DE1608195B1 - Process for the production of ferro-silicon - Google Patents

Description

3 4

the temperature has a major impact on the filling, d. H. Ability to form nodular cast iron occurs, the ferro-silicon alloy to be produced arrives. whereas with an acidic or weakly basic one

Accordingly, it is the object of the invention to provide a pH range of the slag after the end of the drive for the production of alloys on ferrous reaction not a satisfactory ability of the to create silicon-based, which is expected when used as an alloy for the formation of nodular cast iron Additive in the production of nodular cast iron can be.

result in a material with high tensile strength. The use of a basic, refractory material

The solution to this problem is that one rials, ζ. B. of the magnesium oxide type, however, a) introduces lime or limestone into a ladle, inevitably that the lining material reacts with the silicon lined with basic refractory material or is as a slag-forming material, which acts a minimal amount of silicon oxides. In order to avoid erosion of the lining material, b) the pan is heated until the temperature of the lining is avoided, it is therefore preferred to increase the lining lining surface to about 1000 ° C, material burned stones made of magnesium oxide or the like, c) a molten ferrosilicon alloy in which that are insensitive to erosion, is introduced in place of pan, d), the molten metal in the 15 sensitive to erosion castable materials pan at a temperature of at least ⁰ C 15OQ to use,
holds the molten metal in the pan
Shaking movement by eccentric rotation of the

Pan left until the reaction has ended during _2> temperature conditions

the molten metal at such a high temperature
temperature maintains that it after the reaction has ended

has a temperature of at least 1350 ° C and the temperature of the melt after completion

e) pouring the molten metal into a mold. the reaction should not be below 1350 ° C.

In this process, the shaking of an alloys with melting points Von is not Point broken off at which the color of the sparks 25 below 1350 ° C should be the temperature of the geaus the melt changes from red to bluish-white fused alloy after the end of the reac, while the melt at the temperature of tion is not lower than the relevant melting point is kept at least 1350 ° C and the melt is in and the melt is noGh a temperature Casting mold is poured after the melt point at which the molten alloy is a was left still for a while. 30 has considerable fluidity. The results

The product obtained by the above-described method of experiments has shown that an alloy meets the requirements for ferrous additive with a desired ability to silicram alloys for use as additive formation of nodular cast iron not in the manufacture of nodular cast iron. Cast iron, temperature of the melt can be obtained which is not higher than 135O ⁰ C using such a ferrosilicon 35. The reaction between alloy made as an additive possessing a slag-forming material and the alloy to tensile strength of 60 kg / mm ⁸ , when cast ferrosilicon-based according to the invention will be strong with minimal irregularity. Dem- endothermic, so that the temperature of the molten alloy according to the method of the invention falls sharply during the reaction. Therefore, it is possible to produce an excellent filler alloy, 40 the temperature of the molten alloy which enables spheroidal graphite cast iron to be produced with a high tensile strength equal to or greater than 1,350 ° C. or higher upon completion of the reaction. only adhered when the melted

To achieve a satisfactory result in the alloy at a temperature of at least To get driving according to the invention, the 1500 ° C must be kept before shaking. In this Procedure in compliance with the following conditions 45 is when a ladle with a run: capacity of 11 or less capacity

uses wifd and a molten alloy at a temperature of 1700 to 1800 ° C in the course

1. Refractory lining material ^one . less than 10 minutes in the pan

To pour 50 is, at least required, the pan beforehand by means of auxiliary heating devices including

The refractory lining to be used of the introduced slag-forming material

material must be made of such basic, refractory to heat a temperature of about 1000 ° C.

Materials should be selected that have minimal quantities.

contain silicon dioxide and aluminum oxide. 55 over the known process economic advantages

In this regard it is advantageous to use refractory materials in such a way that the process within

materials made of magnesium oxide and of the type which can be carried out for a very short period of time,

Dolomites, but preferably not calcined, that the available percentage of silicon is remarkable.

