Lightweight steel-framed (LSF) structural elements in building construction provide a wayof increasing building sustainability. These structural elements present great potentialfor recycling and reuse, allowing the conservation of natural resources and theenvironment. When compared with other materials, these construction components alsoprovide other advantages: reduced weight with simultaneous high mechanical strength;easier prefabrication, allowing modular elements and higher quality control; shorterperiods for assembling the building on-site; no dimensional variations caused by moisture;and low cost. The high thermal conductivity of steel could be a drawback, leading tothermal bridges if not well designed and executed. In the case of LSF components (e.g.walls and slabs) it is necessary to take special care with the elements’ designoptimisation, with it being essential to use continuous thermal insulation. The buildingenvelope thermal performance is crucial to provide good thermal behaviour and energyefficiency, allowing a reduction of operational energy. In this paper, the LSFconstruction system is analysed in order to show its main advantages and drawbacks. Theassessment of embodied and operational energy is essential to perform a life cycleanalysis. The reduction of both energies’ consumption is crucial to increase thesustainability label. Special focus will be given to the mitigation strategies ofoperational energy in LSF construction.

The present work is concerned with the determination of boron activation energy in theC35 steel and an estimation of the mass gain generated by the boriding treatment. Theboride layers are produced by the pack-boriding method on the C35 steel in the temperaturerange of 800−1000 °C for atreatment time ranging from 0.5 to 8 h. The presence of both FeB and Fe2B phases was confirmed by theX-ray diffraction technique and by a microscopic examination of the cross-sections ofborided samples. The boron activation energy was evaluated as 153.1 kJ mol-1 in the temperature range of800−1000 °C. This value ofenergy is in agreement with the literature data. The mass gain was measured by weighingthe samples before and after the boriding treatment by the weighing technique. Theevolution of mass gain as a function of temperature and time can be described by aparabolic law. Finally, an iso-thickness diagram was established to be used as a tool tooptimize the boride layers thicknesses according to the industrial application.

Maximization of non-coking coal in coal blend is eloquent interest among researchers incoke making throughout the world. To maximize the non-coking coals in coal blend with thescarce and expensive coking coals is an essential practice in the iron and steel industry.The fundamental aspect of the coal blending theory of low value coals to produce goodquality of metallurgical coke in non-recovery coke making process was investigated in thisstudy by using the composite coking potential technique. The implementation of thetechnique has yielded use of up to 25% pulverized coal injection, 20% raw petroleum cokeas a component of coal blend. Results show that the coal blend having composite cokingpotential value of \hbox{$\geqslant $}⩾4.8 is desired to achieve the targeted coke strengthafter reaction of \hbox{$\geqslant $}⩾65.

Certification initiatives are product-focused, rely on standards and use sustainabilitymetrics to inform end-users on the provenance of commodities. In the metals sector, thephenomenon of formal certification programs has recently gained traction. Four initiativesare reviewed to illustrate the status and prospects of metal certification. The prime caseis the Conflict Free Smelter Program operated by the global electronics industry. Thisscheme has developed and applied standards on mineral chain-of-custody, including use ofthird-parties to audit smelters and refineries all over the world. Additional programsdiscussed are the Green Lead Project, Fair Trade and Fair Mined gold, and the ResponsibleJewellery Council. Collectively these initiatives address a variety of sustainabilitycriteria, including social, economic and environmental dimensions, but focus only onprecious and specialty metals (Au, platinum group, Pb, Sn, Ta and W). Metalscertifications programs are building capacity and infrastructure compared to matureprograms in agriculture and other commodity sectors. Opportunities and issues for growthof metals certification are considered.

From a ferrite/martensite cold-rolled microstructure, the interaction between ferriterecrystallization and austenite formation is investigated. It is observed that a slowheating rate promotes the ferrite recrystallization and a homogeneous microstructure,whereas a fast heating rate delays the recrystallization and leads to heterogeneouslydistributed austenite islands.

The beneficial effect of B on the hot ductility of 20CrMnTi steel with 0.05% Sn wasinvestigated. The results show that there is a trough in the hot ductility-temperaturecurve. With the increase in the B content, the trough shifts to a lower temperature andbecomes shallow, and the hot brittle range becomes narrow. In addition, B greatlyenhancing the hot ductility was due mainly to its suppressing the Sn segregation,retarding the austenite/ferrite deformation, accelerating the onset of dynamicrecrystallization (DRX) and promoting the intragranular nucleation of ferrite. Moreover,in the present case, adding 92 ppm B can nucleation of ferrite. Moreover, in the presentcase, adding 92 ppm B can obtain the best effect in improving the hot ductility of20CrMnTi steel with 0.05% Sn.

Hot tearing defects appear during the last steps of casting solidification of dendrites.The crystalline structure traps a small amount of liquid metal, which is depressed, andcavities are spontaneously initiated. Molecular dynamics (MD) simulations of pure iron areable to predict, on one hand, the high temperature elastic modulus of crystals, and on theother hand, the cavitation event in liquid metal and near the solid-liquid growth front.High values of elastic tensor components are predicted close to the melting temperature.We conclude that a weakening of the mechanical properties of the crystal is not the reasonfor failure initiation. The crystals are thinned by partial melting as the effect ofnegative pressure increases. The cavitation is spontaneously initiated under a very highnegative pressure. The cavity expands very quickly and applies a pressure wave to thethinned crystals. We propose that this crystal thinning/pressure wave coupling is able toinitiate cracks inside the crystal.

