UNS N06110 is a Ni-Cr-Mo alloy developed for service in highly corrosive environments. It has higher chromium content than the numerous other "C-type" alloys that have been developed in the last six decades. This higher Cr-content gives N06110 alloy greater resistance to oxidizing environments than is exhibited by other C-type alloys.
In this paper, the corrosion-resistant properties of N06110 alloy in several severe environments pertinent to the Chemical Process Industry (CPI) are described. The corrosion rates of N06110 alloy are compared with those of Alloy 22 (N06022), Alloy 59 (N06059), Alloy 2000 (N06200), Alloy 686 (N06686), and Alloy 276 (N10276).
The corrosion rate of N06110 alloy was measured in a wide range of solutions, including pure acids, mixed acids, oxides, sulfates, organics compounds, and salts. The data shows that N06110 alloy has an excellent corrosion resistance in many solutions, but is best suited for use in wet oxidizing or mildly reducing environments where it demonstrates superior performance in comparison to other Ni-Cr-Mo alloys.
The corrosion performance of N06110 alloy in a mixed environment of sulfuric acid plus sodium chloride is discussed in detail. Unusual features of corrosion in this mixed environment are explored.
Nickel alloys are able to contain greater concentrations of performance enhancing alloying additions, like chromium and molybdenum, than can be accommodated in the iron-base stainless steels. These greater concentrations of chromium, molybdenum, etc., give the Ni-Cr- Mo greater corrosion resistance than is attainable in the Fe-Cr-Ni stainless steels. These Ni- Cr-Mo alloys possess outstanding combinations of strength, ductility, corrosion resistance and fabricability. One of the newer Ni-Cr-Mo alloys is ALLCORR alloy, UNS N06110, which was developed by ATI Allvac for service in highly corrosive environments. It is a single-phase, solid solution, high-nickel alloy. It has higher chromium content than other "C type" alloys that have been developed in the last six decades. This higher Cr-content gives N06110 alloy greater resistance to oxidizing environments than is exhibited by other C-type alloys. Compositions of N06110 and other Ni-Cr-Mo alloys are shown below:
Table 1 ? Composition Range Comparison for selected Ni-Cr-Mo alloys.
Corrosion resistant alloys typically are used for containing fluids, which generally requires flat product (plate, sheet, strip, etc.). ATI Allegheny Ludlum, an Allegheny Technologies company is a long-standing producer of corrosion-resistant flat-rolled products and has generations of experience with these materials. Processing of flat-rolled product is different from that for long products. This combination of experience and processing offered Allegheny Ludlum the opportunity to re-optimize the composition of N06110 alloy for flat-rolled product production and use. Typical composition of this optimized N06110 product is shown in Table 2, below.
