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Electrical discharge machining is a thermal erosion method that can be processed independently of the material's mechanical properties and the workpiece's geometry. Electrical discharge machining processing parameters directly affect the material's surface morphology and processing quality. This study investigated the effects of electrical discharge machining process parameters on the machining quality of AISI H13 hot work tool steel. Electrode material, pulse current and pulse on time were determined as factors for the experimental study. As a methodology, Taguchi L27 (3 × 3 × 3) full-factorial experimental design was used to optimise the effect of process parameters on surface roughness (Ra), processing time, crater diameter and material removal amount, which were identified as output parameters. The optimum factor levels were determined using Taguchi-based signal-to-noise ratio (S/N) criteria to optimise the output parameters. In addition, the analysis of variance results revealed that the pulse current was the most influential parameter for Ra, T and crater diameter. Conversely, the electrode material was the most noteworthy factor in material wear. The experimentation revealed that when the pulse current and pulse on time were increased, the processing time decreased, but the surface quality deteriorated. Moreover, linear and quadratic regression analyses were utilised to forecast the experiment's outcomes. The predicted and measured values exhibited excellent agreement. [ABSTRACT FROM AUTHOR]

In the present paper, an investigation was carried out to understand the microstructure or secondary phase changes formed during thermal ageing at nose temperature (where Cr diffusion was faster) and its influence on the pitting corrosion behaviour of type 316LN SS with marginally lower Cr in as-received (AR) and 10% cold work (CW). X-ray diffraction studies confirmed Cr23C6 and Cr2N in AR and CW conditions. On thermal ageing, AR material from 0 to 10 h and CW from 10 to 24 h, although with lower Cr, the degree of sensitisation (DOS) and pitting potential (Epit) were insignificant due to nitrogen where as above 10 h in AR condition and below 10 h in CW condition resulted reductions in pitting potential (Epit) in different chloride mediums. These results provide new insights on the interplay between pitting, microstructures, alloying elements. [ABSTRACT FROM AUTHOR]

This article proposes a prefabricated steel reactive powder concrete (PSRPC) component. Axial compression tests are conducted with five 3m full-scale column specimens to investigate the specimen damage and failure process and to measure the axial displacement, strain and ultimate bearing capacity in order to study the influences of the RPC strength and the section steel flange thickness on the mechanical properties of the PSRPC. The tests show the following. The ultimate failure mode of the PSRPC is column end splitting. During the loading process, the RPC and the section steel work compatibly, and their strengths are given full play. The lateral effect of the RPC on the section steel and the composite confinement effect of the stirrups and section steel on the RPC core significantly increase the ultimate bearing capacity of the PSRPC, and these effects increase with an increase in the RPC strength. The confinement effect on the RPC core in the enclosed region increases with an increase in the section steel flange thickness, that is, the thicker the section steel flange, the larger the portion of the load taken by the RPC core and the higher the ultimate bearing capacity of the PSRPC. The finite element analysis of PSRPC specimen is carried out by ANSYS software, and the simulation results are in good agreement with the test results. A method for calculating the axial bearing capacity of a full-scale column is proposed, taking the confinement effect of the stirrups and section steel on the RPC core into account. [ABSTRACT FROM AUTHOR]

Steel will be an essential part of any commercial fusion reactor design. Applications in this area involve extreme conditions, imposing particular performance requirements, such as high operational temperature and creep resistance, and also a limitation on the elements that can be used due to the activation that occurs on interaction with irradiation. This work begins with a steel developed for conventional power plant applications, the IBN1 grade developed by IMPACT (a UK consortium of industrial and academic research organisations). This grade has shown excellent properties at high temperature due to high temperature-stable precipitate phases, but contains several elements that would become radiologically active to a degree that is incompatible with the required disposal routes after exposure to the fusion reactor environment. In this study, modifications of the composition are made to remove these elements, and thermodynamic modelling and experimental assessment of the phases that form are undertaken. In this, we have paid particular attention to the prediction of transformation temperatures (to understand if normalisation and tempering can be applied successfully) and the precipitates, to see if suitable phases that are likely to impart creep strength and other desirable properties would be formed. The modifications made include the removal of Nb, Mo, Ni, Co, Cu and Al from the starting alloy, and the substitution of Ta (intended to form carbides, replacing the effect of Nb). Modifications of the amount of retained elemental components, such as C, Mn and Cr, have been made with Thermo-Calc modelling, to ensure preservation of comparable phase transformation temperatures and microstructures. The predicted changes to the alloy are compared to the observations from experimental investigation, finding that tantalum can substitute for niobium in these systems and form similar carbides with similar distribution in the material, and that reduction of Cr to 8 wt% and increase of C to 0.12 wt% raises the Ae4 temperature to allow a high-temperature heat treatment without δ-ferrite formation. While assessment of the mechanical properties of this alloy would be required, the perspectives for these alloys to perform at high temperature that can be inferred from the microstructure are discussed. [ABSTRACT FROM AUTHOR]

