Purpose is to perform analysis of corrosion durability (fatigue) of pump rod materials in terms of various chemically active simulation environments, and study influence of economically modified rare-earth impurity on corrosion fatigue strength of pump rod materials. Methods. 40 and 20N2M steel grades have been applied as well as experimental steel (ES). Steel of the conditinal ES grade has been melted within a pilot site of Institute of Electric Welding Named after E.O. Paton of the National Academy of Sciences of Ukraine. The steel was alloyed economically by means of a micro impurity of a rare-earth element (REE) being 0.03% of cerium; in addition, it contained comparatively low concentration of sulfur and phosphorus as well as minor concentration of dissolved hydrogen. The following has been used as simulation environments: 1) NACE environment (i.e. 5% NaCl solution which contained 0.5% СН3СООН, and saturated H2S; t = 22 ± 2°C; pH = 3.8-4.0); 2) 3% NaCl solution without hydrogen sulphide. Once every day, the environment was replaced to oxygenate it up to 8-10 mg/l concentration. Findings. Stability against sulfide stress-corrosion cracking (SSCC), hydrogen initiated cracking (HIC), and corrosion fatigue of steel of deep pump rods for oil industry has been studied. It has been defined that the experimental steel, modified economically by means of micro impurities of a REE, meets NACE MR0175-96 standard in terms of chemical composition as well as strength; in turn, 20N2M and 40 steel grades have high resistance neither to SSCC (threshold stresses are < 0.8 s) nor to corrosion fatigue attack; moreover, steel grade 40 has demonstrated low resistance to HIC (CLR > 6% and CTR > 3%). Originality. It has been identified that corrosion fatigue attack results from hydrogen penetration of steel initiating its cracking and hence destruction under the effect of alternating loads accelerated by the action of corrosive environment. Further, surface micro destructions, influenced by micro stresses, transform into large discontinuities and cracks with following macro destructions. Practical implications. It has been proved that high resistance to corrosion cracking can be achieved by means of refining of pump-rod steel of ferrite and perlite type using metallurgical methods, i.e. 0.01-0.03% REE microalloying.

Purpose is to analyze steel degradation of the internal well equipment during its continuous service while contacting directly the corrosive environments. Methods. A range of research concerning the damaged metal tubes of the internal equipment for oil and gas wells, in particular regarding continuous service tubing, comprised both standard and specific studies involving different variations of X-ray spectral analysis with the use of scanning electron microscope JSM-35CF (JEOL Company, Japan) and SEM-515 with microanalyzer Link by Philips Company. The studied samples have been made of tubing in the period of the unauthorized and emergency well shutdowns; life of the wells is 0 up to 15 years. To analyze both structure and chemical composition of metal inclusive of such gases as oxygen and hydrogen, chippings were produced mechanically from various parts of tube walls. Findings. X-ray structural studies have made it possible to obtain data confirming cementite decay (Fe3С) in the tube metal during continuous operation of the internal well equipment. X-ray structural analysis methods have helped identify the parameters of crystal lattice of a matrix; and a level of elastic distortions of the lattice (i.e. microstresses of the distortions) has been evaluated as well as carbon distribution within ferrite and cementite. The abovementioned offered the possibility to describe both reason and mechanism of the reduced resistance to corrosion in the context of internal well equipment. Originality. New regularities under cementite decay in tube metal have been identified in addition to changes in the parameters of a crystal a lattice; microstresses of the lattice distortions; and carbon distribution within ferrite and cementite. The aforesaid helps explain in a new way both reason and mechanism of the reduced resistance to corrosion in the context of internal well structures operating continuously in aggressive environments. The basic sources and mechanisms of tube steel degradation, resulting from the metal hydrogenation and oxidation, have been defined which becomes the foundation to develop scientifically the substantiated measures mitigating the negative impact on the condition of the internal well facilities operating continuously in the chemically aggressive environments. Practical implications. Degrading hydrogen effect on the crystal lattice of metal has been proved. The effect creates conditions under which tube structures of oil and gas wells experience their failure.

The article attempts to consider the peculiarities of scientific and technical texts translation and analyzes the fact that all the aspects of original text are interconnected, and the actions of the translator resemble a PC, when all information is simultaneously and successfully processed. Linguistic features of scientific and technical literature, as well as characteristic language constructions and methods of their translation are considered in the work. The main difficulties, stages and types of translation of scientific and technical texts, taking into account lexical-grammatical, morphological and syntactic aspects, are analyzed. In particular, the article considers the aspect of the dependence of grammar on vocabulary (for example, the grammatical meaning of a phrase of a certain syntactic model can change depending on the words used in the phrase), and vocabulary depends on grammatical moments (for example, a change in the typical combination of words can lead to a new vocabulary -of the semantic variant of the word, that is, actually before the formation of a new word).Similarly, vocabulary and grammar are interconnected with genre and stylistic problems. Since the stylistic characteristics of the text include both the frequency of the use of certain words and the use of certain grammatical forms and constructions, that is why the allocation of lexical, terminological and genre-stylistic problems of translation into a separate translation sphere is conditionally and to a certain extent inappropriate. However, considering in the article the problems of translation from the English language with an educational, analytical and, to some extent, heuristic purpose, it is advisable to separately consider various aspects and problems of translation, in this case -lexical, terminological and genre-stylistic difficulties.The article highlights the following lexical difficulties in scientific and technical translation, in particular from English: the polysemy of words (terms) and the choice of an adequate dictionary match or variant of the translation of a word (term), the peculiarities of the use of popular words in scientific and technical texts, the correct use of one or another method of vocabulary translation, determination of the boundaries of the acceptability of the translation of lexical transformations, translation of neologism terms, abbreviations.