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An arc sprayed aluminum (Al) coating on S355 steel was processed using a laser remelting (LR). The microstructures, chemical element composition, and phases of the obtained Al coating were analyzed using a field mission scanning electronic microscope (FESEM), energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively, and the residual stresses were measured using an X-ray diffraction stress tester. The immersion corrosion tests and potentiodynamic polarization of Al coating in 3.5% NaCl solution were performed to investigate the effects of LR on its immersion corrosion behaviors, and the corrosion mechanism of Al coating was also discussed. The results show that the arc sprayed Al coating is composed of Al phase, while that by LR is composed of Al-Fe and AlO 4 FeO 6 phases, and the porosities and cracks in the arc sprayed Al coating are eliminated by LR, The residual stress of arc sprayed Al coating is −5.6 ± 18 MPa, while that after LR is 137.9 ± 12 MPa, which deduces the immersion corrosion resistance of Al coating. The corrosion mechanism of arc sprayed Al coating is pitting corrosion and crevice corrosion, while that by LR is uniform corrosion and pitting corrosion. The corrosion potential of arc sprayed Al coating by LR shifts positively, which improves its immersion corrosion resistance. [ABSTRACT FROM AUTHOR]

In this study, the optimization of pulsed Nd:YAG laser welding parameters was done on the lap-joint of a 316L stainless steel foil with the aim of reducing weld defects through response surface methodology. For this purpose, the effects of peak power, pulse-duration, and frequency were investigated. The most important weld defects seen in this method include underfill and undercut. By presenting a second-order polynomial, the above-mentioned statistical method was managed to be well employed to balance the welding parameters. The results showed that underfill increased with the increased power and reduced frequency, it first increased and then decreased with the increased pulse-duration; and the most important parameter affecting it was the power, whose effect was 65%. The undercut increased with the increased power, pulse-duration, and frequency; and the most important parameter affecting it was the power, whose effect was 64%. Finally, by superimposing different responses, improved conditions were presented to attain a weld with no defects. [ABSTRACT FROM AUTHOR]

Laser bending is a process of bending of plates, small sized sheets, strips and tubes, in which a moving or stationary laser beam heats the workpiece to achieve the desired curvature due to thermal stresses. Researchers studied the effects of different process parameters related to the laser source, material and workpiece geometry on laser bending of metal sheets. The studies are focused on large sized sheets. The workpiece geometry parameters like sheet thickness, length and width also affect the bend angle considerably. In this work, the effects of width and thickness on multi-pass laser bending of AH36 steel strips were studied experimentally and numerically. Finite element model using ABAQUS® was developed to investigate the size effect on the prediction of the bend angle. Microhardness and flexure tests showed an increase in the flexural strength as well as microhardness in the scanned zone. The microstructures of the bent strips also supported the physical observations. [ABSTRACT FROM AUTHOR]

A Ni-Cr-Si-B alloy layer was produced on a type 304 stainless steel plate by laser cladding. In order to produce cladding layer with smooth surface and low dilution, influence of laser beam profile on cladding layer was investigated. A laser beam with a constant spatial intensity at the focus spot was used to suppress droplet formation during the cladding layer formation. This line spot, formed with a focussing unit designed by our group, suppressed droplet generation. The layer formed using this line spot with a constant spatial intensity had a much smoother surface compared to a layer formed using a line spot with a Gaussian-like beam. In addition, the dilution of the former layer was much smaller. These results indicated that a line spot with a constant spatial intensity was more effective in producing a cladding layer with smooth surface and low dilution because it suppressed droplet generation. [ABSTRACT FROM AUTHOR]

The article presents a detailed analysis of the degradation phenomena and mechanisms of selected forging punches made of UNIMAX tool steel. Analyzed punches are used in the manufacture of a constant velocity joint boot forging (CVJB) applied in motorcars with front axle drive. The thorough analysis concerned the punches used in the fourth forging operation after a multi-operational process of forging at elevated temperatures, due to the lowest durability equaling only 4000 forgings. A comparison was made of 5 variants of surface thermo-chemical treatment including 2 types of nitriding (with a low and high potential) and 2 different coatings: CrN and AlCrTiN as well as a punch with and without additional thermo-chemical treatment. The performed complex analysis included a macroscopic analysis combined with scanning of the working surfaces, numerical modeling, microstructural tests, SEM microscopic tests, and microhardness measurements. The obtained results make it possible to select of the optimal variant of thermo-chemical surface treatment which improves the durability of these tools. In particular, the analysis included the manner and areas of wear of the punches as well as their resistance to the particular degradation mechanisms. [ABSTRACT FROM AUTHOR]

