Effect of Grain Refining on Properties of a Cast Superaustenitic Stainless Steel

The superaustenitic stainless steel presents several technological applications, mainly in corrosive environments. The different phase precipitation might alter some of its mechanical properties. Such alterations affect several factors, including the working life of the material under adverse working conditions. In this study, Instrumented Indentation techniques, Tribology and X-ray diffraction (XRD) were used to evaluate alterations in regions close to the surface. The parameters analyzed were: hardness and elastic modulus (instrumented indentation), friction coefficient (tribology) and structural alterations of the unit cell of the identified phases (XRD - Rietveld Refinement). All properties analyzed were compared with those of common austenitic steel. The presence of σ-phase (space group P42mnm) and γ-austenite (space group Fm3m) were detected. Data analyzed indicated that the presence of σ-phase caused small alteration in properties such as hardness in regions close to the surface. In the regions farther from the surface (material bulk) data can be compared to that of conventional austenitic steel.

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Seawater resistance of a second generation superaustenitic stainless steel

Materials and Corrosion ◽

10.1002/maco.19950460602 ◽

1995 ◽

Vol 46 (6) ◽

pp. 347-353 ◽

Cited By ~ 4

Author(s):

B. Wallén ◽

E. Alfonsson

Keyword(s):

Stainless Steel ◽

Second Generation ◽

Superaustenitic Stainless Steel

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A Comparative Study on the Tribological Properties of a Cobalt-Free Superaustenitic Stainless Steel at Elevated Temperature

Metals ◽

10.3390/met10091123 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1123

Author(s):

Frederic van gen Hassend ◽

Sebastian Weber

Keyword(s):

Stainless Steel ◽

Wear Resistance ◽

Elevated Temperature ◽

Superaustenitic Stainless Steel ◽

Material Loss ◽

Hardness Tests ◽

Alternative Material ◽

Wear Tests ◽

Hot Hardness

The properties of a cobalt-free cast superaustenitic stainless steel (SASS) is investigated comparatively to the commercial high-cobalt alloyed GX15CrNiCo21-20-20 (1.4957, N-155) steel regarding its global hardness and wear resistance at elevated temperature by means of in situ hot hardness tests and cyclic abrasive sliding wear tests against an Al2O3 (corundum) counter-body at 600 °C. In the aged condition, results show that the 1.4957 steel suffers a higher material loss due to brittle failure initiated by coarse eutectic Cr-rich carbides which are incorporated into a mechanically mixed layer during abrasive loading. In contrast, within the Co-free steel eutectic M6(C,N) carbonitrides are distributed more homogeneously showing less tendency to form network structures. Due to the combination of primary Nb-rich globular-blocky MX-type carbonitrides and eutectic M6(C,N) carbonitrides dispersed within an Laves phase strengthened austenitic matrix, this steel provides comparable hardness and significantly improved wear resistance at elevated temperature. Thus, it may be an adequate alternative material to commercial SASS and offers the possibility to save cobalt for future applications.

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