DE1758134B1 - Process for casting ferro-alloys - Google Patents

Description

The expression "iron alloys" or "ferrous

alloys "as it is used here, includes ίο the solid casting a segregation or segregation

Compositions of iron with one or more of the elements silicon, chromium and manganese. This definition specifically includes pig iron with a high silicon content, ferrosilicon with 40 to 99% silicon,

can take place.

Furthermore, from the Swedish patent specification 103 824 a method for potting in layers known from ferro alloys in casting molds

high-carbon ferrochrome, feed 15 which the next following layer only then

chromium (standardized and grades with high silicon content), ferrochrome silicon with low Carbon content, silicon manganese, ferromanganese with a manganese content of 86% and more. Although

is poured onto the previous layer when it is substantially solidified. The purpose this method consists in making it easier to break up the layered metal cake because

the invention in relation to the casting of Ferro- ao in the procedure described only a very ge

ring welding of the individual layers at the point of impact of the pouring stream.

Finally, from Osann, "Eisenhüttenkunde", Vol. 1 (1923), p. 780, a method is known in which Iron alloys, namely pig iron, which has only a relatively low content of alloy components has or slags are poured in casting beds. The walls of the casting beds exist made of a metallur-

there is only a negligible loss of material in their handling and transport.

To solve this problem, the invention provides that the ferro alloy in a ground level bed

or iron alloys is described, it goes without saying that it is also applicable to the casting of other metals and alloys which have similar or identical physical properties Have properties.

In the manufacture of ferrous or. Iron alloys Silicon and / or metallic ores are reduced to molten metal in an electric furnace generate at temperatures that are substantial

higher than those normally found in the 30 gisch compatible material.
Melting of most types of iron and steel The invention is based on the object of being used. For example, the process can be created, which makes it possible in a simple and economical way of 50% ferrosilicon, dense and homogeneous 1620 ° C or more. The conversion of the ferro-alloy pieces of the desired size to molten alloy in a non-porous homo-35, which, moreover, are so abrasion-resistant that gene alloy in lump form is difficult and with
associated high costs.

It is known to have the molten alloy in
Cast iron mold or chill molds to pour which with
Graphite are coated or is poured into shell molding sand 40, the bottom and the side walls of which or another material which serves to adhere to or fuse with the mold composition of the cast alloy from an essentially material composition or to prevent mold. In such forms the granular material has been produced and the molten alloy is normally poured in until after cooling has taken place the layered ferrous alloy to a depth which is in the range of 45 alloy with the aid of a shovel loader or the like below about 10 to 36 cm . When the melted
Metal has solidified, but before it has cooled to the temperature at which it was lifted out
Due to the stresses that occur (uneven thermal contraction), cracks show a layer thickness of 5 to 20 cm in the bed or would break, the casting is made from.

Taken out of the form in order to reduce the cooling to the

To finish ambient temperature. The special pouring of sand and graphite or thin layers, which is envisaged on top of each other, must then be cleaned of sand and graphite or thin layers, with these layers being repeatedly cleaned of other foreign matter that is heated and cooled again, arising in its surface. The cleaned casting has individual layers of cracks which, upon removal, are then broken or ground to get it on
Shrink pieces of the size you want for their intended use. In the case of Ferro

being lifted out of bed at the same time as breaking.

According to an advantageous development of the invention it is provided that the ferro alloy with

Layered body from the mold facilitate breaking significantly or the reason for that, for example in the case of the use of an essentially

alloys for a steel-making furnace, the 60 borrowed ground-level cast bed is used to

Ferro-alloy preferably broken into pieces of more or less uniform weight or screen size, from Z. B. less than 34 kg (maximum weight per piece) or a size of 20 X 10 cm, 12.7 X 5 cm or 10 X 2.5 cm as specified in the American Society for Testing Materials (ASTM) standards is specified. The size dimensions refer to the opening of the sieves. The aforementioned ma-

means of a shovel loader can be removed from the mold and thereby automatically in the desired Pieces break, so that additional breaking devices and the like are superfluous.

