Stainless Steel

321

General characteristics

Outokumpu grade 4541 is an austenitic stainless steel, which belongs to the family of the standard CrNi stainless steels. Grade 4541 is the titanium-alloyed variant, which 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, grade 4541 can be used at elevated temperatures. For high temperature applications, the use of the optimised high temperature variant 4878 is recommended. Grade 4541 is available in many product forms and dimensions, commonly also from many stainless steel stockholders. Polishing of grade 4541 is limited due to its titanium-alloying.

Typical applications

  • food & beverage industry
  • chemical industry
  • low temperature equipments
  • chimneys & stack liners
  • exhaust systems
  • heat exchangers
  • storage tanks
  • piping
  • solar power absorber tubes

Product forms, available sizes and finishes

Flat
Product typeFinishesThicknessWidth
Black hot band1U2,40-10,001000-1550
Cold rolled coil2B, 2BB, 2C, 2D, 2E, 2F, 2G, 2H, 2J, 2K, 2M, 2R, 2S0,05-6,353-2032
Cold rolled sheet2B, 2BB, 2C, 2D, 2E, 2F, 2G, 2H, 2J, 2K, 2M, 2R0,20-6,3518-2032
Hot rolled coil, pickled1C, 1D, 1E, 1G, 1M, 1U1,36-12,7035-2032
Precision strip2H, 2R0,05-1,503-650
Quarto plate1C, 1D2,00-110,00400-3200
Rod
Product typeFinishesThicknessWidth
Hexagonal rod9,00-27,009-27
Round rod5,00-27,005-27
Square rod9,00-24,009-24
Semifinished
Product typeFinishesThicknessWidth
Bloom395,00-405,00295-305
Slab165,00-305,001000-1580

Chemical composition

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

CMnCrNiMoNOther
Typical 0.0417.39.1Ti:0.40
AD2000 W2, W10 & EN10028-7 ≤0.08≤2.0017.0-19.09.0-12.0
ASME II A SA-240 ≤0.08≤2.0017.0-19.09.0-12.0≤0.10
ASME II A SA-240M ≤0.08≤2.0017.0-19.09.0-12.0≤0.10
ASTM A240 ≤0.08≤2.0017.0-19.09.0-12.0≤0.10
ASTM A240M ≤0.08≤2.0017.0-19.09.0-12.0≤0.10
EN 10028-7 ≤0.08≤2.0017.0-19.09.0-12.0
EN 10088-2 ≤0.08≤2.017.0-19.09.0-12.0
EN 10088-4 ≤0.08≤2.017.0-19.09.0-12.0
GOST 5632-72 ≤0.08≤2.017.00-19.009.00-11.00≤0.35≤0.10
GOST 5632-72 ≤0.12≤2.017.0-19.09.0-11.0≤0.35≤0.10
TLV936002 ≤0.08≤2.0017.0-19.09.0-12.0

Mechanical properties

The mechanical properties of the available products are given in the table below. In addition to these values, several of the chromium-nickel grades is available in temper rolled condition with higher mechanical strength. Please contact your local Outokumpu sales company for more information.

The mechanical properties of the available products in soft annealed condition at room temperature are given in the table below. Moderate strengths can be reached at elevated temperatures (~550°C / 1022 °F). Temperatures for excessive scaling are close to 850°C/1562°F. This grade among other austenitic corrosion resistant steels exhibits very high ductility and high elongation to fracture. It is not susceptible to brittle fracture in the solution annealed condition.

StandardRp0.2Rp1.0RmElongationImpact strengthRockwellHBHV
 MPaMPaMPa%J
Typical (Thickness 15mm)25029057055
AD2000 W2, W10 & EN10028-7 ≥ 200 ≥ 240500-700 ≥ 40
ASME II A SA-240 ≥ 205 ≥ 515 ≤ 95HRB ≤ 217
ASME II A SA-240M ≥ 205 ≥ 515 ≤ 95HRB ≤ 217
ASTM A240 ≥ 205 ≥ 515 ≤ 95HRB ≤ 217
ASTM A240M ≥ 205 ≥ 515 ≤ 95HRB ≤ 217
EN 10028-7 ≥ 200 ≥ 240500-700 ≥ 40
EN 10088-2 ≥ 200 ≥ 240500-700 ≥ 40
EN 10088-4 ≥ 200 ≥ 240500-700 ≥ 40
TLV936002 ≥ 200 ≥ 240500-700 ≥ 40

