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1 – 10 of 273Zhao-Qin Wang, Yu Shi and Xiao-Rong Wang
The bisection inverse search bow height control interpolation (BIS-BHCI) method for nonuniform rational B-splines (NURBS) curve is proposed to accomplish the serial robotic plasma…
Abstract
Purpose
The bisection inverse search bow height control interpolation (BIS-BHCI) method for nonuniform rational B-splines (NURBS) curve is proposed to accomplish the serial robotic plasma cladding of planar complex curve coating with high precision.
Design/methodology/approach
A plasma–computer integrated cladding system is constructed based on a Motoman-UP6 serial robot and a plasma power. Based on the BIS-BHCI method, combining the serial robotic kinematics with the NURBS curve model, an offline plasma cladding software is developed for Motoman-UP6. Before plasma cladding, a planar NURBS curve coating is designed and defined and its BIS-BHCI is carried out with proper parameters. Then, the cladding programs are generated using the BIS-BHCI results and the robotic kinematics and inputted into the serial robotic controller. After that, the plasma cladding of the planar NURBS curve coating is implemented based on the Motoman-UP6 serial robot.
Findings
The simulation and plasma cladding for the NURBS curve coating shows that the BIS-BHCI method is feasible and effective. Plasma cladding of complex NURBS curve coating based on serial robot is feasible and effective.
Originality/value
The complex NURBS curve coating is prepared based on a serial robot platform for the first time. It provides a theoretical and technical basis for plasma cladding to produce surface coatings of industrial complex parts. With the increasing application of complex parts, the plasma cladding process of complex NURBS curve coatings has a broad application prospect.
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Dongsheng Wang, Xiaohan Sun, Yingchang Jiang, Xueting Chang and Xin Yonglei
Stainless-clad bimetallic steels (SCBS) are widely investigated in some extremely environmental applications areas, such as polar sailing area and tropical oil and gas platforms…
Abstract
Purpose
Stainless-clad bimetallic steels (SCBS) are widely investigated in some extremely environmental applications areas, such as polar sailing area and tropical oil and gas platforms areas, because of their excellent anticorrosion performance and relatively lower production costs. However, the properties of SCBS, including the mechanical strength, weldability and the anticorrosion behavior, have a direct relation with the manufacturing process and can affect their practical applications. This paper aims to review the application and the properties requirements of SCBS in marine environments to promote the application of this new material in more fields.
Design/methodology/approach
In this paper, the manufacturing process, welding and corrosion-resistant properties of SCBS were introduced systematically by reviewing the related literatures, and some results of the authors’ research group were also introduced briefly.
Findings
Different preparation methods, such as rolling composite, casting rolling composite, explosive composite, laser cladding and plasma arc cladding, as well as the process parameters, including the vacuum degree, rolling temperature, rolling reduction ratio, volume ratios of liquid to solid, explosive ratio and the heat treatment, influenced a lot on the properties of the SCBS through changing the interface microstructures. Otherwise, the variations in rolling temperature, pass, reduction and the grain size of clad steel also brought the dissimilarities of the mechanical properties, microhardness, bonding strength and toughness. Another two new processes, clad teeming method and interlayer explosive welding, deserve more attention because of their excellent microstructure control ability. The superior corrosion resistance of SCBS can alleviate the corrosion problem in the marine environment and prolong the service life of the equipment, but the phenomenon of galvanic corrosion should be noted as much as possible. The high dilution rate, welding process specifications and heat treatment can weaken the intergranular corrosion resistance in the weld area.
Originality/value
This paper summarizes the application of SCBS in marine environments and provides an overview and reference for the research of stainless-clad bimetallic steel.
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Thick composite claddings of carbides on a metal matrix are ideal for use in components that are subject to severe abrasive wear. It is a metal matrix composite (MMC) that is…
Abstract
Purpose
Thick composite claddings of carbides on a metal matrix are ideal for use in components that are subject to severe abrasive wear. It is a metal matrix composite (MMC) that is reinforced by an appropriate ceramic phase and nano-diamond cladding to reduce friction and to protect the opposing surface. The paper aims to discuss these issues.
Design/methodology/approach
This work evaluated the wear performance of carbon steel cladded with TiC/nano-diamond powders by gas tungsten arc welding (GTAW) method. The microstructures, chemical compositions, and wear characteristics of cladded surfaces were analyzed by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX).
