bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nitrogen on toughness and strain age embrittlement of ferritic steel weld metal
Authors: Achar D. R. G. , Koçak M. , Evans G. M.
Published: January 2014

Investigations were carried out to evaluate the influence of dissolved nitrogen in ferritic steel weld metal on its toughness and strain aging behaviour through fracture mechanics as well as conventional impact testing approaches. Manual metal arc C–Mn steel weld metals with nitrogen contents between 80 and 210 ppm (wt) were investigated under four different post-weld conditions, namely, (i) as welded, (ii) stress relieved, (iii) artificially strain aged, and (iv) artificially strain aged and stress relieved. Quantitative metallography and low load microhardness studies of microphases were an integral part of these investigations. The results demonstrate the highly detrimental effect of nitrogen on the toughness behaviour of C–Mn steel weld metal, particularly under strain aging conditions. This is substantiated by the decrease of acicular ferrite content with the accompanying increase in primary ferrite and ferrite with second phases in the microstructures. Also, there is a distinctive increase in acicular ferrite microhardness. Post-weld stress relieving heat treatment under these conditions results in only a marginal improvement in toughness and shifts the fracture behaviour from brittle to ductile or quasiductile only for low nitrogen weld metals. Comparing the results of the crack tip opening displacement and Charpy tests, it is observed that both methods show the influence of nitrogen on toughness behaviour to have the same form but the magnitudes of the effect measured are different, the results obtained using the fracture mechanics method appearing very conservative.
Non-destructive measurement of residual stresses in carbon steel weld joints
Authors: Joseph A. , Palanichamy P. , Rai S. K. , Jayakumar T. , Raj B.
Published: January 2014

Residual stress measurements have been carried out on 8 and 12 mm thickness carbon steel single V weld joints by X -ray diffraction and ultrasonic techniques. The maximum tensile and maximum compressive stresses on the surface of the 12 mm carbon steel weld joint are higher than those on the surface of the 8 mm carbon steel weld joint. The results also indicate that the variation in the surface residual stress across the weld is different from that for the through thickness residual stresses. The effect of constraint, which depends on the thickness of the weld joint, is found to influence the surface and through thickness residual stresses. The effect of stress relief annealing heat treatment on residual stresses was also studied.
Analysis of arc voltage, current, and light signals in pulsed gas metal arc welding of aluminium
Authors: Subramaniam S. , White D. R. , Jones J. E. , Lyons D. W.
Published: January 2014

The use of readily acquired weld arc data such as voltage, current, or light emissions to identify droplet transfer events or transfer mode, or for quality purposes such as seam tracking is of interest for thin section applications in arc welding of aluminium. In the present study, voltage, current, and light emission signals are acquired at high rates, and synchronised with high speed shadowgraphing. The usefulness of the various signals for identifying droplet detachment events and transfer modes during pulsed gas metal arc welding of aluminium is compared. It is found that individual droplet detachments are consistently identifiable during globular, spray, and streaming transfer, and during peak and background current detachment, using the voltage signal. Although the arc light signal also contains droplet detachment data, it is difficult to identify droplet detachments occurring during the background phase at low background current levels. Preliminary measurements show that these signals can also be used for seam location in thin section lap fillet welding.
Imaging of modified 9Cr–1Mo ferritic steel weldment via ultrasonic velocity measurements
Authors: Kumar A. , Laha K. , Jayakumar T. , Rao K.B.S. , Raj B.
Published: January 2014

Ultrasonic velocity measurements have been carried out across the weld line in two perpendicular sections of modified 9Cr–1Mo ferritic steel weldments, in the as welded and post-weld heat treated (PWHT) conditions. The ultrasonic velocity plot is correlated with the weld profile in both the sections and with the associated microstructural features in different regions of the weldments for the two conditions investigated. The present study reveals that the weld profile can be imaged and the adequacy of the PWHT can also be assessed in modified 9Cr–1Mo ferritic steel weldments using ultrasonic velocity measurements.
Current Status of Laser Surface Melting of Cast Iron
Authors: Bergmann H. W.
Published: January 2014

This paper reviews the principles of laser melting and some of the processing techniques involved. The main aspects of the laser surface melting of cast irons, including the various microstructures and resultant properties, are discussed in detail and possible applications of laser melted components are also considered.
Engineering the Surface with Boron Based Materials
Authors: Dearnley P. A. , Bell T.
Published: January 2014

Boron, boron carbide, boron nitride, and transition metal borides have many attractive properties, including high melting point and hardness, good wear and corrosion resistance, excellent electrical conductivity, and resistance to attack by molten metals. There therefore appears to be significant scope for enhancing surface properties of metals and ceramics by applying coatings constituted from these materials. Currently, the only commercial coating processes practised have been the thermochemical diffusion techniques termed boronizing or boriding, whereby boron is diffused into, and combines with, the substrate material forming a single or double phase metal boride layer at, and adjacent to, the surface. This review not only describes the various media used for such treatments and their limitations, but attention is also given to the lesser known processes, not yet commercially practised, which provide for the deposition of a wide variety of boron based materials. Such processes, like PVD and CVD, appear to hold great potential for the future. The wear, corrosion, and oxidation properties of boron based coatings are described and specific applications are cited.
Equilibrium and Non-Equilibrium Models of Layer Formation during Plasma and Gas Nitriding
Authors: Marciniak A.
Published: January 2014