It is of particular importance that the size is easily determined by choosing the layer thickness the resulting fragments can be influenced and determined. Is of particular importance

3 4

further that the physical properties of the also provided around or in front of a rigid structure fragments obtained, due to the specific nature of the product, if it is desired to repeat the product Warming and cooling processes, extremely to hold or to protect and to support them. These are favorable and due to the individual layer walls are expediently up to a height th of a layer block already existing fracture S of about 1.2 m or higher built so that they a lines only a very small amount of waste, d. H. accommodate a very considerable depth of cast metal small amount of parts that cannot be made within the, and they can actually move to a larger one Desired order of magnitude are to be built in purchase height when the casting process is continued must become. strides. The bed including the retaining walls The use of a cast bed from a cor- io can expediently be produced by nigen, metallurgically with the alloy to be cast, a heap of the granulated material that forms the bed In foundry technology, material is indeed terials with a leveling device, a small bullnothing Unusual, but spread in connection with a dozer, a muzzle loader or the like, the other features of the new patent application The material from which the bed is made, considerable advantages are thereby achieved, which should be achieved with the alloy cast in the bed especially from the combination of the special casting compatible. This is the case with the invention steps and the use of such a cast bed-forming granulated material essentially bed surrendered. from residues or grit of the material, which is z. B. the casting bed produced in that it is to be potted. For example, at Giedas The bed is formed from a grain of ferro-silicon using a leveling device nigen, in particular from residues of the ferrosilicon grit to be poured, which was obtained from the sieving of the previously ßenden material existing material produced cast batches is obtained. However, it lies is, after the casting process, the material within the scope of this invention, for example by means of a shovel loader directly from other granulated materials for the casting bed dug the ground-level cast bed, using 35 if such materials are able to use the already hold the desired hot material during this excavation and are not of the type Alloy pieces are obtained because of the layer- that they are an intolerable contamination of the end block cause products according to the horizontal separating layers. For example, ferro- and the vertical tear lines in the desired mangangrus can be used as a bed for the Gie manner breaks when excavating. 30 ounces of silicon manganese and some other manganese

It is obvious that in this way a containing alloys.

particularly economical production of the required Since one aim of the invention is to

Ferro alloy pieces is made possible because of a large material handling cost and labor cost too

Casting bed can be produced without special effort, it is desirable to prepare a bed,

which can and no special 35 which a complete batch or a complete one can break

Breaking devices are required. Racking or a full pan filling of the melted

The invention is in the following, for example, on zenen alloy, as can be taken from the

Hand of drawing described; in this shows electric furnace comes. Since the approximate volume of a

F i g. 1 a molten alloy known from such batch to be cast can be the

a ladle is poured into a casting bed, 40 area of the bed to be made from the grit is

F i g. 2 the laminated or layered cast structure, must be tuned to provide a depth or thickness of the

which is excavated from the bed, and cast metal in the bed to produce the

F i g. 3 to meet in detail the type of laminated or the requirements of the work process,

layered casting, in which the remaining part is The alloy to be cast can be poured directly into one of the

shows after a part has been dug away. 45-like bed from the oven or from a pan 13

In practicing the invention, a will be poured. To prevent the possibility

Casting bed 10 prepared in which a suitable measure that the bed erodes or during casting

material in fine particle form or granulated form cracks or breaks, especially in the case of the first or

on the furnace floor or in a corresponding initial molding in the bed, it is desirable to have one

is distributed to the neighboring area. Use the surface, 5 ° pouring spout or pouring spout 14 to

on which the bed is placed, concrete or via the pouring funnel can be poured onto a heap 15 of large

Pour earth or an area with a black top or a product that is suitable for this purpose

be another face; however, concrete is best placed to place on the bottom of the bed

suitable to select the distance of the product to the impact energy of the flowing material flow.

