M. Kh. Ziatdinov

Combustion of vanadium-iron alloys in nitrogen

The starting alloys were prepared from specially pure carbonyl iron (99.8% Fe) and electrolytic vanadium VEL-1 (99.8% V) in a vacuum furnace, crushed to a powder with particle size less than 0.14 mm and pressed into pellets with a relative density of 0.48-0.64. The burning of the alloys is described. The nitrogen pressure in the bomb was varied from 1 to 130 atm. In the experiments the burning specimens were frequently quenched in water. The starting material and combustion products were analyzed radiographically and metallographically. The paper discusses effect of iron content of alloy on burning rate and extent of reaction, as well as laws of combustion of alpha- and sigma-ferrovanadium. A review is given of phase transition to sigma-ferrovanadium combustion. A discussion of the results is presented.

Self-propagating high-temperature synthesis of ferrovanadium nitride for use in smelting high-strength low-alloy steels

A new alloying material for smelting high-strength low-alloy steel is considered: FERVANIT fused ferrovanadium nitride. Self-propagating high-temperature synthesis in the ferrovanadium-nitrogen system permits the development of a new industrial production technology for alloys based on vanadium nitride. Self-propagating high-temperature synthesis requires no electrical energy, is environmentally benign, and results in a product with good operational properties.

Chromium combustion in a nitrogen coflow

The combustion of chromium powder in a coflow of nitrogen-containing gas in a range of specific flow rate of up to 20 cm3/(s · cm2) is studied. The use of forced filtration intensifies the combustion wave propagation in the Cr–N2 system. In this case, the combustion rate increases simultaneously with the decreasing degree of nitridation. The superadiabatic heating modes in the case of purging with pure nitrogen and a hydrogen-argon mixture are revealed. It is shown that the use of the gaseous mixture promotes the formation of the inverse combustion wave. The hardening mode implemented during forced filtration allows fixing the high-temperature single-phase nonstoichiometric nitride Cr2N.

Microalloying of steel with boron and the development of ferrotitanium boride

The smelting of steel microalloyed with boron is considered; the composition of the boron-bearing alloying additives is analyzed. Experience in the production of new boron-containing alloying composites by self-propagating high-temperature synthesis is described. The main aspects of self-propagating high-temperature synthesis in the Ti-(Fe-B) system are studied. Industrial test data for ferrotitanium boride, which is an alloying additive produced by self-propagating high-temperature synthesis, are presented for the smelting of 40γP steel.

Production and use of ferrosilicotitanium produced by self-propagating high-temperature synthesis

The production of silicotitanium alloys by self-propagating high-temperature synthesis in the titanium-ferrosilicon and ferrotitanium-silicon systems is investigated. On the basis of the results, a production technology is developed for a new material: ferrosilicotitanium (titanium ferrosilicide) produced by self-propagating high-temperature synthesis, for use in economical titanium alloying of steel. Industrial tests at OAO MMK show that the assimilation of titanium from titanium ferrosilicide is greater (by a factor of 1.5) and more stable than from ferrotitanium.

SHS Ferrosilicon Nitride NITRO-FESIL®TL as a New TAP-Hole Clay Refractory Component for Blast Furnaces1

The scientific and technical manufacturing firm Étalon developed and perfected industrial technology for manufacturing SHS ferrosilicon nitride NITRO-FESIL® TL, which is a composite consisting of silicon nitride, iron silicide, and free iron. On an industrial scale together with OAO MMK and ZAO Metallurgremont test tap-hole clays are provided containing ferrosilicon nitride NITRO-FESIL® TL. Taphole clays with the new component demonstrate higher corrosion and erosion resistance, and oxidation resistance, and also better sintering capacity. As a result of this reliable sealing of iron tap-holes, a smooth, more prolonged iron and slag flow regime with stable discharge parameters is provided. The clay is recommended for introduction.

Self-propagating high-temperature synthesis of ferrochromium nitride

Ferrochromium nitride obtained by self-propagating high-temperature synthesis is developed as an alloying material for the production of high-purity, corrosion-resistant steel. Self-propagating high-temperature synthesis involves no energy consumption and has no environmental impact. The product has excellent properties.

Sintering of the reaction products of combustion of alloys in nitrogen

An investigation of the mechanism of compacting of Fe-V alloy with a sigma-phase structure, a low porosity composite material consisting of alpha-iron and a filler of delta-vanadium nitride, is made after the synthesis surge. Alloys containing 50 wt.% Fe were prepared by sintering in a vacuum furnace of powders of type VEL-1 vandium and special purity carbonyl iron. The mechanism of compacting was studied on specimens in hardened water. Metallographic investigations were made on MIM-7 and PMT-3 instruments and the phase analysis on a DRON-2 instrument. Rapid compacting in combustion of sigma-FeV in nitrogen is determined by combining of the solid-liquid drops formed in the combustion front and consisting of molten iron and vanadium nitrides.

SHS Technology for Composite Ferroalloys. 1. Metallurgical SHS: Nitrides of Ferrovanadium and Ferrochromium

The development of specialized self-propagating high-temperature synthesis (SHS) for complex ferroalloys used in steel smelting and in blast-furnace technology is discussed. To that end, a new approach to the SHS process has been conceived: the metallurgical SHS process, in which the basic raw material consists of various metallurgical alloys including dusty waste from ferroalloy production. In that case, synthesis involves exchange exothermal reactions. The product is a composite based on the initial inorganic compounds; the binder is iron or an iron alloy. Depending on the state of the initial reagents, the metallurgical SHS processes may be gas-free, gas-absorbing, or gas-liberating. For each case, the combustion conditions will be very different. Thermal matching may be used in organizing the metallurgical SHS process in systems that are not strongly exothermal. The self-propagating high-temperature synthesis of nitrided ferrovanadium and ferrochrome is investigated. It is shown that the phase composition of the initial alloy strongly affects the combustion of ferrovanadium in nitrogen. In the nitriding of σ ferrovanadium, transformation of the intermetallide to an α solid solution is activated on reaching the phase-transition temperature (~1200°C). The composite structure of the nitriding products of ferrovanadium is formed under the influence of solid–liquid droplets consisting of molten iron and solid vanadium nitride. Solid-phase reaction of ferrochrome with nitrogen facilitates high degrees of nitriding. The combustion rate of ferrochrome on nitriding during coflow filtration, as in chromium, increases with increase in the nitrogen flow rate. The degree of nitriding of the ferrochrome in forced filtration (4.7–7.5% N) is much less than that in natural filtration (8.8–14.2% N).

Metallurgical SHS Processes as a Route to Industrial-Scale Implementation: An Autoreview

The paper addresses to the practical development of a novel process technology for large-tonnage SHS-production of alloying agents and master alloys–metallurgical SHS process technology. The suggested and tested technique is based on use of various metallurgically produced allows, including dusty wastes of ferroalloy plants. The replacement of high-purity starting powders by less expensive and accessible ferroalloys afforded for transition from existing laboratory-scale fabrication of SHS materials to large-tonnage SHS manufacture.