Equilibrium and non-equilibrium models of γ'-Fe4N growth during nitriding are considered in an attempt to explain the differences observed in the growth of this phase during glow discharge plasma nitriding and gas nitriding. Calculated results taking account of cathode sputtering agree well with experimentally observed ones. Solutions for the non-equilibrium model approach those of the equilibrium model when mobility of the γ'/α interface approaches infinity.
Proposed Wear Mechanism for Titanium Nitride Coated High Speed Steel
Authors: El-Bialy B. H. , Redford A. H. , Mills B.
Published: January 2014

An extensive study has been carried out to investigate the wear of a range of high speed steel tools coated with an ion plated titanium nitride layer used at a variety of cutting speeds and feed rates when machining cast iron and an AISI/SAE 4140 steel. Examination of the form of flank wear v. cutting time curves indicated that a stable micro built-up edge is produced rapidly on the coated tools which causes reduced primary wear and, hence, increased tool life. The production of the stable micro built-up edge is shown to be a result of a major change in the contact conditions between the chip and the tool for the coated tool which is a consequence of a reduced friction force on the tool face. Supplementary experiments including quick stop tests, cutting force measurements, contact length and chip thickness measurements, and high magnification scanning electron microscopy have confirmed the validity of the proposed mechanism of reduced primary wear for coated tools.
Isothermal and Cyclic Plasma Nitriding of Titanium Alloys
Authors: Roliński E.
Published: January 2014

Plasma nitriding of two titanium alloys was carried out in a specially designed glow discharge chamber with a titanium cathode. The experiments were performed isothermally at 930 and 730°C, and also cyclically over the same temperature range. The tribological characteristics of the surfaces after treatment were evaluated using a modified four ball wear test. It is shown that materials processed at 730° C, which possess a complex titanium nitride based surface structure, have the best wear resistance. This result is attributed to the lower proportion of brittle TiN that is produced at low treatment temperatures.
Residual Stresses in Laser Transformation Hardened Steel
Authors: Li W. B. , Easterling K. E.
Published: January 2014

A simple analytical solution is developed for calculating the residual stresses which occur as a result of the laser transformation hardening of steel surfaces. The solution is based mainly on taking account of the dilatation resulting from the martensitic transformation and allows the influence of the many and varied parameters involved in laser transformation hardening (beam size and intensity, material properties, composition, etc.) to be readily assessed. Satisfactory agreement between the theoretical predictions and reported experilnental measurements of residual stress is obtained.
Ion Vapour Deposition of Aluminium for Corrosion Protection: 10 Years Production Experience
Authors: Ahmed N. A. G.
Published: January 2014

Ion vapour deposition of aluminium has become a recognized process for depositing highly adherent coatings on different materials to impart corrosion resistance. This technology, which was invented in the 1960s, is now used commercially on a production scale to aluminize aircraft and other components to enhance corrosion protection, replacing cadmium electroplating. The continuous need to adapt to different applications has led to the growth of new and more reliable equipment designs. Coating operations have been shown to be clean, simple, and non-labour intensive.
Nylon Powders and their Application as Surface Coatings Using Flame Spraying
Authors: Blackmore C. E.
Published: January 2014

The advantages of powder coating techniques over traditional paint systems are reviewed with reference to Nylon 11 (Rilsan) coatings. The physical, electrical, and chemical resistance properties of such coatings are summarized, and component design for surface coating is discussed. After consideration of surface preparation requirements, the advantages of three application techniques, fluidized bed coating, electrostatic spray coating, and flame spraying, are covered, particular attention being given to flame spraying since the fact that it can be used easily on site suggests widespread future usage. A brief discussion of current industrial applications of flame sprayed nylon coatings is followed by some thoughts on the future development of the process.
Effect of Plasma Nitriding Temperature on Surface Properties of Austenitic Stainless Steel
Authors: Roliński E.
Published: January 2014

A chromium–nickel austenitic stainless steel was plasma nitrided at 535, 585, 650, 735, and 785°C. After nitriding, the structure, thickness, and hardness of the surface layer, as well as the appearance and height of surface irregularities, were determined. The wear and corrosion resistance of the nitrided steels were tested and the percentage of magnetic phases present was determined. It has been established that nitriding markedly raises the wear resistance of the steel at pressures of 50, 200, and 400 MPa. The corrosion resistance of the steel in 0.05 M Na2SO4 at pH 3 decreases as a result of nitriding. Nitriding leads to the appearance of a multi phase structure in the surface layer, the proportion of the ferromagnetic a and γ’ phases being dependant on nitriding temperature. After nitriding at 785°C the proportion of these phases is minimal. At the same time, the steel has a high hardness and wear resistance and is susceptible to passivation.
Formation of Diffusion Coatings on Iron and Steel: 1 Formation Processes
Authors: Sequeira C. A. C. , Nunes C. M. G. S.
Published: January 2014

