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The object of research is the technology of manufacturing «Body»-type shaped castings of the from medium carbon steel in one-time sand molds. The existing problem is that the design of the casting and foundry equipment significantly affect the formation of internal defects in castings. This especially applies to steel castings, the technology of which is more complicated than the technology of cast iron castings due to much worse casting properties of steel. To determine the influence of the location of surpluses on the «Body»-type steel castings of the on the formation of shrinkage shells, computer modeling was used, in the process of which 5 computer experiments were conducted with different sizes and geometries of surpluses. According to the simulation results, it was found that with some technological options, there is a risk of the shrinkage shell penetrating into the casting body. The use of a cylindrical surplus of a rectangular cross-section with fillets ensures complete absorption of the shrink shell in the place of surplus installation. Using an excess round section at the installation location does not guarantee absorption of the shrink shell. The determining factor affecting the coefficient of increase in the depth of the shrinking shell is the excess volume. This influence can be described by a functional dependence of the logarithmic type with the coefficient of determination R2 = 0.82. It was determined that the ratio of the diameter of the inlet to its height does not affect the coefficient of increase in the depth of the shrinking shell. The resulting functional dependence allows to set the excess volume that provides a minimum growth factor while simultaneously preventing excess metal consumption. The presented study will be useful for machine-building enterprises that have foundries in their structure, where shaped castings are made in one-time sand molds. [ABSTRACT FROM AUTHOR]

The foundry industry is an important component of the economy on which other progressive industries depend. The reliability of the products it manufactures is determined by the technologies used, but, most importantly, it ensures the expected level of quality. The purpose of the article is to develop a synergistic quality-cost model for the improvement of casting products. The model is based on an integral methodological configuration that makes it possible to determine the level of relevance of the causes of casting nonconformity in the quality-cost context. The model integrates techniques such as the Pareto-Lorenz diagram, ranking, brainwriting, Ishikawa diagram, Likert rating scale, and matrix diagram. Verification of the method by its implication in the manufacturing process of a gearbox casting is performed. The model makes it possible to identify quality-cost relationships between key categories of problem causes and major product nonconformities. The main causes of the loss of quality stability of the analyzed product are found to be low quality of molding sand, poor technical condition of foundry equipment (too infrequent repairs and overhauls), and ineffective quality control. Carrying out the analysis made it possible to develop appropriate improvement measures. It is proposed to implement changes in the casting process, implement the TPM method, conduct periodic training, develop job instructions, implement a control system, and provide supervision of employees. Further research directions will concern the implications of the method within the other positions in the casting company and its development towards automation of analysis. [ABSTRACT FROM AUTHOR]

To promote the green and sustainable development of the foundry industry, it is necessary to further explore the new method, new technology, and new equipment for green foundry. In this paper, an innovative green casting method is proposed. The digital frozen sand casting technology uses water as the binder to replace the organic/inorganic binder for casting at low temperature, which solves the problems of difficult sand recovery and harmful gas emission during the casting process and realizes the high-performance green casting of complex castings. The green casting technology of digital frozen sand mold is a method to produce sand mold by freezing cutting and printing, and to obtain typical parts by mold assembling and pouring. In this paper, the basic theory, key technologies, and system equipment of frozen sand paving are systematically studied, and the application verification research is carried out on typical aluminum alloy parts. It reduced the amount of resin binder, improved the green level of casting industry, and provided a new green casting method for the casting field. [ABSTRACT FROM AUTHOR]

Compositions of ceramic bodies were developed for obtaining wollastonite-containing ceramics based on home-grown carbonate and siliceous raw materials. Aspects of the formation of the structure and the phase composition of the synthesized ceramic materials are determined in terms of the physicochemical properties and operational characteristics. The influence of a mineralizing additive (natural wollastonite) on the sintering and phase formation processes is determined, and the relationship between the indicators of physical, technical, and thermophysical properties, the firing temperature, and the amount of mineralizer introduced emerged. The results of the investigations are of theoretical and practical interest for organizing the production of wollastonite-based refractory ceramic 'ammo' [resources]. [ABSTRACT FROM AUTHOR]

