% nickel for improved formability.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products. Core 305/4303 is available in many product forms and dimensions. It can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Industrial parts with complex shapes
  • Sinks and other deep-drawn products
  • Complex stamping processes
  • Re-rollers producing very thin gauge coils
Product forms
Chemical composition

Core 321/4541

Core 321/4541 is a titanium-stabilized austenitic stainless steel with improved intergranular corrosion resistance for an extended temperature range. Core 321/4541 is an austenitic stainless steel that belongs to the standard CrNi stainless steel family. Core 321/4541 can be welded in all dimensions without becoming susceptible to intergranular corrosion.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products. Due to its titanium content, Core 321/4541 can be used at elevated temperatures. For high-temperature applications, the use of the optimized high-temperature Therma 321H/4878 is recommended.

Core 321/4541 is available in many product forms and dimensions, often also from many stainless steel stockholders. Polishing of Core 321/4541 is limited due to its titanium alloying.

Typical applications
  • Annealing covers
  • Stack liners
  • Automotive exhaust systems
  • Welded pressure vessels
  • Flanges and valves
Product forms
Chemical composition

Core 347/4550

Core 347/4550 is a niobium stabilized alternative Core 321/4541 with improved intergranular corrosion resistance and good mechanical properties at high temperatures. Core 347/4550 is particularly useful in applications with intermittent heating in the range 400–900 °C/750–1650 °F. Core 347/4550 is an austenitic stainless steel that belongs to the standard CrNi stainless steels. Core 347/4550 can be welded in all dimensions without becoming susceptible to intergranular corrosion.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products.

Typical applications
  • High temperature gaskets
  • Rocket engine parts
  • Expansion joints
  • Aircraft collector rings
  • Exhaust manifolds
  • Chemical production equipment
  • Flanges and valves
Product forms
Chemical composition

Core 301LN/4318

Core 301LN/4318 is a low-carbon, nitrogen alloyed alternative to Core 301/4310 with elevated strength, making it particularly suitable for lightweight construction. Temper rolled Core 301LN/4318 is used for applications that require increased hardness and strength.

Core 301LN/4318 is an austenitic CrNi stainless steel with high nitrogen and relatively low nickel content. Due to its high nitrogen content, Core 301LN/4318 has increased mechanical strength and shows a high degree of work hardening on mechanical deformation. As nitrogen-alloying improves corrosion properties, this product offers similar corrosion resistance to austenitic CrNi standard grades in many corrosive environments.

Core 301LN/4318 is used in applications where corrosion resistance and a combination of high mechanical strength and good formability are needed. Due to its tendency to work hardening, Core 301LN/4318 can absorb an increased amount of energy during deformation. It can be delivered in the temper rolled condition with different strength levels.

Typical applications
  • Automotive applications, especially vehicle chassis
  • Railroad cars
Product forms
Chemical composition

Core 201/4372

Core 201/4372 is a low-nickel stainless steel with properties approaching Core 301/4310 but with a higher work hardening coefficient.

Core 201/4372 is an austenitic stainless steel, which belongs to the family of the austenitic low nickel CrMn stainless steels, in which manganese replaces a part of the nickel that is normally alloyed to CrNi standard grades. It is the basic product of the CrMn stainless steel family. Due to its high nitrogen content, Core 201/4372 has increased mechanical strength and shows a high degree of work hardening on mechanical deformation.

The corrosion resistance of the austenitic CrMn grades is usually slightly below the corrosion resistance of the austenitic CrNi standard grades. Core 201/4372 is used in applications where a combination of high mechanical strength and good formability as well as corrosion resistance is needed. Due to its tendency to work hardening, Core 201/4372 can absorb an increased amount of energy during deformation. It can be delivered in the temper rolled condition with different strength levels.

Typical applications
  • Household appliances
  • Kitchen utensils
  • Sinks
  • Doors and windows
  • Railroad cars
Product forms
Chemical composition

Core 201LN/4372

This low-nickel stainless steel also has properties approaching Core 301/4310, but has a higher strength than Core 201/4372. It hardens more quickly due to its higher work hardening coefficient.

