Two series of experiments on investigation of structure formation in rolled wire of alloy steel of welding function are carried out.
The effect of chemical composition (chromium, nickel, copper, vanadium, molybdenum, nitrogen) and heat treatment regime in a line on weldable reinforcement of strength class 500 structure formation and properties (with respect to yield strength) is considered. High steel alloying efficiency with the above-mentioned elements is demonstrated, in spite of making the steel more expensive. In a number of cases, preparation of a set of structural, mechanical and service properties is only possible with the use of alloying elements, which strengthen steel either by solid solution or dispersion mechanisms.
Short results of the researches, carried out in the conditions of OAO «Moldavian metallurgical works» for recent 25 years and allowed to develop scientifically grounded technological decisions on increase of qualitative characteristics of rolled wire of wide branded grade, are given.
Short results of the researches, carried out in the conditions of OAO «Moldavian metallurgical works» for recent 25 years and allowed to develop scientifically grounded technological decisions on increase of qualitative characteristics of rolled wire of wide branded grade, are given.
The results of investigation of chemical descaling at different temperatures of coil formation both for low- and high-carbon rolled wire are given.
The experimental testing of application of fully magnesia casting ladles is carried out with the purpose of reduction of high-carbon steel contamination with nonmetallic impurities. Methods of appraisal of nonmetallic impurities and choice of their rating criteria are analyzed.
Two series of experiments on investigation of structure formation in rolled wire of alloy steel of welding function are carried out.
This article examines the hereditary effect of microscopic dendritic segregation in the continuous-cast semifinished product on the structure (the presence of segregation-related striae and martensitic sections and their distribution over the cross section) of wire rod made of high-carbon steel. To improve the quality indices of wire rod, the casting technology should be stabilized by adding equipment for stopper-assisted pouring, fully protecting the stream with submersible refractory tubes, using modern mold-oscillation mechanisms (such as lever-type mechanisms), using parabolic molds that speed up crystallization of the CCS, and employing other measures. Maximum use should be made of heat treatment of the CCSs and rolled products, one of the goals here being to increase the degree of homogenization of the cast structure and rolled product and/or residues of that structure. This can often be achieved through longer heating of the CCS in walking-beam furnaces prior to the rolling operation.
Разработаны химический состав стали по принципу минимизации содержания упрочняющих элементов на нижнем уровне требований НД и заказчиков, регламентировании отношения бора к азоту, что в целом увеличивает пластичность катанки. Дополнительная смягчающая поточная термическая обработка на линии Стелмор обусловливает безотжиговое волочение катанки в готовую омедненную проволоку.
Over the past few years, the Moldavian Metallurgical Plant (MMZ) has developed a Program for Development of Production Processes for High-Quality Metal Products with High Added Value and Unique Specifications. Improvement of the characteristics of rolled-wire for direct deep drawing will require the implementation of the following measures to eliminate microdendritic segregation (Cr, Mn, Si, Mo, V): electromagnetic mixing in the sump zone or secondary cooling zone; modernization of the air-cooling section of a Stelmor line, including installation of electric heaters to enable the metal to be held under isothermal conditions for long periods of time.