Statistical quality control is used in foundries to identify special cause defects and root causes by correlating process input variations with casting defects. A difficulty exists in associating process data collected with individual cast parts as the parts are processed through the foundry and then out into the supply chain. Typically, alphanumeric labels for marking castings and manual identification of the castings with route-paper based tracing approaches have been used. Such manual-based systems make root cause analysis of quality defect issues tedious. This study presents the development of a semi-automated approach using 3D printed sand mold inserts shaped as 2D matrix codes which thereby permit directly cast identification code into the parts. This enables automated part tracking at the very beginning of the casting process including mold making. Automated scan based tracking of parts through a foundry and subsequent supply chain allows for statistical process data collected to also be associated with each part processed with unique identification, building upon the part history and pedigree. [ABSTRACT FROM AUTHOR]

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The article presents the results of computer simulation of the crystallization of castings from high-speed steel R6M5, intended for the manufacture of cutters and gear shaping tools in the conditions of OJSC “Minsk Gear Plant”. The use of modeling made it possible to optimize the gating system, reduce this volume of the profitable part by 30–35 % and increase the yield of suitable casting, which made it possible to reduce the consumption of expensive alloying elements introduced into the melt to compensate for burnout during melting and casting.

This article presents several experimental methods for monitoring cast iron foundry equipment using inductive sensors. Inductive proximity sensors M12,15-30V / DC, CONTRINEX DW-AS-509-M12-390, NO (normally open), with a diameter of 12 mm, accuracy class IP67, powered with DC15-30V current and model XS8C4A1MPG13, NO with detection from 10 to 0 mm, were used to perform this experiment. The proximity sensors were mounted next to the sole of a 30KW motor, on a model extraction machine, to detect the accuracy of placing the pallet on the machine chassis and on a machine for closing formed frames, which aims to close the frames. [ABSTRACT FROM AUTHOR]

Smart susceptors are being developed for use as tooling surfaces in molding machines that use apply electro-magnetic induction heating to mold and form plastics or metal powders into structural parts, e.g., on aerospace and automotive manufacturing lines. The optimal magnetic materials for the induction heating process should have large magnetization, high magnetic permeability, but also small thermal expansion coefficient. The Fe0.65Ni0.35 invar alloy with its negligible thermal expansion coefficient is thus a natural choice for this application. Here, we use density functional theory as implemented through the Korringa-Kohn-Rostoker method within the coherent-potential approximation, to design new alloys with the large magnetization desired for smart susceptor applications. We consider the Fe0.65-xNi0.35-yMx+y alloys derived from Fe0.65Ni0.35 invar adding a third element M=Sc, Ti, V, Cr, Mn, or Co with concentration (x + y) reaching up to 5 at. %. We find that the total magnetization depends linearly on the concentration of M. Specifically, the early 3d transition metals from Sc to Cr decrease the magnetization with respect to that of the invar alloy whereas Mn and Co increase it. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the performance characteristics of commercially available US foundry consumables for use in three-dimensional sand printers. The silica sands selected were 57 grain fineness number (GFN) and 70 GFN. These sands were a high-purity round grain silica and had low trace contaminates, to reduce any possible influence from contaminates. The furan resin system was selected since it is the most widely utilized resin system for 3D printed sand in the USA. The furan resin system was from a domestic US foundry supplier. The printed samples were traditional tensile specimen and rectangle samples for the determination of density. The samples were examined for the following properties: tensile strength, loss on ignition, density, scratch hardness, and permeability. The results of this investigation confirmed that the tested domestic resin system and silica sands matched the original equipment manufacturer performance properties. [ABSTRACT FROM AUTHOR]

Synthetic mesophase pitches, extensively used as graphite precursors, manifest particular fluid-dynamic properties given their liquid crystal nature. Their recent use in infiltration processes to manufacture graphite-based monolithic and porous materials demands the study of their physical properties, mainly viscosity and contact angle, under dynamic conditions. In this work a new infiltration device was conceived and constructed to measure the infiltration kinetics of the AR24 naphthalene-based mesophase pitch and TiC nanoparticle-doped AR24 mesophase pitch into preforms of packed NaCl particles. The experiments allowed activation energies for viscosity to be obtained, along with pseudo-equilibrium and advancing contact angles. [ABSTRACT FROM AUTHOR]

