Abstract:
A ferritic stainless steel having improved high temperature mechanical properties includes greater than 25 weight percent chromium, 0.75 up to 1.5 weight percent molybdenum, up to 0.05 weight percent carbon, and at least one of niobium, titanium, and tantalum, wherein the sum of the weight percentages of niobium, titanium, and tantalum satisfies the following equation: 0.4
Abstract:
A method of enhancing the corrosion resistance of an austenitic steel includes removing material from at least a portion of a surface of the steel such that corrosion initiation sites are eliminated or are reduced in number relative to the number resulting from processing in a conventional manner. Material may be removed from the portion by any suitable method, including, for example, grit blasting, grinding and/or acid pickling under conditions more aggressive than those used in conventional processing of the same steel.
Abstract:
An alloy having a composition, by weight, of about 0.025 % or less carbon, about 0.5 to about 4.1 % manganese, about 5.5 to about 6.2 % silicon, about 11 to about 15 % chromium, about 9.0 to about 15.5 % nickel, about 0.8 to about 1.2 % molybdenum and about 0.8 to about 2 % copper and the remainder being essentially iron with incidental impurities. This composition results in lean alloy content in a high silicon austenitic stainless steel for concentrated sulfuric acid service while maintaining a corrosion rate similar to and competitive with existing alloys for such service. Acceptable characteristics were found when hot working was carried out in the range of about 2100 DEG F to about 2200 DEG F. Annealing in the range of about 1925 DEG F to about 2025 DEG F is preferred, as is rapid water quenching after annealing.