Study of Durable Strength of Steel Mining and Metallurgical Equipment

Abstract

Erosion of the metal of mining and metallurgical equipment due to the impact of solid particles is one of the forms of wear that can significantly limit the service life of a working machine or technological equipment, for example, a pipeline conveyor, loading and unloading bodies of mine workings and metallurgical machines. At present, this problem has been little studied and there is not enough information in the literature to form a systematic picture of impact erosion of equipment elements of mining and processing plants. The purpose of the research was to study the fatigue strength and corrosion-mechanical crack resistance of some structural elements of mining and metallurgical equipment with a long service life in chemically aggressive environments. Experimental tests for corrosion fatigue (long-term strength) were performed under bending load. The tests were performed on a bend with zero average voltage and a cycle frequency of 30 Hz. The tests were performed in salt solutions with a concentration of NaCl 5%. To compare the results, tests were sometimes performed in the air. The given data analysis shows that the long-term fatigue of the metal of mining and metallurgical equipment is significantly reduced when reaching 20 years of operation, especially in an aggressive environment containing chlorine ions, which causes severe corrosion damage to steel equipment. In addition, samples cut from metal with a long service life in mining and metallurgical conditions (more than 20 years) are characterized by low long-term strength. It has been found that fatigue resistance decreases with an increase in the number of cycles. Steel samples tested based on N = 106 and especially on the basis of N = 107 cycles have low resistance, which inevitably leads to breakdown with the subsequent destruction of equipment. It has been established that with an increase in the service life of the experimental mining and metallurgical equipment, the fracture toughness of the metal decreases significantly, which causes further failure and destruction of technological equipment.

Perception and Processing Peculiarities of Information Addressed to I and Ii Signaling Systems in the Context of Mild Acquired Myopia

“…To obtain information about neurodynamic properties, we used the method of M. V. Makarenko [11,12,13]. This method was used to study the latent periods of sensorimotor reactions of varying complexity: simple sensorimotor reaction (SSMR), choice reaction 1 out of 3 stimuli (CR1-3), choice reaction 2 out of 3 (CR2-3).…”

“…The data obtained by us, characterising the values of latent periods of visual-motor reactions of different complexity, echo the data presented in the works of Makarenko M.V., Panchenko V.M., Sheiko V.I., Kushch Yu.I. [6,11,12,13,8], but at the same time complement them, namely, by differentiating the processing of stimuli to signal systems.…”

“…Для отримання інформації про нейродинамічні властивості ми використовували методику М. В. Макаренка [11,12,13]. За даною методикою досліджували латентні періоди сенсомоторних реакцій різної складності: проста сенсомоторна реакція (ПСМР), реакція вибору 1 із 3 подразників (РВ1-3), реакція вибору 2 із 3 (РВ2-3).…”

Technologies and materials for the renovation of erosion-worn parts of automobile equipment

“…The minimum chromium content, at which the increased resistance of steel against corrosion in a humid atmosphere and various mildly aggressive solutions is manifested, is approximately 12%. With this chromium content, dense gas-impermeable oxide films are formed on the surface of the metal [2,3,11].…”

“…As evidenced by literary sources [1][2][3][4][5][6][7][8][9]11] and practice, long-term operation of automotive parts in conditions of mechanochemical wear (mechanical friction) is accompanied by local damage (in the form of ulcers), which lead, as a rule, to loss of performance of the unit or device as a whole.…”