This paper presents a numerical methodology based on Euler-Bernoulli theory to simulate the steel, reinforced concrete and composite structures 2D nonlinear behavior. The displacement-based numerical formulation uses the principles of the Refined Plastic Hinge Method (RPHM) to simulate the concentrated plasticity at the corotational finite element nodal points. In order to present a more realistic simulation of the axial and flexural stiffness degradation, the RPHM is coupled with the Strain Compatibility Method (SCM), where the materials constitutive relations are used explicitly. The SCM is also applied in determining the structural elements’ bearing capacity. Moreover, the present approach is not limited to a specific cross-sectional typology. Also addressed are residual stress models; these are introduced explicitly in subareas of steel profiles generated by a two-dimensional cross-sectional discretization. It should be emphasized that this study considers full interaction between the materials. Finally, the results obtained are compared with numerical and experimental findings available in the literature. [ABSTRACT FROM AUTHOR]

The fiber coating is the key part of the solid-phase microextraction (SPME) technique, and it determines the sensitivity, selectivity, and repeatability of the analytical method. In this work, amine (NH)-functionalized material of Institute Lavoisier (MIL)-53(Al) nanoparticles were successfully synthesized, characterized, and applied as the SPME fiber coating for efficient sample pretreatment owing to their unique structures and excellent adsorption properties. Under optimized conditions, the NH-MIL-53(Al)-coated fiber showed good precision, low limits of detection (LODs) [0.025-0.83 ng L for synthetic musks (SMs) and 0.051-0.97 ng L for organochlorine pesticides (OCPs)], and good linearity. Experimental results showed that the NH-MIL-53(Al) SPME coating was solvent resistant and thermostable. In addition, the extraction efficiencies of the NH-MIL-53(Al) coating for SMs and OCPs were higher than those of commercially available SPME fiber coatings such as polydimethylsiloxane, polydimethylsiloxane-divinylbenzene, and polyacrylate. The reasons may be that the analytes are adsorbed on NH-MIL-53(Al) primarily through π- π interactions, electron donor-electron acceptor interactions, and hydrogen bonds between the analytes and organic linkers of the material. Direct immersion (DI) SPME-gas chromatography-mass spectrometry methods based on NH-MIL-53(Al) were successfully applied for the analysis of tap and river water samples. The recoveries were 80.3-115% for SMs and 77.4-117% for OCPs. These results indicate that the NH-MIL-53(Al) coating may be a promising alternative to SPME coatings for the enrichment of SMs and OCPs. [ABSTRACT FROM AUTHOR]

Cold-formed steel hollow flange sections are structurally efficient compared to the conventional open channel sections. They can be of different forms including hollow flange I- and channel sections, which are generally fabricated by first cold-forming a single sheet to form the desired shape and then connecting their flange and web elements by continuous welding. Instead of welding, intermittently screw/rivet fastened or spot welded connection can also be used. A detailed investigation is currently under way on the structural performance characteristics of such intermittently screw/rivet fastened steel hollow flange sections. This paper presents the details of an experimental study performed to investigate the behaviour of built-up cold-formed steel hollow flange sections in compression, where more than 45 stub columns were tested. Both hollow flange I- and channel sections built-up using either single steel sheet or three steel elements were tested. Tests also included built-up hollow flange channel sections with stiffened web elements. Test results including the failure loads, load versus axial deformation plots and failure characteristics are presented in this paper. Test failure loads are compared with the predictions based on both effective width and direct strength methods to verify their adequacy in predicting the section compression capacity of built-up hollow flange sections. This paper has shown that although hollow flange I-sections made of three elements with a 100 mm fastener spacing can perform similar to continuously welded sections, hollow flange channel sections undergo premature failures even with a 50 mm fastener spacing, and the reasons are discussed. [ABSTRACT FROM AUTHOR]

This work reports the influences of helix angle on tool performances of titanium aluminum nitride (TiAlN)- and diamond-like carbon (DLC)-coated carbide end mills for dry side milling of 304L stainless steel. The study results revealed that the number of axis contact points and effective cutting length increased with increasing helix angle, leading to less tool wear and thinner milled chips but higher workpiece temperature. In addition, DLC-coated tools exhibited relatively high workpiece temperature, rapid chipping wear due to thermally induced graphitization, and chip-built-up on side edge while TiAlN-coated end mills displayed less severe abrasive wear on cutting and side edges. Moreover, the DLC-coated end mill with a high helix angle of 60° gave the lowest surface roughness of 0.26 μm within the cutting length of 20 m while the corresponding TiAlN-coated tools offered longer tool cutting length of more than 50 m with comparable surface finish. Consequently, the TiAlN-coated end mill with a high helix angle of 60° offered high-quality surface finish with long tool life time and would be more useful for dry milling of stainless steels. [ABSTRACT FROM AUTHOR]

