WO2001042517A1

WO2001042517A1 - Method for producing injection wire

Info

Publication number: WO2001042517A1
Application number: PCT/EP2000/004631
Authority: WO
Inventors: Alexander Neretin; Juri P. Kutusov
Original assignee: Firma Caltex Gmbh
Priority date: 1999-12-06
Filing date: 2000-05-22
Publication date: 2001-06-14
Also published as: RU2152834C1; AU5069900A; DE10083732B4; DE10083732D2

Abstract

The invention relates to a method for producing injection wire, whereby calcium is fed as a material (A) to be pressed to a first pressing device (c). Said material (A) is pressed in a first pressing process (3) in order to produce a pressed strand (B), whereby the pressed strand (B) is cut according to need into a plurality of pressed blanks (C), whereby at least one pressed blank (C) is fed to a second pressing device (g). The pressed blank (C) is pressed in a second pressing process (7) in order to produce a wire (D). The aim of the invention is to be able to easily and economically produce a calcium injection wire which has a high level of reactivity and comprises favorable mechanical strength properties. To these ends, the invention provides that the material (A) to be pressed is heated to a temperature (T1) of less than 150 °C, preferably in the range of approximately 100 °C, before the first pressing process (3) and/or the pressed blank (B, C) is heated to temperature (T3) of less than 170 °C, preferably in the range of approximately 150 °C, before the second pressing process (7).

Description

Process for the production of injection wire

The invention relates to a method for the production of injection wire, wherein calcium is supplied as a pressing material to a first pressing device, the pressing material being pressed in a first pressing process to produce a pressing strand, the pressing strand being cut into a plurality of pressing blanks as required, at least one pressing blank is fed to a second pressing device and wherein the pressing blank is pressed in a second pressing process to produce a wire.

The use of calcium for the treatment of metallurgical melts is also known, as is the supply of calcium to the melt in the form of an injection wire. In order for the injection wire to be fed to a melt, it must have certain strength properties. Another essential requirement for calcium injection wire is that the wire contains only a very small amount of calcium oxides. Calcium oxides not only adversely affect the injection wire as such, but can also adversely affect the metallurgical properties of the melt. Another requirement for calcium injection wire is that it must be inexpensive. To ensure this, a simple and inexpensive manufacturing process is required.

A two-stage production process for calcium injection wire of the type mentioned at the outset is already known from RU 2 011 685 Cl. Here, the calcium has a temperature between 0.2 to 0.45 of the melting temperature of the calcium during the first pressing process due to the selected process conditions. At a melting temperature of 851 ° C, this corresponds to a temperature range between 170.2 and 382.9 ° C. During the second pressing process, the calcium pressed blank has a temperature between 0.20 and 0.35 of the melting temperature of the calcium, ie one Temperature in the range between 170.2 and 297.8 ° C. A disadvantage of the known method, however, is that the wire produced according to it leaves something to be desired both in terms of its strength properties and in terms of its metallurgical properties.

The object of the present invention is therefore to provide a method of the type mentioned at the outset with which a calcium injection wire can be produced in a simple and inexpensive manner and which has the same strength as in terms of its metallurgical properties in metallurgy requirements.

According to the invention, three alternative configurations are specified in claims 1 to 3 to achieve the object specified above. In the first embodiment according to the invention, it is provided that the material to be pressed is heated to a temperature of less than 150 ° C., preferably in the range of approximately 100 ° C., before the first pressing operation and / or that the pressing blank is brought to a temperature of less before the second pressing operation than 170 ° C, preferably in the range of about 150 ° C. In the second alternative embodiment it is provided that the material to be pressed is pressed in the first pressing device in such a way that the pressing strand emerging from the first pressing device has a temperature of less than 170 ° C., preferably in the range of approximately 150 ° C. The aforementioned temperature means the temperature that the press strand has immediately when it exits the press device. This temperature results from the sum of the previously heated inlet temperature of the material to be pressed when it is inserted into the respective pressing device, the working temperature of the pressing device and the temperature which results from the deformation of the calcium during pressing. In the third embodiment according to the invention it is provided that the material to be pressed is subjected to a mechanical surface treatment before the first pressing operation in order to remove calcium oxides from the surface of the material to be pressed.

