Sanicro® 35

General characteristics

Sanicro® 35 is a newly developed alloy combining the best features of a high performance austenitic stainless steel and nickel based alloys. This grade is our latest addition to the Ultra range, it has excellent corrosion resistance in combination with a high mechanical strength.

Sanicro® 35 is a trademark owned by Alleima AB and produced as plate and sheet by Outokumpu under a license agreement.

Typical applications

  • Plate heat exchangers
  • Tube, plate and shell of tubular heat exchangers
  • Scrubbers
  • Flue gas cleaning
  • Carbon capture
  • Sea water
  • Brine
  • Chlorinated acids
  • Chlorinated hydrocarbons
  • Chemical
  • Petrochemical
  • Refinery industry
  • Inorganic acids
  • Organic acids
  • Fine chemicals
  • Oil & gas equipment
  • Biorefining
  • Geothermal


Product forms, available sizes and finishes


Product typeFinishesThicknessWidth
Quarto plateHot rolled white10,00-50,00≤ 2000
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.


TypicalSanicro® 350.0227.
ASME CODE CASE 2982-1UNS N08935<0.030<1.2026.0-28.034.0-36.06.1-7.10.25-0.36Si:<0.50 P:<0.030 S:<0.020 Cu:<0.40
ASTM B625UNS N08935<0.030<1.2026.0-28.034.0-36.06.1-7.10.25-0.36Si:<0.50 P:<0.030 S:<0.020 Cu:<0.40
Mechanical properties

The mechanical properties of the available products are given in the table below.


StandardGradeRp0.2Rp1.0RmElongationImpact strengthRockwellHBHV
Product type: Cold rolled coil and sheet
Typical (thickness 1 mm)Sanicro® 35Min 425Min 750Min 40
Product type: Hot rolled quarto plate
Typical (thickness 15 mm)Sanicro® 35Min 350Min 700Min 40


Corrosion resistance

Uniform corrosion

Due to the combination of high contents of nickel, chromium and molybdenum, Sanicro® 35 has good resistance to many commonly found acids, such as sulfuric acid, nitric acid, phosphoric acid and organic acids.
Sanicro® 35 has better resistance in hydrochloric acid compared to stainless steels with a lower chromium and molybdenum content and can be useful in environments where moderate levels of hydrochloric acid is present. 
In low to intermediate concentrations of sulfuric acid, the resistance of Sanicro® 35 is similar to or better than Ultra 904L.

In chloride contaminated sulfuric acid, Sanicro® 35 can be expected to offer better resistance than Ultra 904L and Ultra 254 SMO.
In addition, the active corrosion rates are typically lower than that for stainless steel alternatives, due to the high nickel content.

Pitting and crevice corrosion

Resistance to localized corrosion such as pitting, and crevice corrosion is determined mainly by the chromium, molybdenum and nitrogen content in the material.
This is often illustrated using the pitting resistance equivalent (PRE) for the material, which can be calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N.
Although the PRE typically exhibits good agreement with practical performance, it is only a theoretical approximation.
A more reliable means to rank the alloys, based on laboratory testing, is by critical pitting temperatures (CPT) and critical crevice corrosion temperatures (CCT) of the material.

The CPT value for Sanicro® 35 indicates a pitting resistance significantly higher than Ultra 254 SMO, and on a similar level as Alloy 625.
Sanicro® 35 is resistant up to the maximum tested temperatures of 90°C in ASTM G150 and 85°C in ASTM G48 method E.

Stress corrosion cracking

Due to its high nickel content, Sanicro® 35 exhibits excellent resistance to chloride induced stress corrosion cracking (SCC).
Resistance to cracking can be expected in many environments where type 316L and similar grades would be susceptible to SCC.
Cracking may occur in the most extreme conditions, such as in the boiling 45% MgCl2 U-bend test.
Even then, Sanicro® 35 exhibits higher resistance than 6Mo grades such as Ultra 254 SMO.
The grade complies with NACE MR0175/ISO 15156-3 as a type 4a and 4c material, with significantly higher environmental limits than 6Mo grades like Ultra 254 SMO.

Pitting corrosion resistanceCrevice corrosion resistance
52> 90 (maximum test temperature45

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

Physical properties are shown below.


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

*) Austenitic stainless steel grades may be magnetizable to a certain degree after cold deformation, e.g. in temper rolled condition.


As Sanicro® 35 has a high mechanical strength the required force to start plastic deformation is higher than for many other stainless steels and nickel based alloys.
Sanicro® 35 has an excellent formability as indicated by the high elongation value.


The weldability of Sanicro® 35 is good and welding is suitable using TIG (GTAW), MIG/MAG (GMAW), MMA (SMAW).
For multi pass welding it is recommended to use TIG welding for the root pass.
Welding should be undertaken with low heat input, maximum 1.2 kJ/mm, and an interpass temperature of maximum 100 °C.
Nickel based alloy UNS N06059 (ERNiCrMo-13, NiCr23Mo16) e.g. Avesta P16 is recommended as filler material.
Use of filler material is recommended for this material.
Autogenous welding should typically be avoided but if necessary, followed by appropriate and qualified post weld heat treatment.
Ar + 2 %N2 is recommended as shielding gas with TIG welding to achieve the best combination of mechanical properties and corrosion resistance of the welded joints.
Ar + 2 % N2, Pure N2 or N2 + 5 – 10% H2 can be used as backing gas provided that hydrogen addition is allowed according to given application standard.
For MIG/MAG welding Ar + 20 – 40% He + 1 – 3% CO2 is recommended as shielding gas for optimal corrosion resistance and arc stability.
Pure Ar can also be utilized.
Preheating and post-weld heat treatment are not necessary under normal circumstances.
To maintain full corrosion resistance of the welded joint, welding must be followed by thorough cleaning to ensure the removal of all oxides and heat tint.
Welding of fully austenitic stainless steels and nickel based alloys often involves the risk of hot cracking in the welded joints if the weldment is under restraint.
Due to the low level of impurities in Sanicro® 35, the risk of hot cracking is lower than for most nickel based alloys.
Joint type selection should be made according to recommendation for high alloyed austenitic stainless steels and nickel based alloys.


Standards & approvals

Sanicro® 35 as sheet and plate is included in ASTM B625 as UNS N08935.
Sheet, plate, bar and seamless tube and pipe are covered by the ASME Code Case 2982, Boiler and Pressure Vessel Code, Section VIII, Division I and II.
A process has been initiated for a pre-approval for Particular Material Appraisal (PMA), TÜV.


ASTM B625UNS N08935