Vol 2018, No 13 (2018)
- Year: 2018
- Articles: 26
- URL: https://journals.rcsi.science/0036-0295/issue/view/10536
Physical Metallurgy. Thermal and Thermochemical Treatment Technologies
Choice of a Medium for the Heat Treatment of Steels and Alloys
Abstract
The physicochemical and technological properties of the liquid media based on sodium, boron, and silicon oxides and containing other components are studied. The properties of the liquid media, the surface quality, and the corrosion rates of various steels and alloys to be processed in these media are found to be interrelated.
Method of Electric Arc Furnace Dust Processing by Calcination with Lime with Following Alkaline Leaching
Abstract
The paper presents the results of the investigation of elemental and phase composition of zinc-containing electric arc furnace dust, the product formed by the dust calcination with lime, and the residue formed by alkaline leaching of the calcined product. The phase distribution in samples is studied by X-ray diffraction analysis, Mössbauer spectroscopy, and scanning electron microscopy. It is shown that electric arc furnace dust calcination with lime followed by alkaline leaching the calcined product can be used to recycle the dust with recovery of valuable components.
New Materials. Technology of Composite Materials
Analysis of the Nonuniform Reinforcing-Phase Distribution in Cast Rods and a Deposited Layer Made of an Aluminum-Matrix Composite Material
Abstract
Technology of Forming and the Properties of Reinforced Composites Based on an Inorganic Binder
Abstract
Coating Deposition
Technologies of Metallization of Carbon Fabric and the Properties of the Related Carbon Fiber Reinforced Plastics
Abstract
Two technologies of metallization of carbon ribbons in vacuum deposition and magnetron sputtering setups are considered. Titanium is used as a metallic coating. Carbon fiber reinforced plastic samples with a coupling agent based on aminopropyl triethoxysilane are prepared for comparison. The coupling agent is also applied using the following two technologies: in the first technology, it is applied onto a ribbon and is then dried; in the second technology, it is introduced into the composition of a binder. A LUP carbon ribbon and an epoxy binder are used for investigations. The carbon fiber reinforced plastics for all technologies under study are prepared using vacuum infusion. The increase in the interlayer shear strength is found to be maximal for the metallization of the carbon on a Bulat-6 setup.
Automation and Computerization of Technological Processes
Simulation of the Deformational Cutting and the Geometric Parameters of Pin Structures to Analyze the Thermohydraulic Characteristics of Heat-Removal Plates
Abstract
A principle is proposed to form a heat-exchange developed structure with the required thermohydraulic characteristics by deformational cutting using end-to-end computer simulation. Several simulation stages, including the finite element simulation of deformational cutting, are considered using the formation of an acicular pin as an example. The discrepancy between the main geometric parameters of the pin model and a real sample does not exceed 10%.
System Analysis and Simulation of the Characteristics of the Materials of Cryogenic Pipelines
Abstract
The transpiration of liquefied natural gas (LNG) in pipelines decreases the cost of transfer, and pipes of smaller diameters can be used in this case. Based on system analysis, we developed a mathematical model to determine the pipeline wall thickness for LNG transportation as a function of the pipeline diameter and steel grade.
Methods of Studying the Structure and Properties of Materials
Practice of Application of Thermal Cycle Tests in Studying the Thermal Fatigue of Materials
Abstract
The methods of thermal cyclic tests used for determining the thermal fatigue resistance of materials are analyzed using thermal cyclic maps (TC maps). These methods are based on the construction of the dependence of life time N on plastic strain in a cycle εp. An analysis showed that the dependence of N on εp does not give complete information on the thermal fatigue of materials, since it is built without consideration of the peculiarities of developing deformation related to their physicomechanical properties during a thermal cycle of tests. This is observed, for example, in the studies of single-crystal turbine blade materials, in which many conflicting data are obtained according to the results of testing VKNA-1V and ZhC6F alloys.