The IHTC (Interfacial-Heat-Transfer-Coefficient) between 22MnB5 and KDAHP1 hot work tool steel during the hot stamping process is an important thermal parameter to reflect the heat transfer efficiency. The instantaneous heat transfer law for 22MnB5 blank is based on the cylindrical-die model, and the experiment is contained different contact pressure and gap conditions. The average IHTC value is calculated by the heat balance method (HBM) and finite element optimisation method (FEOM). There is a power function relationship between the average IHTC and both the contact pressure and the one-side gap. From the results of the one-side and bilateral gap condition, 0.2 mm can be considered as the 'critical gap' where the heat exchange between the blank and dies starts or ends. [ABSTRACT FROM AUTHOR]

This article explores the relationship between occupational community and restructuring at a UK steelworks. Through historic and contemporary experiences, restructuring has become an internalized feature of the steelworker identity. Zittoun and Gillespie's framework of proximal and distal experiences is adapted to analyse the internalization process. The article argues that experiential resources associated with restructuring are transmitted via the occupational community, forming a part of a collective memory of workplace change. These experiences relate to the historical precedence of restructuring, the role of trade unions in accepting the inevitability of downsizing and prior personal and vicarious experiences of redundancy. The findings build on debates around the determinants of an occupational community, highlighting the role of 'marginality' and how experiences of restructuring bind steelworkers to a broader community of fate. [ABSTRACT FROM AUTHOR]

Decarburisation is found as an undesirable consequence of the heat treatment cycle in hot work tool steels. In this work, an increase in the decarburisation resistance of tool steel through the electroless technique is subjected. For this purpose, the surface of the H13 tool steel was deposited by the electrodes Ni–P, Ni–B and Ni–P–B coatings. Since the carbon loss leads to a decrease in the hardness, the micro-hardness method is applied to find the influence of the mentioned coatings on the decarburisation resistance. The measurements show that all the electroless-plated steels possess higher resistance to the loss of carbon compared to the bare surface (as the reference). The results also confirmed that the incorporation of boron in the matrix of the Ni-plated layer, including Ni–B and especially Ni–P–B, prevents metal from decarburisation more effectively. The Ni–P–B coating could reduce the decarburisation depth from 0.15 to 0.035 mm. [ABSTRACT FROM AUTHOR]

The use of replicative processes has become strategic and critical in industry to produce precise, microscopically detailed metallic parts and devices via low cost manufacturing routes. Metal powder hot embossing is an emerging process that brings some advantages associated with the reduction of production costs relative to powder injection moulding (PIM). The technology involves four distinct steps: preparation of the selected feedstock material (powder and binder); hot embossing; debinding; and sintering. The effect of continuous pressure during the hot embossing step as a means of replicating microdetails in 316L stainless steel parts is examined. Dimensional accuracy, microstructure and mechanical properties of the parts produced were evaluated. For the configuration tested, the most promising results were achieved when processing at 180°C for 30 min at a pressure of 14 MPa. [ABSTRACT FROM AUTHOR]

A physical model was set up to represent the 300 t CAS-OB at Shou Gang Jing Tang Iron and Steel works. The study results indicate that the mixing time decreased and then increased with increasing the distance from the bottom centre of ladle to the bubbling plug, and was the best at the 0·3r position. The mixing time decreased and then increased with increasing gas flow rate. Mixing time is minimum when the flow rate is above 0·49 m3 h−1. In the slagging process, when the gas rate is 0·42 m3 h−1, the diameter of the slag open eye reached the outer diameter of snorkel. Industrial trials showed improved operational performance of the CAS-OB. [ABSTRACT FROM AUTHOR]

This paper presents the numerical simulation of the technology of gaseous fuel utilisation for iron ore sintering. The proposed methodology is to partially replace the solid fuel by steelworks gases. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction and phase transformations was proposed to analyse temperature distributions of the process. A base case of actual industrial operation of a large sintering machine was monitored with thermocouples inserted into the sinter bed to validate the model. The model was used to predict four cases of fuel gas utilisation: feeding from N01 to N15 wind boxes with blast furnace gas (BFG); natural gas (NG); coke oven gas (COG); and a 50-50 mixture of BFG and COG. The model predictions indicated that for all cases the sintering zone is enlarged and the solid fuel consumption could be decreased. [ABSTRACT FROM AUTHOR]