Key Engineering Materials Vol. 839

Abstract: The formation of a welding zone in long pipe billets produced by explosion welding is studied in the paper. The distribution of a melt zone over the diameter of pipe billet is investigated. Melt zones mainly are formed on the ends of the sample. Their thickness increases with increasing the welding conditions. In this work, a solid interlayer of mixed composition is shown to be formed during the explosion welding of steel pipe billets (08Kh18N10T and 37G2F) with a length of 1 meter. Comparison of the data obtained for the welding zones between pipe and sheet billets showed that solid interlayers of melts were formed in pipe billets with a smaller length as compared with sheet billets. A technique for estimating the effect of shock-compressed gas on the surface of the sheets subjected to welding with the adaptation of calculations for the welding of cylindrical products was used for a theoretical estimate of the maximum thickness of melt zones in the welding zone under certain explosion welding conditions along the length of billets. The calculations showed that the geometrical dimensions and thermodynamic parameters of shock-compressed gas will increase linearly depending on the path traveled by the contact point.

Abstract: The FTIR spectroscopy method was used to investigate the changes in palm, sunflower and rapeseed oil at thermal influence up to 195°C, and also in contact with polyethylene terephthalate (PET) and polyamide (PA-6) film for 1 hour 50 minutes. It has been found that heating the oil to 195°C in contact with PET and PA-6 film does not lead to any noticeable changes in the IK oil absorption spectra. Peaks characteristic of polymers (in areas of 1535 and 1634 cm^-1), are not observed.

Abstract: This work presents the experimental results of the study of the effect of heat treatment on the structural-phase state of TiN coatings on the surface of 67KH5B alloy. It is determined that thermal annealing leads to structural phase transformations at the interface between the coating and the substrate. It was established that after annealing at Т=800 ^°С, due to the redistribution of the coating elements and the substrate, a modified coating is formed consisting of the TiN, Ti2N and NiTi phases.

Abstract: The paper discusses the results of studying the structure and properties of powder coatings based on Ti₃SiC₂/TiC, obtained by the method of detonation spraying on the surface of the tool steel N9. It is determined that the coating has a uniform structure, cracks and delaminations are not observed. The results of X-ray structural analysis of coatings showed that the coating before annealing consists of phases TiC and Ti₃SiC₂. After annealing, the formation of TiO₂ phases and an increase in the intensity of the (103) and (108) reflections of the Ti₃SiC₂ phases are observed. It is established that an increase in the content of the phases of Ti₃SiC₂ in coatings leads to an increase in the microhardness of coatings.

Abstract: Magnesium-based materials find their use mainly in manufacturing light-weight constructions in motor-car, airspace industries, and biomedicine due to the low density. This paper provides an overview of introducing magnesium into SLM technology and describes searching experiments to prepare samples of magnesium powder МPF-4 (Russian State Standard 6001-79) conducted in the Laboratory of Yurga Institute of Technology. The study has determined appropriate parameters to synthesize a compact structure: laser output power 100 W, laser beam movement velocity 200 mm/s, scanning pitch 0.1 mm, modulation frequency of laser irradiation m = 2500 Hz, linear energy density Е=5 J/mm², the process is to be carried out in argon shielding medium.

Abstract: For the electrodeposition of corrosion-resistant coatings with zinc alloys with copper, stibium, cobalt, manganese and lead, complex electrolytes based on trilon B have been developed. It is shown that the developed electrolytes are characterized by high scattering power and productivity and allow obtaining fine-crystalline, semi-gloss coatings with an insignificant level of internal stresses.

Abstract: The paper discusses a negative effect of metallurgical waste on the ecosystem, costs and benefits of a potential use of solid metallurgical waste products in production of building materials with the purpose to reduce their harmful effect on the environment and preserve nonrenewable natural resources. The most usable products a component of which is metallurgical waste, such as slag concrete and blocks, as well as break stone are compared with products made of natural raw materials. The most appropriate application fields with the minimal harm to human health and nature are recommended.

Abstract: Retracted: The paper reports on outcomes of research into a road concrete containing coal ash powders of thermal power stations located in Krasnoyarsk. The study was focused on characteristics of a fly ash, and ash taken in an ash-disposal area of Krasnoyarsk Thermal Power Station 1, as well as ash of Beryozovskaya GRES. To compare characteristics a standard limestone powder was used. Physical and mechanical characteristics, chemical and mineral composition of these powders were analyzed. Mineral powders differed in a concentration of free calcium oxide (СаОfr.). Samples of a fine-grained road concrete were composed and prepared using materials above. Physical and mechanical properties of formed road concrete samples were tested. A coefficient K was introduced to assess the relation between key characteristics of a road concrete mix and concentration of free calcium oxide, furthermore, it considers a percentage of СаОfr. in ash (m) and percentage of this ash in a road concrete (n), i.e. К= m·n. It has been established a coefficient К ranging 0 to 32 СаОfr. has no significant effect on characteristics of a road concrete mix. A fly ash and ash taken in an ash-disposal area of Krasnoyarsk thermal power station 1 are recommended for the use in industry as a mineral powder in a road concrete mix. Additionally, ash taken in an ash-disposal area is to be dried and grinded, a maximal content of a fly ash in a road concrete mix is estimated to be 4% provided that a concentration of СаОfr. is less than 8%.

Abstract: The paper analyzes Poisson’s ratios μ₀=μ_100,001=-s₁₂/s₁₁ and elastic anisotropy factor A'=s/s₁₁ (s=s₁₁-s₁₂-s₄₄/2) for single crystal materials of binary and three-component TiNi-TiFe alloys with gradually deteriorating resistance first to one B2-R and further to two martensite transformations B2-R-B19'. The study discusses a ratio H/E of TiNi-TiFe alloys both subject and not exposed to martensite transformations. Surprisingly, this ratio exceeds 0.035 for alloys with martensite transformations, being far higher than in the majority of metals and alloys.

Abstract: The results of the study of the shape, morphology and elemental composition of aluminum powder particles obtained in distilled water with the following electrical parameters of the electroerosive dispersion unit are presented: the capacity of discharge capacitors is 65 μF, voltage 100 V, pulse frequency 50 Hz. It is established that the powder consists of particles of regular spherical shape (or elliptical), irregular shape (conglomerates) and fragmentation, and the main elements of the powder are aluminum and oxygen. The obtained powder materials can be used for the manufacture of powder electrodes used in welding and surfacing of a wide range of parts.