SU1759891A1 - Charge for processing scrap of alloy steel and alloys - Google Patents

Abstract

Summary of the invention: The charge contains metal alloy chips or alloy as the metal additive, oxides of the charge material elements of the billet billet in the form of a basic alloy scale and / or a mixture of oxides as an oxidizer, and aluminum chips and / or aluminum grains as a reducing agent in the following ratio of components , wt.%: chips of alloy steel or alloy 15 - 50; scale of the basic alloy and / or a mixture of oxides of the leading elements of the material of the charge billet 33 - 55; screenings of aluminum chips and / or aluminum grains 17-30. 1 tab.

Description

. The invention relates to ferrous metallurgy, namely, the processing of waste from alloyed steels and alloys formed during machining (chips) and operation of structures and devices from these steels and alloys at high temperatures (scale).

The purpose of the invention is to obtain a charge stock of a given composition for remelting processes, an increase in technical and economic indicators due to a decrease in the carbon loss of alloying elements, an increase in the yield of suitable material, as well as a decrease in the cost of charge stock.

For this, the charge contains as metal additive chips of alloyed steel or alloy, as an oxidizing agent, oxides of the leading elements of the material of the raw material billet in the form of scale of the main alloy and / or mixture of oxides, as a reductant, screenings of aluminum chips and / or aluminum grains in the following ratio of components, wt. .%;

Alloy steel or alloy 15-50 chips

Scale of the main alloy and / or a mixture of oxides of the leading elements of the material of the charge billet33-55

Screenings of aluminum shavings and / or aluminum Krupka17-30

The preparation of a billet for remelting processes of a given composition is achieved by the fact that the mixture is a mixture of components capable of an exothermic reaction, the oxides of the basic elements of the alloy being the oxidizing agent. During the work of the charge, oxygen is exchanged between the oxidizing agent and the reducing agent and there is no impurity that can change the composition of the leading elements in the alloy. The composition of the oxidizing part is chosen so as not to change the quantitative ratios between the leading elements for a given alloy. Besides. when

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the need for the composition of the oxidizing component of the charge allows you to adjust the quantitative composition of the resulting alloy in accordance with the requirements for the composition of the finished charge,

Increase of technical and economic indicators is achieved by self-heating of the charge and a decrease in the volume of slag. The high thermality of the charge allows the metal additive to melt and form liquid slag on the surface of the molten metal. The slag covers the reaction zone, preventing the resulting alloy from oxidation and cooling, which contributes to a more complete separation of the metal and slag phases. In addition, the reducing agent in the reaction zone neutralizes the oxygen of the environment (air in the voids between the components of the charge), protecting the liquid metal from oxidation. The metal is an alloy of the oxidized elements of the oxidizing component of the charge and the heat-melted exothermic reaction of the metal additive from the oxides. Slag consists mainly of aluminum oxide and a minor part of the oxide component.

An increase in the yield is achieved due to a more complete separation of the metal and slag phases, reducing the heating time by electric arcs.

Reducing the cost of the resulting billet is achieved by using alloyed steels and alloys, non-utilizable scale of alloyed alloys and screenings of aluminum chips (ASO) as part of the mixture of chips.

The compositions of the tested charge are given in the table. As the metal additive of the tested charge was used chip waste steel 12X18H10T shop NJ 1 Nikopol South Pipe Plant. Oxides of chromium, nickel, manganese, and iron in the form of ore concentrates and pure oxides of grades H and ČDA, as well as scale of retorts to produce a titanium sponge of the shop, the term titanium of the Berezniki titanium and magnesium plant (retorts made of steel 12X18H10T) were used as the oxide part. As a reductant, screenings of aluminum shavings (ASO) were used according to TU 48-26-52-82 (waste from the production of secondary aluminum from the Vtztsvetmet Mtsensk plant) with an aluminum content of at least 70 May. % and aluminum grains (§8% -AI).

It is established that when the content in the mixture of chips of alloyed steel or alloy is less than 15%, the main scale

alloy and / or a mixture of oxides of the leading elements and screenings of aluminum chips and / or aluminum grit over 55 and 30%, respectively, decreases the yield

due to emissions and removal of dust particles, which is associated with the rapid course of the process.

When the content in the mixture of chips of alloy steel or alloy more than 50%. BOB of aluminum chips and / or aluminum grit less than 17% and base metal and / or mixture of leading elements less than 33% also reduces the yield due to the lack of heat of the exothermic reaction to melt the metal additive and separate the metal and slag. arcs leads to carburization of the alloy and an increase in the carbon alloy of alloying elements.

Satisfactory results for all the main indicators were obtained with the following component composition of the charge: basic alloy scale and / or a mixture of about 5% of the leading elements 33-55%, screenings of aluminum chips and / or aluminum grains 17-30% and chips of alloyed steel or alloy 15- 50%.

Best results are obtained with

0 using the mixture with the following content of components: chips of alloyed steel 28%, scale of the main alloy 46% and screenings of aluminum chips 26%. This composition is optimal for all

5 of the main technological and economic parameters, it allows the process to be conducted both in the furnace and in the after-furnace unit. In this case, a rather complete separation of metal and slag is achieved, which contributes to

0 to increase the yield, and use in the composition of the charge technological waste from other industrial production (chip waste from alloyed steels, scale of alloyed steels and alloys, screenings

5. Aluminum chips) makes its use cost-effective.

It was established that with the content in the charge up to 40% of metal additive, 39% of oxidizing and 21% of reducing parts

0 the process of obtaining the charge billet from the proposed charge can be conducted by extrahepatic method. The heat of the exothermic reaction is sufficient to dissolve the metal additive and separate the metal from the slag. With an increase in the proportion of metal additive, the resulting reaction product must be additionally heated with arcs to allow the separation of metal and slag, but this will decrease the yield and increase the frenzy of alloying elements, and the carbon content in the finished metal will slightly increase.

During the prototype melting, the oxide part consisted of oxides of the leading elements of the alloy.

Example. 1. Chips of steel 12X18H10T in the amount of 7 kg (50% by weight of the mixture) were thoroughly mixed with 4.2 kg (33%) of steel 12X18H10T scale and 2.4 kg (17%) of aluminum grains. The resulting mixture was loaded into the crucible of a laboratory electric arc furnace. The process was conducted with ignition of the charge from above. After the charge subsided, the resulting product was heated by arcs. After disconnecting the arcs, the resulting product was merged into a special metal receiver for the separation of the slag and metal phases. The steel ingot was easily separated from the slag. The ingot weight was 9.4 kg, which is 90.8% of the theoretically possible yield. By chemical analysis of the obtained metal, it was established that the quantitative content of the main elements meets the requirements for the composition of 1X18H10T steel.

2. Chips of steel 12Х18Н10Тv in the amount of 3.92 kg (28% of the mass of the mixture) were thoroughly mixed with 6.44 kg (46%) of steel 12X18H10T and 3.64 kg of scale (26%) of small-scale screenings of aluminum chips. The obtained charge was loaded into a special reactor equipped with a metal receiver. The process was conducted with ignition of the charge from above. After the process was completed, a steel ingot with a mass of 10.2 kg was extracted from the metal receiver, it was 98.9% of the theoretical yield. Chemical analysis confirmed the conformity of the obtained metal to 1X18H10T steel.

Claims (1)

The economic effect in the processing of waste alloy steels and alloys (chips and scale) using the mixture of the proposed composition in the charge billet for remelting processes can be more than 100 rubles per ton of billet. Claims for processing waste alloyed steels and alloys into charge billet, including a metal additive, an oxidizer and a reducing agent, characterized in that, in order to reduce alloy doping, to increase the yield of cost reduction, it contains as a metal additive alloy steel or alloy, as an oxidizing agent - scale of the main alloy and or a mixture of oxides, and as a reducing agent - screenings of aluminum chips and or aluminum grains in the following ratio of components, May .%: chips of alloy steel or alloy - 15-50; scale basic alloy and / or mixtures of oxides - 35-55; screenings of aluminum chips and / or aluminum grains - 17-30.