Currently, it is widely acknowledged that ridging is caused by different plastic deformations from grains with different textures. In this study, a simplified model was used to predict the ridging height with different elongation values based on crystal plasticity (CP) and EBSD information with the purpose of understanding well the effect of texture and average grain size on the ridging generation and reduction of undesirable surface defects of ferritic stainless steel (FSS) 430 during the formation process. The results indicate that the reduction of average grain is effective to improve ridging generation in FSS along tensile directions. The numerical simulation results obtained using the crystal plasticity finite element model (CPFEM) match well with experimental values, which demonstrates that the CPFEM could be employed to analyse the ridging phenomenon under different elongation conditions of FSS. Based on the established models, the ridging modes of colonies with different crystal orientations ({001} <110>, {112} <110> and {114} <110>) are discussed to evaluate the effect of texture structure on ridging generation. [ABSTRACT FROM AUTHOR]

Bio-/environment-friendly cationic gemini surfactant, ethane-1,2-diyl bis( N, N-dimethyl- N-hexadecylammoniumacetoxy)dichloride, referred to as 16- E2-16, was synthesized and characterized. Corrosion inhibition effects of 16- E2-16 on mild steel (MS) surface in 1 M HCl solution at 30, 40, 50 and 60 °C were evaluated using gravimetric analysis, potentiodynamic polarisation and electrochemical impedance spectroscopy measurements. The nature of the protective inhibitor film formed on the MS surface was analysed by SEM, EDAX and FT-IR, while TGA was used to assure the thermal behaviour and stability of the film at high temperature. The formation of [inhibitor-Fe] on the surface of MS was confirmed by UV-visible spectroscopy. The inhibition efficiency of the studied inhibitor increased with increasing concentration and solution temperature. The compound behaved as a mixed type inhibitor and acted by blocking the electrode surface by means of adsorption obeying the Langmuir adsorption isotherm. Surface active properties and corrosion inhibition effects of 16- E2-16 in the presence of inorganic (NaI) and organic (NaSal) salts were also investigated and are discussed. Density functional theory calculations have been carried out to correlate the efficiency of the compound with its intrinsic molecular parameters. [ABSTRACT FROM AUTHOR]

At the present time 9–12% Cr ferritic/martensitic (F/M) steels with target operating temperatures up to 650 °C and higher are being developed in order to further increase thermal efficiency so as to reduce coal consumption and air pollution. An 11% Cr F/M steel was prepared by reference to the nominal chemical composition of SAVE12 steel with an expected maximum use temperature of 650 °C. The precipitate phases of the 11% Cr F/M steel normalized at 1050 °C for 0.5 h and tempered at 780 °C for 1.5 h were investigated by transmission electron microscopy. Except for Cr-/Cr-Fe-Co-rich M 23 C 6 , Nb-/V-/Ta-Nb-/Nd-rich MX, Fe-rich M 5 C 2 , Co-rich M 3 C and Fe-Co-rich M 6 C phases previously identified in the steel, two types of sigma phases consisting of σ-FeCr and σ-FeCrW were found to be also present in the normalized and tempered steel. Identified σ-FeCr and σ-FeCrW phases have a simple tetragonal crystal structure with estimated lattice parameters a /c = 0.8713/0.4986 and 0.9119/0.5053 nm, respectively. The compositions in atomic pct of the observed sigma phases were determined to be approximately 50Fe-50Cr for the σ-FeCr, and 30Fe-55Cr-10W in addition to a small amount of Ta, Co and Mn for the σ-FeCrW. The sigma phases in the steel exhibit various blocky morphologies, and appear to have a smaller amount compared with the dominant phases Cr-rich M 23 C 6 and Nb-/V-/Ta-Nb-rich MX of the steel. The σ-FeCr phase in the steel was found to precipitate at δ-ferrite/martensite boundaries, suggesting that δ-ferrite may rapidly induce the formation of sigma phase at δ-ferrite/martensite boundaries in high Cr F/M steels containing δ-ferrite. The formation mechanism of sigma phases in the steel is also discussed in terms of the presence of δ-ferrite, M 23 C 6 precipitation, precipitation/dissolution of M 2 X, and steel composition. [ABSTRACT FROM AUTHOR]

Though the mechanical properties of shape-memory alloys (SMAs) make them a promising material for reinforcement in concrete structures, their electrochemical behavior in concrete environments has not previously been studied. This study investigated the influence of galvanic coupling between a nickel-titanium (Ni-Ti)–based SMA and a low-carbon steel on their corrosion performance in simulated concrete pore solution. Three measurement cells were considered: SMA alone, low-carbon steel alone, and one with the coupled SMA and carbon steel. The specimens were immersed in the chloride-free pore solution for 20 days and then 3% by weight of NaCl was added to the solution. The specimens were then kept in the chloride-contaminated solution for 70 days. The corrosion resistances of the specimens were assessed by different electrochemical measurement techniques. The results of the electrochemical experiments showed a significant increase in corrosion activity of the coupled specimens compared with that for other measurement cells. [ABSTRACT FROM AUTHOR]

The effect of carbide distribution on the grain refinement in the steel for large-size bearing ring is investigated. It is observed that Ni-containing steel has an obvious grain refinement below 1050 °C, whereas its grain growth trend is steeper than that of Ni-free steel above 1050 °C. No evident segregation of Ni is observed, whereas the pinning effect of carbides distributed along grain boundaries is advantageous for the grain refinement. It is found that Ni addition could affect the type of carbides and contribute to decreasing the size of carbides via accelerating the diffusion of carbon. A stronger pinning effect with smaller carbides distributed along grain boundaries could be obtained, which is beneficial to grain refinement with Ni addition in small amounts. [ABSTRACT FROM AUTHOR]

Given that the modern world cannot be conceived without the existence of the steel and its use, the crude steel consumption may be considered as an indicator characterizing the economic development of a country. The purpose of this paper is to establish the evolution of the world, regional and state consumption of crude steel, both per total, as well as per inhabitant, but also the impact of the economic and financial crisis it had on the evolving evolution of using the crude steel. Data subject to the study are related to the period 2004 - 2014 and concern nine regions of development and ten countries. [ABSTRACT FROM AUTHOR]

Nano-sized SAPO-34 zeolites with high crystallinity are obtained in 10 minutes by fast heating the reaction gel in a stainless steel tubular reactor combined with the seed-assisted method, which show outstanding performance in methanol-to-olefin (MTO) reaction. [ABSTRACT FROM AUTHOR]

The present paper investigates a metastable austenitic stainless steel under different biaxial-planar load paths by using a cruciform specimen geometry. The material behavior was described by stress–strain curves and initial yield surface. Furthermore, the hardening behavior was determined by load sequence tests. To investigate the influence of the stress state on the martensite formation a ferrite sensor as well as electron backscatter diffraction measurements were used. Two cruciform specimen geometries were utilized and compared for the considered load cases. The stress state within the cruciform specimens was evaluated by an elastic unloading procedure with subsequent calculation of the stress components. Isotropic initial yielding and non-isotropic hardening were found. A recommendation for the use of the cruciform specimen geometry with respect to the load case is given. [ABSTRACT FROM AUTHOR]

The present investigation studies the load bearing performance of stainless steel bolted connections. The austenitic stainless steel developed in China containing approximately 17% of Cr, which could be graded as EN 1.4401, has been selected for this research. In order to study the bearing strength of stainless steel bolted connections, experimental tests on 5 specimens have been conducted. In addition, complementary finite element (FE) models, which have been validated by the test results, have been adopted to analyse the effect of the key factors for bearing strength of the stainless steel bolted connections. The key factors include end distance, thickness of connecting plate, diameter of stainless steel bolt and edge distance. According to the FEA results, the loading capacity increases with the increase of the thickness of the plate and the diameter of the bolt approximate linearly. However, the end distance and edge distance have a comparatively complicated influence on the loading capacity of the connection. Based on mathematical analysis of the experimental and FEA results, a calculation method as well as its simplified form for the bearing strength of stainless steel bolted connections has been proposed. [ABSTRACT FROM AUTHOR]