This paper is primarily concerned with metallic diffusion coatings for the protection of iron and steel. Special reference is made to the physicochemical factors determining which metals are able to form diffusion coaiings, the methods of application available, and the nature of the alloy coatings thus formed. The present paper is part 1 of a three part series: part 2 will deal with ‘Theoretical considerations’ and part 3 with ‘Aluminium, chromium, and zinc coatings’.
Collision Dissociation Model in Ion Nitriding
Authors: Bingzhong Xu , Yingzhi Zhang
Published: January 2014

Specimens of iron and various steels were ion nitrided in different atmospheres at different ionic energy levels. A collision dissociation model of ion nitriding is proposed, based on the results of ion nitriding tests and calculations of the densities of ions and neutral particles in the cathode potential drop region, incorporating analysis of the collision process and cathode sputtering effects. In ion nitriding there are several possible processes of nitrogen atom migration from gas phase to solid phase, but ion nitriding is achieved primarily by penetration of active nitrogen atoms produced by collision dissociation. The energy conditions of N2, NH3, and N2–H2 in collision dissociation were analysed and the amount of active nitrogen atoms was calculated semiquantitatively. The calculated values were in agreement with the results of the nitriding tests. The effects of H2 on collision dissociation and the heating of the cathode during ion nitriding are also discussed.
Effects of Deposition Parameters on Structure and Composition of Reactively Sputtered TiNx Films
Authors: Manory R.
Published: January 2014

The effects of different deposition parameters on the composition and crystallographic features of radio frequency magnetron sputtered TiNx films were studied. A ‘phase relation diagram’ correlating film composition and ratio of input power to nitrogen flow is proposed. The partial pressure of nitrogen has been found not to be of importance in determining either the cOlnposition or the orientation of the films. The effects of N2/Ar ratio, nitrogen flow, and total reactor pressure are shown. A linear decrease in lattice paran1eter with increasing target to specimen distance was found. This may serve as a good means of controlling film composition within the range of the gold colour (0.8 ≤ x ≤ 1). The optimum deposition conditions for hard films were determined.
Formation of Diffusion Coatings on Iron and Steel: 2 Theoretical Considerations
Authors: Sequeira C. A. C. , Pacheco A. M. G. , Nunes C. M. G. S.
Published: January 2014

The principles that control the reactions occurring during the formation of metallic diffusion coatings for the protection of iron and steel are reviewed. Thermodynamic principles are used to examine the reaction mechanisms of coating formation, and are related to the composition and structure of the coatings formed. The principles of diffusion are outlined and a description of the experimental determination of diffusivities is given, together with some typical results. The mechanistic aspects are discussed with particular reference to metals. Solutions of the diffusion equations are analysed with respect to the kinetic aspects of diffusion coating formation, which are also often a function of composition and structure.
Diffusion Mechanism of Ion Bombardment
Authors: Li Chengji , Xu Zhong
Published: January 2014

Some new ideas on diffusion modelling under ion bombardment heat treatment conditions are presented. The model put forward may explain why ion bombardment treatment times can be much shorter than those for conventional processes. Some of the problems are discussed, such as the influence of ion bombardment on treated surface structure and vacancy diffusion.
Plasma Processing in Nitrogen Containing Atmospheres: 10 Years Development
Authors: Korhonen A. S. , Molarius J. M. , Sulonen M. S.
Published: January 2014

Metallic composites with specifically defined properties may be produced by various techniques. Thus, for example, high temperature materials can be covered by MCrAIY coatings by means of low pressure plasma spraying. These coatings offer considerable advantages with regard to high temperature oxidation resistance and generally lead to a longer useful life of the coated components. A further possibility to improve the properties of such composites is a post-treatment by hot isostatic pressing (hipping). The hipping process increases the density of the coatings and has so far proved itself in improving the mechanical properties of components made of nickel and cobalt base superalloys.
Influence of Sputtering and Redeposition on Compound Layer Growth during Plasma Nitriding
Authors: Wells A. , Strydom I. le R.
Published: January 2014

Apparently anomalous surface compound layer growth is observed during plasma nitriding, and this has previously been ascribed to the removal of surface material by sputtering. Previous work has produced results which clearly indicated that during plasma nitriding non-uniform sputtering of material occurs on the workpiece and that this gives rise to a net loss of material from high sputtering sites such as edges and corners and to a net redeposition of material on flat faces. In the present work, the γ’–Fe4N compound layers on the flat faces of pure iron workpieces were found to display anomalous growth behaviour, in which the compound layer initially increases and subsequently decreases in thickness. This observation cannot be explained by the removal of layer material by sputtering. The nature of the redeposition of material was examined and it was found that there is a time delay associated with its onset. In addition, examination of the redeposited material by quantitative scanning Auger microprobe depth profiling revealed that oxygen accumulation occurs in the redeposited material. The anomalous growth behaviour of the compound layer can be ascribed to the formation of the redeposited material layer which inhibits further nitriding of the substrate.
Formation of Internally Oxidised Silver-Metal Oxide Composites by Laser Gas Alloying
Authors: Schultz L. , Bergmann H. W.
Published: January 2014

