Download or read book Thermomechanical Surface Treatments of Austenitic Stainless Steels and Their Effects on Subsequent Nitriding During Duplex Treatments written by Youssef Samih and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimizing the surface microstructure and properties is very important to obtain high performance behaviour. Applying appropriate mechanical and thermochemical treatments has been the prime objective of metallurgists. More recently, and particularly for the stainless steels, the Plasma Nitriding was found to be an efficient technique for enhancing the hardness and wear resistance. However, as the nitriding temperature is about 500 °C, the formation of nitrides on the surface leads to a decrease of the corrosion resistance of these alloys. Recent works have shown that using a mechanical pre-treatment allows to decrease the treatment temperature and duration, and also to enhance the nitrogen diffusion within the stainless steels surfaces. In the present work, performances of different Duplex treatments (mechanical + thermochemical) are studied. The Surface Mechanical Attrition Treatment (SMAT), cold rolling and the High Current Pulsed Electron Beam (HCPEB) are used as surface activators prior to plasma nitriding of stainless steels. Before studying the effect of surface activation on the nitrogen diffusion, the effect of the different SMAT parameters (balls size, balls nature, treatment duration ... etc.) on the microstructure is analysed. A new technique based on the notion of Geometrically Necessary Dislocations (GND) is used to depict the thickness of the different SMAT-induced layers and compare the effect of the processing parameters. Then, comparative analysis of the results obtained after nitriding of mechanically deformed samples leads to quantify the effect of the different Duplex treatments. X-Ray Diffraction, Secondary Electron Microscopy associated with Electron BackScattered Diffraction (EBSD), hardness measurement and chemical composition analysis by Glow Discharge Optical Emission Spectroscopy (GD-OES) showed the importance of the surface microstructure and deformation state on the nitrogen diffusion.
Download or read book Plasma Nitriding of Steels written by Hossein Aghajani and published by Springer. This book was released on 2016-09-24 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods.
Download or read book Surface Hardening of Stainless Steel written by Andr√© Paulo Tschiptschin and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The addition of nitrogen to stainless steel improves mechanical and corrosion properties. Nitrogen-bearing stainless steel (HNSS) is a new corrosion-resistant alloy class exhibiting better tribological properties. High-pressure and powder metallurgy techniques were developed for the fabrication of HNSS. Solid-state routes allow nitrogen introduction through thermochemical, implantation, or plasma surface treatments. High-temperature gas nitriding (HTGN), carried out in an N2 atmosphere in the 1000¬∞C range, allows N uptake, obtaining thick, ~0.5,Äì1.0 wt.% N austenitic cases. HTGN is different from conventional nitriding, performed in the 500¬∞C range, where intense CrxNy precipitation occurs, impairing the corrosion resistance. Low-temperature plasma nitriding (LTPN) introduces more N in solution, and colossal supersaturated expanded phases (~45 at.%N) are formed. N supersaturation and compressive stresses increase the hardness of the surface layer to 10,Äì14¬†GPa. Ferritic, martensitic, duplex, and precipitation-hardened stainless steels can be surface-treated by LTPN, obtaining expanded ferrite and martensite. However, single LTPN stainless steel may prematurely fail when submitted to high loading, as the thin and hard expanded layers collapse due to lack of load-bearing capacity. Duplex-nitriding treatment (HTGN¬†+¬†LTPN) results in a thick nitrogen-rich hardened austenite substrate layer, granting mechanical support and adhesion to the expanded austenite layer.
Download or read book Tribology of Diamond like Carbon Films written by Christophe Donnet and published by Springer Science & Business Media. This book was released on 2007-12-06 with total page 673 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights some of the most important structural, chemical, mechanical and tribological characteristics of DLC films. It is particularly dedicated to the fundamental tribological issues that impact the performance and durability of these coatings. The book provides reliable and up-to-date information on available industrial DLC coatings and includes clear definitions and descriptions of various DLC films and their properties.
