Modification of alloys, in particular, by calcium and barium, is one of the promising directions for obtaining alloys with a fine crystalline structure. Complex ferroalloys – ferroalumosilicocalcium and ferrosilicobarium – were developed in the Chemical and Metallurgical Institute after Zh. Abishev. It was shown, that modification of steel by silicon-aluminum complex alloys containing chemically active elements – calcium and barium, should become one of the most effective methods to improve the quality of machine-building metal products.The chemical compositions of the smelted ferroaluminosiliconcalcium and ferrosilicobarium presented. The melting range of the nonmetallic compound formed during the deoxidation of steel by complex alloy containing calcium determined. Results of mechanical tests of the specimens of steel, modified by a complex alloy containing barium considered. A comparison of microstructure of the current production route steel and deoxidized with the complex alloys was carried out.In the course of metallographic studies of experimental steel specimens, a modifying influence on the morphology of nonmetallic inclusions by calcium and barium, supplied in a complex with aluminum and silicon alloys, was established.Metal processing by complex alloys such as ferrosilicoaluminum with calcium (FASC) and ferrosilicobarium (FSAB) indicates the possibility of achieving a higher degree of refining from oxide nonmetallic inclusions and a more even distribution of them in the ingot.The results of the industrial heats also indicated a possibility of improving of quality of casting through the decreasing of hot thermal cracks and gas-shrinkage defects, cleaner grain boundaries, a significant reduction in the number and size of carbide inclusions.
Ахметов Абулхасим Балхиевич кандидат технических наук, заведующий лабораторией "Металлургия стали и материаловедения" ХМИ им. Ж. Абишева, постоянный автор Бюллетеня научно-технической и экономической информации "Черная металлургия". Коллектив редакции Бюллетеня "Черная металлургия" выражает глубочайшие соболезнования родным, близким и коллегам Абулхасима БалхиевичаWe announce with deep regret the sudden death of Akhmetov Abulkhasim Balkhievich that happened on December 25, 2020.
Mr. Akhmetov, was 58 years old, PhD (Tech.), Head of Laboratory "Metallurgy of steel and material science" CMI after Zh. Abishev, permanent author of Bulletin of Scientific, Technical and Economic Information "Ferrous Metallurgy". The collective editorial staff of the Bulletin "Ferrous Metallurgy" presents deep condolences to relatives, family and colleagues of Mr. Akhmetov
Base on laboratory and industrial experiments, as well as subsequent studies of the microstructure of steel samples alloyed with a certain sequence by vanadium, niobium, and titanium, a concept including compliance with the order of those microalloying elements introducing into steel developed and justified. According to the concept, the sequence of introduction is determined by the difference in the degree of their thermodynamic affinity to the nitrogen and carbon dissolved in the steel.Investigations of the microstructure of experimental microalloyed samples by an optical microscope, with a magnification x250, showed the most significant grain refinement with a consecutive additive – first vanadium with niobium and after 10 minutes of holding – titanium.The efficiency of the developed alloying method for the advanced formation of vanadium and niobium carbonitrides was evaluated by studies with the Mira3 Tescan electron scanning microscope having an X-ray energy dispersive microanalysis system X-Act (Oxford Instruments). When studying the compositions and the form of carbonitrides discovered in steel samples alloyed with a different sequence of additives, it was established, that during simultaneous additive of titanium, vanadium and niobium into steel, titanium carbonitrides account for a majority, while vanadium and niobium carbonitrides are not actually formed or are represented by single inclusions. Conversely, in steel samples alloyed with a consecutive additive to steel, first vanadium with niobium and later titanium, carbonitride of vanadium and niobium inclusions prevail. In this case, titanium carbonitrides are represented only by single and fine inclusions. Thus, first introducing of vanadium and niobium, allows them to react fully with stoichiometrically insufficient concentrations of nitrogen and carbon, ahead of the formation of titanium nitrides.Based on the results of the research in JSC “ArcelorMittal Temirtau”, using the developed concept of consecutive alloying by carbonitride-forming elements, the technology of 09G2FB grade steel production with a ferrite-bainite structure developed and implemented, fully meeting API Spec 5L requirements for steel of strength category X80.
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