Heat and corrosion resistant cast CN-12 type stainless steel with improved high temperature strength and ductility

Patent · Tue Aug 14 00:00:00 EDT 2007

OSTI ID:913576

Mazias, Philip J ^[1]; McGreevy, Tim ^[2]; Pollard, Michael James ^[3]; Siebenaler, Chad W ^[4]; Swindeman, Robert W ^[1]

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1. Oak Ridge, TN
2. Morton, IL
3. East Peoria, IL
4. Peoria, IL

A cast stainless steel alloy and articles formed therefrom containing about 0.5 wt. % to about 10 wt. % manganese, 0.02 wt. % to 0.50 wt. % N, and less than 0.15 wt. % sulfur provides high temperature strength both in the matrix and at the grain boundaries without reducing ductility due to cracking along boundaries with continuous or nearly-continuous carbides. Alloys of the present invention also have increased nitrogen solubility thereby enhancing strength at all temperatures because nitride precipitates or nitrogen porosity during casting are not observed. The solubility of nitrogen is dramatically enhanced by the presence of manganese, which also retains or improves the solubility of carbon thereby providing additional solid solution strengthening due to the presence of manganese and nitrogen, and combined carbon. Such solution strengthening enhances the high temperature precipitation-strengthening benefits of fine dispersions of NbC. Such solid solution effects also enhance the stability of the austenite matrix from resistance to excess sigma phase or chrome carbide formation at higher service temperatures. The presence of sulfides is substantially eliminated.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-96OR22464
• Assignee: Caterpillar Inc. (Peoria, IL)
• Patent Number(s): 7,255,755
• Application Number: 10/195,703
• OSTI ID: 913576
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE