Methods of restoring parts in repairs

2021 ◽  
pp. 59-73
Author(s):  
A. B. Istomin ◽  
I. V. Lizunov ◽  
V. O. Dmitriev ◽  
V. B. Kozlov

The article presents the review of the main methods of restoration and repair of machine parts: mechanical and bench work, welding, surfacing, metal coating, chrome plating, nickel plating, steeling (iron plating), bonding, hardening the surface of parts and restoring their shape under pressure. The areas of application of each method, its advantages and disadvantages are noted. Welding and surfacing are used to restore more than half of all repaired car parts. With the help of welding, cracks and fractures on the frame and platform are repaired, patches, various overlays and reinforcing gussets are put, and the crankcases of the units are restored. Damaged or worn threads on stub axles and other parts are restored by welding, followed by cutting a new thread. The internal threads are restored in the same way. Restoration of parts by surfacing consists in surfacing the worn working surfaces in such a way that they can be processed to the nominal or repair dimensions. When repairing cars, automatic and semi-automatic surfacing and welding under a layer of flux or in a carbon dioxide environment are used. Damaged and worn parts can be repaired by pressure. This method is based on the use of the ductility of metals. The parts are restored to their nominal dimensions with the help of special devices, by moving a part of the metal from non-working areas of the part to its worn surfaces. When restoring parts by pressure, not only their external shape changes, but also the structure and mechanical properties of the metal. Plastics are used to restore worn parts when repairing metal-cutting machines. As an adhesive, plastics are widely used for bonding broken parts, as well as for obtaining a fixed connection of parts made of metallic and non-metallic materials. When repairing metal-cutting machines, the most widely used plastics are textolite, wood laminated plastics and fast-hardening plastic — styracryl.

Author(s):  
I Sheka ◽  
Ye Tsivka

Purpose. To analyze composite materials and prospects of their use as fastening materials for mining of coal mines.Perform a comparative analysis of the physical and mechanical properties of the innovative material carbon fiber and metallic materials, as well as compare their features. To determine the possibility of using carbon fiber as a fastening material for mining of coal mines. Research methodology. The generalization of physical and mechanical properties of carbon fiber on the basis of its analysis is performed. The features of mechanical properties of carbon fiber, steel and aluminum are compared, which showed that this composite material has the best physical and mechanical properties and it is expedient to use it in the fastening elements of mine workings. Research results. The areas of use of composite materials in industry are analyzed and generalized, and it is concluded that it is better to use carbon fiber as a fastening material for coal mine workings. A comparative analysis of the physical and mechanical properties of carbon fiber and steel is performed, which shows that this composite material has identical (and sometimes even better) properties as metallic materials. The advantages and disadvantages of carbon fiber as a fastening material for mining of coal mines are estimated. It is specified that the restraining factor, today, is the cost of carbon fiber, and later their price will decrease and demand will increase. It is concluded that when using this composite material in the fasteners of mine workings, it is possible to increase the pace of their implementation, reduce the complexity of the work performed and improve working conditions while facilitating the design. Scientific novelty. It is established that carbon fiber as a composite material can be used in the fastening elements of the preparatory workings of coal mines. Practical value. According to the results of the analysis, it is established that carbon plastics can be used in the fastening elements of mine workings, which will promote the development of underground coal mining.


Author(s):  
Josué Rafael Sánchez-Lerma ◽  
Luis Armando Torres-Rico ◽  
Héctor Huerta-Gámez ◽  
Ismael Ruiz-López

This paper proposes the development of the methodology to be carried out for the metal joining process through the GMAW welding process in the Fanuc LR Mate 200iD industrial robot. The parameters or properties were considered for the application to be as efficient as possible, such parameters as speed of application, characteristics of the filler material, gas to be used as welding protection. The GMAW welding process can be applied semiautomatically using a hand gun, in which the electrode is fed by a coil, or an automatic form that includes automated equipment or robots. The advantages and disadvantages of the GMAW welding process applied in a manual and automated way were commented. The mechanical properties of the materials to which said welding can be applied were investigated; The materials with which this type of welding can be worked are the high strength materials, which are used in the automotive industry, for the forming of sheet metal. To know the properties of the material, destructive tests were carried out on the test material to be used, as well as the mechanical properties of the welding.


2020 ◽  
Vol 67 (2) ◽  
pp. 115-120
Author(s):  
Raisa A. Alekhina ◽  
Victoriya E. Slavkina ◽  
Yuliya A. Lopatina

The article presents options for recycling polymers. The use of biodegradable materials is promising. This is a special class of polymers that can decompose under aerobic or anaerobic conditions under the action of microorganisms or enzymes forming natural products such as carbon dioxide, nitrogen, water, biomass, and inorganic salts. (Research purpose) The research purpose is in reviewing biodegradable materials that can be used for the manufacture of products used in agriculture. (Materials and methods) The study are based on open information sources containing information about biodegradable materials. Research methods are collecting, studying and comparative analysis of information. (Results and discussion) The article presents the advantages and disadvantages of biodegradable materials, mechanical properties of the main groups of biodegradable polymers. The article provides a summary list of agricultural products that can be made from biodegradable polymer materials. It was found that products from the general group are widely used in agriculture. Authors have found that products from a special group can only be made from biodegradable polymers with a controlled decomposition period in the soil, their use contributes to increasing the productivity of crops. (Conclusions) It was found that biodegradable polymer materials, along with environmental safety, have mechanical properties that allow them producing products that do not carry significant loads during operation. We have shown that the creation of responsible products (machine parts) from biodegradable polymers requires an increase in their strength properties, which is achievable by creating composites based on them. It was found that the technological complexity of their manufacture and high cost are the limiting factors for the widespread use of biodegradable polymers at this stage.


