Evolution of microstructure in stainless martensitic steel for seamless tubing

Scanning electron microscopy with orientation analysis by the electron backscatter diffraction (EBSD) method is used to study microstructures and textures formed in the 0.08C-13Cr-3Ni-Mo-V-Nb steel through seamless tube production route: after hot deformation by extrusion; after quenching from various temperatures and subsequent high tempering. It is shown that the martensitic microstructure formed both after hot deformation and after quenching is characterized by the presence of deformation crystallographic texture, which is predetermined by the texture of austenite. The effect of heat treatment on texture, packet refinement, lath width, precipitation of carbides and Charpy impact energy is analyzed. © 2017 Author(s).The work was done using the equipment of the laboratory of Structural Methods of Analysis and Properties of materials and nanomaterials of the Collective Use Center affiliated to Ural Federal University. The study was supported by the program of increasing the competitiveness of the leading Russian universities, RF Government resolution No. 211, contract No. 02.А03.21.0006. We are grateful to the TMK company for their support and assistance in organizing the study

SHEAR BANDS IN STABLE ORIENTATIONS OF BCC-METALS AT DEFORMATION

Методом ориентационной микроскопии (EBSD) были исследованы кристаллографические особенности формирования полос сдвига (ПС) в стабильных при холодной прокатке ориентировках ОЦК-решетки (на примере Fe–3%Si и Mo). В кристаллах {111} формируются ПС с ориентировкой близкой к {110}, находящиеся с матрицей в специальной разориентации близкой к Σ9. В кристаллах {112}…{111} формируются ПС с ориентировками близкими к {110}, находящиеся с матрицей в специальной разориентации, близкой к Σ5. В кристаллах {110} формируются ПС с ориентировками близкими к {100}, находящиеся с матрицей в специальной разориентации, близкой к Σ5. В кристаллах {001} ПС не образуются. Показано, что во всех ориентировках образуются ПС двух типов, отличающиеся углами наклона к плоскости прокатки и степенью рассеяния ориентировки внутри полос.The method of orientation microscopy (EBSD) was investigated by the crystallographic characteristics of shear bands (SBs) formation in the stable by cold rolling orientations of the BCC lattice (Fe–3% Si and Mo). In crystals {111} are formed of SB with the orientation approximate to {110}, which is a matrix in a special orientation near to Σ9. In crystals {112}...{111} SB are generated with orientations approximate to {110}, which is a matrix in a special orientation near to Σ5. In crystals {110} are formed of SB with orientations approximate to {100}, which is a matrix in a special orientation near to Σ5. In crystals {001} SBs are not formed. It is shown that in all orientations of SB are formed of two types with different angles of inclination to the plane of rolling and the degree of scattering orientation within the bands.Работа выполнена в рамках проектной темы МОиН РФ (задание № 11.1465.2014/K). Авторы выражают признательность за содействие Программе поддержки ведущих университетов РФ в целях повышения их конкурентоспособности № 211 Правительства РФ № 02.А03.21.0006

TEXTURAL HEREDITY IN THE PRODUCTION PROCESS OF SEAMLESS TUBES FROM STAINLESS MARTENCITE STEEL

Методом ориентационной микроскопии (EBSD) исследованы особенности формирования структурно-текстурного состояния в бесшовных трубах из высокохромистой стали мартенситного класса после горячей деформации и последующей закалки с высоким отпуском. Показано, что мартенситная структура, сформированная как после горячей деформации, так и после закалки с отпуском характеризуется наличием выраженной ограниченной кристаллографической текстуры, предопределенной деформационной текстурой аустенита.Formation features of structural-texture state were studied with orientational microscopy method (EBSD). These formation features were in seamless pipes from high-chromium martensitic class steels after hot deformation and subsequent hardening with high tempering. It is shown, that the formed martensitic structure both after hot deformation and after quenching with tempering is characterized by the presence of a pronounced limited crystallographic texture predetermined with deformation texture of the austenite.Работа выполнена с использованием оборудования лаборатории «Структурных методов анализа и свойств материалов и наноматериалов» ЦКП УрФУ. Авторы благодарят ПАО «ТМК» за поддержку и содействие в организации исследования

Orientational Effects and Random Mixing in 1-Alkanol + Alkanone Mixtures

1-Alkanol + alkanone systems have been investigated through the data analysis of molar excess functions, enthalpies, isobaric heat capacities, volumes and entropies, and using the Flory model and the formalism of the concentrationconcentration structure factor (SCC(0)). The enthalpy of the hydroxyl-carbonyl interactions has been evaluated. These interactions are stronger in mixtures with shorter alcohols (methanol-1-butanol) and 2-propanone or 2-butanone. However, effects related to the self-association of alcohols and to solvation between unlike molecules are of minor importance when compared with those which arise from dipolar interactions. Physical interactions are more relevant in mixtures with longer 1-alkanols. The studied systems are characterized by large structural effects. The variation of the molar excess enthalpy with the alcohol size along systems with a given ketone or with the alkanone size in solutions with a given alcohol are discussed in terms of the different contributions to this excess function. Mixtures with methanol show rather large orientational effects. The random mixing hypothesis is attained to a large extent for mixtures with 1-alkanols ≠ methanol and 2-alkanones. Steric effects and cyclization lead to stronger orientational effects in mixtures with 3-pentanone, 4-heptanone, or cyclohexanone. The increase of temperature weakens orientational effects. Results from SCC(0) calculations show that homocoordination is predominant and support conclusions obtained from the Flory model.Ministerio de Ciencia e Innovación, under Project FIS2010-1695

