The study investigated novel wear and corrosion resistance of stainless steel and 316 stainless steel samples which were successfully prepared by laser melting deposition. Phase composition, microstructure, microhardness, wear resistance, and electrochemical corrosion resistance were studied. The experimental results showed that novel stainless steel was mainly composed of α-Fe and a few carbide phase (Cr, Fe)7C3. The microhardness of novel stainless steel was about 2.7 times greater than 316 stainless steel. Meanwhile, the specific wear rate of novel stainless steel and 316 stainless steel was 2.63 × 10−5 mm3/N m and 1.63 × 10−4 mm3/N m, respectively. The wear volume of 316 stainless steel was 6.19 times greater than novel stainless steel. The corrosion current and the corrosion potential of novel stainless steel and 316 stainless steel were 1.02 × 10−7 A/cm2 and 1.5 × 10−7 A/cm2, and −138.8 mV, −135.9 mV, respectively, in 3.5 wt% NaCl solution. Therefore, both microhardness and wear resistance of novel stainless steel were greatly improved, with high corrosion resistance.

The LiCoO2 films were directly deposited on stainless steel (SS) using medium-frequency magnetron sputtering, and the effects of annealing parameters, such as ambiences, temperatures, holding times, and heating rates, were systematically compared based on surface morphologies, crystal structures, and electrochemical properties. The results demonstrate that an aerobic atmosphere with 3.5 Pa is the most important parameter to maintain the performance of LiCoO2 films. The influence of the annealing temperature (>550 °C) ranks second because the formed (101) or (104) planes of LiCoO2 facilitate Li+ migration. A short holding time of 20 min and a moderate heating rate of 3 °C/min are selected to reduce the oxidation or inter-diffusion between the LiCoO2 films and the SS substrate. Finally, the optimal annealing process is confirmed and corresponds to the initial discharge capacity of 37.56 μA h/(cm2 μm) and the capacity retention of 83.81% at the 50th cycle.

Intermediate-level radioactive waste is normally encapsulated in cementitious grout. However, for some wastes, grout may not be suitable and polymeric encapsulants are being considered as an alternative. One concern with such encapsulants is their long-term chemical stability and the possibility that release of aggressive degradation products could cause corrosion.

This paper evaluates the potential for three polymeric encapsulants: two epoxy resins (the APS polymer system, (APS) and Alchemix 4760 (ALC)) and a vinyl-ester styrene (VES); to cause internal corrosion of stainless steel waste containers. The corrosion behaviour of stainless steel 316L in contact with each encapsulant was studied in saturated Ca(OH)2 solutions and deionized (DI) water, at 80°C, under non-irradiated and γ-irradiated conditions.

In aerated, alkaline conditions, 316L was resistant to corrosion in all the conditions tested. However, in DI water, the pH fell to values as low as three due to release of acidic species from the polymers. The two epoxy materials (particularly APS) also released significant levels of chloride; VES did not. Chloride release appeared to be increased by γ-irradiation. As a result of the low pH chloride-containing environment created by the APS encapsulant, 316L experienced localized corrosion, whereas coupons in Alchemix 4760 and VES did not. Weight loss measurements correlated with visual observations. γ-irradiation appeared to increase the degree of corrosion.

The joint of dissimilar metals between Mo2FeB2-based cermets and 316L stainless steel was welded by gas tungsten arc welding with no fillers. The weldability was investigated by plate rigid restraint cracking test and transverse rupture strength was measured by the three-point bending test. Microstructure of the weld joint was studied with scanning electron microscope, energy-dispersive spectrometer, X-ray diffractometer and differential scanning calorimeter, etc. Corrosion behavior was investigated by the potentiodynamic polarization test. Results revealed that weld solidification cracking susceptibility existed in the fusion zone. Coarse irregular complex ternary boride phase (M3B2) and hypoeutectic microstructure were formed in weld metal (WM). In heat affected zone (HAZ), a small number of M3B2 grains dissolved into the γ-Fe based binder, with growth and coalescence of the remaining M3B2 grains. Microhardness of HAZ increased slightly and WM presented the highest microhardness in the whole joint. Besides, potentiodynamic polarization test showed that WM had a better corrosion resistance than Mo2FeB2-based cermets, which can be attributed to the higher Cr content and relatively homogenous Mo distribution.

Austenitic 316L stainless steel can be used for orthopedic implants due to its biocompatibility and high corrosion resistance. Its range of applications in this field could be broadened by improving its wear and friction properties. Surface properties can be modified through surface hardening treatments. The effects of such treatments on the microstructure of the alloy were investigated here. Surface Mechanical Attrition Treatment (SMAT) is a surface treatment that enhances mechanical properties of the material surface by creating a thin nanocrystalline layer. After SMAT, some specimens underwent a plasma nitriding process to further enhance their surface properties. Using electron backscatter diffraction, transmission Kikuchi diffraction, energy dispersive spectroscopy, and transmission electron microscopy, the microstructural evolution of the stainless steel after these different surface treatments was characterized. Microstructural features investigated include thickness of the nanocrystalline layer, size of the grains within the nanocrystalline layer, and depth of diffusion of nitrogen atoms within the material.