It should be noted that the implementation of each of the three alternatives mentioned above already improves the properties of the

Calcium injection wire leads in the sense of the solution of the above-mentioned tasks. However, it is particularly advantageous if at least two and in particular all alternatives are used simultaneously in the manufacture of calcium injection wire.

When the invention came about, it was assumed that the calcium oxides on the surface of the material to be pressed, but also the calcium oxides forming on the surface of the metal during the course of the process during production of the wire, can have a very disadvantageous effect on the wire produced. It has been found that at a temperature above 60 ° C the rate of interaction of calcium as an active metal with the atmospheric oxygen increases greatly. Due to the strong heating of the pressed material or the pressed blank during pressing, a comparatively thick layer of oxides forms on the calcium in the prior art. Consequently, in the state of the art, pure calcium is not pressed during pressing, but a heterogeneous system of calcium and calcium oxide. This calcium oxide has a very strong influence on the pressing process, since it settles during pressing in the area of the die of the pressing device and the flow of the metal during pressing is uneven and thus impeded. In addition, the proportion of oxides in the pressed wire is unevenly distributed. The proportion of oxides at the end of the pressed wire is greater than at the beginning of the pressed wire.

The starting point of the invention is now the reduction in the proportion of calcium oxides before and during manufacture and thus also in the wire produced. This is taken into account according to the invention in two alternatives by reducing the process conditions with regard to the temperatures before pressing and during pressing. It has been found that preheating the material to be pressed or the press blank before pressing in the specified, comparatively low temperature range leads to a very thin calcium oxide layer. This calcium oxide layer only insignificantly hinders the respective pressing process. Due to the preheating in the specified temperature range, a lower working temperature can be used during the pressing, so that the calcium oxide layer that forms during pressing is comparatively thin and only insignificantly affects the pressed blank and in particular also the pressed wire with regard to the desired properties. Furthermore, it has been shown in the third alternative according to the invention that the proportion of calcium oxides can also be considerably reduced by mechanically surface-treating the material to be pressed before the first pressing operation, in order to thereby remove the calcium oxide layer from the surface of the calcium. This surface treatment, which precedes the first pressing, enables the first pressing device to be supplied with almost pure calcium.

In comparison tests on the one hand between injection wire produced by the known method and on the other hand by the method according to the invention, it was found that the wire according to the invention not only has a higher activity, i. H. showed a higher reactivity of the calcium, but also increased strength properties, which is important when winding and feeding the wire to the melt.

It is also particularly expedient if, during the second pressing process, temperatures are used at which the yield point of the calcium, which is about 220 ° C. during pressing, is not exceeded. The pressing blank is advantageously pressed in the second pressing device in such a way that the wire emerging from the second pressing device has a temperature of approximately 210 ° C. immediately upon exit. This not only results in a reduction in the formation of calcium oxides on the surface of the pressed wire, but also in that the pressing process of the wire can be carried out in a controlled manner and the wire can be removed and coiled in a controlled manner after pressing.

Furthermore, it has proven to be particularly advantageous that only distilled calcium in block form is used as the pressed material. The block form of the distilled calcium here means an essentially cylindrical body which, owing to the production process, has a funnel at one end. The calcium used in block form has two main advantages. On the one hand, the calcium used in block form has a comparatively small surface area, so that the calcium oxide layer possible on the block is comparatively small in relation to the total volume of the block. In contrast, when using calcium granules, the proportion of oxides is considerably larger due to the larger surface area. In addition, in particular when using the above-mentioned temperatures after pressing, a wire is obtained whose specific weight per unit length is considerably greater than that of wire made from granulate. The use of a block consisting of calcium ultimately leads during the pressing, starting from a dendrite-like structure of the calcium in the pressed material, to a monolithic structure of the calcium in the pressed blank and in the pressed wire, which has an extremely positive effect on the strength properties of the injection wire.