It has been demonstrated that internally oxidised silver-metal oxide composites can be formed by laser melting if an oxygen gas jet is directed on to the melt pool. Me tallographic and electron microprobe investigations have distinguished two types of tin oxide precipitate. The applicability of this technique to the production of Ag–SnO2 material for electrical contact applications is discussed.
Non-Destructive Testing of Arc and Plasma Sprayed Coatings by Ultrasonic Imaging Technique
Authors: Crostack H. , Kruger A. , Steffens H. -D.
Published: January 2014

In ultrasonic testing of thermally sprayed coatings difficulties often occur, which relate partly to poor lateral and axial resolution, partly to the coarse grained structure of the coatings, and partly to insufficient accuracy in defect description. These problems can be reduced by a test procedure in which the ultrasonic pulses sent into the test body are visualised optically. In practice this is achieved by producing high energy ultrasonic pulses with well defined spectral content and by observing the propagating wave optically by holographic interferometry The object to be tested is illuminated twice by a pulsed laser beam for a very short period, and it has proved possible to incorporate the system into a mobile test unit. The complete sound field and interactions of the sound with existing defects are imaged directly with respect to position, shape, and size. Apart from basic discussion of the test method, results of practical applications to flame, arc, and plasma sprayed coatings are presented.
Life of Tin and Ti(C,N) Coated and Uncoated HSS Drills
Authors: Aboukhashaba A. A.
Published: January 2014

TiN and Ti(C,N) coatings have been applied to 156 in (7.94 mm) dia. HSS M2 drills for use on mild steel workpieces. Reactive ion plating utilising an evaporation source was used to produce coating layers 1j1m in thickness. Axial and radial vibration signals were recorded for coated and uncoated HSS drills and subjected to high resolution signal analysis. A lubricant was used and speed and feed were kept constant at 50 m min-1 and 375 mm min-1 respectively throughout. Tool wear was measured on the flank of the drills by means of a television projector. Worn drills were also examined by SEM to determine the failure mode. Surface roughness of the drilled holes was examined for both coated and uncoated tools. Coated tools had longer lives as a result of lower wear rates and smaller built up edges as well as the lower thermal conductivity of the coating.
Kinetics of the Gaseous Nitrocarburising Process
Authors: Slycke J. , Sproge L.
Published: January 2014

Results obtained regarding compound layer phase composition, porosity, and overall thickness after nitrocarburising various steels in various atmospheres are presented. In particular, the gas reactions that take place in the furnace chamber and the mass transfer reactions for nitrogen and carbon are discussed, from practical and theoretical points of view. The compound layer phase compositions obtained with the various types of steel are discussed in connection with the new Fe-N-C phase diagram. It is shown that, by controlling the activity of carbon, oxygen, and nitrogen in the atmosphere, it is possible to control the phase composition, porosity, and growth rate of the compound layer. Furthermore, it is shown that by selecting the atmosphere composition it is possible to obtain optimal results for each type of steel. A brief survey is given characterising the commercial nitrocarburising methods presently available.
Surface Integrity of a Die Steel after Electrodischarge Machining: 1Structure, Composition, and Hardness
Authors: Merdan M. A. E. -R. , Arnell R. D.
Published: January 2014

Cylindrical specimens of KEA 145 (AISI type H 13) hot working die steel were electrodischarge machined using roughing and finishing generators to control the discharge. The resulting microstructures were studied by optical and electron microscopy, and microhardness profiles were obtained on transverse sections. Surface roughness and microcrack density were found to increase with increasing pulse energy. Machining using the roughing generator produced rougher surfaces and fewer, but deeper and wider, microcracks than when using the finishing generator. Five distinct microstructural zones were observed: a glassy, featureless surface zone; a fine polygonal ε carbide structure; a fine acicular or martensitic structure; a fine cellular or polygonised structure; and the matrix structure. This variation was found to be associated with a microhardness variation with depth.
Elimination of Intergranular Corrosion Susceptibility of a Sensitised 304 Steel by Subsequent Laser Surface Melting
Authors: de Damborena J. , Vazquez A. J. , Gonzalez J. A. , West D. R. F.
Published: January 2014

The electrochemical behaviour of a sensitised 304 stainless steel which has subsequently undergone a fusion treatment of its surface with a continuous wave CO2 laser has been studied. The area directly affected by the fusion has a fine scale microstructure of austenite; the intercellular regions are interpreted as containing ferrite. The electrochemical corrosion resistance tests show that, following the laser treatment, the steel has regained its intergranular corrosion resistance properties.
Surface Characteristics of Continuously Annealed Steel Sheet in Overaged Condition
Authors: Leijon W. , Augustsson P. -E. , Olefjord I.
Published: January 2014

