Ferromagnetism in interstitially hardened austenitic stainless steel induced by low-temperature gas-phase nitriding

Wu, Dee H.; Kahn, H.; Michal, G. M.; Ernst, F.; Heuer, A. H.

doi:10.1016/j.scriptamat.2011.09.023

Cited by 17 publications

(21 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The original study [27], which explored plasma nitriding of medical grade CoCrMo alloy with compositions similar to that used in the present work, found that the expanded phase/layer formed at 400°C on this alloy has ferromagnetic properties as evidenced through the observation of stripe domains via MFM imaging and through hysteresis curves via MOKE. In comparison, there are quite a few studies reporting ferromagnetism for the γ N phase/layer formed on austenitic stainless steels by various ion beam as well as gas nitriding processes [19].…”

Section: Discussionmentioning

confidence: 99%

“…In this and many other investigations, the ferromagnetism of the γ N layers in austenitic SS and CoCrMo has been made clear through the stripe domain mapping by MFM imaging analysis [19][20][21][22][23][24]. MFM imaging is also carried out successfully on alloyed and unalloyed ferritic and/or dual phase stainless steels (DSS) as an alternative technique compared to destructive techniques such as chemical etching [32][33][34].…”

Section: Discussionmentioning

confidence: 99%

“…That study [4] suggested that the ferromagnetic γ N phase is achieved above a certain threshold of N content (above about 20 at.%). Two recent studies, involving ion and gas-phase nitrided 316 stainless steels [19,20], however, find a lower threshold N content value, about 14 at.%, for the ferromagnetic expanded phase. After the detailed study [4], a number of publications reported observations related to the magnetic character of the γ N phase formed on austenitic SSs [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 87%

“…The domain size/shape variations observed on the different grains may be due to the different intrinsic magnetic properties of the expanded phase in those grains. Although not carried out in this study, published papers [19,24] have already established correlations between the domain structure and crystal orientation.…”

Section: Magnetic Force Microscopy Imagingmentioning

confidence: 99%

See 3 more Smart Citations

MFM imaging of expanded austenite formed on 304 SS and CoCrMo alloys

Öztürk

Fidan

Mändl

2014

Surface and Coatings Technology

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

Section: Magnetic Force Microscopy Imagingmentioning

confidence: 99%

See 2 more Smart Citations

MFM imaging of expanded austenite formed on 304 SS and CoCrMo alloys

Öztürk

Fidan

Mändl

2014

Surface and Coatings Technology

View full text Add to dashboard Cite

“…The number of nitrogen that form ε-nitride layer in the nitridation process is not only affected by the process but the most important one is the composition of chemical elements in nitriding materials [5]. Wu [6] observed behavior of austenitic type paramagnetic or ferromagnetic material (316L) based on their lattice. Transformation from paramagnetic to ferromagnetic behavior needs about 5% lattice parameter development achieved by adding 14% of nitrogen concentration in the super-saturated nitriding process.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Chemical Compositions of Tool Steel on the Level of White Layers Homogeneity and the Surface Hardness

Widi¹,

Wardana²,

Sujana³

2013

IJMMM

View full text Add to dashboard Cite

Abstract-The process of nitriding is commonly used in electronic hardware besides the automotive components. So far, there are still gains no optimum result. The atom diffusivity homogeneity effects on the material surface mechanical characteristics are yet to be done. The effecting factors like the composition of the chemicals elements in the materials are needed to be observed. In this paper the nitriding process on three types of tool steel materials with a different chemical composition was observed. The nitriding temperature and time is 550 0C and 4 hours, respectively. The white layer formed on the surface was indentified connected to their mechanical properties. The result showed that the hardness of materials is strongly affected by the stability or the homogeneity of the white layer in the surface. The homogeneity is strongly influenced by the chemical elements composition in materials. The highest hardness level, 975.5 HV occurs at the AISI P20 which shows the most homogeneous thickness surface due to Chrom composition of 2%. The next hardness level, 751.2 HV takes place in the AISI 4340 steel with 1.4 % Cr composition, and the lowest hardness, 720.8 HV occurs at the AISI 4140 with 1.07% Chrom.

show abstract

A Novel Concept of Hybrid Treatment for High‐Hardenability Steels: Concomitant Hardening and Paraequilibrium Thermochemical Treatment to Produce Interstitially Hardened/Stabilized Austenite Surfaces

Toscano

Cardoso

Brunatto

2020

steel research int.

View full text Add to dashboard Cite

Steel components' performance requirements are being strongly increased due to the technological evolution of machines. In most of the cases, surface and bulk material requirements are extremely different, so, an optimised component should present different surface and bulk properties. In such a context, the application of surface engineering processes becomes unavoidable and, to achieve the desired performance at acceptable cost, frequently, new materials and/or processing routes are necessary. The novel concept of hybrid treatment proposed here makes possible to obtain components with such characteristics in a single thermal cycle. So it should be a powerful tool helping to overcome the challenges imposed to the metallurgical industry to produce components that present simultaneously high strength and wear and corrosion resistances at lower costs. This process is the subject of a pending patent BR1020180150758 [1] and this communication has the objective of presenting the new hybrid treatment concept, proving its feasibility by means of a case study. The hybrid process, applicable to highhardenability steels, consists in carrying out a thermochemical treatment during the isothermal step of the martempering or austempering hardening treatment (see Figure 1), above the martensite start temperature and so in the metastable austenite field. Thus, this process combines a surface treatment and a substrate bulk treatment, in a same thermal cycle, probably leading to the reduction of the treatment costs as a whole (hardening plus thermochemical treatment). In addition, it enables to produce a hard interstitially hardened/stabilized austenite treated surface, supposedly presenting higher wear and corrosion resistances than the substrate bulk material. In this concept, depending on the steel hardenability and the chosen processing parameters, the bulk material can be either martensitic or bainitic. The stabilized austenite surface can be produced by paraequilibrium nitriding or carburizing thermochemical treatment. The new concept of hybrid treatment is schematically shown in Figure 1. The first step consists in heating a high-hardenability steel component until the austenitizing temperature, waiting for its complete transformation to stable austenite, and this is the "zero" time point in the Figure 1 scheme. In the sequence, the component/part is cooled down to a temperature that enables the paraequilibrium thermochemical treatment to be conducted, in the metastable austenite field, avoiding the martensitic transformation. The paraequilibrium thermochemical treatment step, in the present case nitriding, is successfully performed at temperatures usually below 420 C for austenitic steels. [2-4] As soon as the paraequilibrium thermochemical treatment step is concluded, the component/part can be cooled down to the room temperature. The last cooling step can produce different microstructure in the component bulk (see Figure 1): 1) for the process ending in "A", a martensitic bulk material will be produced;

show abstract

Ferromagnetism in interstitially hardened austenitic stainless steel induced by low-temperature gas-phase nitriding

Cited by 17 publications

References 23 publications

MFM imaging of expanded austenite formed on 304 SS and CoCrMo alloys

MFM imaging of expanded austenite formed on 304 SS and CoCrMo alloys

The Effect of Chemical Compositions of Tool Steel on the Level of White Layers Homogeneity and the Surface Hardness

A Novel Concept of Hybrid Treatment for High‐Hardenability Steels: Concomitant Hardening and Paraequilibrium Thermochemical Treatment to Produce Interstitially Hardened/Stabilized Austenite Surfaces

Contact Info

Product

Resources

About