A novel method of producing multilayered steels (MLS) with harmonically variable composition was developed by stacking the requisite number of layers, drilling uniform holes into the stacked assembly, inserting high strength rods of a suitable diameter into the holes, and hammering to interlock the multiple layers to finally form a multilayer preform. The preform was then subjected to severe plastic deformation processes, like cold forging, cold and/or hot rolling to obtain the final multi-layered product. High Carbon (H), Medium Carbon (M), Low Carbon (LC, L), Stainless steel (SS) sheets and Cr powder were chosen as the stacking materials and various stacking sequences were prepared. The interface between different layers showed strong diffusion bonding with very little or no presence of voids/pores suggesting excellent union. Compositional analysis showed alternate distribution of constituent elements across different layers of steels in different combination of multi-layered products. Flexure test of the SS-LC multilayer showed that the crack initiated due to early failure of SS layer was inhibited from growing due to the energy absorbing tendency of the LC steel on either side of the SS layer. Hardness and tensile properties of multi-layered steels depended on the different alternate combinations of various materials. [ABSTRACT FROM AUTHOR]

Copyright of Eastern-European Journal of Enterprise Technologies is the property of PC TECHNOLOGY CENTER and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical vapour infiltration (CVI) is widely used for fabricating carbon fibre-reinforced carbon materials for aircraft brake disks. This study aims at developing a numerical simulation method for predicting densification of the material during the CVI. Based on the multi-step reaction and deposition models, including the hydrogen inhibition model of pyrocarbon growth, transient 3D simulations of the CVI using methane as a precursor of the pyrocarbon were carried out via the finite element method coupling the mass transfer (by convection and diffusion) and the evolutive porous structure model with gas-phase and surface chemical reactions. The CVI of two different types of preforms was studied. The pore structure evolution models were derived not analytically but numerically with the aid of a computational tool for visualizing the fibre structures. An acceptable agreement was found between the predicted densification profiles and the experimental data obtained using a laboratory CVI reactor at a temperature of 1343 K, a methane pressure of 30 kPa and a total deposition time of 120 h. [ABSTRACT FROM AUTHOR]

Among the processing parameters of additive manufacturing, printing direction is of critical importance. While studies on effects of printing direction have so far mainly focused on mechanical properties of solid specimens, the present research is intended to demonstrate printing direction dependence of mechanical behavior of additively manufactured 3D preforms and their composites. Compressive behavior of additively manufactured 3D braid preforms and composites was investigated for three distinct printing directions (0°, 45° and Z-direction). Fused filament fabrication (FFF) of acrylonitrile-butadiene-styrene (ABS) filament and short carbon fiber/ABS (CF/ABS) filament was adopted. First, solid cube specimens were fabricated; the parts printed along 0° and 45° directions showed more fabrication-induced pores. Then, 3D braid preforms were fabricated and infused with silicone matrix. For preforms printed along 45° direction, inter-yarn adhesion was observed, which enhanced specimen initial modulus. On the other hand, Z-direction specimens showed higher structural ductility, due to inter-yarn slippage. [ABSTRACT FROM AUTHOR]

Centrifugal force was used to produce open-cell Zn-22Al-2Cu alloy foams by the replication method. Three different sizes (0.50, 0.69, and 0.95 mm) of NaCl spherical particles were used as space holders. A relatively low infiltration pressure was required to infiltrate completely the liquid metal into the three pore sizes, and it was determined based on the centrifugation system parameters. The infiltration pressure required was decreased when the diameter of the particle was increased. The porosity of the foam was increased from 58 to 63 pct, when the pore size was increased from 0.50 to 0.95 mm, while the relative density was decreased from 0.42 to 0.36. The NaCl preform was preheated to avoid the freezing and to keep the rheological properties of the melt. The centrifugal-replication method is a suitable technique for the fabrication of open-cell Zn-Al-Cu alloy foams with small pore size. The compressive mechanical properties of the open-cell Zn-22Al-2Cu foams increased when the pore size decreased. [ABSTRACT FROM AUTHOR]

Concrete is the most extensively used construction material in the world, second to water. Increasing rate of urbanization and industrialization has lead to over exploitation of natural resources such as river sand and gravels, which is giving rise to sustainability issues. It has now become imperative to look for alternatives of constituent materials of concrete. Waste foundry sand, a by-product of ferrous and non ferrous metal casting industries is one such promising material which can be used as an alternative to natural sand in concrete. In last few decades, several studies have been conducted to investigate the effect of addition of waste foundry sand as partial and complete replacement of regular sand in concrete. It has been found suitable to be used as partial replacement of sand in structural grade concrete. A number of properties have been reviewed in the current paper, the results observed from the various studies depict that replacement of foundry sand to a certain extent enhance the durability as well as strength properties of the concrete but simultaneously decreases the slump value with the increase of replacement level of waste foundry sand. [ABSTRACT FROM AUTHOR]

