"Nickel alloys are a very mature field of study, most of the latest developments have been evolutionary in nature rather than revolutionary. Two new developments show that changes can even be made to established nickel alloys to further improve their performance”
The first example is a modification of VDM® Alloy 31 with new alloy chemistry and improved fabrication characteristics. The second example is a new C-type alloy (Ni-Cr-Mo) named VDM Alloy 2120 MoN™ that was developed with improved localized corrosion resistance and increased uniform corrosion resistance in certain acids outpacing the C-alloys commonly in use.
VDM Alloy 2120 MoN™: Excellent corrosion resistance in oxidizing and reducing environments
VDM Alloy 2120 MoN™ is a new Ni-Cr-Mo alloy which has been developed by VDM recently. It is intended for applications requiring high resistance to corrosion due to aggressive acidic chloride or other media with oxidizing conditions, and strong resistance to pitting and crevice corrosion. Typical applications include scrubbers and other components in flue gas desulfurization and waste incineration plants, e.g. heat recovery systems for indirect heat transfer.
“VDM Alloy 2120 MoN™ is the first Ni-Cr-Mo alloy containing nitrogen as an alloying constituent”
VDM Alloy 31 Plus®: Dissolving the sigma phase at lower temperature
“VDM Alloy 31 Plus® belongs to the family of austenitic 6Mo stainless steels. The major aim of this new development was to make the alloy’s solution heat treatment more secure and comfortable for the user and to keep the corrosion properties at the level of VDM® Alloy 31”, says Dr. Kloewer.
The new alloy is a further improved version of VDM® Alloy 31. It has a carefully balanced analysis with a higher nickel content and optimized addition of nitrogen. VDM Alloy 31 Plus® has an austenitic microstructure across the entire temperature range. Solution annealing is performed at temperatures between 1,140 to 1,160°C, while its precursor VDM® Alloy 31 requires a solution annealing temperature of 1,180 to 1,200°C.
“Due to its lower sigma-solvus temperature of 1,140 to 1,160°C, VDM Alloy 31 Plus® is much more user friendly and safer. Furthermore, VDM Alloy 31 Plus® has the same or higher corrosion resistance to the known media of the chemical process industry, high strength and a good ductility”, Dr. Kloewer sums up the advantages of the new alloy. Typical applications are seawater piping and condensers, heat exchangers in phosphoric acid plants, dampers and scrubbers in FGD plants or pickling lines in the steel production.
Customers as well as interested companies are cordially invited to learn more about the new alloys at VDM’s booth at this year’s NACE International's Annual Conference and Exposition, Henry B. Gonzalez Convention Center, San Antonio, Texas, taking place March 9 to 13, booth no. 1621.