The overaging treatment of a continuous annealing line was simulated in the laboratory. The chemical state of the surface of low carbon steel sheet was determined by using ESCA and SEM. The surfaces of a conventional, low alloyed deep drawing quality (DDQ) steel and a dual phase (DP) steel alloyed with Mn and Si were characterised in simulated and production line conditions. The influence of the surface state of the steels on the formation of surface phosphates was investigated. During overaging in the temperature range 200–400° C in a protective H2 + N2 atmosphere iron oxide is reduced to metallic iron. The alloying elements manganese and silicon are oxidised. Silicon especially is markedly enriched on the surface, in the form of pure Si02, due to its high diffusibility. The manganese and silicon oxides form particles on the surface during the overaging treatment. The results indicate that iron oxide is dissolved in the particles. Sodium and calcium are also present in their oxide states on the surfaces of the production line sheets; they originate in the rinsing waters used. Temper rolling reduces the amount of surface oxide particles to about half the prerolling value. It is suggested that this is due to the stripping of particles from the surface and the pressing of particles into the steel matrix. The phosphating experiments show that the steel sheets treated in the simulation furnace and taken from the production line form surface phosphates readily. The phosphate crystals are small, uniform, and cover the entire surface.
SURFACE ENGINEERING: PAST, PRESENT, AND FUTURE
Authors: Bell T.
Published: January 2014

The origins of surface engineering lie in antiquity, with the practices in ancient Greece and China of hardening, tempering, and crude forms of case hardening using solid organic materials. However, it was only at the turn of the 20th century, with the advent of widespread research into electrical phenomena, that the extensive portfolio of modern surface technologies emerged. This includes laser, plasma, and ion beam techniques, which are used to produce a composite material showing properties unattainable in either the base or surface materia!. The present report explores the basic principles of surface engineering, and examines the future of the discipline from the perspective of current research into second generation multiple treatments.
MICROSTRUCTURE AND PROPERTIES OF ION PLATED Ti-B-N FILMS
Authors: Wen L. S. , Chen X. Z. , Yang Q. Q. , Zheng Y. Q. , Chuang Y. Z.
Published: January 2014

Ti–B–N films, ∼3μm in thickness, containing 5–16 at.-%B have been deposited on W18Cr4V high speed steels and stainless steels using ion plating. The Vickers microhardness of the films was as high as 35–45 GN m-2 (load 0·25 N) and the critical load during scratch tests 11–15 N. The film/diamond stylus sliding friction coefficient is 0·086–0·097 (load 8·8 N). X-ray and electron diffraction analyses have indicated that the film consists mainly of fcc TiN with dispersed simple orthorhombic TiB, cubic BN, and simple hexagonal Ti–B–N phases. SEM and TEM micrographs of longitudinal and cross-sections of the films show that the film has a very fine, dense fibrous nanocrystalline structure, with grain sizes ranging from several to tens of nanometres. The titanium, boron, and nitrogen contents are homogeneous within the film. A diffusion zone has been shown to exist at the film/substrate interface by ion probe microanalysis and EDAX examination.
INFILTRATION OF WC–Co SPRAYED COATINGS WITH COPPER ALLOYS
Authors: Ito Hiroshi , Nakamura Ryozo
Published: January 2014

The properties of plasma sprayed WC–Co coatings have been improved by infiltration with copper alloys. A Cu–Ni–P alloy and BCuP–3 solder show excellent results as infiltrant materials, and infiltration can be carried out at lower temperatures than conventional infiltration with Ni–P alloys. The hardness of the infiltrated coatings is 1400–1500 BV, which compares favourably with that of cemented carbides. The higher hardness results in considerably lower rates of wear than with as sprayed coatings.
Resistance electroslag cladding of small diameter shafts
Authors:   none
Published: January 2014

The modification of a conventional resistance electroslag (RES) welding head to allow the cladding of shafts >300mm in diameter on an adapted lathe apparatus is described.
Corrosion Behaviour of Ion Implanted Wc–Co and Wc–Ni Alloys in Acid and Chloride Containing Media
Authors: Ringas C. , Robinson F. P. A. , Luyckx S. B. , Sellschop J. P. F.
Published: January 2014

Alloys of WC–Co (6-30 wt-%Co) and WC–Ni (6-15 wt-%Ni) were implanted with chromium, molybdenum, and titanium ions at fluences from 1 × 1021 to 4 × 1021 ions m-2. Their corrosion resistance was evaluated before and after implantation using accelerated electrochemical techniques in a 0.005M H2S04 and a 0.001M NaCl + 0.05M Na2S04 solution. In general, ion implantation tended to decrease the corrosion rate and improve the pitting resistance. The most promising results were obtained with molybdenum implantation, which increased the passive range and substantially raised the pitting potential.
Influence of Predeformation of Workpiece Surface in Intermittent Metal Cutting
Authors: Wallen P. , Jacobson S. , Hogmark S.
Published: January 2014

The cutting performance of surface deformed and undeformed work materials was compared by single edge experiments with a modified Charpy pendulum. The differences were investigated with respect to chip formation mechanisms, specific cutting and thrust forces, and finish of the cut surfaces. Austenitic stainless steel and quenched and tempered steel work materials were investigated. The test method resembles intermittent metal cutting operations such as sawing and milling by generating short cuts with small and varying cutting depths. The most important conclusions are as follows: (1) Surface deformation of the work material surface improves machinability by reducing the cutting and thrust forces. (2) This is mainly the result of a reduced contact length between the chip and the rake face of the edge. (3) Work materials with thick and heavily deformed surface layers, such as austenitic stainless steel, yield high thrust forces at the beginning of the cut. (4) In work materials where the disintegration of the builtup edge degrades the finish of the cut surface, deformation hardening can yield an improvement.
Effects of Metal Ions Present in Iincate Solutions on the Characteristics of Iinc Alloy Films on Aluminium
Authors: Monteiro F. J. , Barbosa M. A. , Gabe D. R. , Ross D. H.
Published: January 2014