The use of capacity design method (CDM) in steel plate shear wall (SPSW) structures results in large vertical boundary elements (VBEs). One way to reduce the force demands on VBEs is to employ outrigger beams in the adjacent spans of SPSW. In this paper, twelve dual SPSW-moment resisting frames are designed and analyzed by FE method to investigate the effects of outrigger system on the behavior of SPSW structures. Results show that outrigger beams can transfer considerable amount of axial force and bending moment from VBEs to the outer spans columns; resulting in smaller sections for VBEs. In addition, the most effective stories to employ outrigger beams are shown to be the stories which undergo larger drifts. Outrigger system also results in a more uniform distribution of structural stiffness along the height of SPSW frames. Furthermore, a design procedure based on the direct analysis method is proposed for the design of SPSW-Outrigger system. The procedure eliminates the excessive capacities in CDM, while satisfying all CDM requirements. [ABSTRACT FROM AUTHOR]

This paper presents pin-ended compression tests on steel equal angles. Three nominal section sizes were tested. Detailed measurements of material properties, residual stresses, and geometrical imperfections were conducted. The pin ended specimens were tested with a minimal eccentricity ofL/1,000 applied about the minor axis to cause compression at the tips of the legs. The test data are compared with the Indian specifications for hot-rolled steel structures. The section capacities obtained from the column tests are found to be between 15 and 40% higher than those calculated according to the specifications. It is concluded that there is no need to include the additional eccentricity specified in the steel structures standards accounting for the shift of the effective centroid, and that the eccentricity ofL/1,000, specified for all section classes, should be applied to slender sections only. [ABSTRACT FROM AUTHOR]

This paper analyzes the influence of technological and composition factors on the structure and quality of ordinary and quality steels for processing forged crankshaft. It is known that influencing factors which determine the properties of ordinary steels are the carbon content and the microstructure. Beside the predominant effects due to the carbon content and the microstructure, the properties of ordinary steels can be modified by the effects of the residual elements (in addition to carbon, manganese, silicon, sulfur and phosphorus that are always present). The properties of steel can be influenced by the presence of gas, particularly oxygen, nitrogen and hydrogen, as well as by the reaction products thereof. These secondary elements usually penetrate the steel from the used scrap, deoxidants or furnace environment. The gas content depends largely on the method used to melt, on the deoxidation and casting, so that the final properties of these steels depend largely on the method used in their preparation. Thus, the factors that condition the steel properties are primarily the carbon content and its microstructure, which is largely determined by the chemical composition and the subsequent final processing of forging or by the heat treatment operations. Secondly, these properties depend on the residual elements of the alloy, non-metallic inclusions and gas content of the steel, which in turn depends on the steelmaking method. [ABSTRACT FROM AUTHOR]

For some powertrain components deep penetration laser welding is considered very advantageous and prospective joining technology. Presented article focuses on heterogeneous laser welds of two widely used materials, ductile iron with pearlitic matrix (e.g. differential carrier) and Cr-Mo low alloy steel (e.g. gears). When homogeneous welds without filler wire are done, both materials show poor laser weldability, because unacceptable welding defects, mainly cracks, are created in the weld. In ductile iron, almost under all welding conditions, cracks in WM and HAZ due to brittle phases (cementite and martensite) are created. Low alloy Cr-Mo steel creates under all welding conditions solidification cracks and microcracks, caused by solidification. Even though homogenous welds of both materials are unacceptable, for heterogeneous welds possibility to create sound welds was found. By mixing of materials approximately 1:1 substantial amount of retained austenite is present in the WM, helping to suppress creation of brittle cracks and also partially suppress solidification cracks. To supress solidification cracks completely, full penetration welds and welds with V shape were used. Also use of Ni filler wire proved successful to create sound welds. The weld joint strength for heterogeneous welds for both used solutions was about 450 N/mm², which is less than BM strength, yet acceptable. Occurring phenomena connected with ration of materials mixing and its influence on WM properties, structure and behaviour is explained. [ABSTRACT FROM AUTHOR]

A literature review was performed to assess the effects of inclusions in carbon and alloy steels on their mechanical properties. Inclusions, including brittle oxides and more ductile manganese sulfides (MnS), affect fatigue endurance limit, fatigue crack propagation rate, fracture toughness, notch toughness, transverse tensile properties, and anisotropy of these properties with respect to the rolling direction. Significant property anisotropy has been documented, which needs to be taken into account in the design phases. Typical fracture morphologies and metallographic appearances of MnS-containing materials that the failure analyst will encounter are illustrated. [ABSTRACT FROM AUTHOR]