Silicon-carbide particle (SiC p ) preforms with particle sizes of 20, 50, 100 and 150 μm were prepared by compression mold forming and heat treatment. A high resolution (~ 1.0 μm) three-dimensional (3D) X-ray micro-computed tomography (X-ray μ-CT) combined with 3D pore-network models were used to study the effect of particle size on 3D characteristics and spatial structures of pores in the preforms. The results demonstrated that as the particle size increased, the gap expansion caused by burning of starch reduced. When the particle size increased from 20 to 100 μm, the average areal porosity, homogeneity of pore distribution, connectivity, the numbers of small pores and throats, and average pore coordination number decreased; the average effective sizes of pores and throats increased. When the particle size further increased to 150 μm, the large gaps were filled by small particles resulted from the broken coarse particles, which decreased the homogeneity and connectivity of pores. As a result, the pore-network analysis shows that the numbers of small pores and throats and average pore coordination number increased. [ABSTRACT FROM AUTHOR]

Composite materials are produced by combining two or more different components to form an individual product with better properties. Manufactured new composite materials may provide better performance than one component can provide by itself. Wood-plastic composites are manufactured by using thermoplastics and annual plant waste. In this study, utilization of eggplant (solanum melongena) stalks as a filler in manufacturing of injection molded PP based composites was investigated. For this purpose, neat polypropylene test samples (control group) and eggplant stalks flour-filled thermoplastic composites with different rates (7.5% 15% and 30%) were produced by using single-screw extruder and injection molding machine. Maleic anhydride polypropylene (MAPP) was utilized as coupling agents. Paraffin wax was used as a lubricant. Mechanical properties (tensile strength, flexural strength and impact strength) of produced composites were determined according to ASTM D 638, ASTM D 790 and ASTM D 256 standards. According to the statistical analysis, eggplant stalk flours had significant effect on tensile strength, tensile modulus, flexural strength, flexural modulus, elongation at break properties and density values. However, it had no significant effect on the impact strength properties. All produced composites provided standards requirements. [ABSTRACT FROM AUTHOR]

This paper describes the experimental investigation of the compaction behavior of dry single-ply and multi-ply fabric stacks (preforms). Utilizing four biaxial (two 0°/90° and two ±45°) and one triaxial (0°±45°) carbon fiber NCF, differing in weight (300 g/m2, 600 g/m2) and type of stitching (tricot, pillar, hybrid), the influence of compaction speed, pre-compaction cycles, number of layers, and stacking sequence on compaction force was examined. In contrast to other studies, the area of interest is limited to 40-50% fiber volume content (FVC), which is based on current continuous preforming conditions. The results showed that higher testing speeds result in increased compaction forces. Pre-compaction cycles (up to 8) significantly reduce (up to 69%) the required compaction forces of preforms for continuous preforming. Furthermore, at an equal total superficial density (1800 g/m2), 6-ply preforms (300 g/m2 each ply) require 75-88% higher compaction forces than 3-ply preforms (600 g/m2 each ply). This relation remains constant with decreasing or increasing total superficial density (ply number). Also the stacking sequence of 6-ply preforms (300 g/m2 each ply) remarkably influences the compaction force, whereby the stitching seam pattern and their alignment (superposition) to each other were the main influencing factors. POLYM. COMPOS., 38:2609-2625, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Among the family of liquid composite molding techniques, bladder-assisted resin transfer molding (BARTM) enables efficient manufacturing of hollow composite parts based on tubular reinforcing textiles. However, resin injection under certain processing conditions can result in high filling times or improper parts and finding the optimal process parameters is often a difficult task. This paper studies the impregnation behavior of a biaxial braided fabric in pressure-driven BARTM under a wide range of injection and bladder pressures. Saturation experiments were accomplished by means of a specifically developed injection test rig comprising an under-sized elastomeric bladder and a monolithic transparent mold. The results obtained show significant influence of the relevant process parameters on local preform compaction, apparent global permeability and filling time. Based on the experiments, a universal moldability diagram was derived that enables identification of admissible and critical operating conditions in BARTM, which supports the finding of optimal part filling settings. [ABSTRACT FROM AUTHOR]

In the injection molding of long fiber-reinforced resins, the breakage of fibers during the plastication process and while they are flowing past the check ring (CHR) is a common problem faced on manufacturing sites. However, no systematic research has been carried out. For the first time, the authors develop a heating cylinder with multiple ports on the wall for extracting the melted resin from the cylinder inside to perform in-process sampling of the resin. In this study, the new device was used to sample melted resin before and after CHR and to investigate the effects of the shape of the CHR on glass-fiber breakage. The experimental results clearly demonstrate that the breakage of fiber can be minimized to an extent where there is enough space for melted resin to gently flow and bypass the CHR. In addition, it was confirmed that the length of the CHR does not significantly affect glass-fiber breakage. [ABSTRACT FROM AUTHOR]