A commercially available modified alloy zincate solution with various metal ion additions has been used to produce immersion films on aluminium, enabling it to be electroplated with other metals to attain good adhesion. The effects of nickel, iron, copper, and nitrate added to the zincate solution have been followed by atomic absorption spectrophotometry, electrochemical potential measurements, X-ray wavelength dispersive spectroscopy, and Auger electron spectroscopy. The results show that nickel acts mainly on the nucleation stages, iron controls the crystallite size, copper affects the bonding to the substrate, while nitrate acts as an inhibitor to aluminium corrosion reactions.
Nitrocarburising and its Influence on Design in the Automotive Sector
Authors: Dawes C.
Published: January 2014

Nitrocarburising is outstanding for the profusion of proprietary names and claims it has attracted during its 40 year existence. It can be characterised as a low distortion treatment for ferrous materials where surface enrichment, predominantly by nitrogen, forms a hard surface layer of ε iron nitride, beneath which there is a nitrogen diffusion zone. The surface layer imparts wear and corrosion resistance and the diffusion zone increases the yield and fatigue strength, particularly in thin sections. Process developments have significantly enhanced the corrosion resistance and aesthetic appearance of treated components to make nitrocarburising competitive with electroplated finishes. Major commercialisation took place duringthe 1980s, and examples are given of a wide range of successful applications from wheel bearings to bumper armatures, which use combinations of the properties obtainable from the process to provide cost and weight savings. Advances in equipment and process materials offer a treatment which greatly reduces environmental pollution.
Importance of Substrate in Surface Engineering
Authors: Priestner R. , Priestner D. M.
Published: January 2014

The substrate plays an important role in the application of surface engineering processes. It provides mechanical support for the surface layer in components and may also interact with a surface layer during processing. The term ‘subsurface engineering’ has been coined to describe the deliberate selection or alteration of substrates to satisfy engineering and processing requirements economically. ’Passive’ subsurface engineering describes the conscious selection of a core material and its initial constitution to match it to a proposed surface engineering process. The materials engineering involved in selecting core materials for traditional thermochemical processes is well established. This is not generally so for new processes, or when older processes are applied to other types of substrate, as is illustrated with respect to the plasma nitriding of SG cast iron. ‘Active’ subsurface engineering entails the production of an intermediate layer on the core material. Often, the materials engineering requires account to be taken of the interaction of this subsurface layer with the surface layer created during processing, and this is illustrated by reference to some experiments on the CVD production of a TiC coating on a precarburised steel. Some mechanical requirements of a subsurface layer are illustrated by reference to the stress systems present in bending, in rolling contact, and in gears.
Advanced surface engineering by hipping
Authors: Blackford J. , Tidbury L. , Evans D.
Published: January 2014

Aluminide coatings produced by an ion vapour deposition and hipping process show certain technical advantages over those produced by conventional pack techniques. Examples are given of aluminide coatings produced on nickel based superalloys.
Engineering the Surface of Grey Cast Irons for a Sugar Milling Application
Authors: Sare I. R. , Constantine A. G. , Mason V. , Thwaite E. G.
Published: January 2014

An investigation has been carried out on a series of 22 grey cast irons to determine the influence of carbon equivalent and sulphur content on tensile strength, and on the ability of cast iron to develop a roughened surface under the action of a high speed open arc weld deposition process. The tensile strength decreased linearly with increasing carbon equivalent, in the expected manner, but showed no significant dependence on sulphur content. The surface roughness, quantified as the mean aspect ratio of the deposited weld metal droplets, showed a significant dependence on carbon equivalent and a very strong dependence on sulphur content. The effect exerted by sulphur on the roughening phenomenon was shown to be consistent with a model developed earlier to account for the surface perturbations formed under the action of a gas tungsten arc. In the model, sulphur exerts a strong depressive influence on the surface tensions which exist in the system, but since its effect on the solid-vapour surface tension is greater than on the liquid-vapour surface tension, non-wetting tends to develop as the sulphur content increases. The results have been used to formulate a modified grey cast composition for the manufacture of sugar cane crushing roll shells, which possesses both adequate strength, by virtue of its lowered carbon equivalent, and an adequate roughening ability, by virtue of its enhanced sulphur content.
Diffusion Chromising of Steel by CYD Using Chloride Compounds: 3 Thermodynamic and Kinetic Aspects
Authors: Jyrkäs K.
Published: January 2014

