Sanicro® 41, commonly known as Alloy 825, is an austenitic corrosion resistant Ni-Fe-Cr alloy. It is characterized by:
- Excellent resistance to stress corrosion cracking in chloride and sour (H2S/Cl- ) environments
- Excellent resistance to attack by acidic media such as sulfuric and phosphoric acid
- Better resistance to pitting and crevice corrosion compared to steels of the ASTM 316 type
- Good weldability
- ASTM: 825
- UNS: N08825
- W.Nr.: 2.4858
- DIN: NiCr 21 Mo
- BS: NA14
Suitable for production of flanges etc. according to ASTM B564
Status according to EN 10 204 3.1
Chemical composition (nominal) %
Forms of supply
Sizes and tolerances
Round-cornered square, as well as round billets, are produced in a wide range of sizes according to the following tables. Larger sizes offered on request.
Unground, spot ground or fully ground condition.
Peel turned or black condition.
|80||+/-2||4 - 6.3|
|100, 114, 126, 140, 150||+/-3||4 - 6.3|
|160, 180, 195, 200||+/-4||4 - 6.3|
|>200 - 350||+/-5||3 - 5.3|
Sizes and tolerances apply to the rolled/forged condition.
|75 - 200 (5 mm interval)||+/-1||max 10|
|>200 - 450||+/-3||3 - 8|
|77 - 112 (5 mm interval)||+/-2||max 10|
|124, 134||+/-2||max 10|
|127, 147, 157||+/-2||max 10|
|142, 152, 163||+/-2||max 10|
|168, 178, 188||+/-2||max 10|
|183, 193||+/-2||max 10|
- Welding wire
- Covered electrodes
- Seamless tube and pipe
- Hollow bars
Sanicro® 41 conforms to the required mechanical properties according to specification ASTM B564. Testing is performed on separately solution annealed and quenched test piece.
At 20 oC
At 68 oF
1) Corresponds to 0.2 % offset yield strength
At high temperatures
Fig. 1 shows indicative values for tensile strength properties of Sanicro 41 at high temperatures.
|Temperature, °C||J/(Kg °C)||Temperature, °F||Btu/(lb °F)|
1) typical value
|Temperature, °C||W/(kg oC)||Temperature, °F||Btu/(ft h oF)|
1) typical value
|Temperature, °C||Per °C||Temperature, °F||Per °F|
1) typical values (x10-6)
Sanicro® 41 possesses excellent resistance to corrosion. The material is clearly superior to standard molybdenum-alloyed steels such as AISI 316L, particularly when exposed to non-oxidizing media, such as sulfuric or phosphoric acid. The resistance to highly oxidizing agents, such as nitric acid, is also satisfactory.
Pitting and crevice corrosion
The resistance of Sanicro® 41 to pitting and crevice corrosion is superior to that of AISI 316 - a result of the higher chromium and molybdenum contents in the material.
Stress corrosion cracking
The high nickel content of the material promotes excellent resistance to stress corrosion cracking induced by both chlorides and alkalis. Sanicro® 41 has shown excellent resistant to stress corrosion cracking in sour environments.
Since the material is titanium-stabilized, the risk of intergranular corrosion is minimized.
For further information on corrosion resistance of Sanicro® 41, please see the datasheet - Seamless tube and pipe Sanicro® 41. The data should be considered in the knowledge that it may not be applicable for thick sections, such as forgings.
The hot forming range for Sanicro® 41 is 900-1175°C (1740-2150°F), followed by quenching in water. Subsequent heat treatment should be carried out in accordance with the recommendations given for heat treatment.
Billets are delivered in hot worked condition. The following heat treatment is recommended for finished products.
930-980°C (1700-1800°F) followed by quenching in water.
The weldability of Sanicro® 41 is good. Suitable methods of fusion welding are manual metal-arc (MMA), tungsten inert gas (TIG) and metal inert gas welding (MIG). Preheating and post-weld heat treatment are normally not necessary.
The standard of cleanliness required when welding fully austenitic stainless steels is particularly strict. Joint surfaces and filler metals must be free from grease, paint and other contaminants. The weld zone should be cleaned, as required, using a suitable solvent, such as acetone or alcohol.
Sanicro® 41, like other austenitic materials, has a high coefficient of thermal expansion. Welding should, therefore, be carried out with a low heat input, using well prepared welding procedures to control distortion of the welded construction.
As fully austenitic materials are rather sensitive to hot cracking, welding should be carried out with the lowest practical heat input, <1.0kJ/mm and an interpass temperature of < 100°C (210 oF).
The recommended filler metal for TIG and MIG welding is Sandvik 27.31.4.LCu. For both TIG and MIG/MAG welding, pure argon should be used as a shielding gas and for MIG/MAG welding a pulsed current is suggested. For manual metal-arc welding (MMA), Sandvik 27.31.4.LCuR is the recommended choice.
Machining Sanicro® 41, as with other stainless steels, requires an adjustment to tooling data and machining method, in order to achieve satisfactory results. Compared to Sanmac® 316/316L, the cutting speed must be reduced by approximately 55-60%, when turning Sanicro® 41 with coated, cemented carbide tools. Much the same applies to other operations. Feeds should be reduced by approximately 10-15% and with care.
Detailed recommendations for the choice of tools and cutting data are provided in the data sheet for Sanmac® 316/316L.
Sanicro® 41 has good resistance to general and localized corrosion under diverse conditions. Applications can be found in chemical processing, oil and gas production, acid production, pickling operations and corrosive environments containing sulfuric acid, phosphoric acid, sulfur containing gases, oil wells and sea water.
|Industrial categories||Typical applications|
|Food industry||Valves and discs|
|Pulp and paper industry||Couplings|
|Pickling equipment||Rings and seals|
|Oil & Gas industry||Bolts and nuts|
|Nuclear fuel reprocessing||Shafts|