Experiments have also shown that, in order to carry out the method according to the invention, it is expedient to press the material to be pressed with a shape change coefficient of greater than or equal to 6 and the pressed blank with a shape change coefficient between 130 and 200.

If a block of the aforementioned type is pressed in the manner described above, a press strand with a not inconsiderable length results. In order to be able to handle such a press strand when pressing the wire, the press strand is divided into a number of shorter pieces or press blanks after the first pressing operation. It goes without saying that the cutting can also be omitted if the press strand has a length that can still be handled for the second pressing process.

Since the pressing or the production of the press strand can be carried out considerably faster than the pressing of the same amount of wire with a pressing device, it is also provided that the cut press blanks are at least partially stored after the first pressing process before the second pressing process is carried out. In this context, it is particularly advantageous that the intermediate storage is carried out in vacuo or under inert gas, so that oxidation of the calcium can be ruled out.

The wire produced according to the invention can be used directly as an injection wire, that is to say as a so-called calcium solid wire, or else as Inner wire of a covered injection wire. A steel or aluminum jacket is suitable for the jacket, for example.

When using a sheathed injection wire, it is advantageous if the pressed wire is first wound up after the second pressing process and sheathed only after the reeling. It has proven to be advantageous not to carry out the sheathing immediately after the pressing, since in this case the pressing speed would have to be coordinated with the speed during the sheathing, which can have a disadvantageous effect on the pressing process.

Further features and advantages of the invention result from the following description of an exemplary embodiment with reference to the drawing, in which a possible process sequence of the method according to the invention is shown schematically.

In the process shown in the figure, only distilled calcium in block form is used as pressed material A. The pressed material A is a single cylindrical block. Due to the manufacturing process, the pressed material has a spongy, porous structure, which is referred to as dendrite-like. The pressed material A is subjected to a mechanical surface treatment at the beginning of the process by means of a surface treatment device a, not shown in detail, as is indicated in the drawing in stage 1. In this mechanical surface treatment, the calcium oxides located on the outer surface of the material A to be pressed or the calcium oxide layer located thereon are at least substantially removed.

Immediately after the surface treatment, the pressed material A is heated in a furnace b, the working temperature of which is approximately 450 ° C. to 500 ° C. in the stage 2, for a short time until a temperature Ti of the pressed material A of preferably approximately 100 ° C. results , The preheating stage 2 is followed by the first pressing process 3 or the first pressing stage 3 in the first pressing device c after the material A to be pressed has been fed to the first pressing device c from the oven b. The pressed material A is pressed during rend the first pressing operation 3 at such a speed or at such a pressure that the extruding strand B emerging from the first pressing device c exits from the first pressing device c at a temperature T ₂ of approximately 150 ° C.

In this context, it should be pointed out that the task of the first pressing process is

1. to produce the press strand,

2. to bring about a structural change in the calcium, namely to produce a monolithic structure from the dendrite-like structure, and 3. to achieve a reduction in the outer surface of the distilled calcium and thus a reduction in the contact area with the ambient air, so that fewer calcium oxides on the surface of the Calcium arise.

After the end of the first pressing process, the pressing die of the first pressing device c being designed as a single-channel pressing die, a press strand B of comparatively large length results. Since the press strand B with the aforementioned length is not suitable for the direct processing of wire, it is cut in step 4 by a cutting device d into pieces of shorter length, so that a plurality of press blanks C results. The press blanks C are temporarily stored in stage 5 in a store e before this material is further processed in the second pressing process 7. The intermediate storage takes place in a vacuum or under inert gas.

It should be pointed out that it is also possible in principle to temporarily store the press strand B and to cut it into smaller pieces shortly before use in the second press stage.

In stage 6, the press blanks C are fed individually to an oven f and heated to the temperature T ₃ of approximately 150 ° C. Then the press blank C is fed to a second press device g, in which the second press operation 7 is carried out. The press blank C is art in the second press device g that the wire D emerging from the second press device g has a temperature of approximately 210 ° C immediately upon exit. In the second press device g, too, the press die is designed as a single-channel press die.