Alumina stones to be used. The value can be increased, since no silicon is inhospitable

Basicity of the fire used for lining 60 is consumed by oxidation, like that

solid material has a great influence on which was the case in the known method, and that

Ability to form nodular cast iron that does not have the heating energy that was previously required

alloy to be produced, since the use of one is required because of the introduction of hot

carbonaceous material to introduce ferro-silicon. The method according to the invention

Carbon - albeit in a small amount - in 65 is particularly advantageous as alloys

the alloy to be produced leads, with the result, on ferrosilicon basis, which make it possible to produce spherical

that the alloy, after casting, tends to cast graphite with a tensile strength of 60 kg / mm ²

to be destroyed, although no change in it or above to be established, preserved on a stable basis

can be and further, than when carrying out the method under the same conditions a Change in the value of the tensile strength of the spheroidal graphite cast iron produced with the aid of the alloy produced can be reduced to a minimum, taking into account a desired value can, so that alloys that are able to have a desired tensile strength in the produced therewith To produce ductile iron can be produced with a minimal percentage of rejects. Previously, the tensile strength of a nodular cast iron was determined by actually measuring the tensile strength found on a sample taken from each tap. According to the procedure according to of the invention, such a sampling is not required, and the production can be by means of only a control diagram. As a result, the inspection cost can be substantial be reduced.

The method according to the invention is described below using an example with reference to FIG the drawing depicting microscopic photographs showing the structures of the with the according to the Invention produced alloys show obtained spheroidal graphite castings, explained in more detail.

example

The method according to the invention has been carried out using one with magnesia bricks lined ladle with a capacity of 500 kg (calculated on the basis of pig iron). First, the surface of the lining was made using a fuel oil burner 1 hour before execution of the process heated. 15 minutes after the start of heating, it became a slagging one Material was placed in the ladle, and immediately afterwards the combustion temperature of the heating oil was set by mixing oxygen into the compressed air for the torch it increases the temperature to increase the surface area of the lining. Than the temperature of the lining surface over 1000 ° C a molten ferrous silicon was placed in the ladle. The burner was removed when the amount of molten ferro-silicon in the ladle reached about 300 kg, and a device for shaking the ladle was then immediately set in motion to the Pan along a horizontal circle of 90 mm diameter at a speed of 92 rev / Min. To rotate. The pan was alternately moved in this way for 7 seconds long in one direction and after holding stationary for 1.5 seconds in the opposite direction Rotated for 7 seconds. In the meantime the color of the inside of the changed Pan with a spark of white smoke spurting from red to bluish-white, and the movement; the pan was stopped at this point. The pan was kept still, and after the surface layer When the slag had solidified, the pan was tilted and the melt came out of it Pan in a mold through a hole drilled through the lower part of the solidified slag poured. The method described above was carried out using different slag-forming materials in each different one Amounts repeated and the results obtained are shown in the table below.

Kate
gorie Ver
search S.
Before the analysis
i
After of the Schm
C.
Before the olzenen M
a
After etalls (%)
1
Before the After metal Composition (leg)
Slagging material Aluminum
oxide Fluorite No. Be
plot Be
plot Be
plot Be
plot Be
plot Be
plot 275 Quick lime 7.5 6.9 I. 1 68.7 67.4 0.11 1.22 0.22 0.65 245 15.6 7.5 6.9 2 71.0 68.8 0.44 1.34 0.44 0.72 335 15.6 9 3 3 72.9 70.6 1.10 1.45 0.39 2.21 255 18th 9 S. 4th 67.2 68.5 0.88 1.36 0.64 1.96 235 18th Coals III 5 64.5 64.4 0.08 0.88 0.40 1.48 18th material powder 2 350 Coals 6th 69.1 69.1 1.02 1.31 0.77 1.74 18th material powder 2 265 - - rv 7th 70.2 71.4 0.32 1.52 0.82 0.98 290 20th - - 8th 71.8 71.4 0.31 0.55 0.60 0.58 275 20th V 9 71.8 71.0 0.38 0.52 0.67 0.59 275 10 - - 10 69.7 66.7 1.15 1.48 0.49 0.90 300 20th - - 11th 68.7 67.4 1.48 1.48 0.74 0.96 Calcium carbonate 175 20th 4.4 4.6. VI 12th 71.2 69.6 1.01 1.23 0.68 1.34 109 11th 5 - 13th 69.3 67.5 0.87 1.96 0.67 1.87 300 30th 3 VII 14th 98.5 97.5 0.15 0.90 0.10 0.53 310 20th - 3- 15th 98.2 97.2 0.20 1.02 0.08 0.61 20th

