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1 – 10 of over 1000Xiaodong Zhang, Xiaohua Jie, Liuyan Zhang, Song Luo and Qiongbin Zheng
This paper aims to discuss that a WC/Co-Cr alloy coating was applied to the surface of H13 steel by laser cladding.
Abstract
Purpose
This paper aims to discuss that a WC/Co-Cr alloy coating was applied to the surface of H13 steel by laser cladding.
Design/methodology/approach
The oxidation behavior of the WC/Co-Cr alloy coating at 600°C was investigated by comparing it with the performance of the steel substrate to better understand the thermal stability of H13 steel.
Findings
The results showed that the WC/Co-Cr alloy coating exhibited better high-temperature oxidation resistance and thermal stability than did uncoated H13 steel. The coated H13 steel had a lower mass gain rate and higher microhardness than did the substrate after different oxidation times.
Originality/value
The WC/Co-Cr alloy coating was composed of e-Co, CW3, Co6W6C, Cr23C6 and Cr7C3; this mixture offered good thermal stability and better high-temperature oxidation resistance.
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Maciej Mazur, Martin Leary, Matthew McMillan, Joe Elambasseril and Milan Brandt
Additive manufacture (AM) such as selective laser melting (SLM) provides significant geometric design freedom in comparison with traditional manufacturing methods. Such freedom…
Abstract
Purpose
Additive manufacture (AM) such as selective laser melting (SLM) provides significant geometric design freedom in comparison with traditional manufacturing methods. Such freedom enables the construction of injection moulding tools with conformal cooling channels that optimize heat transfer while incorporating efficient internal lattice structures that can ground loads and provide thermal insulation. Despite the opportunities enabled by AM, there remain a number of design and processing uncertainties associated with the application of SLM to injection mould tool manufacture, in particular from H13/DIN 1.2344 steel as commonly used in injection moulds. This paper aims to address several associated uncertainties.
Design/methodology/approach
A number of physical and numerical experimental studies are conducted to quantify SLM-manufactured H13 material properties, part manufacturability and part characteristics.
Findings
Findings are presented which quantify the effect of SLM processing parameters on the density of H13 steel components; the manufacturability of standard and self-supporting conformal cooling channels, as well as structural lattices in H13; the surface roughness of SLM-manufactured cooling channels; the effect of cooling channel layout on the associated stress concentration factor and cooling uniformity; and the structural and thermal insulating properties of a number of structural lattices.
Originality/value
The contributions of this work with regards to SLM manufacture of H13 of injection mould tooling can be applied in the design of conformal cooling channels and lattice structures for increased thermal performance.
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Lino Costa, Deepak Rajput, Kathleen Lansford, Wenqiang Yue, Alexander Terekhov and William Hofmeister
The purpose of this paper is to develop a simple, easy to implement powder delivery strategy for solid freeform fabrication (SFF) processing.
Abstract
Purpose
The purpose of this paper is to develop a simple, easy to implement powder delivery strategy for solid freeform fabrication (SFF) processing.
Design/methodology/approach
A specially designed “tower nozzle” located at the center of the processing area dispenses the feedstock powders continuously and uniformly onto the processing area, where powders accumulate progressively as a flat powder bed. During the dispensing, powders are selectively consolidated by melting and solidification using a laser beam which was scanned in a predefined pattern using a galvo‐mirror scan head.
Findings
Experiments performed with AISI H13 steel show that the tower nozzle powder delivery strategy is suitable for SFF processing.
Practical implications
Both powder delivery and laser consolidation are performed simultaneously and without interruption with simple apparatus. No powder delivery scrapers or rollers are used.
Originality/value
The main characteristics of a prototype tower nozzle and the typical processing conditions used to form thin wall AISI H13 steel shapes are presented.
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Kong Dejun and Li Jiahong
The purpose of this paper is to evaluate the salt spray corrosion (SSC) and electrochemical corrosion performances of CrNi, TiAlN/NiCr and CrNi–Al2O3–TiO2 coatings on H13 steel…
Abstract
Purpose
The purpose of this paper is to evaluate the salt spray corrosion (SSC) and electrochemical corrosion performances of CrNi, TiAlN/NiCr and CrNi–Al2O3–TiO2 coatings on H13 steel, which improved the corrosion resistance of H13 hot work mold.