The demand for continuous fiber-reinforced thermoplastics has steadily increased during the last years due to their specific properties. But considering the applications in large-scale production, the price for the organic sheets is still too high in order to compete with the metal counterparts. A starting point for the reduction of the total costs is the acceleration of the impregnation process by in-plane polymer flow. For this reason, this scientific report provides an insight into the production process using a continuous compression molding machine. In order to analyze the in-plane polymer flow and its driving forces, a method for the evaluation of the pressure distribution is presented in a first step. The examination revealed a significant inhomogeneous pressure distribution for the whole pressing area, which could be affected by different temperature settings. Afterward, the impregnation quality was correlated with the different settings, followed by the illustration of a huge potential for increasing the impregnation speed. [ABSTRACT FROM AUTHOR]

Abstract A356/316L interpenetrating phase composites were fabricated by infiltrating additively manufactured 316L lattices with molten A356. Measurements of the thermal conductivity of the composites showed an inverse rule-of-mixtures dependence on the 316L volume fraction. Compression tests revealed that the stress-strain response of the composites can be tailored by adjusting both the volume fraction and the topology of the 316L reinforcement. Tension tests on composites with 39 vol% 316L showed a strain to failure of 32%, representing an order of magnitude improvement over the strain to failure of monolithic A356. Inspection of the as-tested tensile specimens suggested that this exceptional damage tolerance is a result of the interpenetrating structure of the constituents. These results together demonstrate that this infiltration processing route avoids problems with intermetallic formation, cracking, and poor resolution that limit current fusion-based additive manufacturing techniques for printing metallic composites. [ABSTRACT FROM AUTHOR]

In order to perform accurate parasitic extraction, foundries must provide the cross section profile of devices, and IP vendors must provide sufficient layout information. However, foundries and IP vendors are increasingly reluctant to reveal such sensitive information, especially for advanced devices. Therefore, the industry is faced with the following challenges: 1) foundries/IP vendors need to protect their trade secrets; 2) electronic design automation vendors need to integrate foundry data into extraction tools; and 3) IC designers need to have the accurate parasitic data. In this paper, we propose an innovative and practical solution to these challenges, by building a macro model around any region in 2-D/3-D on a circuit where foundries or IP vendors wish to hide information, yet the macro model allows accurate capacitance extraction inside and outside of the region. We first give algorithms to construct the macro model. Then, we describe how existing extraction algorithms can interface with the macro model to perform extraction for the entire circuit at the same accuracy as if complete information was given. The macro model can be used in finite difference method/finite element method and floating random walk, due to an equivalence theorem we proved. Finally, we propose the concept of equivalent profile and describe how to find one based on the macro model. Experimental results show the macro model can be efficiently constructed and used to produce accurate capacitance extraction. [ABSTRACT FROM AUTHOR]

A modularisation method of product design was put forward based on the integration of axiomatic design matrix (ADM) and design structure matrix (DSM). Because of the complementarity between ADM and DSM, the ADM is used to conduct inter-domain mapping and overall product design in function, while DSM is utilised for analysis and process the correlation and sensitivity among the design parameters, and provide a structured expression of the procedure and content of modular partition. Through the synchronous evolution and integration of ADM and DSM, a modularisation method of product design was presented with the combination of function and structure. Finally, a case is given to show the feasibility and the validity of this new method to implement the product's modularisation design. [ABSTRACT FROM AUTHOR]

