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Foundry
The company Kutes Metall equips its foundry with a SEIATSU molding plant manufactured by Heinrich Wagner Sinto. The special feature of this molding plant. The SEIATSU.plus compaction process which enables different compaction techniques and combinations depending on requirements. In particular, with an occupancy up to the edge of the molding box optimum pressure values and consequently good casting qualities are achieved.
The mechanism and causes of the formation of casting defects, manifested in the deviation of the geometry of the internal cavities from the «cylindrical», are investigated. It is shown that the causes of distortion of the geometric shape are associated with deformation of the casting rod during thermal and mechanical interaction with the melt. Using the possibilities of computer simulation in the MAGMASOFT package, the temperature distributions of the metal in the casting body during the casting and solidification were analyzed. Areas of distortion of the geometric shape of the inner part of the casting correspond to the area of the rod subjected to the highest and longest thermal loads. The characteristics of the temperature fields in the respective zones indicate overheating of individual areas of the rod to temperatures causing phase stresses in the structure of the core mixture, sufficient for the occurrence of deformations in it. To eliminate the defect under consideration, two approaches were used to reduce the magnitude of phase stresses in the casting rod and to adjust the design of the rod tooling.
On the basis of the General criterion of quality the problem-oriented program technological algorithm for adjustment of technological parameters at the expense of reception of the characteristics investigated thermophysical properties of the profits providing the steady mode of imposing of hydrodynamic pressure before the beginning of crystallization of casting as a result of heating of profitable part of the interconnected elements «Gating system–casting» is developed. The software algorithm uses the means of computational experiment to determine the optimal values of the parameters in the development of cast processes. Optimization of the thermal regime is reduced to the analysis of the results of the studied thermophysical properties of top ingot due to the heating of the profitable part of the Gating-feeding system. The tested parameters are: temperature in top ingot in crystallized metal; wall thickness of top ingot; thermophysical reaction; the speed of the die casting liquid steel; the height of the heel of metal in top ingot.
This paper describes the factors that affect gas content in castings during pressure molding. The possibility of removing air and gases from the cavity of the mold through the ventilation channels in the process of filling it with liquid metal is considered. It is shown that the previously used assumption about the outflow of gases from the mold as through a hole in a thin wall is not correct. The calculations, taking into account the friction factor in narrow ventilation ducts, showed that the required crosssectional area of the ventilation ducts increases 4–6 times with a depth of 0,12 mm. If the obtained value of the cross-sectional area of the ventilation ducts is not possible to realize, at a given depth, it is proposed to use an accompanying vacuum to solve the problem.
In the article on the basis of the conducted researches and available technical documentation on modern non-contact electric devices the approach to perfect a control system of heating element of equipment for the production of gasified models. The thermophysical features and mode of operation of heating elements used in equipment for the production of gasified models is given. The numerical value of the working temperature of the spiral of heating element is determined. It is shown that application of three phase Solid State Relays (SSR) increased the life of heating elements by an average of 400–450 hours. SSR in the systems for controlling the heating of liquid heat carrier of plants for the production of gasified models are promising.
The article presents an alternative method of recycling of dispersed metal waste, based on a continuous solid-liquid-phase process, implemented in rotary tilting furnaces (RTF). The new proposed method of recycling allows processing wastes with almost any composition and state from metal to oxide and multicomponent wastes (shavings, fine scrap, mill scale, aspiration dust, sludge, etc.). The wastes can be even contaminated with moisture, oil, and organic impurities. The method developed does not require preliminary preparation of the initial materials (cleaning, homogenization, pelletizing, etc.). The finished products are ingots (pigs) for subsequent processing aiming the particular chemical composition or cast alloys of certain brend.