Design/methodology/approach
CrNi, TiAlN/NiCr and CrNi–Al2O3–TiO2 coatings were fabricated on H13 hot work mold steel using a laser cladding and cathodic arc ion plating. The SSC and electrochemical performances of obtained coatings were investigated using a corrosion test chamber and electrochemical workstation, respectively. The corrosion morphologies, microstructure and phases were analyzed using an electron scanning microscope, optical microscope and X-ray diffraction, respectively, and the mechanisms of corrosion resistance were also discussed.
Findings
The CrNi coating is penetrated by corrosion media, producing the oxide of Fe3O4 on the coating surface; and the TiAlN coating is corroded to enter into the CrNi coating, forming the oxides of TiO and NiO, the mechanism is pitting corrosion, whereas the CrNi–Al2O3–TiO2 coating is not penetrated, with no oxides, showing the highest SSC resistance among the three kinds of coatings. The corrosion potential of CrNi coating, TiAlN/CrNi and CrNi–Al2O3–TiO2 coatings was –0.444, –0.481 and –0.334 V, respectively, and the corresponding polarization resistances were 3,074, 2,425 and 86,648 cm2, respectively. The electrochemical corrosion resistance of CrNi–Al2O3–TiO2 coating is the highest, which is enhanced by the additions of Al2O3 and TiO2.
Originality/value
The CrNi, TiAlN/CrNi and CrNi–Al2O3–TiO2 coatings on H13 hot work mold were firstly evaluated by the SSC and electrochemical performances.
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Magdalena Cortina, Jon Iñaki Arrizubieta, Aitzol Lamikiz and Eneko Ukar
This paper aims to analyse the effects derived from the presence of residual coolant from machining operations on the Directed Energy Deposition of AISI H13 tool steel and the…
Abstract
Purpose
This paper aims to analyse the effects derived from the presence of residual coolant from machining operations on the Directed Energy Deposition of AISI H13 tool steel and the quality of the resulting part.
Design/methodology/approach
In the present paper, the effectiveness of various cleaning techniques, including laser vaporising and air blasting, applied to different water/oil concentrations are studied. For this purpose, single-layer and multi-layer depositions are performed. Besides, the influence of the powder adhered to the coolant residues remaining on the surface of the workpiece is analysed. In all cases, cross-sections are studied in-depth, including metallographic, microhardness, scanning electron microscopy and crack mechanism analyses.
Findings
The results show that, although no significant differences were found for low oil concentrations when remarkably high oil concentrations were used the deposited material cracked, regardless of the cleaning technique applied. The crack initiation and propagation mechanisms have been analysed, concluding that the presence of oil leads to hydrogen induced cracking.
Originality/value
High oil concentration residues from previous machining operations in hybrid manufacturing led to hydrogen induced cracking when working with AISI H13 tool steel. The results obtained will help in defining future hybrid manufacturing processes that combine additive and subtractive operations.
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Denis Cormier, Ola Harrysson and Harvey West
Electron beam melting (EBM) is a direct‐metal freeform fabrication technique in which a 4 kW electron beam is used to melt metal powder in a layer‐wise fashion. As this process is…
Abstract
Electron beam melting (EBM) is a direct‐metal freeform fabrication technique in which a 4 kW electron beam is used to melt metal powder in a layer‐wise fashion. As this process is relatively new, there have not yet been any independently published studies on the H13 steel microstructural properties. This paper describes the EBM process and presents results of microstructural analyses on H13 tool steel processed via EBM.
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Kong Weicheng, Shen Hui, Gao Jiaxu, Wu Jie and Lu Yuling
This study aims to investigate the electrochemical corrosion performance of high velocity oxygen fuel (HVOF) sprayed WC–12Co coating in 3.5 Wt.% NaCl solution, which provided a…
Abstract
Purpose
This study aims to investigate the electrochemical corrosion performance of high velocity oxygen fuel (HVOF) sprayed WC–12Co coating in 3.5 Wt.% NaCl solution, which provided a guiding significance on the corrosion resistance of H13 hot work mould steel.