support and avoid contamination. 55 end of the casting process to absorb. It can

The bottom 11 and the walls 12 of the bed have several such beds in the same casting area

a thickness sufficient to allow the infusions to be formed close to each other, with a dam

to keep molten alloy so that it is not made of granular material as a common wall

these are penetrated. The bottom of the bed is used for adjacent beds, as is the case in the

should have a depth or thickness of about 15 to 20 cm 60 F i g. 1 and 2 is shown.

to have. The same granulated material is mixed with the first batch of alloy directly into the

greater depth or thickness around the perimeter of the bed cast to a cast of molten

tes piled to form the walls or dams 12 into alloy of a desired depth or thickness.

form, around the molten metal poured therein, which with the physical or material

to keep. These walls or dams can be made from 65 requirements or standards that conform to

unsupported heaps of the granulated material affect the market or sales requirements of the subject

and are set to their natural angle of repose absorbing product, usually in

be slanted. The walls or dams could be of the order of 5 to 20 cm. That so

Cast metal is then allowed to cool and solidify to form the base layer 16 of the cast alloy to build. The cool down time is usually a few hours. In accordance with the alloy produced, an electric furnace can be tapped at such time intervals that, either With the help of or without the use of a holding vessel, the previously cast metal can do this will solidify and cool enough so that the bed can accommodate the next batch. A second batch is then poured directly onto the previously cast metal, which is now sufficient is cooled to a connection or an adhesion or a fusion or amalgamation of the Avoid layers. This sequence can continue until a large number of consecutive ones Layers 17,18,19 of cast metal are built up in the bed. For example, twelve can Batches are cast in a single bed in this way to form a cast structure or build-up from twelve layers, each having the desired thickness.

In order to remove the cast alloy from the bed, a mechanical device, e.g. B. a Muzzle loader 20, used, which is in the bed by as one of the granulated walls digs into it. It was found that the metal used in the previously described Way was poured, easily breaks along the levels, which the successive Layers of the layer structure separates and that continues the pieces of each individual layer tend to break into pieces that are length and width relative to thickness; H., the thicker the layer, the larger the piece size. In some cases, the alloy can be like them broken and taken out of bed can be used for the intended purpose, for example as part of the charge in a furnace for making steel. In other cases it must the product, when it is dug out of the bed, must be sieved to separate the gravel that can be re-used to make additional beds for further casting operations. In other cases, the material dug out of the bed may be ground or crushed before it is sieved.

The basic requirement for the granular material used to make the casting bed, including the floor and supporting sidewalls or levees, is that it must be able to contain the hot metal and not significantly contaminate the cast product by it undesirably alloys with it or by being trapped as inclusions or by adhering to the surface. It is evident that if the granulated material used for this purpose is of the same composition as the metal to be cast, any alloy or inclusion that may take place will have no effect on the composition of the final product and that it will not be detrimental is when something of this material adheres to the surface. In either of these circumstances the effect is neither detrimental nor even to be welcomed. Some of the fine particles or grit that would otherwise be waste material is incorporated into the product and becomes salable. It has been found that a grit of less than 12.7 mm gm is very suitable as a material for the casting bed. ™

Claims (2)

Patent claims: 1. Process for casting ferro alloys with at least 40% alloy components in lump form, in which the molten alloy is poured into a casting mold in layers the next following layer only then on the layer below is poured when it has already solidified, characterized in that the ferro-alloy is poured into a bed at ground level, the bottom and the side walls of one granularly corresponding essentially to the material composition of the cast alloy Material have been produced, and that after cooling has taken place, the layered ferro-alloy with the help of a shovel loader or the like. Lifted out of bed while breaking at the same time will. 2. The method according to claim 1, characterized in that the ferro alloy with a ^ Layer thickness of 5 to 20 cm is poured into the bed. 1 sheet of drawings