Cold Deformation and Hardness on Superaustenitic Stainless Steel: Evaluation Methods

The paper presents selected aspects of analysis cold micro-forging process of a screw made of austenitic stainless steel, concerning relation between strain and hardness. Strain hardening character of a material in consecutive forming operations was analyzed experimentally by the measurement of hardness distribution made on longitudinal axial sections of screws. The relationship between hardness and effective strain (hardness curve) was determined, which made it possible to obtain strain distributions in different regions of a material subjected to cold deformation on the basis of strain distribution numerically estimated with FEM simulation performed using QForm2D/3D commercial software. Conclusions were formulated concerning strain inhomogeneity and strain-hardening intensity with respect to the correlation between strain and hardness. It was also concluded, that nonuniformity of hardening rate in a bulk can lead to local variations in flow stress and eventually, to occurrence of the metal flow related defects, which was illustrated with a case study of cold heading of self-tapping screw of AISI 304Cu stainless steel, with large head diameter to shank diameter ratio. In order to validate the obtained results, the same method was used for analysis of hardness development in steel 19MnB4.

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Intermetallic precipitates in superaustenitic stainless steel welds

Electron Microscopy and Analysis 1997 ◽

10.1201/9781003063056-144 ◽

2022 ◽

pp. 557-560

Author(s):

S Heino ◽

E M Knutson-Wedel ◽

B Karlsson

Keyword(s):

Stainless Steel ◽

Superaustenitic Stainless Steel ◽

Intermetallic Precipitates ◽

Steel Welds

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Mechanical, structural and tribological properties of superaustenitic stainless steel submitted at solution heat treatment

Matéria (Rio de Janeiro) ◽

10.1590/s1517-707620150001.0016 ◽

2015 ◽

Vol 20 (1) ◽

pp. 160-168 ◽

Cited By ~ 2

Author(s):

Fabiana Cristina Nascimento Borges ◽

Willian Rafael de Oliveira ◽

Jonas Kublitski

Keyword(s):

Stainless Steel ◽

Austenitic Steel ◽

Instrumented Indentation ◽

X Ray Diffraction ◽

Superaustenitic Stainless Steel ◽

Space Group ◽

X Ray ◽

Σ Phase ◽

Bulk Data ◽

Corrosive Environments

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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