Materials Science Forum Vol. 973

Abstract: The electron microscopic and diffraction analysis presented in the article showed that the structure of the surface layer of the titanium alloy OT4 after implantation at an accelerating voltage of 30 kV from the cathode Cu-Pb-Bi has a different hierarchical character. As a result of investigations of each of the levels, it was determined experimentally that the deformation mechanism under the action of internal stresses, as well as diffusion-relaxation reactions, are the main reasons for their formation, leading to the appearance of structural features in the surface layer of the OT4 alloy. In this case, penetration of alloying components to a depth of 10-25 nm is observed.

Abstract: The use of metal-polymers in the manufacture of mold-forming parts allows for the significant reduction in price and time used in manufacturing of parts. Using data on the thermal conductivity of metal-polymers in calculations of the cooling system of molds allows calculating the optimal cycle of obtaining the product. The authors propose a method of determining the coefficient of heat transfer of metal-polymers based on a die matrix, filled with aluminum. The chosen equipment or measuring tool by them, allows determining the heat transfer coefficient of the material in use. The values of the coefficient of heat transfer of the material in question, obtained in the course of the research can be use in different databases of applications used for modeling production by injection molding. The described method of determining the coefficient of heat transfer may be repeated for samples of metal-polymers.

Abstract: The paper considers the possibility of improving the quality of gray cast iron castings by controlling the cooling rate of castings in a mold. It is shown that the use of differentiated cooling can increase tensile strength of cast iron by 12-16%

Abstract: The paper reports findings on the morphology of non-metallic inclusions in low carbon pre-peritectic and peritectic steel grades used for the fabrication of seamless pipes. It is demonstrated that the distribution of non-metallic inclusions over the cross section area of continuously cast billets is of a step-like nature conditioned by the features of billet solidification. In all the steels analyzed the non-metallic inclusions are presented by oxides, sulfides and complex oxi-sulfides not larger than 2 μm.

Abstract: In this work were studied the properties of moulding bentonite clay calcined at different temperatures and the properties of moulding sand-clay mixtures based on these clays.

Abstract: In order to verify the new theory of adhesing the upsetting process of cylindrical specimens of steel 3 with different value of heat removal from their surfaces are considered in the article. Form of the specimens after upsetting and their structure after upsetting in the central and peripheral parts are described.

Abstract: Optical and electron microscopy are used in the paper to analyze the quality of the cast metal of a 1.53 ton ingot of steel 38ХН3МФАteemed with a cooling feeder head. In addition, the analysis of the metal of hollow forgings produced from ingots with “cooled” and thermally insulated feeders is performed. A metallographic study reveals that if the ingot top is cooled down, it results in an accelerated solidification throughout the entire mass of the ingot; in addition, the thermal centre shifts to the ingot central axial area.

Abstract: The paper shows that in the conditions of a deficit of high-quality metal charge in steels melting production, the effective use of waste from abrasive grinding in the composition of the metal charge is a promising method for reducing the cost of steel. The most rational solution for the disposal of metallurgical wastes may be the agglomeration of fine-grained and fine-dispersed materials using briquetting technology widely used in many countries around the world to produce multi-purpose briquettes.

Abstract: The article considers efficiency increase of formation of surface performance characteristics of machine components. The possibility of structuring control of facial layer on the basis of measuring of thermoelectromotive force (thermo-emf), cutting force component and also vibroacoustic signal has been scrutinized.