ALLOY 20

These consumables are engineered to produce a fully austenitic weld metal, skillfully stabilized with niobium, and enriched with the alloying elements of molybdenum and copper. This meticulous formulation imparts a weld metal that exhibits exceptional resistance to corrosion across a spectrum of challenging environments, including sulphuric acid, various mineral acids, organic acids, and their intricate mixtures. Tailored primarily for castings, these consumables extend their application prowess to a wide array of scenarios, serving notably in tanks, process piping, heat exchangers, agitators, rotors, as well as cast pumps and valves. Their versatility finds a fitting niche in industries engaged in chemical processing, metal cleaning, and pickling. Furthermore, these consumables, bearing the designation 825, stand as akin to other high-alloy corrosion-resistant products. This similarity positions them as a technically compatible alternative in select applications, offering flexibility and adaptability to meet diverse corrosion-resistant needs across different industrial settings.

20%Cr-34%Ni-3.5%Cu-2.5%Mo (alloy 20) austenitic corrosion resistant alloy.

In the as-welded condition the microstructure is fully austenitic.

ASTM: A351, A744 gr. CN-7M.
PROPRIETARY: Alloy 20, 20Cb, 20Cb-3 (Carpenter), Paramount P20 (Lake, Elliot), Langalloy 20V (Meighs).

No preheating is necessary, and it is imperative to control the interpass temperature, ensuring it does not exceed 150°C. Additionally, close scrutiny of heat input, especially when employing 4mm diameter electrodes, is crucial. Repairing alloy 20 castings may pose challenges, as Heat-Affected Zone (HAZ) regions are prone to fissuring, and weld metal becomes more susceptible to cracking if silicon pick-up occurs. Addressing problematic castings may involve buttering at extremely low heat input using small diameter electrodes to minimize dilution. Typically, welds are left in the as-welded condition. However, castings adhering to ASTM specifications might necessitate a solution treatment at 1125°C following significant repairs.