Application of the Graph Theory to Describe Technological Heredity
Abstract
The phenomenon of technological heredity is considered, and a geometric approach to describing the technology of transferring an inherited sign using the graph theory is proposed. This approach makes it possible to find the cause–effect relations between technological objects of various physical origins. Various structures of graphs are analyzed, and the main laws of technological heredity are described.
Foundry
Effect of Technological Casting Conditions on the Structure of Single-Crystal Blades Made of a Carbon-Free Nickel Superalloy
Abstract
The process of casting carbonless VZhM4 nickel superalloy cooled blades with a single-crystal 〈001〉 structure on UVNK plants is developed. Model blade units with seed parts for the formation of a single-crystal structure in a turbine blade are designed, the structure of the alloy is studied, and experimental batches of single-crystal blade ingots are cast. The influence of the directional solidification conditions on the structure of the carbonless alloy and the susceptibility of the single-crystal structure of the ingots to defect formation are investigated.
Nanotechnologies and Nanomaterials
Nanomodification of a Metal during Casting and Welding
Abstract
Adhesive Joints
Service Properties of the Thermoplastic Polymer Materials Used for Repairing Road-Building Machines
Abstract
The service properties of thermoplastic materials (molten adhesives) are studied to estimate the possibility of their application for repairing road-building machines. The swelling resistance of molten adhesives in working media, namely, water, motor oil, and antifreeze, is investigated. Dynamomechanical analysis is used to analyze the deformation properties of the molten adhesives. The adhesion strengths of the epoxy adhesives traditionally used in repairing machines and the thermoplastic molten adhesives are compared.
Equipment and Devices
Quality Control of Equipment, Constructions, and Materials
Structuring of the Functionality Parameters of Hydrocarbon Transportation Systems with Allowance for a Failure Flow
Abstract
The problems of functionality of pipelines are considered. Algorithms are proposed to calculate the functionality indices of a pipeline, which are the most important characteristics to be quantitatively estimated. The functionality of a pipeline is estimated by engineering methods, which are directly related to the main indices of erecting the pipeline with allowance for a failure flow, and this is the basis of designing a building structure.
Methodology of Analyzing the Causes of Accidental Failure of Pipes Made of Various Steel Grades
Abstract
The statistics of the emergency of gas lines induced by stress corrosion cracking (SCC) is presented. A model is proposed to study accidental failure, and a method is suggested to estimate the behavior of steels under complex line conditions and to choose SCC-resistant steel grades for the line sections that are susceptible to SCC.
Machining of Blanks and Assembly
Brittle Fracture of a Material upon Microcutting of the Workpiece Surface by the Microrelief Protrusions of Loose Abrasive Grains
Abstract
The peculiarities of processing of the workpiece surface by a loose polishing material in the areas of small cutting depth not exceeding 1 μm are considered, and mathematical models for the impact of abrasive grain microrelief on processed workpiece surface are presented. It is demonstrated that the fracture of the surface metal layer is more brittle in comparison with microcutting of the workpiece surface by the top of an abrasive grain at a preset force and working parameters of workpiece processing by the surface protrusions of abrasive grains. This intensifies chip formation and promotes the achievement of a given surface quality.
Machining of the Ceramic Oxide Coating Formed by Plasma Electrolytic Oxidation
Abstract
Plasma electrolytic oxidation (PEO) is one of the methods to produce thin ceramic oxide coatings on the parts made of aluminum alloys and to increase their wear resistance and service life significantly. A PEO coating consists of upper and lower layers. The microhardness of a ceramic oxide coating is nonuniform across thickness. It is necessary to ensure the accuracy of the sizes and shapes and the surface roughness of the surfaces formed upon finishing of ceramic oxide coatings. The effect of the characteristics of abrasive discs on the coating quality is studied. Technological recommendations are developed for the machining of such ceramic oxide coatings. Abrasive polishing should be used for final machining. The investigation results can be used in the machine building and repair enterprises that deal with the production, repair, and hardening of parts.
