SU1167210A1 - Slag-forming mixture for steel teeming - Google Patents

Abstract

Slag-forming mixture for steel casting, including manganese ore, fluorspar, aluminum-containing material, sawdust. characterized in that, in order to improve the surface quality of the bottom part of the ingot and reduce non-metallic inclusions in it, the mixture additionally contains steelmaking slag, and aluminum-based electrothermal silumin production as an aluminum-containing material in the following ratio of ingredients, wt.%: 2- 8 Manganese ore 0.5-7.0 Fluorspar Aluminum electro-chemical slag 15-25 silumin production 3-6 Sawdust Slag of steelmaking JV Production rest

Description

111 The invention relates to ferrous metallurgy, in particular, to the compositions of slag-forming mixtures used in steel casting. The aim of the invention is to improve the quality of the surface of the bottom part of the ingot and the reduction in it of non-metallic inclusions. The aluminum slag of electrothermal silumin production used (TU 48-01-13-75) used for preparing the proposed mixture contains 20–40% aluminum, 10–20% silicon, and the rest of the slag phase. Due to the absence of magnesium and chlorides in the aluminum slag, as is the case in the dump slag of aluminum production contained in the known composition, the use of the proposed slag-forming mixture is not accompanied by a pyroelectric effect and the release of harmful substances into the atmosphere of the workshop. The slag of steelmaking, which is the basis of the proposed composition, contains 15-30% of silica, 5-16% of aluminum oxide, 40-53% of calcium oxide and up to 8% of manganese oxides and iron. The ratio of oxides in the specified slag, as well as its content in the mixture in combination with the other components ensures the rapid formation of slag (within 15–20 s), keeping it in a liquid-mobile state in the required amount to form a slag crust between the walls of the ingot and the mold and the slag cover on the surface of the liquid metal and throughout the entire time of filling the mold, resulting in obtaining ingots without surface defects with a minimum content of nonmetallic inclusions in the Table. Table 1 lists the compositions of various slag-forming mixtures, and Table. 02 2 - physical properties of these mixtures and their slag melts, which allows to judge about the role of the content of each of the ingredients in the proposed composition on its properties and physical characteristics of the slag melt mixture. As follows from the data table. 2, the surface tension of slags in the proposed mixture (2-4) is 363391 dyn / cm, the melting temperature range is 980-1030 ° C, and the viscosity at casting temperatures is 1520-1580 ° C 0.9-1.3 Pz. These properties fully satisfy the requirements for slags for steel casting. The optimal variant of the mixture is mixture 3. With a decrease or increase in the content of the components of the mixture (mixture 1 and 5), the ability of the obtained slag to wet and dissolve oxides decreases, which negatively affects the quality of the metal to be cast. Under production conditions, the mixture was tested when casting from above five heats of forging ingots with a weight of 15-20 tons. The mixture is introduced into the mold before the metal is cast. Upon receipt of the first portions of the metal, slag is formed in the mold. Mixture consumption 3.5-4 kg / t. In tab. 3 shows the results of testing the proposed and known mixtures. The data table. 3 show that the use of the proposed slag-forming mixture when casting steel into molds allows to significantly improve the surface quality of the bottom part of the ingots, as well as to reduce the content of oxide nonmetallic inclusions in it 5 times.

Table 1

Aluminum slag. electrothermal production of silumin 12

Sawdust 2

Steelmaking slag

production 84.7 Temperature 1080 1000 980 melting, ° С 1.8 1.1 1.3 Viscosity, Пз Surface tension of slag, 315 384 391 dyn / cm Slag formation time 32 19 17, s

29 7

25

47

Table 2 1030 1090 1050 0.9 2.0 1.8 363 320 21 36

Mixture

Quality of the surface;

Known surface without diagrams., Bottom part up to 1/3 of the height, shame metal size up to 15 cm.

: .. ..;: ;;. h.:; and & ...:. ..-:,;:

; lymvta lychesichA klk; f

(check in don jA sacTti;. tile,%

(

0,042-0,058 Surface without defects, clean with single sections (0 -10 mm) of adhered slag in the bottom part at a height of up to 27 cm О ,, 030 -0 „036

Claims (1)

SLAG-FORMING MIXTURE FOR STEEL Pouring, including manganese ore, fluorspar, aluminum-containing material, sawdust. characterized in that, in order to improve the surface quality of the bottom of the ingot and to reduce non-metallic inclusions in it, the mixture additionally contains slag from steelmaking, and aluminum-containing slag from electrothermal production of silumin as an aluminum-containing material in the following ratio of ingredients, wt.%: Manganese ore 2-8 Fluorspar 0.5-7.0 Aluminum slag electrothermal • silumin production 15-25 Sawdust 3-6 Steelmaking Slag production Rest _w -SU.n> 11.67210