Chemical vapour deposition of chromium using CrCl2 produced by the reaction of FeCl3 with metallic chromium has been examined both thermodynamically and kinetically. The chemical processes occurring during coating have been examined by thermodynamic calculations and verified by comparison with experimental results. Kinetic measurements have been made on chromium diffusion in titanium alloyed mild steel. The diffusion promoting effect of titanium is explained thermodynamically. Reaction of FeCl3 and chromium occurs in two stages. Initially FeCl2 and CrCl2 are formed above 200°C and the FeCl2 formed reacts above 500°C, forming metallic iron and CrCl2. The beginning of the coating process, which is mainly diffusion controlled, is determined by the evaporation of CrCl2. The interdiffusion coefficient of chromium in the steel has been determined by various methods. Enhanced diffusion wasfound below 860°C, but the diffusion rate is too low to allow these temperatures to be used in practice. A strong dependence of the interdiffusion coefficient on chromium concentration was found in the temperature range 860–980°C.
Wear Characteristics and Cultlng Performance of Diamond Coated Ceramic Tools
Authors: Narutaki N. , Usukia H. , Itoh T. , Yamane Y.
Published: January 2014

By using the plasma CVD method with hydrocarbon and carbon monoxide gas mixtures with hydrogen, a synthesised diamond film was deposited on cutting tools. In order to clarify the wear characteristics and cutting performance of the diamond coated tools, turning tests were carried out on Al–Si alloy, carbon fibre reinforced polymer (CF RP), and glass fibre reinforced polymer (GFRP). The diamond coated tools were found to have a cutting performance equal to that of sintered diamond tools when machining materials which did not present the greatest cutting difficulties such as low Si Al alloys, GFRP, and CFRP. However, when machining high Si Al alloys, the synthesised diamond film showed a cutting performance inferior to that of sintered diamond tools.
Iron–Zinc Alloying Reaction on Interstitial Free Steels
Authors: Inagaki J. , Morita M. , Sagiyama M.
Published: January 2014

Effects of the processing conditions on the coating microstructure of galvannealed steel sheets have been investigated with special reference to the Fe–Zn alloying reaction on an interstitial free steel substrate. The results showed that the Fe–Zn alloying reaction could be classified into three processes: suppression of Fe–Zn alloying reaction by Fe–Al intermetallic compound, formation of ζ-phase, and rapid growth of outburst structure (mainly composed of δ1-phase). The formation of ζ-phase was closely correlated with alloying temperature, and was explained in terms of Zn–Fe equilibrium phase diagram. The relationships between properties and coating microstructure were also investigated. An increase in the amount of ζ-phase increases the frictional coefficient while enhancing the antipowdering property of the coating. However, the frictional properties of the galvannealed layer could be improved by electroplating with an Fe rich Fe–Zn alloy layer of more than 2 g m-2.
Fatigue Strength of Laser Beam Surface Treated Structural Steels
Authors: Merrien P. , Lieurade H. P. , Theobalt M. , Baudry G. , Puig T. , Leroy F.
Published: January 2014

An industrial advantage of laser processing is that it permits local treatment of mechanical components on those specific areas subject to high stress levels. The way in which this type of laser treatment enhances structural steel properties has been studied. The 42CD4 and X C42 steel specimens were notched to create a stress concentrationfactor identical to that observedfor gears. The work involved optimising three parameters: the laser beam itself, i.e. the beam energy-time of interaction couple; specimen preparation, i.e. selection of the best laser beam-specimen coupling medium (phosphating gave the best emissivity coefficient while avoiding specimen contamination); the metallurgical heat treatment, designed to obtain both high toughness and good ductility. Specimens tempered at various temperatures before the laser treatment were fatigue tested. The results enabled the selection of an intermediate tempering temperature resulting in the highest fatigue limit. They also showed that, in regard to fatigue behaviour, laser surface treatment compared favourably with thermochemical carbonitriding.
Laser coating proven in practice
Authors: Ritter U. , Kahrmann W. , Kiipfer R. , Glardont R.
Published: January 2014

Surfaces can be changed to suit a particular purpose by means of laser coatings. The method features advantages compared with other surface treatment processes, e.g. it requires scarcely any finishing off and provides high reproducibility, ease of automation, and minimum consumption of expensive alloying elements. Applications for laser coating are to be found principally in the automobile industry, in the aerospace sector, and in general mechanical engineering. Coatings giving protection against wear are deposited. A further application is the repair of damaged or worn component locations/contours. The examples given below demonstrate how laser coatings can be applied to advantage.
Wear mechanisms of physical and chemical vapour deposited ceramic coatings used in metal cunlng applications
Authors: Dearnley P. A. , Fowle R. F. , Corbett N. M. , Doyle D.
Published: January 2014

A series of turning and drilling tests has been carriedout on tool materials coated with titanium nitride usingarc or electron beam evaporation source physicalvapour deposition (PVD) methods. Cemented carbidesubstrates were used for the turning tests while highspeed steel (HSS) substrates were used for the drilltests. Emphasis has been placed on elucidating themechanisms of wear of the coatings, using microscopy.Some comparisons were made with chemical vapourdeposited (CVD) coatings for the turning experiments.When turning plain carbon steel at 300 m min−1 and 0·25 mm rev−1 feed, rake face wear mechanisms involvea combination of discrete plastic flow and dissolutiondiffusionwear; these are identical to the wear mechanismsof CVD coatings when used under the sameconditions. However, the arc source PVD coatingsexhibited relatively poor adherence. Drilling tests werecarried out on austenitic stainless steel at 19·9 m min−1 and 0·08 mm rev−1. Coating failure was dominated byplastic shearing of the HSS substrate. The measuredflank ‘wear land’ varied widely for titanium nitridecoated and uncoated HSS drills – this may be relatedto variation in the high temperature shear strength ofthe HSS drills. Coating loss was sporadic in natureand there was some evidence that fracture of the PVDtitanium nitride coatings took place during metalcutting.
7th International Conference on Surface Modification Technologies
Authors:   none
Published: January 2014