An interesting experimental phenomenon was obtained by Mintz that the hot ductility of an austenitic steel decreases with decreasing strain rate whereas that of a ferritic steel increases. However, the mechanism is still unclear. In this study, the critical time and critical cooling rate of nonequilibrium grain-boundary segregation (NGS) are calculated. It is shown that for Mintz's thermal cycle prior to tensile testing, the effective time of the austenitic steel is shorter than the critical time and that of the ferritic steel is longer than the critical time. When the strain rate decreases, the elastic stress aging time increases. As a result, for the austenitic steel, the grain-boundary segregation of impurity increases, thereby reducing the hot ductility, whereas for the ferritic steel, the segregation of impurity decreases, thereby enhancing the hot ductility. Consequently, the hot ductility loss of both austenitic and ferritic stainless steels is induced by NGS of impurity.

To obtain a nanocrystalline surface layer, 316L stainless steel was treated by fast multiple rotation rolling (FMRR). The microstructure, after FMRR treatment and annealing treatment, was characterized by transmission electron microscopy and x-ray diffraction. Equiaxed nanocrystalline with the average grain size about 12 nm is obtained on the surface layer of FMRR sample. The investigation of thermal stability of the nanocrystalline layer indicates that the grains are still nanocrystalline and the average grain size is about 60 nm for annealing at 500 °C. In addition, the amount of α-martensite increases markedly as the annealing temperature increases from 300 to 500 °C. However, it begins to reduce at 600 °C due to the reversion transformation from martensite to austenite. After annealing at 400 °C, the microhardness of the annealed FMRR sample reaches a maximum value of about 660 HV, and it is four times higher than that of the original sample.

Today, stainless steel is widely used in automotive industry due to its high impact resistance, corrosion resistance and light weight. This paper present the research carried out to study the differences between microstructure and mechanical properties of 409 and 308 stainless steel sheets, each joints by gas tungsten arc welding (GTAW). For each of weldments, detailed analysis was conducted on the chemical composition, microstructure characteristics and mechanical properties of base metal (BM), heat affected zone (HAZ) and fusion zone (FZ). Scanning electron microscopy (SEM) and optical microscopy were used to analyze microstructural changes and mechanical properties, including microhardness and tensile test. This study can be a practical guide in the selection of other materials in order to determine the important to use in structural automotive industry.

An interception trap to collect airborne arthropods under extreme weather conditions is described. The trap, constructed from durable materials, is operated by wind pressure. It consists of a funnel of fine brass gauze mounted inside a cylinder of stainless steel that rotates into the wind on a mast at 1.5 m from the ground. The gauze funnel terminates in a removable, propanol-filled, collecting bottle into which airborne material accumulates. The counterbalanced cylinder rotates around a central shaft on roller bearings and faces into the wind. Two traps were successfully operated continuously for four and five years, respectively, on sub-Antarctic Macquarie Island and have collected large numbers of airborne arthropods and other biological material over this period.

Residual stresses impact on a wide variety of industrial sectors including the automotive, power generation, industrial plant, construction, aerospace, railway and transport industries, and a range of materials manufacturers and processing companies. The X-ray diffraction (XRD) technique is one of the most popular methods for measuring residual stress (Kandil et al., 2001) used routinely in quality control and materials characterization for validating models and design. The VAMAS TWA20 Project 3 activity on the “Measurement of Residual Stresses by X-ray Diffraction” was initiated by NPL in 2005 to examine various aspects of the XRD test procedure in support of work aimed at developing an international standard in this area. The purpose of this project was to examine and reduce some of the sources of scatter and uncertainty in the measurement of residual stress by X-ray diffraction on metallic materials, through an international intercomparison and validation exercise. One of the major issues the intercomparison highlighted was the problem associated with measuring residual stresses in austenitic stainless steel. The following paper describes this intercomparison, reviews the results of the exercise and details additional work looking at developing best practice for measuring residual stresses in austenitic stainless steel, for which X-ray measurements are somewhat unreliable and problematic.

This study consisted of the characterization of longitudinal cracking pattern observed in weld joint in the manufacture of 304L steel pipelines with thin wall thickness by GTAW process. These tubes are used in food and automotive industries. The cracks grown in the liquid-solid interdendritic zones at high temperatures. It was found that the cracks are associated with change on solidification mode and presence of the holes produced by shrinkage. The change in the solidification mode was associated with the presence of second phase particles. The results suggest that the formation of cracks is promoted by increasing current during the welding although the heat input is constant.

In order to increase the wettability and capillary forces of the filler metal between micro-cracking and micro-porous on the fracture surfaces of 304 stainless steels, methods of impregnation of Si and growth of Ni nanoparticles were used. These nanoparticles have a role inside the Transient Liquid Phase (TLP) and the substrate when using Brazing process. TLP can react with the nanoparticles previously deposited between micro-cracking and micro-porous and therefore promotes the nucleation and growth sites of phases and decreases the formation of eutectic structures. This method increases the effectiveness of metallic components reparation using Brazing process. Such effectiveness is indicated by an inspection of microstructural failure analysis, as a first stage, in the covered zone by the filler metal.