Welding Technologies. Soldering
Effect of the Conditions of Machine Hidden Arc Welding with an Additional Hot Additive (Flux-Cored Electrode) on the Formation of a Joint Weld
Abstract
The influence of the parameters of feeding and heating of an additional flux-cored electrode during machine hidden arc welding with an additional hot additive on the process is considered. Beads are deposited onto a 10-mm-thick steel (St3sp steel, GOST 380) plate, and the addition conditions, namely, the distance between the flux-cored electrode and the filler wire and the filler wire feed rate, are varied. The filler wire feed rate is found to depend on the electric current used for heating and to be independent of the distance between the point of introduction of the additional hot additive and the main arc. The limiting amount of the filler wire additive at which the transition from a deposited metal to the base metal is not sharp is determined.
Nonmetallic Materials and Their Processing into Products
Effect of the Technology of Sewing Carbon Fabric on the Properties of Carbon Fiber Reinforced Plastic
Abstract
The modern laying technologies of molding parts made of polymer composite materials are analyzed and compared, and the advantages and disadvantages of sewed fabric fillers are considered. The state of stress in carbon fiber reinforced plastic made of sewed fabric is calculated as a function of the filament thickness and step. Several stacks of carbon fabric consisting of various numbers of sewed layers are considered.
Electrophysical, Electrochemical, and Other Treatment Methods
Experimental Evaluation of the Methods of Laser Cementation of Low-Alloy Tool Steels
Abstract
Combined Treatment Methods
Technological Possibilities of Increasing the Quality and Decreasing the Cost of the Products Operating under High Loads at the Stage of Metallurgical Treatment
Abstract
The influence of modification by ultradispersed materials on the structure and physicomechanical properties of alloys is considered. Nanostructured boron nitride and aluminum hydroxide monohydrate (boehmite) are chosen as modifying additions to study their influence on the structure formation in a zinc–aluminum–copper antifriction alloy. Scanning electron microscopy and electron-probe microanalysis are used to identify high-hardness phases in the alloy structure. Modifying particles are found to affect the hardness of the alloy, which increases significantly with the number of particles. The strength of the alloy depends on both the number and the size of introduced particles, and powders with small grain sizes are more effective to increase the strength of the alloy. Moreover, silicon carbide is shown to exert a stronger effect on the strength of silumins than alumina does.
Metal Forming
Choice of Criteria to Find Deformation Zone Regions during Lengthwise Rolling
Abstract
Processes of Manufacture of Ferrous and Nonferrous Metals
Reduction of Silicon from a Ceramic Mold during Directional Solidification of Single-Crystal Nickel Superalloys
Abstract
Silicon is one of the most harmful impurities in nickel superalloys used for casting aviation turbines: it decreases the high-temperature strength and the ductility. The reduction of silicon from a ceramic mold is experimentally studied during the directional solidification of a single-crystal nickel superalloy.
Electrophysical, Electrochemical, and Other Processing Methods
Increasing the Wear Resistance of Steels by Multichannel Laser Hardening
Abstract
Formation of the Properties of the Working Surfaces of Important Parts by Plasma Surfacing and Surface Heat Treatment by a Reversed-Polarity Current
Abstract
The properties of surface layers can be formed by changing their structure using heat treatment and their composition and structure via the supply of an additional material to a treatment zone. The structural and phase transformations in the near-surface layer are determined by the thermal cycle in a treatment zone. To control the heating spot area at a uniform energy distribution and a high energy concentration is a challenging problem for surface heat treatment and deposition (surfacing). The results of studying plasma surface heat treatment and surfacing with a reversed-polarity current are presented. The contribution of the heat transfer from nonstationary cathode spots to an article during plasma surface treatment using a reversed-polarity current is separated. The advantages of surface heat treatment of medium- and high-alloy steels and the deposition of similar and dissimilar alloys using a reversed-polarity current constricted direct arc are presented.
Repair and Modification of Equipment
Technology of Plastic Deformation Repair of Metallurgical Machine Parts
Abstract
The technologies of repairing the worn parts of metallurgical equipment using plastic deformation methods, namely, expansion, swaging, upsetting, pressing, knurling, and forge-rolling, are described. Recommendations are given to choose temperature conditions in repairing the parts and determining the deformation forces.