This article describes the findings of a detailed investigation into the failure of a final super heater tube in a 140 MW thermal power plant. Preliminary macroscopic examinations along with visual examination, dimensional measurement, chemical analysis, evaluation of mechanical properties, and oxide scale thickness measurement were carried out to deduce the probable cause of failure. In addition, optical microscopy was a necessary supplement to understand the cause of failure. It was concluded that the tube had failed due to stress rupture. The tube metal had been exposed to a temperature above the safe operating limit for a long duration. As a result the tube metal had lost its strength, suffered creep deformation and failed to support the working stress resulting in final rupture. The adherent scale, particularly on internal surface formed due to exposure at high temperature. It had acted as an insulating blanket in view of its much lower thermal conductivity than that of the tube metal. The progressive build-up of scale had greatly affected heat transfer and raised the tube metal temperature above A1 for a short duration before bursting of the tube. The overheating in this case may be due to poor circulation over the localized area. [ABSTRACT FROM AUTHOR]

Screw-thread steel bars made of high strength steel fractured after exposure to a constant pre-stress of 650 MPa for more than 10 h. Visual examination, chemical analysis, mechanical tests, metallographic analysis, and fractographic examination were carried out in order to determine the causes of this failure. The fracture surfaces consisted of three regions: the crack source or fracture origin region, steady-state crack growth, and unstable or final fracture region. The crack initiated at the center of the cross section and then propagated to the periphery. The fracture exhibited a brittle appearance, accompanied with secondary cracks, tear ridges, and micropores on the grain boundary. The results revealed that this failure was due to hydrogen embrittlement of the steel. [ABSTRACT FROM AUTHOR]

After approximately fifteen months of service, cracking was detected in the journal section of a 3-MW electric motor shaft used to drive a reciprocating gas compressor. A detailed failure analysis revealed sulfide inclusion and quench crack-initiated fatigue cracks. Two crack orientations were observed, axial and angular. The axial cracks are believed to be quench cracks which initiated along sulfide stringers; the angular cracks were found to be high-cycle fatigue cracks emanating from the axial cracks. Recommendations included the use of a reduced sulfur content shaft steel (0.010 wt.% max) and a pre-service non-destructive inspection to detect the presence of quench cracks or other surface imperfections. [ABSTRACT FROM AUTHOR]

In this paper, the deformation behaviors of elastic-plastic asperity on rough roll surface in a strip steel mill were simulated by a three-dimensional finite element (FE) model. The asperity characterized a sinusoidal profile and all objects in the FE model were elastic-plastic with linear strain hardening. The deformation behaviors including contact stresses, strains (including elastic and plastic strains), and contact radii of different rolling force densities and different geometrical shapes and sizes were calculated and analyzed. It revealed that the tall-thin type asperity caused larger plastic strain in the asperity itself and larger Von Mises stress in the mating roll subsurface. Long-term repeated effects of large cyclic strain and stress were liable to spark subsurface cracks and increased the risk of fatigue failure of rolls in strip rolling mills. [ABSTRACT FROM AUTHOR]

This paper describes the changes to design provisions for embedded steel reinforcement in the fib Model Code for Concrete Structures 2010. The changes introduce new coefficients for steel grade and clear spacing between bars, and extend the range of concrete strengths covered. The way in which the contribution of hooks or anchorages is calculated has been revised and the contribution of end bearing to laps and anchorages of compression bars is recognized. The revised rules represent a move away from a distinction between laps and anchorages per se towards a distinction based on the presence or absence of transverse pressure perpendicular to the bar axis within the bond length. The benefits of staggering laps with only a proportion of bars lapped at a section are also reviewed. Finally, the potential impact of lap and anchorage performance on structural robustness is discussed, and it is concluded that this can only be achieved if bar yield precedes splitting mode bond failures. [ABSTRACT FROM AUTHOR]

The material characterization of steel fibre-reinforced concrete (SFRC), which is required for its implementation in design codes, should be based on nominal properties that describe its post-cracking strength in tension. In the case of brittle and quasi-brittle materials, such as concrete, the tensile parameters are often derived indirectly. However, for materials with more ductility, such as SFRC, there is conjecture as to whether or not an indirect measure may be used to establish the stress versus crack opening displacement relationship, such as the use of a three- or four-point prism test combined with an inverse analysis. In this paper a simple and efficient inverse analysis technique is developed and shown to compare well with data obtained from direct tension tests. Furthermore, the methodology proposed by the fib Model Code for Concrete Structures 2010 has been investigated and recommendations made to improve its accuracy. [ABSTRACT FROM AUTHOR]