Findings
The cladding was uniform, continuous, and almost defect-free, and particles were evenly distributed throughout the cladding layer. The results of wear test indicate that the friction coefficient of the TiC+1.5% nano-diamond cladding is lower than that of AISI 1020 carbon steel. Thus, the wear scar area of the TiC+1.5% nano-diamond cladding is only one-tenth of the AISI 1020 carbon steel.
Originality/value
The experiments in this study confirm that, by reducing friction and anti-wear, the cladding layer prepared using the proposed methods can prolong machinery operating life.
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This paper aims to compare the wear performance of carbon steel specimens clad with TiC, WC and TiN powders by the gas tungsten arc welding (GTAW) method under optimum processing…
Abstract
Purpose
This paper aims to compare the wear performance of carbon steel specimens clad with TiC, WC and TiN powders by the gas tungsten arc welding (GTAW) method under optimum processing conditions.
Design/methodology/approach
Various ceramic powders (TiC, WC and TiN) with equal percentages by weight were prepared for use as cladding materials to compare their effects on wear resistance. The wear behaviors of different cladding specimens were evaluated with a rotating-type tribometer under dry sliding conditions. The cladding microstructures were characterized by optical microscopy, scanning electron microscopy and X-ray energy dispersive spectrometry.
Findings
The experimental results confirmed that the hardness was also much higher in the carbon steel with cladding than in carbon steel without cladding. The pin-on-disc wear test showed that the wear-resistance of ceramics clad with TiC is better than that in ceramics clad with WC or TiN. The wear scar area of the specimen with TiC cladding was only one-tenth that of carbon steel without cladding.
Originality/value
The experiments confirm that the cladding surfaces of ceramic particles reduce wear rate and friction.
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Harpreet Singh, D. Puri and S. Prakash
Plasma spray coating technologies are capable of depositing a wide range of compositions without significantly heating the substrate. The objective is to characterise plasma…
Abstract
Purpose
Plasma spray coating technologies are capable of depositing a wide range of compositions without significantly heating the substrate. The objective is to characterise plasma sprayed metallic coatings on a Fe‐based superalloy.
Design/methodology/approach
NiCrAlY, Ni‐20Cr, Ni3Al and Stellite‐6 metallic coatings were deposited on a Fe‐based superalloy (32Ni‐21Cr‐0.3Al‐0.3Ti‐1.5Mn‐1.0Si‐0.1C‐Bal Fe) by the shrouded plasma spray process. The coatings were characterised in relation to coating thickness, porosity, microhardness and microstructure. The high temperature oxidation behaviour of the coatings was investigated in brief. The techniques used in the present investigation include metallography, XRD and SEM/EDAX.
Findings
All the coatings exhibited a lamellar structure with distinctive boundaries along with the presence of some porosity and oxide inclusions. The microhardness of the coatings was observed to vary with the distance from the coating‐substrate interface. The St‐6 coating had the maximum microhardness, whereas the lowest hardness was exhibited by the Ni3Al coating. The phases revealed by XRD of the coatings confirmed the formation of solid solutions, whereas EDAX analysis of the as‐sprayed coatings confirmed the presence of basic elements of the coating powders. So far as high temperature oxidation behaviour is concerned, all of the coatings followed the parabolic rate law and resulted in the formation of protective oxide scales on the substrate superalloy.
Originality/value
The plasma spray process provides the possibility of developing coatings of Ni3Al as well as commercial available NiCrAlY, Ni‐20Cr and St‐6 powders on Fe‐based superalloy Superfer 800H
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Hu Yan and Kong Dejun
This paper aims to investigate the effects of Cr and Ta additions on the friction performance and corrosion-wear mechanism of Fe90-Al2O3 coating in 3.5% NaCl solution.
Abstract
Purpose
This paper aims to investigate the effects of Cr and Ta additions on the friction performance and corrosion-wear mechanism of Fe90-Al2O3 coating in 3.5% NaCl solution.
Design/methodology/approach
Cr and Ta reinforced Fe90-Al2O3 coatings were prepared on Q235 steel by laser cladding. The effects of Cr and Ta addition on the coefficient of friction (COF) and wear rate of Fe90-Al2O3 coating were investigated using a friction tester, and the wear model was established to discuss its corrosion-wear mechanism.
Findings
The average COFs of Fe90-Al2O3, Fe90-Al2O3-10%Cr and Fe90-Al2O3-10%Ta coatings in 3.5% NaCl solution are 0.57, 0.42 and 0.75, respectively, and the corresponding wear rates are 9.42 × 10−7, 5.31 × 10−7 and 7.02 × 10−7 mm3 s−1 N−1, respectively. The corrosion-wear resistance of Fe90-Al2O3-10%Cr coating is the best among the three kinds of coatings, in which the additions of Cr and Ta play a role in solid solution strengthening.
Originality/value
The Fe90-Al2O3 coating was strengthened by the additions of Cr and Ta to improve its corrosion-wear resistance in 3.5% NaCl solution.
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Yan Hu and Dejun Kong
This paper aims to improve the friction reduction and wear resistance of Fe90 alloy coating by the addition of Al2O3.
Abstract
Purpose
This paper aims to improve the friction reduction and wear resistance of Fe90 alloy coating by the addition of Al2O3.
Design/methodology/approach
Fe90 alloy coatings with the different Al2O3 mass fractions were prepared on Q235 steel by laser cladding (LC). The morphologies, phases and hardness of Fe90 alloy coating were analyzed using a scanning electron microscope (SEM), X-ray diffraction (XRD) and microhardness tester, respectively. The effects of Al2O3 mass fraction on the coefficient of friction (COF) and wear rates of Fe90 alloy coating were investigated using a friction tester, and the wear model was built to discuss the wear mechanism of Al2O3-reinforced Fe90 alloy coating.
Findings
The results show that the large number of Fe carbides is generated on the Fe90–Al2O3 coatings by the effect of laser high energy, and the hardness of Fe90–coating is 806 HV0.5, which is 4.48 times of substrate. The average COFs of Fe90–Al2O3 alloy coatings decrease from 0.73 to 0.55, and the wear rates are also reduced from 447.78 to 274.63 µm3•s–1•N–1 by the addition of Al2O3. The Fe90–6% Al2O3 coating presents the highest wear resistance among the three kinds of coatings, and the wear mechanism is abrasive wear and micro-cutting wear.
Originality/value
The Al2O3-reinforced Fe90 alloy coating was first fabricated by laser cladding, and the effect of Al2O3 on the friction-wear performance of Fe90 alloy coating was investigated.
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Gökçe Mehmet AY and Osman Nuri ÇELİK
Plasma transferred arc (PTA) coating is a novel method for surface-coating applications. In this method, the substrate is melted using a plasma arc, and surfacing agents such as…
Abstract
Purpose
Plasma transferred arc (PTA) coating is a novel method for surface-coating applications. In this method, the substrate is melted using a plasma arc, and surfacing agents such as carbides are introduced to the melt pool. The purpose of this study is to investigate the effect of boron carbide (B4C) in nickel-based coating on AISI 4140 steel.
Design/methodology/approach
Samples were tested on a ball-on-disc wear device, and the microstructure, as well as wear properties, were investigated using SEM and XRD.
Findings
The effect of B4C addition was shown to be linear, with a p-value of 0.0248, indicating strong evidence. The reason for this increase was found to be the increase in third-body generation resulting from hard phases that form couples with the soft base material, nickel. It was concluded that using 6 per cent B4C was the optimal solution.
Originality/value
In the literature, the effect of neither low temperature on a nickel coating with B4C nor B4C as a single surfacing agent in a nickel base has been investigated.
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Thomas Himmer, Anja Techel, Steffen Nowotny and Eckhard Beyer
Time reduction and quick geometrical changes of complex components and tools are currently the most important demands in product development. The manufacturing process presented…
Abstract
Time reduction and quick geometrical changes of complex components and tools are currently the most important demands in product development. The manufacturing process presented in this paper is based on multiple additive and subtractive technologies such as laser cutting, laser welding, direct laser metal deposition and CNC milling. The process chain is similar to layer‐based Rapid Prototyping Techniques. In the first step, the 3D CAD geometry is sliced into layers by a specially developed software. These slices are cut by high speed laser cutting and then joined together. In this way laminated tools or parts are built. To improve surface quality and to increase wear resistance a CNC machining center is used. The system consists of a CNC milling machine, in which a 3 kW Nd:YAG laser, a coaxial powder nozzle and a digitizing system are integrated.
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Lino Costa and Rui Vilar
The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense functional…
Abstract
Purpose
The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense functional items from a wide range of common engineering materials, such as aluminum alloys, steels, titanium alloys, nickel superalloys and refractory materials.
Design/methodology/approach
The main R&D efforts and the major issues related to LPD are revisited.
Findings
During recent years, a worldwide series of R&D efforts have been undertaken to develop and explore the capabilities of LPD and to tap into the possible cost and time savings and many potential applications that this technology offers.
Originality/value
These R&D efforts have produced a wealth of knowledge, the main points of which are highlighted herein.
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