Customers often have mail to ask: what is the material UNS N08031? Control? What alloy? What is the implementation standard? Chemical composition, density, hardness, heat treatment......
Today, AlloyO gives you a general idea of the material.
UNS N08031 is a kind of nitrogen containing iron nickel chromium molybdenum alloy, the performance between super austenitic stainless steel and the existing nickel based alloy. Suitable for chemical and petrochemical industry, environmental engineering and oil, gas production and other industrial fields.
An advanced super-austenitic, high-chromium 6 M0 alloy called alloy 31 (UNS N08031) bridges the cost / performance gap between high-performance N i-Cr-Mo alloys and the 300 series stainless steels. It is especially suitable as a material of construction for the modern chemical process and petrochemical industries, where materials must not only resist uniform corrosion caused by a range of corrodents, but also must have effective resistance to localized corrosion and stress corrosion cracking in halide and other media.
The addition of nitrogen provided the added benefits of improved localized corrosion resistance, stronger mechanical properties, and higher thermal stability.
Alloy 31, known as the “advanced 6 Mo alloy” is the higher-chromium-and—nickel version, and imparts significantly improved corrosion resistance in a variety of media. Its localized corrosion resistance is superior to many alloys, including the N i-Cr—Mo alloy 625, as shown per ASTM G-48 testing. Its uniform corrosion resistance in sulfuric acid in the medium concentration range is superior to even that of Alloy C-276 and alloy 20. As a result, the 6Mo alloys have been applied extensively in pulp and paper production, phosphoric acid production, copper smelters, and sulfuric acid production / reclamation.
The alloy 1925hMo, a “standard 6Mo alloy,” is readily weldable with over-alloyed filler metals such as alloy 625, C-27 6, or 59. These filler metals compensate for the segregation of molybdenum into the interdendrite regions of weldments. On the other hand, Alloy 31 is welded only with alloy 59, except for applications such as chlorine-dioxide bleach washers in the pulp and paper industry.
Alloy 31 is also frequently selected for equipment in pollution control and in the production of phosphoric acid, rayon, and specialty chemicals. Its resistance to salt water corrosion has made it successful in marine and offshore applications, pickling baths, and heat exchangers for which seawater and
brackish water act as coolants. One recent application of Alloy 31 has been in the pressure acid leaching process of recovering nickel from the lateritic ore deposits in Australia. Many hundreds of tons of this alloy have been used in this technology.
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