A Mo2NiB2 cermet coating on steel substrate was fabricated by laser cladding technique. The laser cladding samples were subjected to various microstructure examinations, hardness, and wear and corrosion tests. The results showed that a continuous, dense and adherent laser‐clad coating was formed on the steel substrate. The coating consisted of γ‐(Fe, Ni) as a metallic matrix binder and Mo2NiB2 particles as a reinforced phase distributed uniformly in the microstructure. Average hardness of the coating up to 700 HV was significantly higher than that of the matrix 150 HV. The coating exhibited a dry‐sliding wear resistance that was increased by about 6 times relative to the steel substrate. Extensive pits formation on the surface and through the inner part had taken place for 304 stainless steel, while it disappeared in the coating. A novel method to synthesize Mo2NiB2 boride cermet coating on Q235 steel substrate, consisting of Mo2NiB2‐type ternary boride as a reinforced phase and a γ‐(Fe, Ni) base binder, is realized with laser cladding technique. The wear resistance of the Q235 substrate is greatly improved. As compared to 304 stainless steel, lower corrosion rate is obtained for the coating and pitting corrosion disappeare in particular. [ABSTRACT FROM AUTHOR]

Methods are considered for preparing periclase-carbon refractories of 'mini-key' (MK) format by compaction sideways and edgeways. Under OOO Ogneupor conditions objects are prepared with dimensions 102/113/160/200 mm that are installed edgeways in the lining of OAO MMK steel-pouring ladles. Objects demonstrate good life, there are no typical vertical cracks, and there is no erosion of horizontal joints. [ABSTRACT FROM AUTHOR]

European iron and steel producers are working towards increased energy efficiency to meet requirements set by European policies such as the Energy Efficiency Directive. In this study, we show that the specific energy consumption (SEC), representing the iron and steel sector in the Odyssee energy efficiency index (ODEX)-the tool for policy evaluation recommended by the European Commission-is insufficient for capturing energy efficiency trends of European iron and steel production. European producers focus on niche markets, diversifying and specialising their set of products well beyond crude steel, which is the benchmark product for deriving the SEC. We compare the SEC with the more comprehensive Malmquist productivity index (MPI) methodology, which is calculated using data envelopment analysis (DEA) techniques. An evaluation of energy efficiency trends during 2000-2010 showed that the SEC overestimated energy efficiency improvements for European steel industries, while underestimating the improvements achieved by Swedish steel industries. A comparison between the SEC, the MPI/DEA approach, and energy intensity based on value added in the Swedish case provides further insight to the methodological differences between the approaches. We conclude that the approaches highlight different aspects of energy efficiency analyses and that the SEC is not sufficient for capturing the energy efficiency of steel industries. [ABSTRACT FROM AUTHOR]

The present paper aims to investigate on corrosion behaviour of carbon steel in the nutrient-rich simulated sea water medium in presence of Pseudomonas aeruginosa bacteria. Different techniques such as scanning electron microscopy (SEM), visual inspection, X-ray diffraction (XRD) and weight loss measurement were used to characterize the corrosion products and biofilm layer. The SEM results show the formation of filamentous heterogeneous biofilm layer on the steel substrate due to presence of P. aeruginosa bacteria in a medium. The visual inspection preliminary results show the more severe corrosion damages occurred on the steel substrate exposed to bacteria-contained medium compared with the steel substrate immersed in the sterile medium. The weight loss results show that the corrosion rate of steel substrates in bacteria-contained medium was around 1.6 times higher than corrosion rate of steel substrates in sterile medium indicating the aggressive role of bacteria on corrosion acceleration. XRD results show that the corrosion products are composed of FeOOH, FeO, FeO and FeO ·FeO due to metabolism activity of the bacteria. From the present study, it is inferred that bacterium. P. aeruginosa is responsible for severe corrosion of steel substrate in the sea water medium. [ABSTRACT FROM AUTHOR]

Compression tests were carried out on pin-ended cold-formed steel box stub columns subjected to uniaxial moments. Twenty stub columns with flat width-to-thickness ratio less than the limiting value and twenty stub columns with flat width-to-thickness ratio greater than the limiting value was tested up to collapse. The effect of shape, flat width-to-thickness ratio, slenderness ratio and the eccentricity of loading on the ultimate load-carrying capacity of the box stub columns were studied. It was observed that AISC method of estimating the ultimate load is conservative. Load versus axial shortening behaviour, load versus lateral deflection behaviour and load versus strain behaviour were also studied. The change in eccentricity from r/4 to r/2 decreases the ultimate load-carrying capacity by 15% for square box stub columns and 20% for rectangular box stub columns in uniaxial loading and increase in slenderness ratio from 15 to 20 does not significantly reduce the ultimate load-carrying capacity. The change in flat width-to-thickness ratio for less than the limiting to a greater extent is uneconomical for both square and rectangular sections with side ratios of 1:1.5 and 1:2. Initial stiffness was more for columns loaded with an eccentricity along major axis. There was reversal of strain from compression to tension for rectangular box columns beyond 75% of ultimate load. [ABSTRACT FROM AUTHOR]