Metallurgy
The problem of friction, wear of machine parts and cutting tools, the need to increase the life of machines makes the task of creating new high-performance, energy-saving technologies of hardening one of the main in engineering. In mechanical engineering, the problem of improving the physical, mechanical and operational properties in thin surface layers (~10 microns) of such parts as shafts, gears, measuring tools, drills, cylinders of internal combustion engines, etc. is important. Currently, these tasks are often solved by applying reinforcing coatings. Cementation is economical. The technology of cemented steels smelting, which is currently used by metallurgical plants, does not ensure stable production of fine-grained structure in products. At the same time, the capacity of machines and units are growing, and to obtain parts that can withstand higher loads while maintaining their overall dimensions, new steel grades are needed. The complexity of the configuration of gears with a thin tooth and a massive sleeve, and the need for minimal warping make heat treatment as difficult and responsible as a complex tool, such as shaped cutters. Therefore, for the manufacture of gears you want to assign steel with small hereditary grain size. In this article we will focus on the development and production of cemented steel in the conditions of OJSC «BSW – Management Company of Holding «BMC», in particular, the steel brand 16MnCrS5 commissioned by the European manufacturer of gearboxes and motors. To determine the grain size of the metal must be subjected to special types of processing for the manifestation of certain characteristics. These results allow us to draw conclusions about the need to adjust the chemical composition of steel grade 16MnCrS5 by introducing a system of modifying elements, which will reduce the tendency of steel to overheating, therefore, reduce the size of austenitic grains. On the basis of the revealed regularities on the influence of carbide-forming elements, a further system of steel modification is determined, which includes a complex of elements V, Nb, Ti.
At OJSC «BSW – Management Company of Holding «BMC» were tested nesting well blocks for lining of steel-tapping hole of steel-teeming ladles ЭСПЦ-1, 2 with the working lining of piece goods. In the conditions of the enterprise during the full campaign of the working lining of steel ladles, intermediate repair of the slag belt, bottom blowing units and the steel-tapping holes is carried out. The steel-tapping hole is used to release steel from the steel ladle into the intermediate ladle. The purpose of the tests is to replace the «traditional» filling of the steel outlet with refractory concrete manually by molded nesting wellblocks due to the reduced risk of accident due to the lack of probability of metal «penetration» into the concrete, as well as reducing the volume and duration of repair of the working lining of steel ladles.
The article describes the experience of using deoxidizing powder in the technological process of production of hot-rolled seamless pipes; the processes that occur when applying to the inner surface of the hollow billet deoxidizing powder. The results of experimental and industrial tests of deoxidizing powder of different chemical composition are presented. The influence of the chemical composition of the deoxidizing powder on the formation of defects on the inner surface of the pipes is shown. Describes the stages of metallographic analysis of the defects on the inner surface of the pipe, provided the reasons for the formation of the defect «pipe rolling lap (skin)».
This article identifies factors influencing hardenability of steels in manufacturing conditions of OJSC « BSW – Management Company of Holding «BMC». The article contains results of a study on dependence of hardenability of steel grade 42CrMoS4 on design features of the equipment and the process aimed to ensure correspondence of the fi al product to the requirements. Measures that minimize spread of values due to preparation of samples for hardenability test in industrial conditions are presented. When predicting hardenability band, it is necessary implement a package of application programs that consider influence of factors existing in the conditions of a particular steel manufacturer.
A serious barrier to the sale of products on the market is the trust in organizations that perform measurements during product testing, as well as calibration (verification) of the used measuring instruments. Confidence and recognition of measurement results at the international level is ensured through an accreditation mechanism. To ensure effective functioning at the international level, accreditation organizations enter into a multilateral agreement that provides for the use of common standards in the conduct of accreditation. One of the important requirements of these standards is the implementation and demonstration of metrological traceability, which is a tool for ensuring the uniformity of measurements.
The parameters of wire production affecting the distribution of residual stresses and strains on the wire cross section are considered. It is determined that the modes of coarse drawing can affect the complex of mechanical properties of thin wire due to the uneven distribution of equivalent stresses and strains. The rough drawing speed is chosen as the investigated parameter.
The effect of the coarse drawing rate of high-carbon steel wire on the distribution of equivalent residual stresses and strains over the wire cross section is studied by numerical simulation of wire drawing at different speeds by the finite element method. The values of equivalent residual stresses for the selected drawing route along the wire cross-section zones are determined. The analysis of the equivalent stress distribution over the wire cross section is made.
It is shown that the increase in the speed of coarse drawing increases the uniformity of the distribution of equivalent residual stresses, does not have a negative effect on the deformed state of the wire, increases the absolute values of equivalent residual stresses, slightly reduces the absolute values of residual deformations.
The peculiarity of the rod of chromium-nickel-molybdenum steel grades, used in the production of fasteners and automotive components by cold forming, are the high requirements for the quality of the surface, microstructure and physical and mechanical properties.
In the process of development of production technology were developed and implemented measures to minimize the identified design features of heat treatment furnaces, and developed methods for obtaining the most optimal primary hot-rolled metal microstructure for further spheroidizing annealing
In industrial conditions OJSC «BSW – Management Company of Holding «BMC» was mastered the most optimal regimes of heat treatment of wire rod from chromium-nickel-molybdenum steel grades, which required the consumer a full range of physical and mechanical properties of wire rod from steel grades 38ХНГМ, 40XH2MA and 41Х1 used further in the manufacture of fasteners and automotive components by cold forging.
