There are many standards that tell us in which ranges the geometry of equipment, piping systems or individual elements of the facility can change. The authors of the article set the task to assess ...the change in the state of one equipment with possible permissible geometric deviations. As part of the study of the experimental sample, a combination of different variants of ovality was modeled at different pressures up to the yield point. It is shown that there are situations that can reach the yield point at significantly lower loads on the apparatus, as a result of the occurrence of zones of local stress concentrations. Recommendations are given on the real maximum stress-deformed state in the investigated apparatus depending on geometric deviations.
Ethyl 2-5-aryl-2-oxofuran-3(2
H
)-ylideneamino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylates reacted with secondary amines to give 4-aryl-2-(thiophen-2-yl)-4-oxobutanamides, whereas their ...reaction with piperazine afforded
N
,
N′
-disubstituted piperazine derivatives regardless of the reactant ratio.
—For rolling of balls, one of the main parameters for both calculating passes and developing a model for a roll is the roll spacing at the crossing point (zones where the edges of the rolls are as ...close as possible to each other) in addition to the roll diameter, the roll body length, and the section length. A method is developed to calculate the roll spacing at the crossing point. The calculation results are used to analyze and choose rational tuning parameters of rolls for rolling balls at the EVRAZ NTMK ball-rolling mill. The analysis is carried out on new rolls and rolls after the first, second, third, and fourth remachining of screw ball-rolling grooves. The data are systematized to plot point curves for tuning indicators, and the graphical data are used to make a polynomial approximation. Equations are derived for the functions of the tuning parameters.
The paper describes the main stages of the development of sectional and shaped profiles by the JSC “EVRAZ NTMK” over the past years. The plant operates three longitudinal rolling mills, each of which ...has been producing both construction metal structures and transport products for many decades. Every year, market competition causes increased consumer requirements toward product quality and requires expansion of the product assortment. Therefore, developing new profiles is an ongoing process at the JSC “EVRAZ NTMK.” The following transport profiles have been developed: stirrup stop bar, rail pad bar R-65, insulated joint core bar ApATeK R-65 MK-BO, guard-rail angle SP850, subway conductor rail, I-beam No. 19 used in the construction of a center girder of the pivoted unit of the rail cars, and a non-standard I-beam 13C1 manufactured according to the technical agreement with the Research and Production Enterprise (RPE) “Uralvagonzavod.” Due to consumer requests, the heavy-section and rail-and-beam shops of the JSC “EVRAZ NTMK” started production of the U-channel line, since such series is more preferable when manufacturing metal constructions compared to V-channel sloping along the inner side of the flange, previously produced at the JSC “EVRAZ NTMK.” In recent years, the railand-beam shop started production of the entire line of crane rails. In just the past 5 years, over 60 standard I-beam sizes have been implemented under the wide-flange beam rolling shop conditions according to various standards, including a foreign ASTM A6/A6M-2017a standard and BS EN 10365–2017 standard, as well as GOST R 57837–2017 developed by EVRAZ together with the Central Research Institute of Building Structures (TsNIISK) named after V. A. Kucherenko. The process of developing new profiles at the JSC “EVRAZ NTMK” continues. In 2020 alone, it is planned to start production of more than 20 new types and nominal sizes of the hot-rolled sectional and shaped profiles.
New 4-aryl-2-(4-arylamino)-1-(piperazin-1-yl)but-2-ene-1,4-diones and 2-{2-(3-R-adamantan-1-yl)-2-oxoethylidenehydrazinyl}-4-(het)aryl-4-oxobut-2-enoic acids were synthesized and used to obtain ...water-soluble compounds. Their influence on the blood coagulation system was studied, which revealed compounds with a high hemostatic activity and a low acute toxicity. A relationship between structure and pharmacological effect of the synthesized compounds was established.
4-Aryl-2-arylamino-4-oxo-2-butenoic acid hetarylamides were synthesized by the reaction of 4-aryl-2-hydroxy-4-oxo-2-butenoic acid hetarylamides with aromatic amines and also by ring opening of ...5-aryl-3-arylamino-3
H
-furan-2-ones by heterocyclic amines. Their analgesic activity was studied. Compounds with activity comparable to and exceeding that of the reference drugs and with low toxicity were found.
The downtime of ball-rolling mills is largely associated with the replacement of worn rollers. In the present work, the degree and location of critical roller wear are studied: the greatest wear is ...observed at the flanges in the billet-capture zone. The conditions required for billet capture and successful rolling are determined analytically. Variation in roller speed during billet supply is proposed. Tests are conducted with linear and quadratic variation in roller speed. The familiar formulas for the mean deformation rate are modified for linear and quadratic variation in roller speed. Experiments are conducted on the ball-rolling mill of AO EVRAZ Nizhnetagil’skii Metallurgicheskii Kombinat (NTMK), in rolling 60-mm ШЗГsteel grinding balls on a 40–80 rolling mill. In the experiments, the roller speed is varied manually according to a specified program, with billet capture by the rollers. It is found that speed variation significantly affects the mean pressure at the instant of billet capture. Time dependences of the torque and the mean contact pressure are plotted on the basis of calculation results and experimental data. Empirical characteristics with linear and quadratic variation in roller speed are presented. The permissible agreement of the calculated and empirical results is determined. The installation of a thyristor converter is proposed, so as to decrease the roller speed before billet capture and restore the speed to the rated value in specified fashion after capture. That yields a uniform distribution of the mean contact pressure over the roller length during automatic operation of the mill in different conditions. As a result, the roller wear is decreased, without loss of mill productivity. That reduces roller consumption and the mill downtime for roller replacement.
PDF