A mechanistic approach based on finite element analysis of continuum damage as proposed by Kachanov has been used to assess and compare creep deformation, damage and rupture behaviour of 2·25Cr-1Mo, 9Cr-1Mo and modified 9Cr-1Mo ferritic steels. Creep tests were carried out on the steels at 873 K over a stress range of 90-230 MPa. Modified 9Cr-1Mo steel was found to have highest creep deformation and rupture strength whereas 2·25Cr-1Mo steel showed the lowest among the three ferritic steels. Creep damage in the steels has been manifested as the microstructural degradation. 2·25Cr-1Mo steel was more prone to creep damage than 9Cr-steels. Finite element estimation of creep deformation and rupture lives were found to be in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The tensile deformation behaviour of 316LN stainless steel was investigated from ambient temperature up to 1000°C. The hardness and microstructure of area near tensile fracture were characterised. The results show that the engineering stress increases smoothly with engineering strain when the tensile temperature is at 400°C or below, while the plastic deformation stage displays a serrated/jerky flow at 600°C. At tensile temperatures of 800°C or above, the plastic deformation stage is dramatically prolonged. The deformation mechanisms of 316LN stainless steel are proposed to be sliding and twinning at 400°C or below, tangle dislocations due to cross-slipping at 600°C, dynamic recovery at 700°C, and dynamic recrystallisation at 800°C or above. The finding provides useful guidelines for the processing and service of 316LN stainless steel components at high temperatures. [ABSTRACT FROM AUTHOR]

Partial linear regularization networks (PLRN) combined with sparse representation technique is developed to establish the steel temperature prediction model for LF. Parametric linear part is introduced into the classical regularization networks in order to fit the partial linear structured temperature model, which is obtained by analyzing the mechanism of LF thermal system in detail. Improvement in prediction accuracy is achieved due to the well learning performance of regularization networks and the modification according to the special structure. Furthermore, sparse representation technique is adopted on original PLRN for the sake of reducing computational cost and further improving the generalization performance. Learning scheme of recursive version is designed to train the sparsely represented PLRN, in which support vectors is selected one-by-one and recursive algorithm is adopted for computational efficiency. The proposed method is examined by practical data. The experiment results demonstrate that the proposed method can both improve the prediction accuracy and lead to sparse solution, so that it reduce the storage need and the prediction time for practical application. [ABSTRACT FROM AUTHOR]

Existence of hollow sections in precast hollow core wall makes it sceptical to resist earthquake loading. However, this wall can resist earthquake loading if it is designed as a hybrid wall system. It is equipped with unbonded tendons and bonded "fuse-bars" to dissipate energy. It rocks steel-on-steel without inducing any structural damages. In-plane lateral cyclic loading is applied on the wall. Experimental results show that the wall is able to resist earthquake loading without any structural damage. Direct displacement based approach is used to validate the experimental results. There are good correlations between them with very a small percentage of discrepancies. [ABSTRACT FROM AUTHOR]

Abstract: Holding yokes made of investment cast 17-4PH stainless steel were too soft (below 20HRC). Optical microscopy of the parts showed that there is a high fraction of retained austenite after oil quench due to high amount of molybdenum found in parts as an impurity. Subzero treatment in liquid nitrogen after solution heat treating was used to convert retained austenite to martensite but parts became too brittle and fractured during post-heat treating machining. Double and triple aging at 538°C (1000°F) after subzero cooling was done on parts. Detailed fractography and tensile testing along with optical microscopy (OM) investigation proved that repeated aging at 538°C (1000°F) led to lower strain microstructure and improved elongation without reduction in tensile strength. Tensile and non-destructive testing after machining proved that problem has been solved. [Copyright &y& Elsevier]

High-energy ball-milling in an oxidative atmosphere caused gradual transition of pure zincite into zinc ferrite due to the oxidation of steel contamination. The rate of contamination increased dramatically (＞3×) in an inert atmosphere due to the abrasion of milling tools by the steel chips coming from it. [ABSTRACT FROM AUTHOR]