Low-temperature coiling in the Stelmor line (∼850°C) is best for chemical scale removal. In that case, thin, dense scale is formed, without peeling, spots, or blisters. For low-carbon wire rod, the plasticity declines monotonically, while the strength increases. For high-carbon wire rod, the microstructure is unsatisfactory: tempering sorbite and also bainite and pearlite of reduced dispersity. (The optimum scale consists of wustite.) With increase in coiling temperature (950–1000°C), mechanical scale removal is best, on account of the difference in thermal expansion of the scale and the metal. In storage and prolonged transportation, blisters and scale-free sections may lead to corrosion and, on etching, to overetching of the metal.

The results of investigation of chemical descaling at different temperatures of coil formation both for lowand high-carbon rolled wire are given.

The results of investigation of chemical descaling at different temperatures of coil formation both for lowand high-carbon rolled wire 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.

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.

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.

The rolling of steel transforms certain defects formed during the steelmaking operation into other, outwardly similar defects (such as blowholes, longitudinal cracks, and folds). Like steelmaking defects, the defects formed during rolling cannot always be unambiguously evaluated by visual inspection and distinguished from the flaws formed during production of the steel. For example, it is sometimes difficult to distinguish laps from rolled-in cracks or to distinguish rolled-in scabs from folds. Accurate classification of surface defects on rolled products according to their causes and the stage of the production process in which they were formed is essential to improving product quality and reducing the cost of producing steel and rolled products, since it makes it possible to promptly make corrections to the process. The degree of accuracy with which the origin of a given defect is determined depends on the degree of perfection and reliability of the inspection methods and equipment used, as well as on the system implemented to monitor the production process.

A comprehensive study of the quality of experimental wire rod made of steel C82D2 with 0.30% chromium has shown that this material can be used as a replacement for vanadium-bearing wire rod. In this case, it is necessary to subject the rod to two-stage cooling on a Stelmor line in a process that includes the following: • coil formation at tco = 940–970°C; for 12.0-mm-diam. wire rod, tco = 960–1000°C; • the operation of six jet-cooling blocks operating with a motor speed of 1480 min−1; • transport of the metal on a roller converyor moving at a speed of 0.5 m/sec. The presence of martensitic sections and a cementite (carbide) network in the structure of the metal is not grounds for rejection of the product.