This study is designing a mechanism with functions of rotational and positioning calibrations. This mechanism was applied to a hot embossing mold used for replications of double-sided structure. The hot embossed product was measured for double sided structures. The rotational and positioning alignment errors for both sides were measured by using a microscope. According to the results, the errors were calibrated wit this mechanism. The positioning and rotational resolutions of this mechanism are 40 μm and 0.5°, respectively. The results show that the mechanism has acceptable calibration accuracy. The average calibration accuracy for X-axis, Y-axis and C-axis were 92.5, 91.75 and 98.67 %, respectively. The small errors were induced by the large temperature difference between upper die and lower die during rapid cooling of a hot embossing process. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to identify changes in sheet shape during thermoforming and the effect of the model position in the molding machine on fabricated mouthguard thickness.Materials and Methods: Ethylene vinyl acetate mouthguard sheets (3.8 mm thick) were used that had cross-stripes (10 × 10 mm), and the anteroposterior and bilateral lengths were used for measurements. Two forming machines were used: a vacuum- and a pressure-forming machine, and two heating conditions were investigated that defined as the time when sagging of the softened sheet was 15 mm (H-15) and 20 mm (H-20) below the clamp, and the length of each cross-stripes was measured. The area of each lattice was calculated using Bretschneider's formula to compare changes in sheet shape for each condition. Next, mouthguards were molded by forming machine where the working model was positioned under two different conditions: with the model anterior centered in the forming unit and with the model centered. The sheet thickness after fabrication was determined for the incisal and the molar portion, and dimensional measurements were obtained using a measuring device. Differences in the thickness were analyzed by two-way analysis of variance (anova).Result: In both molding machines, the change in the area under H-20 was greater than H-15. While the increase in area tended to expand from the center of the sheet in concentric circles, the difference between the central and surrounding areas was only approximately 5%. For both molding machines, differences in thickness after molding due to setting position of the model were not observed.Conclusion: The results showed that shape changes of the sheet during thermoforming tend to concentrically and almost uniformly expand from the center and that it is important to center the sheet and the model when positioning the model in the forming unit. [ABSTRACT FROM AUTHOR]

Sulfur polymer concrete (SPC) is a relatively new material used to replace Portland cement for manufacturing sewer pipes. The objective of this work is to develop an efficient molding machine with an inner rotating die to mix, compress and shape the SPC pipe. First, the alternative concepts were generated based on the TRIZ principles to overcome the drawbacks of existing machines. Then, the concept scoring technique was used to identify the best design in terms of machine structure and product quality. Finally, topology optimization was applied with the support of the density method to reduce mass and to displace the inner die. Results showed that the die volume can be reduced by approximately 9% and the displacement can be decreased by approximately 3% when compared with the initial design. This work is expected to improve the manufacturing efficiency of the concrete pipe molding machine. [ABSTRACT FROM AUTHOR]

Barium sulfate (BaSO4)-containing polytetrafluoroethylene (PTFE) granular powder was prepared through a two-phase emulsion dispersion granulation method. Because of its large bulk density, small average particle size, narrow particle size distribution, and superior powder flowability, the granular powder is suitable for use in automatic molding machines. The effects of granulation on the tensile strength of the BaSO4/PTFE composite were investigated, and the composite’s microstructures were characterized and analyzed using scanning electron microscopy. All these indicated that the granulation could make BaSO4 disperse more homogeneously in PTFE and reduce many defects in molded articles. So the properties of the BaSO4/PTFE composites made by the granular powder were superior to the composite obtained from the nongranular powder. The tensile strength and elongation of the composite obtained from the granular powder could be achieved to a level of 19.4 MPa and 420%, respectively. [ABSTRACT FROM AUTHOR]

A new process was developed to produce full-size carbon/carbon-SiC brake discs consisting of two friction layers and a structural layer. Different lengths of chopped carbon fibers were used for the friction layers and structural layer. A preform of each layer was produced by hot-pressing a mixture of resin and carbon fibers. After pyrolyzing the preforms, the layers were joined by hot-pressing. Finally, liquid Si infiltration was performed to obtain a C/C-SiC brake disc. The tensile strength, compressive strength, and bending strength were 40, 46, and 61 MPa, respectively. The density of the disc was 2.1 g/Cm3. The heat transfer coefficient in the vertical direction was 16.5 W/m-°C, and it was 45.9 in the horizontal direction. The friction coefficients obtained under various braking conditions showed stable and suitable values, 0.2–0.6. [ABSTRACT FROM PUBLISHER]

The structure and properties of wear- and corrosion-resistant alloy of Fe-Cr-V-Mo-Ni-C system were investigated for plasma surfacing of screw conveyors of extruders and injection molding machines. It was shown that combination of high wear resistance and ductility of the alloy is achieved due to formation of a large amount of primary vanadium carbides VC and eutectics, located in the viscous austenitic-martensitic matrix in the form of single colonies. The alloy has an excellent formation and high resistance of the deposited bead to crack formation in surfacing, that allows surfacing rather massive parts without preheating. The service life of screw conveyors deposited using this alloy is 3-5 times higher than that of nitrated screws. [ABSTRACT FROM AUTHOR]