category attempt
No. Shaking time
(Minutes) Molten metal temperature ( ³ C)
Before the treatment! After treatment 1365
1380 1445
1440 1370
1490 tensile strenght
(kg / mm ² ) I. 1
2 5
3 1580
1545 1450 ^! 1340
1510 1360 1570, 1430
1595; 1420
1650, 1380 1470
1480 72.4
74.0 II 3
4th 3
5 1620; 1430
1590; 1400 1470
1580 56.2
60.2 IH 5
6th 2
5 1630
1600 1580
1610 69.3
61.7 IV 7th
8th 4th
4th 73.5
70.7 V 9
10
11th 4th
4th
4th 65.2
63.7
63.9 VI 12th
13th - 52.4
35.5 VII 14th
15th 2
2 71.3
74.0

Remarks:

No. 12. The molten metal was vigorously stirred for 3 minutes by introducing green wood. No. 13. The molten metal was vigorously stirred for 5 minutes by introducing green wood.

Using the alloys thus prepared, spheroidal graphite castings were made, and the tensile strength of the individual nodular cast iron was measured in the manner described below.

In a basic-lined electric arc furnace with a capacity of 50 kg, 50 kg of scrap steel were produced introduced with the addition of such an amount of carbon that the carbon content of the melt drops to a value within the range of 3.8 to 4% after the slag has been removed. To the Melt became a basic flux for reduction and refining and then 800 g of one Ferrosilicon alloy to be investigated is added. The resulting molten metal was Cast in the temperature range from 1470 to 1500 ° C. The molten metal was also in poured a separate ladle in an amount of 10 kg, and after adding 300 g of the to be examined Ferrosilicon alloy for this purpose, the molten metal immediately became a stacking block potted with a wall thickness of 40 mm, to be a test piece of the Japanese Industrial Standards No. 4 type on which the tensile strength of the nodular cast iron was measured.

In the table, the tests in categories I through VI were carried out with a ferro-silicon containing about 70% silicon and those in category VII with metallic silicon containing about 98% silicon. The tests in Category VI were carried out with vigorous stirring of the molten metal without shaking the pan with the aid of gases which developed strongly after green wood was placed in the molten metal. In these cases the tensile strength of the cast irons produced was not higher than 60 kg per mm ² , ie lower than that of the cast irons in the other tests. This fact proves the need for shaking. Tests No. 3 and 4 in Category II are representative of many tests by which it was found that a tensile strength of a cast iron of 60 kg per mm ² or higher cannot be expected if the temperature of the molten metal is not after the end of the shaking process is higher than 1350 ° C. The structures of the spheroidal graphite castings obtained from Experiments Nos. 1 and 6 are shown in the microscopic photographs of the drawing at a magnification of 120 times.

1 sheet of drawings

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209 511/223

Claims (1)

