SU1617003A1 - Pulverulent mixture for dephosphorizing chromium-containing melts - Google Patents

Abstract

The invention relates to ferrous metallurgy, in particular to the production of steel in electric arc furnaces, and can most effectively be used to intensify the process of deformation of chromium melts. The purpose of the invention is to increase the dephosphorization capacity of the mixture. Powder mixture for dephosphorization of chromium-containing melts contains, wt%: iron oxides 10-15

grinding waste of 40-50 alloyed steel and recirculated basic slag - the rest. The use of the mixture makes it possible to increase the degree of dephosphorization of chromium-containing melts by 10–15% and to reduce chromium from the melt. 1 tab.

Description

The invention relates to ferrous metallurgy, namely to the production of steel in electric arc furnaces, and can be used most effectively to intensify the process of the dephosphorization of chromium melts.

The purpose of the invention is to increase the dephosphorization capacity of the mixture.

The proposed powder mixture for dephosphorizing chromium-containing melts contains iron oxides, recirculated basic slag and pip waste from alloyed steel in the following ratio of components, wt.%:

Iron oxides 10 - 15

Grinding waste

40 - 50 alloy steel

Recycling - main pshak Else

Introduction to the mixture of steel grinding waste (40–50%) has the following effect

The metal component of the waste grinding of alloyed steel increases the oxidative potential of the mixture, which significantly reduces the temperature in the metal melt in the purge zone and improves the thermodynamic conditions of the dephosphorization process.

The oxides of aluminum present in the grinding waste of the alloyed steel produce a liquefied effect in the donkey, improving the kinetic conditions for the transfer of phosphorus from the metal to slag phase.

The use of grinding waste of different grades of steel makes it possible to alloy the metal with various

O5

P1

oh oh

elements (Ni, Mo, Co and nuclei), while improving the technical and economic indicators of production by reducing the consumption of expensive alloy materials with

Reducing the content of grinding waste of alloyed steel in a mixture of less than 40% does not lead to a sufficient decrease in the temperature of the melt in the purge zone, which thermodynamically hampers the phosphorus removal process, and an increase in the content of grinding waste of alloyed steel more than 50% reduces the oxidation and basicity of the slag mixture which is also a disadvantage Affects the projection of dephosphorization

The content of iron oxides of less than 10% leads to a decrease in the oxidizing potential of the mixture, and the content of oxides above 15% leads to a decrease in the basicity of the slag mixture. In these cases, the flow of dephosphorization is difficult

A change in the amount of recirculated main shpak in a mixture of less than 35% and more than 50% leads in the first case to low calcium oxide activity in the slag, and in the second to a decrease in the oxidizing potential of the mixture, which worsens the thermodynamic conditions of the process, thereby making it difficult to remove phosphorus from metal melt.

In order to confirm the optimality of the composition of the proposed powder-like dephosphating mixture in the main electric arc furnace with a capacity of 5 tons, a series of melts of steel 5HNM was performed by remelting alloyed waste using the proposed and known mixtures

As a material containing iron oxides, use blacksmith dross containing 98.7% of iron oxide (Fe-O). The grinding waste from alloy AY 435 containing, in mass%, A1 gOz 6.5 | Ni 68,; 6; Fe 4.6; Cr 18.7; Si 0.51; Mp 0.6 and C, titanium, copper and other elements 0.5.

The chemical composition of the recirculated main slag - the slag of the recovery period in the smelting

five

0

five

0

five

0

five

0

trostali - next, wt%: CaO 64.3; MgO 11.7; SiO 12.3; FeO 0.8; CaFj, 4.6; 4.2 and other compounds 2.1 o

Grinding of scale, chrome ore and recirculated basic pshak is carried out in runners to a fraction of not more than 2 mm.

The powder mixture for dephosphorization in the amount of 1.8% by weight of the metal is injected with an argon jet with an intensity of 4.8 - 5.1 kg / t.min into a metal melt having a temperature of 1560 - 1570 ° C,

The melt before blowing has the following chemical composition, mayL: carbon 0.44 - 0.49; manganese 0.35 - 0.42; chromium 0.57 - 0.68; Nickel 0.80 - 1.12; molybdenum 0.08 - 0.15; phosphorus 0.019 - Metal samples for phosphorus and chromium content in steel are taken immediately before the injection of the powdery dephosphorus mixture and after 2 minutes after the end of the purge. Table 1 shows the results of testing

The proposed powder mixture for the dephosphorization of chromium-containing melts compared to the known one allows to obtain low concentrations of phosphorus in the finished metal, a high degree of assimilation of chromium from the metal / melt, and to carry out the alloying of the melt with nickel and chromium contained in the waste steel alloy.

Claims (1)

Invention Formula Powder mixture for dephosphorization of chromium-containing melts containing iron oxides, recirculated basic pshak, characterized in that, in order to increase the dephosphorization capacity of the mixture, it additionally contains grinding waste of alloyed steel at the following ratio of components,% by mass: Iron oxides 10-15 Grinding waste 40-50 alloy steel Registrar main slag Compiled by “Sorokin Editor MoPetrova Tehred L. Serdyukva Proofreader L. Pilipenko Order 4098 Circulation 505 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production Plant Patent, Uzhgorod, ul. Gagarin, lOt Subscription