Alloy 20 is an austenitic material ("super alloy") based on nickel-iron-chromium with additions of copper and molybdenum and stabilized with niobium.

Initially, Alloy 20 alloy was created for the production of products, parts, assemblies, the operation of which will be associated with contacts with sulfuric acid, with environments with its presence. However, according to the results of the work of this alloy, it turned out that it has many advantages, which expanded the scope of its use.
Alloy 20 exhibits amazing resistance to any corrosive formation in a wide variety of aggressive environments, and is not susceptible to cracking and crevice corrosion. By stabilizing Alloy 20 N08020 with niobium, carbide deposition during welding is minimized. Strength and resistance to mechanical stress also exceeds the same qualities of other materials.
Corrosion resistance
Nicrofer 3620 Nb has excellent corrosion resistance in sulfuric, phosphoric and organic acids, as well as in aqueous solutions of their salts. Good stability is also maintained in nitric acid.
Due to its proven chemical composition, the alloy exhibits excellent resistance to intracrystalline corrosion and corrosion cracking. The molybdenum component of the alloys guarantees resistance to pitting and crevice corrosion.
Optimum corrosion resistance is only possible when the material to be processed is clean.
Nicrofer 3620 Nb can be welded conventionally with the same type of metal and many other metals. The following methods have been tested: DSPE, DSPE and DSPE, plasma welding, electronic welding.
When welding with shielding gas, the pulse technique is preferred.
The following welding consumable is recommended:
Nicrofer S6020 W.-Nr. 2.4831
SG-NiCr21 Mo9Nb
AWSA5.14 ERNiCrMo-3
W.-Nr. 2.4607
AWSA5.14 ERNiCrMo-13
For electronic welding
W.-Nr. 2.4621
AWSA5.11 ERNiCrMo-3
W. Nr. 2.4609
AWSA5.11 ERNiCrMo-13
Main features and advantages of the alloy:
Excellent resistance to sulfuric and phosphoric acids;
Good resistance to intracrystalline corrosion;
Very good resistance to chloride-induced stress corrosion cracking;
Resistant to pitting and crevice corrosion;
Good mechanical properties, both at room temperature and at elevated temperatures.
The main uses for Incoloy 20 are:
facilities for the production of sulfuric acid, as well as processes based on the use of sulfuric acid;
extraction columns in the production of amino acids and for the production of medicines;
production of synthetic artificial materials;
systems for food production.
food industry;
chemical industry and allied ones;
production of dyes;
manufacturing of heat exchanger elements;
production of explosives, synthetic rubber and plastics;
pharmaceutical industry.
Various products are produced from this alloy according to ASTM standards:
B366 - Forged fittings;
B462 - forged and rolled pipe flanges, forged fittings, parts for high temperature corrosive service;
B463 - plates, sheets, strips;
B464, B468 - pipes;
B471 - springs;
B472 - Reforging blanks;
B473 - Bars and wires;
B474 - welded pipes;
B475 - round braiding wire;
B729 - seamless pipes;
B751, B775 - welded pipes;
B829 - Seamless pipes and tubes.
Other materials

Steel EN-GJS-450-18C - 5.3108
Steel M250-50A - 1.0891
Steel Ni6062
Steel X46MS - 1.1032

Steel XAR 500
Alloy LC-NiCr15Fe - 2.4817
Steel S420QLHHO - 1.8852
Steel S355MLHCO - 1.8674