For microorganisms, the preferred living state is adhering to surfaces that can lead tothe development of a biofilm. In drinking water networks, a biofilm can affect theorganoleptic quality of the water as well as whether it is safe to drink. This is due tothe probable presence of pathogens inside the biofilm which may be spread in the water. Tokeep the water quality safe, sanitization processes are regularly carried out usingoxidizing biocides which can alter the physico-chemical properties of the material. Due totheir surface physico-chemical properties and their high corrosion resistance, stainlesssteels seem to be good candidates for the making of drinking water systems. In this 2 yearstudy, stainless steel grades were compared with materials commonly used, in respect offouling, biofilm development and composition. The tested stainless steels include ferritic(444/EN 1.4521), three austenitic (304L/EN 1.4307, 316L/EN 1.4404, and 316LN/EN 1.4429)and two duplex (2304 /EN 1.4362, and 2205/EN 1.4462) grades. The experiments wereperformed in a pilot specially designed to assess the material biocontamination on anatural drinking water loop for more than 2 years. The results confirmed the significantimpact of the material on the biofilm development in terms of formation kinetic andecology. No differences were observed between stainless steel grades whereas theydisplayed an intermediate behaviour compared to other materials. Corrosion attacks wereonly observed on galvanised carbon steel while on stainless steels, negligible releaserates, much below international health requirements were measured. So stainless steelsoffer a good compromise to make drinking water pipes.

X-ray diffraction contrast tomography is a non-destructive technique for the 3D characterisation of polycrystalline microstructures containing up to a few 1000 grains. The sample is illuminated with a monochromatic beam of high energy synchrotron radiation. As the sample is rotated, and as grains pass through alignments for Bragg diffraction, diffraction spots are recorded on a 2D detector placed close behind the sample. The diffraction geometry is used to assign spots to the grains from which they arise, and to determine the crystallographic orientations of grains. The spots are used as projections of the grains to reconstruct the grain shapes. The technique has been applied to several materials science investigations in stainless steels, including the 3D characterisation of grain boundary networks, and in-situ studies of intergranular stress corrosion cracking.

A thermal fatigue test (INTHERPOL) was developed by EDF in order to study the initiationof cracks. These tests are carried out on tubular specimens under various thermal loadingsand surface finish qualities in order to give an account of these parameters on crackinitiation. The main topic of this study is to test the sensitivity of different fatiguecriteria to surface conditions using a micro/macro modelling approach. Therefore a 304Lpolycrystalline aggregate, used for cyclic plasticity based FE modelling, have beenconsidered as a Representative Volume Element located at the surface and subsurface of thetest tube. This aggregate has been cyclically strained according to the results issuedfrom FE simulation of INTHERPOL thermal fatigue experiment. Different surface parametershave been numerically simulated: effects of local microstructure and of grainsorientation, effects of machining: metallurgical prehardening, residual stress gradient,and surface roughness. Three different fatigue criteria (Manson Coffin, Fatemi Socie anddissipated energy types), previously fitted at a macroscale for thermal fatigue of 304L,have been computed at a meso scale, in order to show the surface “hot spots” features andtest the sensitivity of these three criteria to different surface conditions. Results showthat grain orientation and neighbouring play an important role on the location of hotspots, and also that the positive effect of prestraining and the negative effect ofroughness on fatigue life are not all similarly predicted by these different fatiguecriteria.

La topographie de surface est une caractéristique à prendre en considération au même titre que la composition chimique pour décrire la fonctionnalité d'une surface. Cette topographie peut être décrite par des paramètres de rugosité d'amplitude, de fréquence ou hybrides. L'évolution de deux paramètres d'amplitude Ra et Rt en fonction de la longueur d'évaluation est ici étudiée sur un acier inoxydable de type 316L dont la surface est obtenue par polissage pour différents grades de papier. Cette étude montre l'existence de trois régimes en fonction de l'échelle d'observation des valeurs de Ra et Rt. Un premier régime où l'endommagement des surfaces ne comporte pas de loi d'échelle entre les différents grades de papier. Un régime transitoire est aussi identifié et caractérisé par un paramètre d'évaluation appelé Cut-Off qui suit une loi logarithmique en fonction de la taille de grain du papier. Enfin un troisième régime où les paramètres de rugosité suivent une parfaite loi d'échelle prouve que pour ce régime les mécanismes d'endommagement sont identiques à des échelles différentes.

To study the cutting forces, the carbide tip's surface temperature, and the mechanism of secondary chip and main chip formation of face milling stainless steel with a chamfered main cutting edge has been investigated. Theoretical values of cutting forces were calculated and compared to the experimental results with SUS 304 stainless steel plate as a workpiece material. Force data from these tests were used to estimate the empirical constants of the mechanical model and to verify its prediction capabilities. A comparison of the predicted and measured forces shows good agreement. A preliminary discussion is also made for the design of special tool holders and their geometrical configurations. Next, the tips mounted in the tool holders are ground to a chamfered width and the tool dimensions are measured by using a toolmaker microscope.