Steels for Bridge Structures Morozov, Yu. D.; Pemov, I. F.; Matrosov, M. Yu ...
Metallurgist (New York),
2020/1, Letnik:
63, Številka:
9-10
Journal Article
Recenzirano
We consider domestic and foreign standards for rolled metals used in bridge building. Domestic standards contain elevated requirements to the reliability of rolled metals in terms of their fracture ...resistance by delamination. Foreign standards admit the application of rolled metals in broader strength ranges but do not contain obligatory requirements imposed on Z-properties and the necessity of monitoring of possible delaminations. Due to the obligatory control of reliability, bridge steels of domestic production are also extensively used in the construction of special building structures.
This article presents a survey of reports delivered at an International Conference hosted by the I. P. Bardin Central Research Institute of Ferrous Metallurgy in February 2008. Presentations given by ...specialists from Russia’ Ukraine’ the United States’ Belgium’ Brazil’ and Austria focused on important problems being encountered in ensuring that Russian pipe manufacturers have an adequate supply of high-quality steel for the construction of pipelines that are being built or have been planned. The reports examined aspects of the production of high-strength tube steels at Russian plants and experiences with the use of steels of strength classes X80–X100 in pipelines.
A screening strategy for evaluation of genotoxic potential of drinking water has been proposed in the present work. Genotoxicity assays with tap water collected at three different sampling points in ...Ljubljana drinking water region are presented here. In vitro alkaline version of the comet assay was performed with human HepG2 and Caco2 cell lines and protozoa (Tetrahymena thermophila) cells. Parallel genotoxicity evaluation on the same samples was carried out by the Ames test (with/without exogenous metabolic activation) using Salmonella typhimurium TA97a, TA100 and TA1535 strains. Nonconcentrated and concentrated water samples were tested in both bioassays, and chemical analyses were performed to check the contents of pesticides and nitrates. There was no indication of genotoxic activity in any of the drinking water samples according to the Ames test. The results of the comet assays showed differences and possible genotoxic potential among the water samples tested on different cell types, which were, however, statistically not significant, except in two cases. Statistical analyses showed the comet assay was more sensitive than the Ames test for genotoxicity detection in drinking water samples.
The scale on which oxygen is now being used in steelmaking worldwide is remarkable. To illustrate, the unit consumption of oxygen is approaching 65 m exp 3 /ton in converter steelmaking, 35 m exp 3 .../ton in electric steelmaking, and 70 m exp 3 /ton in the operation of two-bath open-hearth (OH) furnaces. This advance has been made possible by important contributions that scientists, designers, and production specialists have made to the development of oxygen steelmaking over a long period of time. Theoretical studies and the initial experiments indicated that the process might be highly explosive. More thorough studies were needed along with some revolutionary developments not only in refining practices, but also in the methods used to introduce the oxygen.
The use of controlled rolling for coiled steels of type 05G1B -- which are distinguished by their low carbon content (0.04-07%), economical alloying (Cr, Ni, Cu), and microalloying with niobium -- ...ensures formation of the requisite set of characteristics in the coiled product: a combination of high strength with good weldability and cold resistance. This is achieved through the formation of a ferritic-bainitic structure with fine ferrite grains and dispersion-hardening of the steel by niobium carbonitrides. New high-weldability steel 05G1B can be recommended for use in the production of electric-welded large-diameter gas-line pipe of strength class K56.PUBLICATION ABSTRACT
The problem of reducing the volume of iron-bearing waste materials generated in industrial operations (technologenic wastes) and making effective use of those wastes is not new, but its importance ...has increased dramatically in connection with the steady increase in the output of metal products, the accumulation of substantial amounts of metal equipment, the aging of that equipment,and the need to mine low-grade deposits of iron ore. World steel production this year may reach 800 million tons, and the nations with a developed metallurgical industry are already producing 6-15 tons of metal per capita. The need to recycle aging metal equipment was the stimulus for the developed of the electric-arc method of steelmaking.
The Fourth Congress of Steelmakers, organized by the Association of Steelmakers, was held in Moscow in October of 1996. Deputy Minister of Industry S. Z. Afonin delivered a speech on "The Development ...of Metallurgy in Russia and the Nations of the CIS" at the plenary session of the conference. L. N. Shevelev and O. V. Yuzov (respectively representing the Metallurgy Committee of the Russian Federation and the Moscow Institute of Steel and Alloys, or MISiS) spoke on "Trends in the World Market for Steel," L. I. Leont'ev and Yu. S. Yusfin (Ministry of Science of the Russian Federation and MISiS) gave an address on "Modern High-Efficiency Furnaces for Steelmaking Shops," and G. Fuchs (from the German firm "Fuchs Sistemteknik) discussed the "Status and Prospects of New Types of Metal Charges for Steelmaking in Russia and Abroad." G. A. Dorofeev (of the company "Intermet-Servis i Ko") and others also addressed the session. Among the sections organized at the conference was "Converter Steelmaking," where 49 papers and reports were presented, "Electrical Steelmaking" (44 presentations), "Steel Production in Open-Hearth Shops," (12 presentations), "Treatment of Pig Iron and Steel Outside the Furnace," (52 presentations), and "Teeming of Steel" (56 presentations).PUBLICATION ABSTRACT
It is proposed that many idled steel furnaces in Russia be modified to make use of solid industrial, household wastes and low-grade fuel as raw materials and charge components. Unused steel converter ...capacity especially could be used to recycle waste and produce commercial products. However, environmentally clean melting of solid carbon-bearing metallic waste (technogenic) charges requires modification of the converter combustion and melting process. By melting technogenic charges in a slag melt outside the area of contact with the combustion flame oxidation loss of iron was negligible and dust in the flue gas was absent. Heat balance studies showed that 26-36% of the heat is consumed by heating of the metallic charge, 10-20% by the heating of the bubbled gas and 55-60% during tilting of the converter. The higher the rate of charging, the smaller the heat loss and the greater the amount of heat used for melting. Recommendations are made for oxidation-reduction refining operations involving slag-fuel heating to processs technogenic charge in converters.