Download or read book Surface Hardening of Duplex Stainless Steel 2205 written by John Christian Dalton and published by . This book was released on 2017 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increased use of second-generation duplex stainless steels is expected as demands for tougher, more economical, and corrosion resistant alloys increase. A novel gas-phase carburizing and nitriding procedure operating in the temperature range of 325 °C to 440 °C was utilized with the intent of improving both the tribological and electrochemical performance of the 2205 duplex alloy (22Cr-5Ni-3Mo-0.15N) under so-called paraequilibrium conditions. A suite of state-of-the-art microchemical and structural characterization tools were employed following each treatment, and performance of the treated alloys assessed by chloride-based cyclic polarization and nano-indentation hardness measurements. Particular emphasis was placed on understanding the response of the ferritic phase, which has been a source of speculation and confusion since the development of such treatments. CALPHAD-based thermodynamic modeling was also used to predict phase stability in the 2205 system subjected to gas-phase paraequilibrium nitridation or carburization. Analysis of the interstitially-hardened layer in the austenitic phase of 2205 provides results consistent with similar surface hardening treatments of single-phase austenitic stainless steels: a colossally supersaturated and precipitate-free hardened layer of expanded austenite is formed. The interstitial concentration, case depth, and concomitant mechanical properties can be tailored through control of the temperature, duration, and chemical activity with the gas-phase process. Spatially-resolved chemical and structural analysis within the d-ferrite of 2205 revealed two competitive transformation behaviors following nitridation, while carburization led to only one response. For both carburization and nitridation, carbon or nitrogen supersaturations in ferrite on the order of 20 at.% and 25 at.%, respectively, were observed--greater than 10^6 times the equilibrium concentration at room temperature, yet remarkably with unmeasurable expansion or distortion of the bcc lattice. These supersaturated ferrite grains appear `featureless' in the TEM, suggesting the presence of a high density of strain centers. High-resolution TEM revealed that, unlike austenite, ferrite may accommodate colossal concentrations of carbon or nitrogen through the formation of an ultra-high density dislocation network = 10^16 m-2, as opposed to occupation of lattice-expanding interstitial sites. These linear defects, presumably formed during yielding under the large residual stresses of restricted lattice expansion, enhanced the kinetics of spinodal-like decomposition of the ferrite to nm-scale Fe-rich (aFe) and Cr-rich (aCr) ferrite domains within the carburized or nitrided layer, and apparently provide lower-energy sites for carbon and nitrogen than in potential secondary phases. Elsewhere in the case of nitrided 2205, an isothermal, nitrogen-induced ferrite-to-austenite phase transformation occurred due to the potent austenite-stabilizing nature of nitrogen. The austenite transformation product formed in a partitionless manner from the parent ferrite with a high-aspect-ratio plate-like morphology in Nishiyama-Wassermann orientation relationship. These, and other microstructural signatures lead to the conclusion that the austenite formed by a shear-like mechanism characteristic of martensitic reactions. The microstructural evolution of these phase transformations in d-ferrite accompanying low-temperature nitridation of 2205, and lack of carburization-induced transformation of ferrite to austenite, are discussed in light of the chemical and strain energies involved.
Download or read book The Combined Effects of Temperature and Irradiation on the Mechanical Properties of Austenitic Stainless Steels written by J. E. Irvin and published by . This book was released on 1965 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hybrid Process of Low Temperature Nitriding carburizing for Austenitic Stainless Steel written by Askar Triwiyanto and published by . This book was released on 2010 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Austenitic stainless steels are the most widely used in the chemical and petrochemical industry, cryogenic vessels, heat exchangers, machinery for paper, pulp, textile, pharmaceutical, and domestic equipment. This type of steels has excellent corrosion resistance and forming characteristics. However, due to its inherent austenitic structure this material has relatively low hardness as well as poor wear resistance. Earlier attempts to increase the surface hardness and wear resistance of austenitic stainless steels by surface treatments, such as conventional nitriding and nitrocarburizing, led to the deterioration in corrosion resistance arising from the depletion in chromium in the hardened layer. Attempts have been made to harden the surface of these materials without compromising their good corrosion resistance. These led to the development of low temperature nitriding and carburizing processes which are carried out at temperatures lower than 500 °C. So far, low temperature nitriding and caruburising of austenitic stainless steels have been successfully conducted by innovative techniques, including plasma nitriding, ion beam nitriding and ion implantation. However, no attempts have been made to harden these materials commercially using conventional processes such as gaseous and fluidized bed processes. This work describes the results of diferent thermochemical treatments of austenitic stainless steels carried out at 450 oC and 470 oC in a fluidised bed furnace which nitriding, carburizing and the newly developed hybrid process involving the simultaneous and sequential incorporation of nitrogen and carbon to form a dual layer structure. All these treatments formed alloyed layers with a common feature of being precipitation-free and supersaturated with nitrogen, or carbon or both in the austenite lattice which is known as S-Phase or expanded austenite. However the layer thickness was not uniform in any of these treatments and an effective layer was produced after 8h treatment duration. The nitriding treatment produced thicker and harder layer compared to other treatments; the maximum hardness was over 1500 Hv for nitriding and it was 500 Hv for carburizing treatment. The nitriding treatment sample showed better wear properties due to higher hardness value. The hybrid process of this thermochemical treatment at 470 oC showed superior thickness of 8.4 @m to 12.2 @m expanded austenite layer compared to another treatments at 450 oC without the presence of nitride particles.
Download or read book High Performance Stainless Steels written by Curtis W. Kovach and published by . This book was released on 2000 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Treatments Of Steels and Steel Nitriding written by Okba Belahssen and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enormous progress has been made in the field of materials science, it is still many technological challenges, including the development of materials and taking into account the social and environmental impact of their production and use. In this work, the surface treatments of steels are exposed using an accessible and clear terminology. Treatment methods are explained in detail. An example of a plasma nitriding treatment was introduced; this treatment was carried out under different conditions. This book is intended for students and researchers in post graduation.
