JPH03134111A - Filling wire for treating molten metal treatable at a constant depth - Google Patents

Abstract

PURPOSE: To make it possible to melt a coating over the entire circumference at the same speed and to introduce a powdery treating maternal into molten metal by forming a coating layer consisting of two layers formed by winding a hoop around the treating material and seaming the hoop in superposition.

CONSTITUTION: The filler wire 1 is formed by winding the coating made from the hoop 7 in two layers 3, 4 on the circumference of the treating material 2. The two side edges 5, 6 of the coating are parallel with the axis X₁ of the wire 1 and one thereof exists on the inner side of the coating and the other on the outer side. These edges are constituted in proximity to each other via the thickness of the hoop 7 and the powdery or granular treating material 2 is solidified therein.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the treatment of metal baths having a certain depth, and is particularly suitable for the treatment of steel baths having a relatively shallow depth of, for example, 2 meters or less. The invention relates to a filling wire.

[Conventional technology]

The treatment of metal baths with filler wire is well known. French Patent No. 2,476,542 describes composite tubular products in which a generally compacted pulverulent or granular treatment substance is contained in a metal clad tube. Sealing of the covering is accomplished by caulking along its generatrix. Other methods of closure of the covering may also be used.

Welding with good sealing and without overfilling has the drawback of being relatively expensive and most often of altering the compositional properties of the processing materials used.

Closure of the sheath by single overlapping as described in Japanese Patent Publication No. 56-32369 has great practical simplicity as disclosed in this publication. - Heavy overlapping is suitable for applications that do not require very high stiffness, even without good load-bearing properties such as caulking or welding.

Caulked filler wire is very commonly used. In particular, these filler wires are used for processing steel in tins. In this case, the depth of the steel bath is generally more than 2 meters.

The speed at which the filler wire is introduced into the steel bath usually depends on the temperature, depth and thickness of the steel bath, so that melting of the coating takes place at a depth near the bottom of the ladle. adjusted. However, the thickness of the caulked part is 3 to 4 times thicker than that of the non-caulked part, and therefore the caulked part melts later than the non-caulked part, and often deviates from its initial trajectory while remaining in the steel bath. However, this is usually not a significant drawback.

In many cases described in Japanese Patent Publication No. 56-32369, a local double thickness of the coating is used in the case of partially overlapping filling wires which provides sufficient protection of the material being treated. The overlapping portions forming the layer retard the end of melting of the coating.

In that case, the lower part of the coating overlap continues to be introduced into the steel bath, as in the case of the caulked filler wire, but the depth of this introduction is shallower than that of the caulked wire and melts. Therefore, there are no major problems in processing the steel bath in a deep ladle.

On the contrary, when using filler wires with a covering closed by caulking or by partial overlap for the direct processing of steel baths in the molds of continuous casting installations, immediately after the wire introduction A phenomenon occurs in which some of the base metal and coating attached to the wire are not completely dissolved.
The problem arises of material non-uniformity.

[Problem to be solved by the invention]

Under these conditions, it is necessary to precisely adjust the introduction speed of the filler wire and the thickness of the coating in order to obtain dissolution of the coating at a predetermined depth and dispersed dissolution of the treatment substance. turns out to be difficult.

In fact, in the case of multilayer coatings, some parts of the coating, including the bare metal that adheres to the wire immediately after the wire is introduced, do not completely dissolve and become undissolved residues within the slab, resulting in uneven areas. The heterogeneous portion may contain small amounts of treatment substances.

These failures occur whenever an attempt is made to introduce the filler wire into a shallow bath. In the case of steel, this situation is found, for example, when the wire is introduced into tumble brushes, grooves, ingots, etc. These obstacles can also cause problems associated with non-uniform thickness of the wire coating when the temperature of the processing bath is close to or below the melting temperature of the wire coating used. It can happen in some cases.

[Means to solve the problem]

The possibility of producing a filled wire was investigated, the coating of which melts at the same rate over its entire circumference and which allows powdered or granular treatment substances to be introduced into a bath of liquid metal, in particular molten steel.

Furthermore, efforts have been made to eliminate the risk of delayed dissolution in crimped or overlapping areas. This delay can lead to material defects due to non-uniformities within the initial solidification zone of the steel bath in the mold of the continuous casting machine.

According to the filling wire that is the object of the present invention, the following results can be obtained.

This filling wire, which has a generally circular cross section, is capable of processing steel baths and contains a compacted powder or granular processing substance. This material is contained in a sheath made from hoops. At a limited depth in the steel bath,
In order to ensure that the coating obtains complete dissolution over its entire circumference, this coating is created by wrapping a hoop around the material to be treated so that two layers are formed that are fastened together. . The edges of the two sides of the hoop are parallel to the axis of the filler wire, one edge inside the sheathing and the other edge outside the sheathing, close to each other but separated by thickness.