Recently, the issue of sustainable resource management has been increasingly recognized.Economic growth of human activity is associated with a rapid rise in the use of resourcesin our economy, and society has a potential environmental impact. The UNEP InternationalResource Panel (IRP) pointed out the importance of decoupling resource use and negativeenvironmental impacts from economic activity (UNEP IRP 2011). In order tooptimize the material cycles and increase resource efficiency, material flow analysis(MFA) is a powerful tool to understand the resource consumption and material cycle in thenational economy. In this study, we present the results of global material flow analysisof nickel, which is one of the important resources for reducing energy use andCO2 emission inour society, and discuss the importance and possibility of controlling its resourcelogistics. This study also introduces the challenge of identifying the land-use changes innickel mining sites by a remote-sensing technique, and knowledge to increase the resourceefficiency in metal recycling based on the metallurgical thermodynamic approach. Theresults indicated the importance of recovery of nickel in recycling policies forend-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies andimplementation of designs for recycling/disassembly at the manufacturing phase are needed.Possible solutions include development of sorting processes for steel scrap andintroduction of easier methods for identifying the composition of secondary resources.Recovery of steel scrap with a high alloy content will reduce primary inputs of alloyingelements and contribute to more efficient resource use.

The accuracy of the parameters is of great importance in the calculation and simulationof the COREX process. Therefore, it is necessary to measure some parameters, especiallythe heat loss and its distribution, which have not been reported before. Based on thecharacteristics of the two sets of the Baosteel COREX-3000 process, a method and standardare established for the heat loss and its distribution. Then the heat loss anddistribution are calculated based on the measured parameters. The results show that thetotal heat loss of the two COREX processes is 495.4 MJ/tHM and 413.7 MJ/tHM. The heat losscaused by cooling water accounts for more than 93% of the total heat loss while the heatloss of furnace shells is less than 7%. The main heat loss caused by cooling water takesplace at the tap hole zone, which is also the part of the COREX system with the most heatloss Its heat loss is about 30% of the heat loss caused by cooling water and 28% of thetotal heat loss of the COREX system. The main heat loss of furnace shells takes place atthe dome of the melter-gasifier and the reducing gas entrance position of the shaftfurnace, where the heat loss accounts for nearly 90% of the heat loss of furnace shells.It is also found that the energy utilization efficiency of the 1# COREX system is muchlower than that of the 2# COREX system after comparison.

The growth velocity during solidification of an undercooled melt of a Co-Cu alloyprocessed by electromagnetic levitation was measured using a high speed video camera.Applying a model of local non-equilibrium solidification, theoretical predictions ofdendrite growth velocity and dendritic growth radii are compared with high-accuracymeasurements of the growth kinetics. As the undercooling ΔT reaches a critical valueconsistent with the dendrite growth velocity being equal to the atomic diffusion speedVD in bulk liquid,ΔT =ΔT(VD),the velocity-undercooling relationship exhibits a break-point. A distinct change in thedendritic growth mechanism exists with the onset of complete solute trapping andchemically partitionless solidification of the core of the main stems of the dendritesoccurs. A complete transition to the thermally controlled growth of dendrites occurs atΔT =ΔT(VD)that leads to essential changes in the microstructure of dendritic patterns The phenomenonof dendritic fragmentation in Co-Cu melts, solidifying at ΔT <ΔT(VD),is discussed.

The nature of the intermetallic layer which forms on the steel surface during immersionin typical galvanizing baths for galvannealed (GA) sheets production has been investigatedon two commercial Titanium-stabilized Interstitial-Free (Ti-IF) steel substratesgalvanized in baths with different Al contents. Results from this study show that in bothcases the inhibition layer is biphasic and composed of a very thin Al-rich phase layer,identified as Fe2Al5Znx, and a thicker Zn-rich phase layeron top of it, identified as δ. Experimental results also show that theFe2Al5Znx phase layer becomes discontinuouswhen decreasing the bath Al content. Discussions about the mechanisms of formation and thefinal microstructure of this inhibiting layer are also tackled in this paper by means ofthe Al-Fe-Zn ternary phase diagram at 460 °C and assumptions to justify any deviation fromthermodynamic equilibrium are as well proposed.

