An Enhanced Superaustenitic Stainless Steel Offers Resistance to Aggressive Media
Summary:
must be economical to produce and buy. Alloys such
as UNS N06686 or UNS N10276 exhibit excellent corrosion
resistance, but at a high price. Other alloys, like those
in the 6% molybdenum superaustenitic stainless steel (6%Mo
SS) family are more economical, but sacrifice much of
the corrosion resistance of the higher alloyed materials.
Thus, an alloy that could approach the corrosion resistance
of UNS N10276, but with a price near the 6%Mo SS alloys
would satisfy both of the requirements for marine service.
To meet these requirements, a new superaustenitic stainless
steel with enhanced corrosion resistance to both general
and localized environments has been developed. Corrosion
rates for this new alloy and competitive alloys in seawater,
in chloride environments, and other applications relevant
to marine service are discussed. Many of the new alloys
invented or commercialized recently share a common theme.
By increasing the alloying elements, various corrosion
or mechanical properties will be improved. Many of these
inventions, however, fall short as far as fabricability
is concerned. For every elemental addition to an alloy
for property improvement, a reaction
on the processibility side will occur. For example, many
corrosion resistant alloys
require a very high (1200 °C or higher) anneal and
water quench to avoid secondary
phase formation. Others will crack if cold worked. Furthermore,
many of the new Ni-Cr- Mo alloys carry a price tag many
times that of common stainless steels. To mitigate some
of these concerns, a new alloy has been developed that
improves on both the corrosion resistance and mechanical
properties whilst maintaining similar fabricability and
price compared to current 6%Mo SS alloys.
Format:
Pages : 16
Size: 345 kb
Author :N.C. Eisinger, J.R. Crum, L.E. Shoemaker ; Special
Metals Corporation
3200 Riverside Drive Huntington, WV 25705 ; USA
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