Also, the outer wall of this filler wire is separated from the outer edge of the layer separating the outer edge from the inner edge in the transition area between the first layer and the second layer, without the outer edge of the hoop protruding. It is arranged so that it is supported by a “depression” and is circular in shape.

The outer diameter of this filler wire is usually in the range 4-20+nm and the sidewall thickness is in the range 0.5-2 mm.

The invention is also suitable for the treatment with filler wires of molten steel fed to continuous casting equipment.

The filled wire with a two-layer coating created by the hoop winding of the invention is introduced directly into a steel bath placed in a continuous casting mold. This filling wire with a roughly circular cross section is either in the form of a hardened powder or
Contains particulate processing material. According to the invention, the thickness of the coating is adjusted by choosing a hoop of appropriate thickness. The rate of introduction of the filler wire into the steel bath is also adjusted so as to obtain, at a certain depth of the molten steel, a complete dissolution of the coating and a dispersed dissolution of the treatment substances contained within the coating. .

〔Example〕

FIG. 1 and the examples below provide a non-limiting description of the particular method of manufacturing the filler wire according to the invention and its use.

FIG. 1 shows a cross section of a filling wire according to the invention.

A filled wire filled with powdered sulfur as a treatment substance was produced. A mild steel hoop approximately 35+ nm wide and 0.625 mm thick was used. This hoop and the supply of processing substances,
Its winding in the next step was carried out by methods well known to those skilled in the art.

This hoop was given a packet shape similar to that described on page 3, lines 12 to 21 of French Patent No. 2,476,542;
did not match. Next, filling of the treatment substance using the nozzle was performed, and then the filling layer was equalized. Additionally, several sets of forming rolls bring the edges together so that they overlap, and other sets of rolls close down the overlapping areas until the coating has two layers around its entire circumference. The diameter of the coating was gradually reduced while simultaneously increasing the range of .

The filling is passed through one or several dies and then through the final die, tightening the second layer onto the first layer so that a perfectly circular outer contour of the coating is obtained. The cross section of the wire further shrunk a little. The figure shows a cross-section 1 of a filler wire of axis Xl containing a consolidated treatment substance 2. FIG. - Two outer layers 3 and an inner layer 4 are shown, created by wrapping a book hoop.

The outer edge 5 and inner edge 6 of the hoop are supported in the "indentation" of the layer separating the outer layer 3 and the inner layer 4 in the transition area between them. This final tightening provided good adhesion between the two layers without binder. This close contact protected the contents of the filler wire from the outside air, and the winding and unwinding operations of the filler wire were performed without significant loosening of the coating.

To give a specific example, by using a hoop with a width of 35mm and a thickness of 0.625mm, and with 11 sets of rolls and 1
With these dies, it was possible to cold-form a filled wire with an outer diameter of 7 mm. The total sidewall thickness of the coating was therefore 1.25 mm. Such a filled wire was loaded with 25 g/m of sulfur.

〔Effect of the invention〕

When using the wire according to the invention, complete dissolution of the entire circumference of the coating of the filler wire was observed at shallow depths of the liquid metal, and inspection of the produced slabs revealed that the treated slab The complete homogeneity of the filled filling and the absence of any undissolved residues of coating or metal adhering to the coating were confirmed. It should be noted that the addition yield of the treatment substance (in this case sulfur) is very high and completely reproducible.

[Brief explanation of the drawing]

FIG. 1 shows a filling wire according to the present invention. It is a pier. 1... Filling wire 3...outer layer, 5...outer edge, 7... Hoop, 2...processing substance, 4...Inner layer, 6...Internal relationship, xl...axis. Yar cross-sectional slope

Claims (1)

Claims: 1. A covering made of hoops is wrapped in two layers 3, 4 around the substance 2 to be treated to form a filling wire 1, with two side edges 5, 6 of said covering being wrapped around said filling wire. The hoops 7 are parallel to the axis (X_1) of the hoop 7, and one of them is located inside the covering and the other one is located outside, and they are arranged close to each other through the thickness of the hoop 7. Filler wire for the processing of molten metal, in particular molten steel, having a generally circular cross-section with a solidified powder or granular processing substance inside. 2. The outer wall of the sheathing does not protrude the outer edge 5 of the hoop, in the transition area between the outer layer 3 and the inner layer 4,
2. Filler wire according to claim 1, having a circular shape resting on a "recess" in the layer separating from the inner edge. 3. The outer diameter is 4-20mm and the side wall thickness is 0.5-2m.
The filling wire according to claim 1 or 2, which is m. 4. Claims 1 and 2 of adding it to a steel bath in a continuous casting mold.
or the filling wire described in 3.