2020 ◽  
Vol 4 (141) ◽  
pp. 114-122
Author(s):  
DAR’YA LEBEDEVA ◽  
◽  
ANNA KARPUNICHEVA

Large forces and significant thermal effects are created on the rolls when rolling sheets. The higher the stability of the rolls, the less downtime during their rerolling and higher productivity. (Research purpose) The research purpose is in analyzing the ways of restoring rolls and choose the most appropriate method for restoring these parts. (Materials and methods) The article presents the analysis of the scientific and technical literature on the topic of rolling production, methods for restoring large-sized machine parts of machine-building and metallurgical industries that work in difficult conditions and are subject to a high degree of wear. Authors try to solve the problem by means of comparative and logical analysis based on theoretical and empirical methods of scientific research. (Results and discussion) The article presents two groups of methods for restoring rolled rolls: banding and surfacing the working layer of the roll. Authors have analyzed each method in terms of technology, equipment, and feasibility. The article presents the advantages and disadvantages of the methods under consideration. (Conclusions) The most acceptable way to restore parts with a high degree of wear is surfacing. It is most efficient to apply submerged surfacing using an additional hot additive. Such surfacing, despite some complication of the equipment design, allows to deposit the metal on the roll with low heat input and in most cases in one pass. Surfacing using an additional hot additive allows to increase the productivity of the process by up to 250 percent while reducing the penetration depth by 2-3 times and saving energy by up to 40 percent.


2018 ◽  
Vol 216 ◽  
pp. 03001 ◽  
Author(s):  
Evgeny Ivanayskiy ◽  
Aleksei Ishkov ◽  
Aleksandr Ivanayskiy ◽  
Iakov Ochakovskii

The paper studies the influence of shielding gas on the composition and the structure of weld joint metal of 30MnB5 steel applied in essential parts of automobiles and tractors. The welding was performed in inert, oxidizing and reducing atmospheres. It was established that TIG welding with argon used as shielding gas did not provide the required mechanical properties when using conventional welding materials. Carbon dioxide during MAG welding caused partial burning of alloying elements. Carbon monoxide used as shielding gas was proved to form reducing atmosphere enabling to obtain chemical composition close to the base metal composition. Metallographic examinations were carried out. The obtained results provided full-strength weld, as well as the required reliability and durability of welded components and joints.


2017 ◽  
Vol 883 ◽  
pp. 75-84 ◽  
Author(s):  
Nireeksha Karode ◽  
Laurence Fitzhenry ◽  
Siobhán Matthews ◽  
Philip Walsh ◽  
Austin Coffey

Medical tubing used in minimally invasive devices presents a number of design considerations depending on the material used, design requirements (such as sufficient stiffness, flexibility and biocompatibility) and processing conditions. Currently, manufacturing industries adopt co-extrusion systems to meet design specifications, by using multilayer configuration leading to higher cost per device and increased complexity. This paper investigates the mechanical performance of nanocomposites using supercritical carbon dioxide assisted polymer processing technique. The use of innovative medical compounds such as PEBAX graphene nanocomposites have resulted in measurable improvements in mechanical properties. This study also presents the effect of supercritical carbon dioxide on the mechanical and physical properties of the polymer matrix. The mechanical properties have been investigated using dynamic mechanical analysis (DMA) and mechanical tensile test, where sufficient reinforcement was observed depending on the composition of graphene within PEBAX matrix. ATR-FTIR was used to further analyze the effect of supercritical carbon dioxide and interactions within the polymer composite matrix.


2013 ◽  
Vol 46 ◽  
pp. 201-209 ◽  
Author(s):  
Weiguo Liu ◽  
Jiafei Zhao ◽  
Yuan Luo ◽  
Yongchen Song ◽  
Yanghui Li ◽  
...  

2014 ◽  
Vol 891-892 ◽  
pp. 1639-1644 ◽  
Author(s):  
Kazutaka Mukoyama ◽  
Koushu Hanaki ◽  
Kenji Okada ◽  
Akiyoshi Sakaida ◽  
Atsushi Sugeta ◽  
...  

The aim of this study is to develop a statistical estimation method of S-N curve for iron and structural steels by using their static mechanical properties. In this study, firstly, the S-N data for pure iron and structural steels were extracted from "Database on fatigue strength of Metallic Materials" published by the Society of Materials Science, Japan (JSMS) and S-N curve regression model was applied based on the JSMS standard, "Standard Evaluation Method of Fatigue Reliability for Metallic Materials -Standard Regression Method of S-N Curve-". Secondly, correlations between regression parameters and static mechanical properties were investigated. As a result, the relationship between the regression parameters and static mechanical properties (e.g. fatigue limit E and static tensile strength σB) showed strong correlations, respectively. Using these correlations, it is revealed that S-N curve for iron and structural steels can be predicted easily from the static mechanical properties.


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