SU1830393A1 - Process for production of composite boron-containing alloys for doping steels - Google Patents

Description

The invention relates to powder metallurgy, in particular to methods for producing boron-containing alloys for alloying and modifying steels, cast irons and nickel-based alloys.

The purpose of the invention is to increase the productivity of the process and reduce the cost of the product by reducing the synthesis time and duration of cooling, expanding the class of starting materials.

The purpose of the invention is achieved by the fact that in the known method for producing boron-containing alloying alloys, comprising preparing a reaction mixture of powders of boron-containing alloys and metals of groups IV-VII, carrying out a combustion reaction and subsequent cooling of the product in an inert medium, a mixture consisting of powders of one go several boron-containing alloys of iron, nickel, cobalt, chromium and / or manganese and powders of one or more metals of groups IV-VII and / or alloys containing 15-88% of these metal Group VIII metal, and burning and cooling the reaction product is carried out in a cocurrent inert gas stream at a rate of 0,083-6,25 l / s (or at a rate 0,00230,171 l / s.sm ^2). From the practice of SHS processes, it is known that the burning of weakly exothermic, gas-free systems, for example, such as alloy-alloy, occurs only at high initial temperatures. From the technological side, this is associated with significant energy costs, the use of sophisticated special equipment. In addition, to prevent oxidation, the product is cooled in an inert environment for a sufficiently long time.

The invention proposes to realize the combustion and cooling of the product of such systems in a satellite inert gas stream. those.

the direction of propagation of the combustion front coincides with the direction of the gas stream. The main advantage of this method is that. that heat, which is extracted from the combustion product filtered by gas, is returned to the reaction zone, i.e. there is practically no heat loss to the environment. The regeneration effect that takes place here essentially increases the combustion temperature, hence, the burning rate also increases. Thus, the flow of inert gas, on the one hand, acts as a coolant that increases the burning rate, on the other hand, prevents oxidation of the product and cools the burnt layers of the mixture, i.e. the whole technological operation is reduced to a minimum. In addition, this method allows to significantly reduce the cost of the process due to the use of alloys as starting materials. Thus, the base of raw materials is expanding significantly. In the invention, the gas flow rate is limited to 0.083-6.25 l / s (or a gas flow rate of 0.0023-

0.171 l / s.cm ² ), because the burning time of the mixture at a gas flow rate of less than 0.083 l / s (or at a gas flow rate of less than 0.0023 l / s * asm ² ) does not occur, and the value of the upper limit is critical, i.e. at a gas flow rate of more than 6.25 l / s (or at a gas flow rate of more than 0.171 l / s), the gas slips through the reaction zone and simulates combustion. In this case, the product contains either unreacted particles or the mixture completely decays.

In the invention, the content of boride-forming metals of groups IV-VII in alloys is limited to 15% and 88%. In mixtures where alloys contain less than 15% of metals IV – VII, the combustion reaction cannot be carried out even at high gas flow rates. The use of alloys containing more than 88% boride-forming metals increases the productivity of the process, but does not give a cheaper effect, since the costs associated with obtaining such alloys and their subsequent grinding often exceed the cost of powders of pure metals.

Example: obtaining a composite material Tl-B-Fe. Industrial alloys are used as starting materials: ferroboron grade ФБ 20 (GOST 14849-69) and ferrotitanium grade ФТи65 (GOST 4761-80), which are ground into a powder with a particle size of 0.005-0.4 cm and mixed with an atomic ratio of titanium to boron equal to 1.5, which corresponds to a weight content of ferroboron of 52.3% and ferrotitanium of 47.7%. The resulting mixture in an amount of 40 kg is loaded into a flow reactor. The thermocouples ВР5 / ВР20 are installed in the mixture to fix the temperature and purged with argon, which is inert with gas, before and during the combustion process with a flow rate of 2.6 l / s or at a rate of 0.072 l / s.cm ² ) and ignite using an exothermic composition. Then there is a forced propagation of the combustion front due to the exothermic reaction of the formation of titanium and iron borides, as well as intermetallic compounds. In addition, convective heat transfer downstream of the gas makes a significant contribution to the increase in the burning rate. The burning time of the mixture is 4 minutes. The burnt layers of the charge are cooled by an argon flow - this is indicated by the temperature values on the devices supplied to the thermocouples. At the end of combustion, the product is completely cooled in 4 minutes, after which the gas is shut off and the product is recovered. The technological operation for obtaining the Ti-B-Fe ligature by the prototype method lasts 37.2 minutes. Thus, the productivity of the process increases by more than 4 times, and the use of an alloy of ferrotitanium instead of titanium reduces the cost of the product by 3 times, for example: the cost of 1 kg of titanium PTM 10 rubles, and the cost of the alloy 1 kg of ferrotitanium, including grinding 3.2 rubles. The combustion of the ferroboron – titanium mixture without gas purging was not possible.

Other examples of the method and comparison with the prototype are summarized in table.

A comparative analysis of the proposed solution with the prototype showed that the claimed method differs from the known starting material, the implementation of the combustion reaction and subsequent cooling of the product in a satellite stream of inert gas, as a result of which the productivity of the process increases, and the use of alloys instead of pure metals significantly reduces the cost of the product.

Claims (1)

Claim A method of producing composite boron-containing alloys for alloying steels, comprising preparing a reaction mixture of powders of boron-containing alloys and metals of groups IV-VII of the periodic system, carrying out a combustion reaction in an inert medium and subsequent cooling of the reaction products, characterized in that, in order to increase the productivity of the process, the reaction combustion is carried out in a satellite stream of inert gas with a flow rate of 0.083-2.5 l / s.cm ² . The original mixture Sod.bor Inert Consumption Soon I eat Time Burden Power and metal. gas gas gas burning ohla "- grotesque UB ^ LICHR- IV-VII gr. l / s flow mixtures denia sa niya pro in alloys l / s-sn ² min min min CREATE- % body ty Ferroboron Titanium 21,4 Argo ") Suggestion Prototype 1.5 0 0,061 0. Nickelbor Zirconium • Chrome 17.5 Helium Suggestion Prototype 2.0 0 0,055 L Ferrochrombor Titanium 30,2 Also Suggestion Prototype 0.083 0. 0.0023 0 Ferroboron Titanium 21,4 _i i _w Suggestion Prototype 6.25 0 0.171  0 Ferroboron Ferrotitanium 21,4 69.6 . ¹ ·. Suggestion 2.6 0 0,072 0 Ferroboron Nickeltitan 17.8 88 . ¹ ·. Also 5 88 about' 0, 162 0 Nickelbor 18.5 Helium -and- 3.3 0,091 Ferrosilicozirconium silicon zirconium 15 Ί; 0 0 0 Cobaltbor Ferrovanadium Hafnium 25.1 75 Argon - 1 '. 2.19 0.06 0 Ferrochrombor Ferrotitanium 29.5 6.96 Also - 0.083 0 0,023 0 Ferroboron 21.6 . * · _ - and. 5.44 0.15 Ferromanganese Molybdenum 70,2 0 0 Manganesebor thirty - * ·. 2.9 0.08 Ferroniobium fifteen 0 0 Ferroboron. Ferro-tungsten 21.6 79.1 _and_ '3.26 0 o.oe 0 Ferroboron Teagan 21,4 6.3 0.173 Ferrochrombor Titanium 30,2 Helium . ♦ - 0.08 0.0022 Manganesebor Ferroniobium thirty 14.2 Argon 2.9 0.08 4 7 eleven 7.2 thirty 37,2 8 5 thirteen fifteen thirty 45 8 7 fifteen fifteen thirty 45 3 6 9 7.2 thirty 37,2 4 4 e Not Burns th B ABOUT Not burns 4 3 7 Not burns about m t eleven Not burns 12 Not 3 BURN fifteen 7 Not 3 burns 10 8 Not k is on 12 5 Not e is on about v Burning stops 10 ErenA burning does not increase Does not burn Note. Gas flow rate® ...... reactor cross-sectional area ® 55.3 cm ²