Typical applications
  • Railroad freight cars
  • Truck trailers
  • Coal handling
  • Bulk transport equipment
Product forms
Chemical composition

Core 441/4509

Core 441/4509 is a nickel-free 17% chromium ferritic stainless steel originally designed for exhaust systems, with good corrosion resistance and high-temperature strength. Core 441/4509 is available with a single (niobium) or dual (niobium and titanium) stabilizer. Due to good formability and weldability, it is often a suitable replacement for Core 301/4310.

Core 441/4509 can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Indoor cladding
  • Restaurant equipment and appliances
  • Tubes
  • Heat exchangers
Product forms
Chemical composition

Core 4622

Core 4622 is a nickel-free, high-chromium (21Cr) ferritic stainless steel with equal corrosion resistance to Core 304/4301. Core 4622 has excellent deep drawability and is almost ridging free, meaning it is easier to polish and has a lower overall production cost.

Core 4622 is a 21% chromium ferritic stainless steel, which can be used in many corrosive environments. Because of its titanium and niobium alloying, Core 4622 can be welded in all dimensions without becoming susceptible to intergranular corrosion. It is possible to use Core 4622 at elevated temperatures, like for instance in automotive exhaust systems. Core 4622 can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Household, catering and architectural applications (indoor and outdoor)
  • Tubular products for automotive and process industries
  • Tanks and process equipment
Product forms
Chemical composition

Circle Green Core 304/4301

Circle Green® is the world’s first towards zero carbon stainless steel. It has the lowest carbon footprint in the industry.

Circle Green Core 304/4301 is a classic 18% chromium, 8% nickel austenitic stainless steel. It’s an all-purpose product with good corrosion resistance and is suitable for a wide variety of applications that require good formability and weldability. Circle Green Core 304/4301 can be delivered with a variety of surface finishes.

Circle Green Core 304/4301 is an austenitic stainless steel, which belongs to the standard CrNi stainless steel family. Circle Green Core 304/4301 is the basic variant with normal carbon and nickel content.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products.

Circle Green Core 304/4301 is commonly available from many stainless steel stockists in many product forms and dimensions. It can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Household appliances and consumer goods
  • Kitchen equipment
  • Indoor and outdoor cladding, handrails, and window frames
  • Food and beverage industry equipment
  • Storage tanks
  • Flanges and valves
Product forms
Chemical composition

Circle Green Core 304L/4307

Circle Green® is the world’s first towards zero carbon stainless steel. It has the lowest carbon footprint in the industry.

Circle Green Core 304L/4307 is a low-carbon alternative to Circle Green Core 304/4301. The lower carbon content minimizes carbide precipitation as a result of heat input, for example during welding, giving improved resistance against intergranular corrosion. It’s suitable for a wide variety of applications that require good formability and weldability, and can be delivered with a variety of surface finishes.

Circle Green Core 304L/4307 is an austenitic stainless steel that belongs to the standard CrNi stainless steel family.

The austenitic CrNi standard grades are the most widely used group of stainless steels. Their well-balanced material properties make them suitable for the fabrication of many products.

Circle Green Core 304L/4307 is commonly available from many stainless steel stockists in many product forms and dimensions. Circle Green Core 304L/4307 is also available in the temper rolled condition with higher strength.

Typical applications
  • Food and beverage industry equipment
  • Chemical and pharmaceutical industry equipment
  • Heat exchangers
  • Storage tanks and containers
  • Pipes
  • Flanges and valves
Product forms
Chemical composition

Circle Green Core 441/4509

Circle Green® is the world’s first towards zero carbon stainless steel. It has the lowest carbon footprint in the industry.

Circle Green Core 441/4509 is a nickel-free 17% chromium ferritic stainless steel originally designed for exhaust systems, with good corrosion resistance and high-temperature strength. Circle Green Core 441/4509 is available with a single (niobium) or dual (niobium and titanium) stabilizer. Due to good formability and weldability, it is often a suitable replacement for Core 301/4310.

Circle Green Core 441/4509 can be supplied with a wide range of functional and aesthetic surface finishes.

Typical applications
  • Indoor cladding
  • Restaurant equipment and appliances
  • Tubes
  • Heat exchangers
Product forms
Chemical composition

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For Mild to medium Corrosive Environments

Core

The Core range contains austenitic and ferritic stainless steels grades for mild to medium corrosive environments in PRE range 17 – 22. 