Dr WAYNE E. REITZ of Babcock and Wilcox, Lynchburg, VA reviews the latest in this series of conferences, which was attended by nearly 120 professionals from approximately 15 countries and which was held in Sanjo-Tsumbe, Japan on 1–6 November 1993.
Oxygen Probes for Controlling Nitriding and Nitrocarburising Atmospheres
Authors: Böhmer S. , Spies H.-I. , Berg H.-I. , Zimdars H.
Published: January 2014

By analogy with carburising, electrochemical concentration cells with oxygen conducting solid electrolytes have proved their suitability for the control of oxynitriding atmospheres, both as oxygen probes and as nitriding probes using two cells. Their application to nitrocarburising atmospheres is currently under evaluation. The measurements and calculations described in the present paper make possible the development of computer aided control of gas nitriding atmospheres. Process control on the basis of probe signals provides a more precise and flexible approach to meeting the demands made on surface layers. It can prevent disturbances caused by uncontrolled oxygen intake andfacilitates a rational gas regime, thus contributing to process and product optimisation.
EVALUATION OF HARDNESS OF SPUTTERED W–C–Co THIN FILMS
Authors: Cavaleiro A. , Vieira M. T.
Published: January 2014

Sputter deposited W–C–Co films with different thicknesses were prepared on substrates that had been given various hardening treatments. After physical and chelnical characterisation, the hardness of the films was evaluated by applying a model to the experimental hardness data obtained by micro indentation equipment. Good results for the hardness were obtained for all the film thicknesses and substrate hardnesses investigated. However, if the substrate hardness was less than 600 HV, the calculated hardness for the fibns decreasedwith decreasing substrate hardness.
COMPARISON OF SLIDING WEAR RESISTANCE OF PLASMA ENHANCED CVD MULTILAYER COATED TiN AND TiC ON TOOL STEEL
Authors: Wang H. L. , He J. L. , Hon M. H.
Published: January 2014

The sliding wear resistance of single layer and multilayer TiN and TiC coatings produced by plasma enhanced CVD on tool steel has been evaluated using a washer on disc test method. The relative pelformances of the coatings were studied using X-ray diffractometric characterisation and observation byscanning electron microscopy. The wear behaviour of the coated specimens was such that: all the coated specimens showed better wear resistance than the blank material but with varying degrees of improvement, TiN coatings were superior to TiC, multilayer coatings were better than single layer coatings, and multilayer coatings having TiN as the outermost surface were better than those having TiC as the outermost surface. It was found that the fracture toughness of the coating and not its hardness determined wear resistance. This was confirmed by an indentation testing method.
Laser Induced Shock Waves as Surface Treatment for 7075–T7351 Aluminium Alloy
Authors: Peyre P. , Merrien P. , Lieurade R. P. , Fabbro R.
Published: January 2014

A novel mechanical surface treatment using laser induced shock waves has been applied to the wrought aerospace aluminium alloy 7075–T7 351 to improve its fatigue behaviour. Optimisation of the shock parametersand mechanical effects produced by the treatment have been investigated and fatigue performance is compared with that of conventionally shot peened specimens. It is shown that use of a one-dimensional Lagrangian hydrodynamic shock wave analysis code allows the attenuation of shock waves to be simulated and the depth of the plastically affected zone to be predicted. An analytical model developed to predict residual stress levels gave good agreement with experimental values. The fatigue limit of laser shocked specimens was found to be higher than that following shot peening. This large increase (22%) appeared to result from the high levels of residual stress and the greater extent of the stress field in the laser treated specimens and, most importantly, from the preservation of the surface condition. All these factors greatly increased the duration of the crack initiation stage of fatigue, as was confirmed by ac potential drop measurements.
EFFECT OF THERMAL SPRAY PROCESS SELECTION ON TRIBOLOGICAL PERFORMANCE OF WC–Co AND Al2O3–TiO2 COATINGS
Authors: Naerheim Y. , Coddet C. , Droit P.
Published: January 2014

High velocity oxyfuel (HVOF), air plasma spraying (APS), and low pressure plasma spraying (LPPS)techniques were used to deposit WC–Co and APS was used to deposit A12O3–TiO2 coatings on ASTM 4130 steel in a study of the effect of process selection on the friction and wear of the coatings under dry sliding conditions in air. The LPPS WC–Co, which had a cobalt matrix with few brittle η-carbides (CO3w3C and C06w6C), small and evenly dispersed WC, and high residual compressive stress, was most abrasive to Al2O3–TiO2.