Retardation of intermetallic phase formation in experimental superferritic stainless steels

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/BF02652337· OSTI ID:382497

Nana, S; Cortie, M B ^[1]

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1. Mintek, Randburg (South Africa). Physical Metallurgy Div.

While superferritic stainless steels containing 29 pct chromium possess excellent resistance to corrosion, they may, under certain conditions, be embrittled by the precipitation of intermetallic phases. The extent to which the precipitation reactions can be retarded by alloying additions of aluminum and copper has been evaluated. It was found that additions of aluminum to an Fe-29 pct Cr-4 pct Mo-1.5 pct Ni base alloy suppress the precipitation of the undesirable sigma and chi intermetallic phases, but additions of up to 3 pct aluminum promote 475 C embrittlement. Additions of copper slightly reduce the precipitation of sigma and chi phases under most conditions but enhance 475 C embrittlement. The resistance to corrosion in 10 pct H{sub 2}SO{sub 4} and 10 pct FeCl{sub 3} was assessed. All the aluminum-containing alloys performed significantly better in H{sub 2}SO{sub 4} than the base alloy; however, large additions of aluminum had a deleterious effect on the pitting resistance in FeCl{sub 3}. Additions of copper improved the resistance to FeCl{sub 3} and lowered the rate of corrosion in the H{sub 2}SO{sub 4} solution used.

• Sponsoring Organization: USDOE
• OSTI ID: 382497
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 9 Vol. 27; ISSN MMTAEB; ISSN 1073-5623
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ADDITIONS
CHEMICAL COMPOSITION
CHROMIUM ALLOYS
COPPER ADDITIONS
CORROSION RESISTANCE
EMBRITTLEMENT
INTERMETALLIC COMPOUNDS
IRON BASE ALLOYS
IRON CHLORIDES
KINETICS
MOLYBDENUM ALLOYS
PHASE STUDIES
PRECIPITATION
SULFURIC ACID