One of the most important indicators of the quality of the metal cord is the strength of its adhesion to the compound, i.e. adhesive strength. This is due to the fact that the value of adhesive strength significantly affects the performance of tires.
The article analyzes how the use of different test methods could determine the adhesive strength and the use of compounds of different consumers affect the amount of adhesion of the metal cord. Three methods of testing of different consumers are considered and compared, the features of each method are revealed. Tests were carried out using different methods and compounds of different consumers; the factors affecting the value of adhesive strength were determined.
For metal products manufactured by hardware shops (metal cord, PML wire and side bronzed wire), the most important mechanical properties are those, that determine the strength, ductility and other characteristics of the materials. The article describes the characteristics of breaking test unit that affect the results of tests of plastic properties of RML wire. The analysis of the test conditions and factors affecting the test results was made.
The data on the creation of the Minsk automobile plant, the formation and development of its foundre shops, measures taken to ensure the growth of the volume and quality of iron and steel casting on MAW are given. The measures to improve working conditions at the plant and improve the environmental situation are shown. The brief characteristics of the technological processes created at MAW for obtaining steel cast heat-treated shot and briquetting metal chips using induction heating, as well as modern molding and core mixtures and equipment developed at MAW and eqiopment created at OJSC «BELNIILIT», are given.
Science of materials
The article deals with the quality of structural steel supplied by metallurgical enterprises. It is shown that the pipes made of steel 20, used in the oil and gas industry, contain structurally free cementite in the structure, often in the form of a grid (points 4 and 5 according to GOST 5640–68). This structure is the cause of faulty production: the subsequent cold treatment pressure formed sags on the surface of the product, and there is a violation of the continuity of the material up to the formation of through cracks. Formation of structurally-free cementite in steel 40KHN2MA with structure of the top bainite which was formed at violation of regulations of heat treatment of a semi-finished product is also found. When nitriding with heating to 490 ° C and holding at this temperature, there was a decay of bainite with the formation of tertiary cementite along the grain boundaries. Discussed the possibility of culling the poor quality of delivery at the consumer. It is also noted that many enterprises have now abolished entrance control, which has the most negative consequences both in terms of product quality and safety, especially in the oil and gas industry.
The article presents the results on the structure formation of deposited coatings obtained from steel chips P6M5 subjected to diffusion nitrogen-carbon doping. It was found that the diffusion doping with nitrogen-carbon steel chip waste P6M5 carbon content in them varies between 1.75–3.14%, nitrogen – 0.43–1.24%. The phase composition includes phases: a-Fe, M6C, Fe3C, (Cr, Fe)2N1–x, Fe3N, Cr0.63C0.35N0.03, M4(C, N) depending on the temperature and time of diffusion doping. When surfacing these materials in the deposited coating contains carbide-forming elements 8,6–9,3%, carbon 1,04–1,94%, nitrogen 0,08–0,25%. The structure consists of carbide M23S6, martensite and austenite, while the content of austenite in dendrites can reach 70–90%. It is shown that nitrogen doping of the deposited coatings obtained from steel chips P6M5, subjected to saturation with nitrogen-carbon, more effectively increases the amount of austenite in the structure than alloying the deposited coatings with nitrogen ferroalloys.
The results of the study of the phase composition and physical and mechanical properties of multicomponent coatings Ti– Cr–B–N formed by magnetron sputtering at a constant current from composite targets are presented. The features of phase formation of coatings when spraying targets containing titanium diboride (TiB2) or boron nitride (BN) as a boron-containing component are studied. The conditions of deposition of coatings with microhardness up to 32 GPA and heat resistance up to 800 °C are established.
A comparative analysis and assessment of the impact of the method of introducing the modifying additive in the form of dispersed and ultrafine particles into the electrode coating on their welding-technological properties and mechanical properties of the weld metal is carried out. It has been established that a modifying additive containing such chemical elements as barium, strontium, potassium, silicon, aluminum, vanadium is a mixture of stable alkaline-earth metal compounds in the form of carbonates and is inserted into the coating of the electrodes by applying its dry mixture into the composition prior to their crimping, allows to improve the welding-technological characteristics of the electrode and grind the structure of the weld metal, which contributes to the improvement of its mechanical properties particularly ductility.
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ISSN 2414-0406 (Online)