Materials Science Forum Vol. 946

Abstract: This article presents the results of the effect of drawing speed on the strain rate and resistance to plastic deformation. The wire drawing on modern high speed wire drawing machines significantly increases the required amount of drawing dies. The influence of the technological parameters: speed drawing, half-angle of the die, wire diameter and a single strain on the rate of deformation of the metal. The influence of the technological parameters: speed drawing, half-angle of the die, wire diameter and a single strain on the rate of deformation of the metal. It is found that increasing the resistance to drawing dies and achieve passport velocities drawing, when selecting process parameters drawing guided by the principle of uniform strain over the cross section of the wire by matching the single strain with half-angle dies and friction coefficient on the formula given in the article.

Abstract: The existing problems of rolls handling facilities, as in the case of PJSC "Magnitogorsk Iron and Steel Works" Long products shop were considered in terms of a proposition to have them solved by means of introduction of an automated information system for accounting and management. A review of literary sources on issues of information technology, management, logistics and organization of rolls handling facilities was performed. The basic provisions of automated information system have been developed, and the issue of rolls handling facilities management on its basis is considered.

Abstract: The evolution of structure, strength and ductile properties of M001 grade copper wire after the coarse and medium drawing were studied using the metallography, micro-indentation and tensile testing. Coefficient for evaluation the ultimate tensile strength from the micro-indentation data was determined. The formula was proposed for estimation the dislocation density the stress strain curves and from the data on the grain size in the transverse section of the wire.

Abstract: The article is devoted to the study of energy-force parameters of combined process "rolling-equal-channel angular pressing". The objectives of the work were to determine the forces of rolling and pressing in the deformation by this combined method. The strength calculation of the matrix and the experiment on deformation of AISI 6063 aluminum samples were carried out. During the experiment, the force values were recorded using a tensometric station. The results of the strength analysis showed that this matrix design is suitable for creating an experimental stand of combined process "rolling – equal-channel angular pressing", since the calculated safety margin is sufficient to implement the pressing under extreme conditions. Analysis of the results of force measurement showed that rolling forces at all stages of deformation exceed the corresponding pressing forces, which is a necessary condition for the implementation of this combined process. The obtained results can be used in the design of experimental stands that implement investigated combined process. At the same time, the used tensometric technique for studying strength characteristics is suitable for the case of calibrated rolls.

Abstract: The Gleeble-3800 unit was used to simulate physically the upsetting of cast and hot rolled semi-finished products from aluminum-lithium alloy V-1461 over the temperature range of 400-460°C and the strain rates of 1-60 s^-1. Following texture analysis of upset samples showed the most typical preferred crystallographic orientations and its formation features depending on the temperature-strain rate schedules. The formation of recrystallization type orientations at a strain rate of 60 s^-1 is a distinctive feature of the cast samples’ behavior during deformation. In general, the established regularities of texture formation allow to produce a hot-rolled semi-finished products from V-1461 alloy with a given structure’s crystallography in compliance with requirements for blank’s forming and product’s operation.

Abstract: Elastoplastic deformation on the presses and high-temperature heating of the steel sheet cause the large residual stresses in the sheet’s and bar’s wall. The technological operations of the obtaining of metal products, their shape and linear dimensions strongly affect on the distribution within the metal and the maximum values of residual stresses. The uneven cooling of various parts of the sheet and bar, obtained by bending, stamping and forging, also leads to the large residual stresses inside the metal. The greatest residual stresses occur in the weld area, where there is a strong heterogeneity of mechanical and physical properties of the metal due to uneven heating and cooling. Below the new analytical method for calculating of the residual stresses of a round steel bar in the elastoplastic bending is obtained. This method takes into account the diameter of the bar, as well as the modulus of elasticity, the yield strength and the hardening modulus of steel’s bar.

Abstract: In the straight-seam tubes, the appearance of defects in the area of the welding seam welded under the flux layer and the seam geometry are closely related to the technology and metallurgy of welding process. Possible defects are the pores, incisions, slag inclusions and cracks. The pores can appear in different shapes, with different distribution and in different amounts during the solidification of welding seam. When molten metal solidifies, the gas bubbles can come to the surface or remain inside the metal. The incisions may occur due to the fact that the juncture is not completely filled. Such incisions, passing most often along the edge of welding seam, are explained by the discrepancy between the amount of metal deposited per unit of time and the volume of the juncture. The occurrence of the slag inclusions is determined by the metallurgical reactions between the slag and the drop, separating from the end of the electrode, as well as the bath of molten metal. The cracks differ depending on the size, the nature of location and the causes. There are the macro-cracks and micro-cracks, the hot and cold cracks. In this paper the critical in-tube pressure, at which the destruction of tube occurs at the partial faulty fusion of the tube’s welding seam, is obtained. The results can be used in the diagnosis of the causes of the destruction of the steel large-diameter tubes of the main gas-oil tube-lines.

Abstract: For experimental substantiation of plasmatrons work efficiency the technological regulations of quality and safety parameters test for plasma-arc cutting of metals technology are taken. For the integral evaluation of the obtained results it is proposed to use the methods of qualimetric analysis adapted to the technology of plasma cutting. The obtained integral parameters indicate the effectiveness of the new plasmatrons, designed by the authors in comparison with previously produced analogues, as well as with modern domestic and foreign samples.

Abstract: Enough works in which positive action of the vibration fluctuations imposed both in the course of welding of a design and after it is specified are known. In the article features of influence of low-frequency vibration fluctuations in the course of a welding cycle on properties of welded connections from steel A 516-55 are considered. The conducted pilot studies of influence of vibration influence of a welding bathtub in the course of welding on structure and physico-mechanical properties of metal of welded connections have allowed to prove positive action of this technology which leads to increase in durability and fatigue endurance of welded connections. This fact will allow to expand using of technology of vibration processing in the course of welding for production of the welded equipment of various type.

Abstract: This paper gives the analysis of energy costs for arc automatic welding under the flux of double-sided butt joint without edge preparation according to the thickness of welding sheets. The coefficients for a linear dependence of specific energy from plate thickness are obtained. From this, a calculation method of effective power, current and arc voltage is proposed according to the joint formation speed. To calculate a fusion area of a weld section, a model of a surficial normal-circular heat source with an average heat flow in a heating spot 14−16 kW/cm² is used. Acceptable convergence of target and experimental cross-section areas of a weld is achieved for an arc reverse polarity. Calculation method let take into account the influence of arc polarity on a fusion area of a base metal. Main efficiency factors of a double-sided welding are defined. Possible reasons of augmentation of fusion effectiveness of a base metal in comparison with the electrode metal are noted.