Manganese Content Control in Weld Metal During MAG Welding

The influence of the welding current and method of gas shielding in MAG welding on the content of manganese is considered in the paper. Results of study of the welded specimens of steels 45 when applying welding wire of different formulas and different types of gas shielding (traditional shielding and double-jet shielding) are given. It is found that in MAG welding the value of the welding current and the speed of the gas flow from the welding nozzle have a considerable impact on the chemical composition of the weld metal. The consumable electrode welding under double-jet gas shielding provides the directed gas-dynamics in the welding area and enables controlling the electrode metal transfer and the chemical composition of a weld

Study of Falling Roof Vibrations in a Production Face at Roof Support Resistance in the Form of Concentrated Force

One of the main reasons of roof support failures in production faces is mismatch of their parameters and parameters of dynamic impact on the metal structure from the falling roof during its secondary convergences. To assess the parameters of vibrational interaction of roof support with the roof, it was suggested to use computational models of forces application and a partial differential equation of fourth order describing this process, its numerical solution allowed to assess frequency, amplitude and speed of roof strata movement depending on physical and mechanical properties of the roof strata as well as on load bearing and geometry parameters of the roof support. To simplify solving of the differential equation, roof support response was taken as the concentrated force

Results of the modal analysis of the underground mine hydraulic leg in various modes of its operation

The article describes the construction of models and the initial conditions for the various modes of legs operation. The article presents the way of setting the initial conditions for the initial thrust with constant pressure and for leg operation in the mode of increased pressure caused by the lowering of the roof. The results of modal analyses conducted for 2 modes of leg operation are shown. It is shown that the form and frequency of natural oscillations of hydraulic legs are determined by their design, pressures of the initial thrust and nominal operating resistance, as well as by the operating modes which differ in schemes of interaction of leg elements with interacting elements of the support and the roof and floor strata. At the same time, changing the operating mode of the legs changes the natural frequency both to the higher and to the lower side, as well as the form of oscillations of certain frequencies. For more accurate calculation of the frequency response of hydraulic legs to the external load of frequencies, it is proposed to take into account not only their design and power properties, but also the modes of their loading

Manganese Content Control in Weld Metal During MAG Welding

The influence of the welding current and method of gas shielding in MAG welding on the content of manganese is considered in the paper. Results of study of the welded specimens of steels 45 when applying welding wire of different formulas and different types of gas shielding (traditional shielding and double-jet shielding) are given. It is found that in MAG welding the value of the welding current and the speed of the gas flow from the welding nozzle have a considerable impact on the chemical composition of the weld metal. The consumable electrode welding under double-jet gas shielding provides the directed gas-dynamics in the welding area and enables controlling the electrode metal transfer and the chemical composition of a weld

Development and Study of Hard-Facing Materials on the Base of Heat-Resisting High-Hardness Steels for Plasma-Jet Hard- Facing in Shielding-Doping Nitrogen Atmosphere

The authors develop hard-facing materials on the base of heat-resisting highhardness steels for plasma-jet hard-facing in nitrogen atmosphere for manufacturing parts of mining and metallurgic equipment which significantly simplify the production process and effect a saving when producing bimetallic parts and tools

Acid-Base Properties Of Glass Substrate And SiO[2]-Bi[2]O[3]Thin-Film Systems Obtained On It

The article describes an experimental research as a result of which SiO[2]–Bi[2]O[3] films have been synthesized of film-forming solutions based on tetraethoxysilane and bismuth nitrate (III). Acid-base properties of a glass substrate and SiO[2]–Bi[2]O[3] films obtained on it have been studied. The dependency of physical and chemical properties of SiO[2]–Bi[2]O[3] composites on their percentage composition have been revealed

Processing Behavior of Electrodes Made with Addition of Nanopowder

The study analyzes the processing behavior of welding electrodes made with addition of nanopowder, and compares them to standard welding electrodes (without addition of nanopowder). The effect of nanopowder of complex composition on the electrode metal transfer process is analyzed as well

Extraction of Chromium from Carbon Ferrochromium Residual Wastes

This work reports the problem of processing residual wastes after producing carbon ferrochrome by recycling dust using a hydrometallurgical method with the purpose of extracting the basic component - chromium. The X-ray diffraction analysis results, chemical and granulometric compositions of dust from the carbon ferrochrome production are given. The method for the production of chemical-enrichment concentrate (CEC) by processing ferrous dust is described, with obtaining a middling product - sodium mono-chromate with its further reduction to chromium hydroxide, followed by autoclave leaching, and resulting in the production of chemically enriched chrome concentrate. The plant used for autoclave leaching and filtering is schematically depicted. The smelting process of metallic chromium using the ladle aluminothermic method is described

Titanium Carbide: Nanotechnology, Properties, Application

The paper develops scientific and technological bases for fabrication of titanium carbide which is a nanocomponent of composite materials. The authors determine optimum technology specifications and the main titanium carbide properties: fineness of titaniferous raw materials, carbide-forming agent quantity, set temperature of plasma flow, tempering temperature, titanium carbide yield, productivity, specific surface, size and shape of particles. The paper includes equations to describe how the major specifications of the fabrication technique influence the content of titanium carbide and free carbon in the end product