Download or read book Surface Hardening of Austenitic Stainless Steels Via Low temperature Colossal Supersaturation written by Yan Cao (Ph. D.) and published by . This book was released on 2003 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low Temperature Surface Carburization of Stainless Steels written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Encyclopedia of Iron Steel and Their Alloys Online Version written by Rafael Colás and published by CRC Press. This book was released on 2016-01-06 with total page 3918 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first of many important works featured in CRC Press’ Metals and Alloys Encyclopedia Collection, the Encyclopedia of Iron, Steel, and Their Alloys covers all the fundamental, theoretical, and application-related aspects of the metallurgical science, engineering, and technology of iron, steel, and their alloys. This Five-Volume Set addresses topics such as extractive metallurgy, powder metallurgy and processing, physical metallurgy, production engineering, corrosion engineering, thermal processing, metalworking, welding, iron- and steelmaking, heat treating, rolling, casting, hot and cold forming, surface finishing and coating, crystallography, metallography, computational metallurgy, metal-matrix composites, intermetallics, nano- and micro-structured metals and alloys, nano- and micro-alloying effects, special steels, and mining. A valuable reference for materials scientists and engineers, chemists, manufacturers, miners, researchers, and students, this must-have encyclopedia: Provides extensive coverage of properties and recommended practices Includes a wealth of helpful charts, nomograms, and figures Contains cross referencing for quick and easy search Each entry is written by a subject-matter expert and reviewed by an international panel of renowned researchers from academia, government, and industry. Also Available Online This Taylor & Francis encyclopedia is also available through online subscription, offering a variety of extra benefits for researchers, students, and librarians, including: Citation tracking and alerts Active reference linking Saved searches and marked lists HTML and PDF format options Contact Taylor and Francis for more information or to inquire about subscription options and print/online combination packages. US: (Tel) 1.888.318.2367; (E-mail) [email protected] International: (Tel) +44 (0) 20 7017 6062; (E-mail) [email protected]

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 Low Temperature Surface Hardening of Stainless Steel written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Hardening of Steels written by Joseph R. Davis and published by ASM International. This book was released on 2002-01-01 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation A practical selection guide to help engineers and technicians choose the mot efficient surface hardening techniques that offer consistent and repeatable results. Emphasis is placed on characteristics such as processing temperature, case/coating thickness, bond strength, and hardness level obtained. The advantages and limitations of the various thermochemical, thermal and coating/surface modification technologies are compared

Download or read book Stainless Steels written by Joseph Ki Leuk Lai and published by Bentham Science Publishers. This book was released on 2012 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Stainless Steels: An Introduction and Their Recent Developments explains issues related to surface treatment, grain refinement, coloration, defect detection and powder metallurgy of stainless steels in detail with reference to new research findings. It al"

Download or read book Low Temperature Plasma Nitriding of Austenitic Stainless Steels written by Tatsuhiko Aizawa and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A low temperature plasma nitriding process has become one of the most promising methods to make solid-solution hardening by the nitrogen super-saturation, being free from toxicity and energy consumption. High-density radio-frequency and direct current (RF/DC) plasma nitriding process was applied to synthesize the nitrided AISI304 microstructure and to describe the essential mechanism of inner nitriding in this low temperature nitriding (LTN) process. In case of the nitrided AISI304 at 673¬†K for 14.4 ks, the nitrided layer thickness became 66.5¬†Œom with the surface hardness of 1550¬†HV and the surface nitrogen content of 9 mass%. This inner nitriding process was governed by the synergetic interrelation among the nitrogen super-saturation, the lattice expansion, the phase transformation, the plastic straining, the microstructure refinement, and the acceleration of nitrogen diffusion. When this interrelation is sustained during the nitriding process, the original austenitic microstructure is homogeneously nitrided to have fine-grained microstructure with the average size of 0.1¬†Œom. Once this interrelation does not work anymore, the homogeneous microstructure changed itself to the heterogeneous one. The plastic straining took place in the selected coarse grains so that the parts of them were only refined. This plastic localization accompanied with the localized phase transformation.

Download or read book Advanced Experimental and Numerical Techniques for Cavitation Erosion Prediction written by Ki-Han Kim and published by Springer. This book was released on 2014-07-08 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive treatment of the cavitation erosion phenomenon and state-of-the-art research in the field. It is divided into two parts. Part 1 consists of seven chapters, offering a wide range of computational and experimental approaches to cavitation erosion. It includes a general introduction to cavitation and cavitation erosion a detailed description of facilities and measurement techniques commonly used in cavitation erosion studies, an extensive presentation of various stages of cavitation damage (including incubation and mass loss) and insights into the contribution of computational methods to the analysis of both fluid and material behavior. The proposed approach is based on a detailed description of impact loads generated by collapsing cavitation bubbles and a physical analysis of the material response to these loads. Part 2 is devoted to a selection of nine papers presented at the International Workshop on Advanced Experimental and Numerical Techniques for Cavitation Erosion Prediction (Grenoble, France, 1-2 March 2011) representing the forefront of research on cavitation erosion. Innovative numerical and experimental investigations illustrate the most advanced breakthroughs in cavitation erosion research.