1 2 suggested such alloys that are made from no more Claim: as 90% iron and from 10 to 99% silicon as the base components with an addition of not more than Process for the production of ferrosilicon- 4% calcium, not more than 10 ⁰ J ₀ aluminum, alloys for use as an additive at 5 not showing the total value of the calcium multiplied by 10 of the production of nodular cast iron, geke η n percentage and the aluminum percentage by the following, sometimes smaller than 3, not more than 0.05% silica or known process steps that one silicate and impurities, which inevitably in such alloys are introduced, together a) lime or limestone in a ladle are set one ^tenth brings that with basic refractory material Die in the process of said Japanese is lined that a minimal amount of patent specification 300 442 used ferrosilicon Le- Silicon oxides containing alloys were previously prepared by b) the cup is heated until the temperature of the off pieces or chunks of clothing increased surface commercially available at about 1000 ⁰ C ¹ S Fetrosiliaums m rnit a magnesium oxide excluded ■ _t dressed Heroult furnace is introduced, the Ferrosihcmm m . . ' , ".,. . _T. . the furnace with the addition of a slag-forming c) a molten ferrous silicon alloy in _{material of} quick lime, dolomite and fluorite melts, which brings in Pianne, _{the gescmno} i _zene ferrosilicon can stand still d) removed, and then the molten a temperature of at least 1500 ⁰ C ferro-silicon is poured, the molten metal in the ladle slag at ₂₀ in a mold. The spheroidal graphite cast iron produced with the in holds, the molten metal in the ladle in the manner described, a shaking motion produced by eccentric alloys has a rotation of the ladle granted until the reaction tensile strength in the range of 50 to 80 kg / mm ² . However, that is finished while maintaining the molten _a5 tensile strength varies widely from cast iron to metal at such a high temperature, cast iron, and it is extremely difficult to obtain a cast iron that, after the reaction has finished, it has a uniform temperature of a desired tensile strength at least 1350 ° C. In addition, since the process was based on the ^{un (} i use of cold ferrosilicon as starting material) e) pouring the molten metal into a mold. 30 material was produced, the loss of silicon large as a result of oxidation during the melting process, with the percentage of silicon available is at most only 90%. 'Experiments, varying the known procedures 35 ferrosilicon alloys to produce, whereby one instead of cold, melted ferro-silicon and a layer of magnesium oxide The invention relates to a method for clad pouring ladle applied, did not lead to Manufacture of ferrosilicon alloys for use- success because the alloys obtained have a ball as an additive in the production of spheroidal graphite cast 40, its tensile strength in wide cast graphite. Limits varied and overall was too low. It is from the German Auslegeschrift 1030 037 Furthermore are from the German Auslegeschrift known, known in the implementation of metallurgical 1 270 822 silicon aggregate alloys, deReaktionen between molten metal and solid, ren functionality depends on the liquid or gaseous reactants an oxygen content is limited to below 0.004%. Use a separate reaction vessel (shaking pan) to reduce the oxygen content to one and as a reactant pulverized lime at such a low percentage are extremely expensive set. It acts z. B. in steel baths the lime required as a measure. Also play at this one Means for removing impurities, in particular alloy, other constituents such as Mn and especially for binding silica. In this way 50 Ca plays an essential role one cannot produce ferrosilicon alloys, for the large-scale production of spheroidal graphs which phitguß come to the use of good nodular cast iron these known alloys would be suitable. Additives are practically out of the question, since their position in Japanese patent application 24 212/64 is too complicated and the way in which the production of spheroidal graphite cast iron works by adding 55 is dependent on too many variables.
a ferrosilicon alloy that is only available from the German Auslegeschrift special Ca, Al and SiO ₂ content leads to success. 1 213 088 Burner for drying and heating of This Japanese patent for the casting of liquid metals is known about the special production of pans, converters and the like that are particularly good for transport and a suitable alloy. After that, nothing should be taken from the message. 60 heating up before filling a pan as well In Japanese patent specification 300 442, a mold holding association is required in order to achieve the drive to the production of nodular cast iron by jumping the lining when filling the pans wrote to prevent iron alloys with ferrosilicon. Here is a procedure, with special levels of carbon in certain regardless of the type of filling, especially the Shares will be merged. However, not every 65 aggregate is intended. One such process-ferrosilicon for use in this process guide is for the production of the invention suitable. Ferrosilicon alloys provided as suitable ferrosilicon alloys are completely unrecognized in the Japanese patent application 24 212/64, since it is here, among other things, for the setting