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

Outokumpu grade 4541 has excellent corrosion resistance in solutions of many halogen-free organic and inorganic compounds over a wide temperature and concentration range. It can withstand many organic and sufficiently diluted mineral acids depending on the temperature of the solution. Grade 4541 may suffer from uniform corrosion in strong mineral acids, like for instance hot concentrated nitric acid, and hot strong alkaline solutions. More detailed information on corrosion properties of grade 4541 can be found in Outokumpu’s Corrosion Tables published in the Outokumpu Corrosion Handbook and on www.outokumpu.com. Due to its titanium content, the risk of sensitisation for intergranular corrosion is strongly reduced when compared to other austenitic CrNi standards grades with normal carbon content. In aqueous solutions containing halogenides like e.g. chlorides or bromides, pitting and crevice corrosion may occur depending on halogenide concentration, temperature, pH-value, concentration of oxidizing compounds and crevice geometry, if applicable. The presence of corrosion inhibiting or accelerating compounds like e.g. transition metal ions or organic compounds may influence the corrosion behaviour of grade 4541. Grade 4541 is prone to chloride-induced stress corrosion cracking at temperatures over about 50°C depending on the applied stress and the chloride concentration in the environment. Prior cold deformation of the structure under load increases the risk for stress corrosion cracking. Due to its titanium stabilisation against intergranular corrosion, grade 4541 can be used in the temperature range in which chromium carbides would precipitate in other austenitic CrNi standard grades. Its maximum service temperature in dry air is 850°C. The presence of other corrosive compounds in the hot atmosphere like water or sulphur compounds may reduce the maximum service temperature significantly. For more information on corrosion resistance refer to the Outokumpu Corrosion Handbook or contact the Outokumpu corrosion experts.

Pitting corrosion resistanceCrevice corrosion resistance
PRECPTCCT
17<10<0

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

Physical properties

DensityModulus of elasticityThermal exp. at 100°CThermal conductivityThermal capacityElectrical resistanceMagnetisability
kg/dm3GPa10-6/°CW/m°CJ/kg°CµΩm
7.920016,0155000.73No

Fabrication

Cold forming

These grades can be readily formed and fabricated by a full range of cold working operations. They can be used in heading, drawing and bending. Any cold working operations will increase the strength and hardness of the material and may leave it slightly magnetic. Work hardening is aaccentuated by the partial transformation of the austenite phase of the material to hard martensite. Hot forming Hot working can be carried out in the 850 – 1150°C range. For maximum corrosion resistance, forgings should be annealed at 1050°C and rapidly cooled in air or water after hot working operations.

Welding

Austenitic stainless steel 4541 grade has excellent weldability and is suited to a full range of conventional welding methods (like MMA, MIG, MAG, TIG, SAW, LBW or RSW), except gas welding. Austenitic 4541 have about 50% higher thermal expansion and lower heat conductivity compared to carbon steels. This means that larger deformation and higher shrinkage stresses may result from welding. In thin sections, autogenous welding may be used. To ensure that the weld metal properties (e.g. strength, corrosion resistance) are equivalent to those of the parent metal, matching or slightly over-alloyed fillers should preferably be used. Suitable filler metals: 19 9 Nb or 19 9 L Generally post weld heat treatment is not required. In special cases with high risks of stress corrosion cracking or fatigue, stress relief treatment may be considered. 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 concerning welding procedures can be obtained from the Outokumpu Welding Handbook, available from our sales offices.

Standards & approvals

The most commonly used international product standards are given in the table below.

Standard Designation
AD 2000 W2, W10 & EN10028-7, PED 97/23/EC1.4541
ASME SA-240M Code Sect. II. Part ATYPE 321; TYPE 321 / UNS S32100
ASTM A240/A240MTYPE 321 / UNS S32100
ASTM A240MTYPE 321
EN 10028-7, PED 97/23/EC1.4541
EN 10088-21.4541
EN 10088-41.4541
GOST 5632-7208X18H10T; 12X18H10T
Siemens AG spec. TLV 9360 021.4541
Disclaimer

All data provided is for information and guidance only. Information above is not for design purposes and comes without warranty or guarantee with respect to the subject matter or fitness for purpose.