When a pressing process has been completed, a wire of a predetermined length has been pressed. The next pressing or extrusion process for the production of wire then follows. For this purpose, a new pressing blank C is inserted into the second pressing device g and the pressing process is started accordingly. This ultimately results in an endless wire.

While the pressing of the material to be pressed results in a reduction in cross-section from the material to be pressed and thus a coefficient of deformation greater than or equal to 6, the pressed blank is pressed with a coefficient of change in the range between 130 to 200.

After pressing or extruding, the pressed wire D is coiled in stage 8 via a coiler h. The coiled wire D can then be used directly as an injection wire if the use of solid calcium wire is desired. If, on the other hand, the use of a sheathed injection wire is desired, the coiled wire is sheathed in step 9 by a corresponding sheathing device i. For this purpose, the wire D is unwound again and coated with an appropriate sheathing, for example made of aluminum or steel.

Claims

claims:

1. A process for the production of injection wire, wherein calcium is pressed as a pressing material (A) to a first pressing device (c), the pressing material (A) being pressed in a first pressing process (3) to produce a pressing strand (B), the pressing strand (B) is cut into a plurality of press blanks (C) as required, at least one press blank (C) being fed to a second press device (g) and the press blank (C) in a second pressing process (7) for producing a wire (D ) is pressed, characterized in that the material to be pressed (A) is heated to a temperature (Ti) of less than 150 ° C, preferably in the range of about 100 ° C, before the first pressing process (3) and / or that the press blank ( C) before the second pressing process (7) to a temperature (T ₃ ) of less than 170 ° C, preferably in the range of about 150 ° C is heated.

2. A process for the production of injection wire, wherein calcium is fed to the first pressing device (c) as the pressing material (A), the pressing material (A) being pressed in a first pressing process (3) to produce a pressing strand (B), the pressing strand (B) is cut into a plurality of press blanks (C) as required, at least one press blank (C) being fed to a second press device (g) and the press blank (C) in a second pressing process (7) for producing a wire (D) is pressed, in particular according to claim 1, characterized in that the material to be pressed (A) is pressed in the first pressing device (c) in such a way that the pressing strand (B) has a temperature (T) when it emerges from the first pressing device (c) ₂ ) of less than 170 ° C, preferably in the range of about 150 ° C.

3. A process for the production of injection wire, wherein calcium is pressed as a pressing material (A) to a first pressing device (c), the pressing material (A) being pressed in a first pressing process (3) to produce a pressing strand (B), the pressing strand (B) is cut into a plurality of press blanks (C) as required, at least one press blank (C) being fed to a second press device (g) and the press blank (C) in a second pressing process (7) for producing a wire (D ) pressed is, in particular according to claim 1 or 2, characterized in that the material to be pressed (A) is subjected to a mechanical surface treatment before the first pressing operation (3) in order to remove calcium oxides from the surface of the material to be pressed (A).

4. The method according to any one of the preceding claims, characterized in that the press blank (C) is pressed in the second press device (g) such that the wire (D) at the exit from the second press device (g) has a temperature of less than 250 ° C, preferably in the range of about 210 ° C.

5. The method according to any one of the preceding claims, characterized in that only distilled calcium with dendrite-like structure in block form is used as the pressed material (A), the first pressing device (c) for each first pressing process (3) always only a single block is fed.

6. The method according to any one of the preceding claims, characterized in that a block with a weight between 25 and 100 kg is used as the pressed material (A) and / or that the pressed material (A) is pressed with a shape change coefficient of greater than or equal to 6 and / or that the press blank (C) is pressed with a coefficient of deformation between 130 and 200.

7. The method according to any one of the preceding claims, characterized in that the press blanks (C) after the first pressing process (3) and before the second pressing process (7) are at least partially stored.

8. The method according to claim 7, characterized in that the intermediate storage takes place in a vacuum or under inert gas.

9. The method according to any one of the preceding claims, characterized in that the pressed wire (D) is used as an injection wire or as an inner wire of a covered injection wire. 1/42517 ^{"1 1}

10. The method according to any one of the preceding claims, characterized in that the pressed wire (D) is wound up after the second pressing operation (7) and that, preferably, the wire (D) is sheathed only after the reeling.