Download or read book Stainless Steel 2000 written by Dr. Tom Bell and published by . This book was released on 2019 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Austenitic stainless steels lend themselves to a wide range of applications. However, they normally stiffer from poor wear resistance and do not respond well to traditional surface treatments. This volume. the fruit of a current status seminar, reflects the enormous strides which have been made in the last few years in the study of the expanded austenite phase (also called the S phase) and the development of new surface treatment techniques. As well as the papers presented at the seminar, the book contains selection from related papers and a comprehensive bibliography of the literature on the subject from 1979 to 2000.
Download or read book The Influence of Pre Irradiation Heat Treatments on Thermal Non Equilibrium and Radiation Induced Segregation Behavior in Model Austenitic Stainless Steel Alloys written by GS. Was and published by . This book was released on 2004 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of pre-irradiation heat treatments on thermal non-equilibrium grain boundary segregation (TNES) and subsequent radiation-induced grain boundary segregation (RIS) is studied in a series of model austenitic stainless steels. The alloys used for this study are based on AISI 316 stainless steel and have the following nominal compositions: Fe-16Cr-13Ni-1.25Mn (base 316), Fe-16Cr-13Ni-1.25Mn-2.0Mo (316 + Mo) and Fe-16Cr-13Ni-1.25Mn-2.0Mo-0.07P (316 + Mo + P). Samples were heat treated at temperatures ranging from 1100 to 1300°C and cooled at four different rates (salt brine quench, water quench, air cool and furnace cool) to evaluate the effect of annealing temperature and quench rate on TNES. The alloys were then processed with the treatment (temperature and cooling rate) that resulted in the maximum Cr enrichment. Alloys with and without the heat treatment to enrich the grain boundaries with Cr were characterized following irradiation to 1 dpa at 400°C with high-energy protons in order to understand the influence of alloying additions and pre-irradiation grain boundary chemistry on irradiation-induced elemental enrichment and depletion profiles. Various mechanistic models will be examined to explain the observed behavior.
Download or read book Duplex Stainless Steels written by R Gunn and published by Woodhead Publishing. This book was released on 1997-10-21 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two very successful conferences - in Glasgow and Beaune - were held on duplex stainless steels during the first half of the '90s. This book takes keynote papers from each, and develops and expands them to bring the topics right up to date. There is new material to cover grades, specifications and standards, and the book is fully cross-references and indexed. The first reference book to be published on the increasingly popular duplex stainless steels, it will be widely welcomed by metallurgists, design and materials engineers, oil and gas engineers and anyone involved in materials development and properties. The first reference book on this relatively new engineering material Based on keynote papers from major international contributors Covers grades, standards and specifications
Download or read book Surface Treatments for Precipitation hardening Stainless Steels written by and published by . This book was released on 1967 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nitriding of Type 304 Stainless Steel in a Sodium nitrogen System written by J. J. Gill and published by . This book was released on 1961 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An XPS and Electrochemical Study of the Influence of Molybdenum and Nitrogen on the Passivity of Austenitic Stainless Steel written by R. D. Willenbruch and published by . This book was released on 1989 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: In previous surface studies of N bearing stainless steels exposed to acidic environments we have determined that N is anodically segregated as a surface nitride phase. In this paper we have focused on the nature of the surface nitride and its role in the passivity of each of the constituent elements comprising a Mo bearing stainless steel. To facilitate this study, surface nitrides were generated electrochemically at room temperature on the surface of high purity samples of Cr, Mo, Fe and Ni and on the surface of types 304, 317LX, 904L and A16X stainless steels. The effect of the surface nitriding treatment on the anodic kinetics of the stainless steels was in close agreement with the effect of N alloying. The surface nitriding of Cr resulted in the complete elimination of the active nose in deaerated 0.1 MHC1. Nitride; Molybdenum; Stainless steel. (jes).
Download or read book Manufacturing and Application of Stainless Steels written by Andrea Di Schino and published by MDPI. This book was released on 2020-04-15 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stainless steels represent a quite interesting material family, both from a scientific and commercial point of view, following to their excellent combination in terms of strength and ductility together with corrosion resistance. Thanks to such properties, stainless steels have been indispensable for the technological progress during the last century and their annual consumption increased faster than other materials. They find application in all these fields requiring good corrosion resistance together with ability to be worked into complex geometries. Despite to their diffusion as a consolidated materials, many research fields are active regarding the possibility to increase stainless steels mechanical properties and corrosion resistance by grain refinement or by alloying by interstitial elements. At the same time innovations are coming from the manufacturing process of such a family of materials, also including the possibility to manufacture them starting from metals powder for 3D printing. The Special Issue scope embraces interdisciplinary work covering physical metallurgy and processes, reporting about experimental and theoretical progress concerning microstructural evolution during processing, microstructure-properties relations, applications including automotive, energy and structural.