The influence of TiO2 addition to LF refining slag on Ti-stabilized stainlesssteel was evaluated using a vacuum induction furnace at 1873 K. The effect ofCaO-SiO2-MgO-Al2O3 basic slags with different TiO2 contents on the titanium loss,aluminum loss and total oxygen content in the steel was studied. It was observed that theoxidation rate of Ti first decreases and then increases with the increase in the contentof TiO2 in slag andreaches the minimum when 8%TiO2 is added to the slag. However, the change in theoxidation rate of Al shows the opposite tendency. The total oxygen in the molten steelremains unchanged with time when 8%TiO2 is added to the slag, and the total oxygen of theothers increases monotonically with time. The activities of TiO2 and Al2O3 from the calculation of the ionand molecule coexistence theory (IMCT) in the initial slag present the same changetendency, and both first increase and then decrease with the gradual increase inTiO2 in the slagand reach the maximum when 8%TiO2 is added to the slag. The results of a kinetic analysisshowed that the rate-determining step of the oxidation of Ti in the steel is the masstransfer on the slag side, and the rate-determining step of the oxidation of Al in thesteel is the mass transfer on the metal side.

Brass-graphite composites were fabricated by adding graphite/Cu/Zn compact powderusingthe stir-casting technique and their tribological behavior against a brass disk wasstudied under simulated actual conditions, in comparison with the common graphite/brasscomposite The tribological properties of the brass-graphite composite were compared withdifferent percentages of graphite in the structure using the pin-on-disk method. Theexperimental results showed that the 7−9 wt.% graphite creates a better wear resistance in high-pressureapplications. Continuous Zn layers successfully covered the surface of the graphiteparticles, which could contribute to the improvement of interfacial wettability betweengraphite and brass. In this study, brass-graphite composites containing 8.4 ~ 15 wt.% of Ni-coated graphitewere fabricated. The friction coefficient of composites decreased with increasing graphitecontent. The wear resistance was improved by the addition of Ni-coated graphite butdegraded at high graphite content. The results indicated this composite showed much bettermechanical properties and tribological properties in comparison with brass. The compositewith 11.7 wt.% nickel-coated graphite showed the best tribological properties.

Since sustainability and environmental issues rose lately, lightweighting has been the point of interest for automotive and aerospace sectors. Lightweighting reduces the fuel consumption of the vehicles and as a result of this reduces emissions. Aluminum, especially wrought aluminum alloys, have large potentials for dramatic weight reduction of structural parts while maintaining the safety and performance. Wrought aluminum alloys are used in automotive skin, bumpers and suspension parts etc. Lightweight suspension parts improve the ride quality and handling, additional to fuel consumption and emission reduction. Holistic life cycle approach takes into account the material flows and related information flows in order to achieve these material flows through the life cycle of the components as well as performance characteristics not only in technical and economic terms but also environmental and social terms. It is necessary to have seamless information flow through the life cycle of the components that could be enabled by the closed-loop product life cycle management (PLM). Closed-loop PLM may also help collection of life cycle information which is necessary to generate performance characteristics and distribution of performance characteristics among life cycle actors.

There are many examples world-wide how mining contributes to sustainable regionaldevelopment. The LKAB mining and processing of iron ore in the north of Sweden, in theArctic Region, is such an example. The definition of sustainable mining is however notclear-cut and further studies are necessary to fully understand the impacts on economy,society and environment.

In regard to the sustainability of future cities, an increase in sustainable energysources needs to be managed. Therefore, the German government decided on increasing theratio of green energy up to 20% by 2020. In accordance with this, offshore wind energyparks will be constructed, as they provide the advantage of lasting air cleanliness andpreserving natural resources. To ensure construction safety, wind energy mills areconstructed using ductile steels of large thickness. Here, an application of high-strengthsteels provides the possibility of reducing the amount of material while constructionsafety is still ensured. Considering the long life cycle of wind energy mills’ foundationstructures and the recyclability of the steel grades used, their construction becomes arelevant factor in reducing CO2 emissions. Furthermore, the use of less material reducesCO2 emissions.Due to existing safety concepts, however, the application of high-strength steels is onlyconditionally allowed. Thus, the current study concerns the development of a safetyconcept based on the existing concepts to allow the application of high-strength steels.Furthermore, as the structural steel parts need to be joined, an energy-efficient weldingprocess is utilised: electron beam welding. The structural steel parts and weld joints areinvestigated with respect to their mechanical properties by analysing their loadability incombination with safety concepts. The load on the material is evaluated to ensureconstruction safety. In addition to the investigation of safety requirements, the suppliedmechanical properties are investigated. As the weld joints show different properties fromthe base material, the joints are considered the critical part. The joints areinvestigated concerning strength and toughness. Afterwards the mechanical properties arecorrelated with the wind energy structures. The prevention of failure is fulfilled whenthe mechanical properties of the weld joints exceed the required mechanicalproperties.

The influence of LF refining slag composition on desulfurization and inclusionmodification was investigated through industrial experiments and thermodynamic analysis.The results show that the sulfide capacity decreases with the decrease in(%CaO)/(%SiO2)and (%CaO)/(%Al2O3) of the slag. The theoretical sulfur distributions agreewell with the analysis results when the sulfide capacity is calculated by Zhang’s model,but the theoretical sulfur distributions are higher than the analysis results when thesulfide capacity is calculated by the KTH model. During the LF refining process,inclusions are transformed from Al2O3 inclusions into CaO-MgO-Al2O3 system inclusions. Higher slagbasicity results in higher CaO and MgO and lower Al2O3 content inclusions in moltensteel at the end of the LF process.