Download or read book Thermochemical Surface Engineering of Steels Improving Materials Performance written by Eric J. Mittemeijer and published by Woodhead Publishing. This book was released on 2017-11-13 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermochemical surface engineering significantly improves the properties of steels. Edited by two of the world s leading authorities, this important book summarises the range of techniques and their applications. It covers nitriding, nitrocarburizing and carburizing. There are also chapters on low temperature techniques as well as boriding, sheradizing, aluminizing, chromizing, thermo-reactive deposition and diffusion. Reviews the fundamentals of surface treatments and current performance of improved materialsCovers nitriding, nitrocarburizing and carburizing of iron and iron carbon alloysExamines how different thermochemical surface engineering methods can help against corrosion"

Download or read book Stainless Steel 2000 written by Tom Bell and published by CRC Press. This book was released on 2020-01-31 with total page 428 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 Low temperature Interstitial Hardening of 15 5 Precipitation Hardening Martensitic Stainless Steel written by Amirali Zangiabadi and published by . This book was released on 2016 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface engineering is a relatively new branch of science and technology. Low-temperature (= 723K) interstitial hardening via carburization and nitridation are effective ways to enhance engineering performance of stainless steels surfaces and developed in the past 20 years. At these para-equilibrium processing temperatures, the substitutional elements in the steels are effectively immobilized, thereby suppressing carbide or nitride formation. The surface hardness, fatigue resistance, and corrosion resistance are significantly enhanced due to the resulting "colossal" interstitial super-saturations achieved during such para-equilibrium interstitial hardening. The studies on 15-5PH precipitation hardening martensitic stainless steels resulted in unusual phenomena, following para-equilibrium nitridation. Firstly, isothermal martensite-to-austenite phase transformation has been observed after low-temperature nitridation in the martensite phase. The transformation occurs in the near-surface regions of the alloy, in which the nitrogen concentration reaches more than 15%at. These observations are consistent with the notion that nitrogen is a strong austenite stabilizer and substitutional diffusion is effectively frozen at the processing temperature. Our microstructural observations and diffraction analyses provide conclusive evidence for the martensitic nature of this phase transformation. The second response of this alloy (similar to the other alloys, e.g. 13-8 PH, 17-7 PH and 2205) is an anomaly in the martensite (or ferrite) lattice, which can be attributed to the enormous tetragonality, approaching c/a = 1.12. Due to the distortion of both phases at the interface, it is sometimes hard to differentiate one from another in their DPs (diffraction patterns). The phenomenological crystallographic theory of the martensite-to-austenite phase transformation has been applied. The theory indicates that the martensitic phase transformation necessitates the closed-packed planes (i.e. {111}¿) of the newly-formed austenite phase undergo shearing. The microstructural studies confirm this internal shearing of the austenite phase. It further appears that the martensitic austenite observed in this work deviates from cubic symmetry. Finally, this study shows that high concentrations of nitrogen interstitials cannot be realized in marten- site or ferrite even under "nitrogen paraequilibrium" conditions, because of the formation of martensitic austenite.

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 Low Temperature Gas Phase Nitriding and Nitrocarburizing of 316L Austenitic Stainless Steel written by Dandan Wu and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Low temperature paraequilibrium nitriding is an effective method to enhance surface hardness and corrosion resistance in austenitic stainless steels, provided that equilibrium nitride formation is suppressed. Following the standard double HCl zactivation & rdquo; procedure developed by Swagelok Company to remove the passivating Cr2O3-rich native oxide, nitriding was done in a gas mixture of NH3/H2/N2. Three processing parameters (nitriding temperature, nitriding activity and duration) were controlled independently to understand both thermodynamic and kinetic aspects of the process. Supersaturated nitrogen interstitials (7 ~ 25 at.%) were introduced into 316L stainless steel samples, which yielded a lattice expansion ranging from 1% to 10%. Room temperature ferromagnetism in expanded austenite in stainless steels was then induced due to the great increase in Fe-Fe interatomic distance. A combined of XRD, MFM and EBSD study revealed that the minimum lattice expansion required for ferromagnetism is ~ 5%. A nitrogen content of ~ 14 at.% was estimated (by AES) as the threshold required for the paramagnetic-to-ferromagnetic transition. The correlation of lattice parameter expansion and nitrogen content indicates that transition from paramagnetic austenite to ferromagnetic austenite played a role in the highly distorted lattice parameters of nitrogen-enriched expanded austenite. Orientation-dependent nitrogen surface concentration and case depth were investigated using EBSD orientation mapping and AES cross-sectional line scans. In particular, 100-oriented grains demonstrated a higher surface nitrogen concentration and a deeper case depth as compared to 111-oriented grains. Three different scenarios of low-temperature gas-phase nitrocarburizing processes were designed and compared. Dual-layered expanded austenites were obtained. The concentration depth profiles of nitrogen and carbon atoms can all be described as an outer layer of nitrogen-enriched region, with carbon atoms accumulated at the diffusion front of nitrogen. The total case depth obtained is mainly determined by the diffusion time of carbon. Grazing angle XRD and TEM were employed to study the precipitates formed after nitrocarburizing.

Download or read book Energy Materials Coordinating Committe EMaCC Fiscal Year 2004 Annual Technical Report written by and published by DIANE Publishing. This book was released on with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low Temperature Surface Hardening of Stainless Steel written by Thomas Christiansen and published by . This book was released on 2004 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: