SU1560568A1 - Alloying mixture - Google Patents

Abstract

The invention relates to ferrous metallurgy and can be used in the smelting of vanadium-containing steels in electric furnaces with an acid lining. The goal is to reduce the consumption of vanadium and high-quality steel scrap, the level of rejection of castings on hot cracks by reducing the amount of non-ferrous metal impurities and non-metallic inclusions in the metal and increasing its uniformity. The use of an alloying mixture for melting vanadium-containing steel in the following ratio of components, wt.%: Vanadium metal product 85-95 with a vanadium content of 1-10, aluminum-magnesium briquettes 1-3, quartz sand else. 2 tab.

Description

The invention relates to ferrous metallurgy and can be used in the smelting of vanadium-containing steels in electric furnaces with an acid lining.

The aim of the invention is to reduce the consumption of vanadium and high-quality steel scrap, the reject level of pb hot cracks by reducing the amount of non-ferrous metal impurities and non-metallic inclusions in the metal and increasing its homogeneity.

The proposed alloying mixture, including vanadium-containing material, reducing agent and slag-forming material, contains vanadium metal product as a vanadium-containing material with a content of

Vanadium is 1-10%, as a reducing agent - briquettes of an aluminum-magnesium alloy, and as a slag-forming material - quartz sand in the following ratio of components, wt.%:

Vanadium metal products85-95 Aluminum-magnesium briquettes1-3

Quartz sandEverything else

The vanadium metal product is a slag metal material formed during magnetic separation of crushed vanadium converter slag. The metal product consists of an IC of 60-85% metal and 15-40% vanadium slag located on the metal surface. SLF

SP

but

wasp

The main components of the metal phase are iron (96-99%) and carbon (0.5-3.5%). The slag part of the metal product has the following composition, May. %:

Vanadium thioxide 1.8-17.8

(vanadium content 1-10%)

Iron oxides21.7-36.1

Manganese oxides7.0-12.0

Silicon oxides 15.0-25.0

Titanium oxides6.0-10.0

Chromium oxides1.8-3.0

Calcium oxides,

magnesium, aluminum Else

The reduction in the scrap steel consumption is provided by the metal phase, which is part of the metal product to be set down. When melted, this metal is completely transformed into a metal melt. The presence in the metal phase of the carbon metal product contributes to the acceleration of the reduction processes of vanadium and other oxides from the slag phase and their more uniform distribution in the liquid metal.

Briquettes of aluminum-magnesium alloy shavings, containing 93–95% aluminum and 5–7% magnesium, weighing 3–4 kg provide strict dosing and the required ratio of components in the mixture.

The quartz sand used for furnace charging and slagging contains 95-99% silica.

The use of a vanadium metal product in the mixture below the lower limit (less than 85%) does not provide the necessary content of vanadium in the metal, and above the upper (more than 95%) it creates excess (harmful for cast steel) vanadium concentrations and makes doping more expensive.

The introduction of aluminum-magnesium alloy briquettes below the lower limit (M%) does not provide the necessary degree of reduction of vanadium and manganese from oxides, and above the upper level causes the formation of a trough-effect and excessive reduction of silicon.

Inadequate - the addition of silica sand does not affect the thickening of the furnace slag, which reduces the intensity of the silicon-reducing processes, and a large (3%) leads to an increase in the viscosity of the slag and causes an intense excess recovery.

ten

15

20

25 jq

605684

silicon, which ultimately leads to embrittlement of steel.

When processing parts with aluminum-magnesium briquettes, the effect of metal sparging is created, due to which better mixing conditions are achieved, as a result, metal uniformity is increased and its more complete removal from non-metallic inclusions and sulfur occurs.

Replacing recycled aluminum and parts of steel scrap containing fairly high concentrations of non-ferrous impurities with aluminum-magnesium briquettes and metal product reduces the concentrations of tin, lead, mouse and copper in the metal. The use of recycled aluminum to deoxidize steel and purchased scrap leads to the systematic accumulation of these elements in steel, which, dissolved in the metal matrix 1 and located along the grain boundaries, embrittle the metal. This manifests itself at the points of transition from a thin section to a thick casting, where hot cracks are most likely to form.

Example. For comparative analysis, industrial 45-FL was melted using an alloying mixture (known and proposed) in industrial 6-s acid lining electric arc furnaces.

The mass of the injected mixtures is calculated from the conditions for the introduction of vanadium within the limits of the grade composition 1 of the 45 FL steel and its reduction to within 90-95%.

The mixture (known and proposed) was introduced at the beginning of the recovery period of smelting after preliminary metal deoxidation with lump ferrosilicon.

The results of the experimental heats are given in table 1 and 2.

The data in table 2 show a decrease in the consumption of vanadium and scrap metal in the processing of steel with the proposed mixture. The additive of the vanadium metal product is calculated to obtain the specified vanadium content in the steel, and since it contains a significant (60-85%) part of the metal phase, which includes carbon (6.5-3.5%) and vanadium (0, 04-0.12%), the consumption of vanadium and purchased steel scrap is reduced. In addition to vanishing, vanadium is distributed in liquid

35

40

45

50

55

515

the metal is more evenly, since it is recovered from the slag phase of the metal product (2% vanadium) and goes into the metal less concentrated than when recovered from vanadium slag (where the content of vanadium X-1 is 0%). The metal phase of the metal product and the carbon contained in it promote the acceleration of the reduction processes and the uniform distribution of vanadium in the liquid metal and metal. The presence of quartz sand in the mixture thickens the furnace slag, increases its melting temperature and promotes reduction reactions during the silicon-manganese-manganese reduction process, and the slag flowability before the metal is released from the furnace is achieved by lime additives.

The aluminum-magnesium briquettes and quartz sand introduced together by the metal product stimulate reduction reactions and stabilize the metal temperature, since significant

A considerable amount of heat for these reactions prevents the metal from overheating in the zones of heat sources.

From table 1 it is seen that due to the vanadium metal product, the consumption of the alloying mixture of the proposed composition increases (in comparison with the prototype). However, with the slag phase of the metal product, a smaller amount of vanadium is introduced.

In addition, a marked decrease in the content of non-ferrous metal impurities and non-metallic inclusions was noted. The reduction of silica sand additive leads to an increase in the oxidation of furnace slag (an increase in the content of iron, manganese, and vanadium oxides in it) and the concentration of non-metallic inclusions in steel. This leads to an increase in hot cracks in the castings, as well as to a deterioration in the recovery of vanadium from the slag phase.

Table 2 presents data on the decrease in the duration of the bottoms with

0

five

five

0

the optimal ratio of metal products, aluminum-magnesium briquettes and quartz sand. The reduction in the consumption of steel scrap in the charge is proportional to the increase in consumption of the proposed mixture, however, this reduces the degree of reduction of vanadium and manganese and increases the duration of smelting. In addition, the homogeneity of the metal in terms of the content of elements in various sections of castings decreases as the metal is cast into the molds, and the number of hot cracks increases.

The use of the proposed alloying mixture in the process of steel smelting reduces the costs of doping by reducing the consumption of vanadium, steel scrap, the level of rejects for hot cracks, the duration of heats.

Claims (1)

Invention Formula An alloying mixture containing a vanadium-containing material, a reducing agent and a slag-forming material, which is such that, in order to reduce the consumption of vanadium and high-quality steel scrap, the level of scrap in hot cracks due to a decrease in the amount of non-ferrous metal impurities in the metal and non-metallic inclusions and increasing its homogeneity, it contains as a vanadium-containing material a vanadium metal product with a vanadium content in it of 1–10%; as a reducing agent, aluminum magnesium briquettes VA, and as a slag-forming material - quartz sand in the following ratio of components, wt.%: Vanadium metal products85-95 Briquettes of aluminum-magnesium alloy1-3 Quartz sand Else (l ON ON U1 about OS Known mixture of 10 / 35,7 0,6 / 2,12,4 / 8,6 We offer a mixture 0.009 0.004 0.014 0.10 0.017 91.1 table 2