The most widely used austenitic stainless grade, Core 304L/4307 (EN 1.4307), defines the overall landscape of the Core range. The Core range is complemented by modern stabilized nickel-free 18 – 21% chromium ferritic stainless steels, like Core 441/4509 (EN 1.4509), and low-nickel austenitic alternatives.

The latest Core range addition is the stabilized 21% chromium ferritic stainless steel, Core 4622 (EN 1.4622). Nickel-free Core 4622 offers similar corrosion resistance, weldability and better heat transfer, machinability and deep-drawability compared to 304L.

Core range Cr-Ni austenitic stainless steels have good corrosion resistance, welding and forming, especially stretch-forming characteristics. Austenitic steels exhibit very high ductility also down to cryogenic temperatures. Due to the higher toughness and work hardening nature of the austenitic stainless steels, special attention may be needed during forming and machining operations compared to ferritic stainless or carbon steels. 

Modern Core range stabilized ferritic stainless steels have good corrosion resistance, welding and deep-drawing properties. Thanks to phase structure, nickel-free ferritic stainless steels grades have excellent resistances to chloride-induced stress-corrosion cracking. Ferritics have good heat transfer properties that can be utilized in applications where uniform and fast heat transfer is preferred. Good heat transfer with lower thermal expansion eases weldability via smaller weld distortion and buckling behavior than austenitics. In addition, ferritics have similar machinability as carbon streels, due to low work hardening characteristics.

Core range grades can be used in a wide range of applications supported with a broad selection of surface finishes from mills and service centers.

Standards and approvals for Core range

EN ISO 18286 Hot-rolled stainless steel plates – Tolerances on dimensions and shape 
EN 10051 Hot-rolled steel strip
EN 10088-1 Stainless steels – list of stainless steels 
ISO 15510
Stainless steels – chemical composition 
EN ISO 9445   Cold-rolled stainless narrow strip, wide strip, plate/sheet and cut lengths. 
ASTM A 480  General requirements for flat-rolled stainless and heat resisting steel 
ASTM A 959  Harmonized standard grade compositions for wrought stainless steels 
ASME IID  Materials – Physical properties tables 

EN 10028-7  Flat products for pressure purposes – Stainless steels
EN 10088-2  Stainless steels – sheet/plate and strip for general purposes 
EN 10088-3  Stainless steels – semi-finished products, bars, rods sections for general purposes 
EN 10088-4  Technical delivery conditions for sheet/plate and strip 
EN 10095  Heat resisting steels and nickel alloys 
EN 10151  Stainless steel strip for springs 
EN 10217-7  Welded steel tubes for pressure purposes – Stainless steel tubes 
EN 10296-2  Welded circular steel tubes for mechanical and general engineering purposes – Stainless Steel tubes 
EN 10302  Creep resisting steels, nickel and cobalt alloys 
ASTM A 167  Stainless and heat-resisting Cr-Ni steel plate, sheet, and strip 
ASTM A 176  Stainless and heat-resisting Cr steel plate, sheet, and strip 
ASTM A182/ ASME SA-182  Stainless steel and heat resisting steel bars and shapes 
ASTM A 240  Cr and Cr-Ni stainless steel plate, sheet and strip for pressure vessels 
ASTM A276  Stainless steel and heat-resisting steel rod and wire for cold heading and forging 
ASTM A479/ ASME SA-479  General requirements for stainless and heat resistant steel wire and wire rod 
ASTM A 666  Austenitic stainless steel sheet, strip, plate, bar for structural and architectural applications 
ASME IIA Materials. Part A  Ferrous Material Specifications 
Eurocode 3 / EN 1993-1-4  Design of steel structures – Part 1-4: General rules – Supplementary rules for stainless steel 

Outokumpu meets the most common certifications and approvals, including:

  • AD 2000 Merkblatt
  • Approval of Material Manufacturers
  • Factory Production Control Certificate
  • ISO 9001
  • ISO 14001
  • ISO 50001
  • ISO/TS 16949
  • NORSOK
  • OHSAS 18001
  • Pressure Equipment Directive (PED)

Downloads

Outokumpu Core range datasheet
Outokumpu 4622 and 316plus brochure
Machining guidelines for standard austenitic stainless steel grades
Outokumpu Product Ranges chart