Orientational Effects and Random Mixing in 1‑Alkanol + Nitrile Mixtures

1-Alkanol + alkanenitrile or + benzonitrile systems have been investigated by means of the molar excess functionsenthalpies (Hm E ), isobaric heat capacities (Cp,m E ), volumes (Vm E ), and entropiesand using the Flory model and the concentration−concentration structure factor (SCC(0)) formalism. From the analysis of the experimental data available in the literature, it is concluded that interactions are mainly of dipolar type. In addition, large Hm E values contrast with rather low Vm E values, indicating the existence of strong structural effects. Hm E measurements have been used to evaluate the enthalpy of the hydroxyl−nitrile interactions (ΔHOH−CN). They are stronger in methanol systems and become weaker when the alcohol size increases. In solutions with a given short chain 1-alkanol (up to 1-butanol), the replacement of ethanenitrile by butanenitrile weakens the mentioned interactions. Application of the Flory model shows that orientational effects exist in methanol or 1- nonanol, or 1-decanol + ethanenitrile mixtures. In the former solution, this is due to the existence of interactions between unlike molecules. For mixtures including 1-nonanol or 1-decanol, the systems at 298.15 K are close to their UCST (upper critical solution temperature), and interactions between like molecules are dominant. Orientational effects also are encountered in methanol or ethanol + butanenitrile mixtures because self-association of the alcohol plays a more important role. Aromaticity effect seems to enhance orientational effects. For the remainder of the systems under consideration, the random mixing hypothesis is attained to a rather large extent. Results from the application of the SCC(0) formalism show that homocoordination is the dominant trend in the investigated solutions, and are consistent with those obtained from the Flory model

ONTOGENETIC MUSEUM OF PLANTS OF MARI STATE UNIVERSITY

Detailed studies of individual life – ontogenesis – of the living beings that make up the biosphere, form the basis for preserving and maintaining biological diversity. The purpose of the study undertaken is generalization of the data accumulated up to now about the plant ontogenesis that form the basis of vegetation of Russian natural zones and visualization of these data in the materials of the ontogenetic museum, which was created on the initiative of Professor L. A. Zhukova in 1991 and which is included in the Eurasian Association of university museums, and since 2013 has been officially registered (code MARI) in the New York Botanical Garden database. Theoretical bases and methods of researching the plant ontogeny and cenotic population structure were created by T. A. Rabotnov and A. A. Uranov and were implemented by their students and followers in the study of ontogenesis and ontogenetic structure of plant cenotic populations of different natural zones. The results are reflected in the seven volumes of ontogenetic atlas of medicinal plants and are visualized in the herbarium of ontogenetic states of plants, which currently includes 607 species of higher plants. These materials contribute to the development of population-ontogenetic trend in botany and plant ecology and are the basis for preparing highly qualified biologists

ENTEROBACTERIACAE, PRODUCING ESBLS AND METALLO-β-LACTAMASE NDM-1, ISOLATED IN HOSPITALS OF BALTIC REGION COUNTRIES

Abstract. We studied the prevalence of K. pneumoniae and E. coli resistance to extended spectrum cephalosporins and carbapenems, isolated from patients of eight hospitals in St-Petersburg from January to May, 2012. Prevalence of cephalosporin resistant isolates varied in different hospitals: E. coli – from 7,8 to 50%, K. pneumoniae – from 25,4 to 88,4%. Isolates produced extended spectrum beta-lactamases СТХ-М, mainly СТХ-М-1, also СТХ-М-2 and СТХ-М-9. Twenty two carbapenem-resistant K. pneumoniae strains (also resistant to other antimicrobials) were isolated in three hospitals. MALDI-TOF MS showed that carbapenem resistance was caused by carbapenemase. Carbapenemases of all isolates belonged to metallo-β-lactamases according to results of the ROSCO Diagnostica tests. The gene coding production of New Delhi metallo-β-lactamase (blaNDM-1) were detected in all strains. Our data confirmed that the main cephalosporin resistance mechanism of E. coli и K. pneumoniae in Baltic region (including Russia, St-Petersburg) is CTX-M-1 production. For the first time in Russia K. pneumoniae strains  producing metallo-β-lactamases NDM-1 were isolated in several hospitals of St-Petersburg