Cast Heat-Resistant Austenitic Steel with Improved Temperature Creep Properties and Balanced Alloying Element Additions and Methodology for Development of the Same
AssigneeUT-Battelle, LLC
InventorsRoman I. Pankiw, Govindarajan Muralidharan, Vinod Kumar Sikka, Philip J. Maziasz
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Abstract
The present invention addresses the need for new austenitic steel compositions with higher creep strength and higher upper temperatures. The present invention also discloses a methodology for the development of new austenitic steel compositions with higher creep strength and higher upper temperatures.
Claims16
A cast heat-resistant austenitic steel alloy with improved temperature creep properties and balanced alloyed element additions, said alloy comprising:
- about 0.4 to about 0.7 wt. % carbon;
- about 20 to about 35 wt. % chromium;
- about 30 to about 45 wt. % nickel;
- about 0.5 to about 1.5 wt. % manganese;
- about 0.6. to about 2.0 wt. % silicon;
- up to about 1.5 wt. % niobium;
- up to about 1.5 wt. % tungsten;
- up to about 1.5 wt. % molybdenum;
- and,
- the remainder being iron.
A cast heat-resistant austenitic steel alloy with improved temperature creep properties and balanced alloyed elements additions, said alloy comprising:
- about 0.4 wt. % carbon;
- about 24 wt. % chromium;
- about 35 wt. % nickel;
- about 1.0 wt. % manganese;
- about 0.7 wt. % silicon;
- about 0.3 wt. % niobium;
- about 0.08 wt. % tungsten;
- about 0.5 to about 1.5 wt. % molybdenum;
- about 0.1 to about 0.4 wt. % titanium;
- and,
- the rest being iron.
A method for evaluating compositions of HP and HK alloys comprising the steps of:
- calculating the effect of an addition of alloying elements on the stability of M23C6 and MC utilizing thermodynamic models;
- using said HP and HK alloys as a base reference for said calculations;
- and,
- wherein said addition of alloying elements are used to stabilize strengthening phases at a required temperature as indicated by the results of said thermodynamic calculations to provide improved creep-resistance.
Dependencies are inferred from the claim text.