Core 4622

General characteristics

Core 4622 is a stabilized, nickel-free 21% chromium ferritic stainless being competitive alternative for Core 304L/4307 in wide range of applications. Core 4622 offers similar corrosion resistance, better heat transfer, machinability and deep-drawability compared to Core 304L/4307. Core 4622 have good weldability via smaller weld distortion and buckling behavior than austenitics. Thanks to improved phase structure, Core 4622 is almost ridging free providing easy polishing when compared to traditional ferritic stainless steels. Core 4622 have excellent resistances to chloride-induced stress-corrosion cracking. It is possible to use Core 4622 at elevated temperatures, like in automotive exhaust systems. Core 4622 can be supplied with a wide range of 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, available sizes and finishes


Product typeFinishesThicknessWidth
Cold rolled coil and sheet2B, 2E0,50-4,50≤ 1524
Hot rolled coil and plateMechanically descale3,00-5,50≤ 1524
Chemical composition


The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by mass.

TypicalCore 46220.0221.00.02Cu:0.4 Ti Nb
ASTM A240/A240MUNS S44330<0.025<120.0-23.0<0.025Si:<1 P:<0.040 S:<0.030 Cu:0.30-0.80
Mechanical properties



StandardGradeRp0.2Rp1.0RmElongationImpact strengthRockwellHBHV
Product type: Cold rolled coil and sheet
Typical (thickness 1 mm)Core 4622360365470
Product type: Hot rolled coil and sheet
Typical (thickness 4 mm)Core 4622355365470

1)Elongation according to EN standard:
A80 for thickness below 3 mm.
A for thickness = 3 mm.
Elongation according to ASTM standard A2” or A50.

Corrosion resistance

Core 4622 has good corrosion resistance in solutions of many halogen-free organic and inorganic compounds over a wide temperature and concentration range. It can withstand many sufficiently diluted organic and mineral acids, depending on the temperature and concentration of the solution. Core 4622 may suffer from uniform corrosion in strong organic and mineral acids, as well as in hot concentrated alkaline solutions.

In aqueous solutions containing halogenides, e.g. chlorides or bromides, pitting and crevice corrosion may occur, depending on the halogenide concentration, temperature, pH-value, concentration of oxidizing compounds, and crevice geometry, if applicable. For a short period of time, for instance during cooking of food in stainless steel dishes, Core 4622 can tolerate even relatively high chloride concentrations. The presence of corrosion inhibiting or accelerating compounds like transition metal ions or organic compounds may influence the corrosion behavior of Core 4622. Due to its ferritic crystal structure, Core 4622 is not prone to chloride-induced stress corrosion cracking.

Core 4622 can be used for indoor and outdoor applications in rural areas and urban environments where chloride contamination is low. The best material performance is usually reached with the help of adequate design, correct post-weld treatment, and regular cleaning during use (if applicable).

Due to its titanium and niobium content, the risk of sensitization to intergranular corrosion is strongly reduced when compared to non-stabilised ferritic grades. Core 4622 can be used in the temperature range in which chromium carbides would precipitate in non-stabilised ferritic grades. Its maximum service temperature in dry air is 950 °C. The presence of other corrosive compounds in the hot atmosphere like water or sulfur compounds may reduce the maximum service temperature significantly.
For more information on corrosion resistance, please refer to the Outokumpu Corrosion Handbook or contact our corrosion experts.

Pitting corrosion resistanceCrevice corrosion resistance

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
CPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).
CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F


For a more detailed description of their corrosion resistance properties in different environments see Outokumpu Corrosion Handbook.

Physical properties

The crystal structure is ferritic, and therefore material is ferromagnetic as soft annealed condition.


DensityModulus of elasticityThermal exp. at 100 °CThermal conductivityThermal capacityElectrical resistanceMagnetizable


Core 4622 can be formed using typical forming processes like folding, bending, drawing, etc. Grade has slightly higher yield strength than standard austenitic stainless steel grade 1.4301/AISI 304 in combination with lower work hardening.

Due to the stabilization, its R-value is higher compared to non-stabilized ferritic stainless steel. These characteristics mean excellent deep-drawability.


Conventional welding methods (like MMA, MIG, MAG, TIG, SAW, LBW or RSW) except gas welding are applicable. Austenitic 19 12 3 L (316L) filler metals can be used.

Shielding gases should be Ar/He based, mixed with maximum of 2% oxygen to improve the arc stability. Hydrogen and nitrogen additions are forbidden.

Heat input should be minimized to reduce the grain growth in the heat-affected-zone.

Stabilization prevents sensitization in the welds.

In order to fully restore the corrosion resistance of the weld seam, the weld discoloration should be removed by pickling, and passivation.

More detailed information about welding procedures can be obtained from the Outokumpu Welding Handbook, available from our sales offices.

Standards & approvals

Core 4622 is a trademark of Outokumpu. Its EN number is 1.4622 and the grade fulfills ASTM UNS S44330 requirements.
Work is in progress for further EN standardization.


ASTM A240/A240MUNS S44330