Design/methodology/approach
A WC–12Co coating was fabricated on H13 hot work mould steel using a HVOF, and the electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution was measured using open circuit potential (OCP), potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) tests.
Findings
The OCP and PPC of WC–12Co coating positively shift than those of substrate, its corrosion tendency and corrosion rate decrease to enhance its corrosion resistance. The curvature radius of capacitance curve on the WC–12Co coating is larger than that on the substrate, and the impedance and polarization resistance of WC–12Co coating increase faster than those of substrate, which reduces the corrosion process.
Originality/value
The electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution is first measured using OCP, PPC and EIS tests, which improve the electrochemical corrosion resistance of H13 hot work mould steel.
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K.W. Dalgarno and R.D. Goodridge
This paper reports the results of a compression test benchmarking study carried out to investigate the mechanical properties of layer manufactured metal components in order to…
Abstract
This paper reports the results of a compression test benchmarking study carried out to investigate the mechanical properties of layer manufactured metal components in order to assess their suitability in load bearing applications. Compression tests were carried out on the DTM LaserForm ST‐100 material, ARCAM processed H13 tool steel, EOS DirectSteel (50 μm), and the ProMetal material. It is concluded that the LaserForm ST‐100 material, the ARCAM H13 tool steel material, and the ProMetal material all exhibit responses to compressive loads which make them suitable for use in load bearing situations, whilst the EOS DirectSteel (50 μm) exhibits a small permanent set in compression, making it less suitable in these situations.
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Gregory John Gibbons, Robert G. Hansell, A.J. Norwood and P.M. Dickens
This paper details the development of a rapid tooling manufacturing route for the gravity and high‐pressure die‐casting industries, resulting from an EPSRC funded collaborative…
Abstract
This paper details the development of a rapid tooling manufacturing route for the gravity and high‐pressure die‐casting industries, resulting from an EPSRC funded collaborative research project between the Universities of Warwick, Loughborough and DeMontfort, with industrial support from, amongst others, MG Rover, TRW Automotive, Sulzer Metco UK Ltd and Kemlows Diecasting Products Ltd. The developed process offers the rapid generation of mould tools from laser‐cut laminated sheets of H13 steel, bolted or brazed together and finish machined. The paper discusses the down‐selection of materials, bonding methods and machining methods, the effect of conformal cooling channels on process efficiency, and the evaluation of a number of test tools developed for the industrial partners. The paper also demonstrates the cost and time advantages (up to 50 and 54 per cent, respectively) of the tooling route compared to traditional fabrication methods.
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Peyman Taheri, Mahmood Aliofkhazraei, Changiz Dehghanian and Alireza Sabour Rouhaghdam
Plasma electrolytic saturation (PES) treatments were applied on the surface of AISI H13 steel and corrosion resistance of the treated samples was investigated using…
Abstract
Purpose
Plasma electrolytic saturation (PES) treatments were applied on the surface of AISI H13 steel and corrosion resistance of the treated samples was investigated using electrochemical test methods. The aim was to obtain optimal corrosion resistance of the differently treated samples.
Design/methodology/approach
Nitrocarburized and boride layers were produced on AISI H13 steel by the means of the PES technique. Different experimental parameters during each treatment provided different microstructural and electrochemical properties. The techniques used in the present investigation included X‐ray diffraction, SEM, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS).
Findings
The plasma electrolytic nitrocarburising coating was characterized by lower integrity than a PEB coating. All PES coated steels had a noble electrochemical behavior compared to the untreated steel. Different nano‐structures and morphologies obtained by different experimental parameters produced different electrochemical behaviors.
Practical implications
The results obtained in this research into PES techniques can be used wherever good corrosion resistance with the highest efficiency is required.
Originality/value
The speed of treatment by plasma electrolytic saturation techniques makes this method very suitable for industrial production of components.
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