JPH08246020A - Lance nozzle for blowing-in converter - Google Patents

Abstract

PURPOSE: To extend the service life of a lance nozzle by fitting and extending a reinforcing material in the longitudinal direction of oxygen jetting holes for blowing. CONSTITUTION: In the metal-made lance nozzle excellent in heat conductivity, plural oxygen jetting holes 5 for blowing and a cooling water 4 passage are arranged. Gaseous oxygen is jetted at high speed from the oxygen jetting holes 5 for blowing. A rib 8 as the reinforcing material for supporting the inner wall of the oxygen jetting holes 5 for blowing is arranged for resisting the stress of deforming the circular cross section of this hole 5 into a flat or an elliptical shape. The rib 8 is fitted and extended in the longitudinal direction of the jetting holes 5 and supported with a fitting 9. The reinforcing material (rib) 8 is made of a stainless steel, copper or copper alloy, and the shape thereof is made to I-type, triarrow-type or cross-type. By this method, the flow of the oxygen jet can be kept in a prescribed flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter blowing lance nozzle, and more particularly to a converter blowing lance nozzle which prevents thermal deformation of the blowing oxygen blowing holes at the tip of the lance due to radiant heat.

[0002]

2. Description of the Related Art Conventionally, as a lance nozzle for blowing a converter, a lance nozzle made of copper or a copper alloy and a cooling double water pipe for cooling the lance nozzle are integrally used. On this occasion,
It has been a problem that the tip portion of the oxygen blowing hole for blowing, which blows an oxygen jet onto the molten steel surface, is greatly subjected to thermal deformation due to radiant heat.

FIGS. 5 and 6 show an example of a conventional lance nozzle having five oxygen blowing holes for blowing. Figure 5
In the figure, a plurality of blowing oxygen blowing holes 5 are provided at the tip of the oxygen supply pipe 3, and pure oxygen is blown as a gaseous oxygen jet stream 12 onto the molten steel surface. In these figures, for cooling the vicinity of the blowing oxygen blowing hole 5, cooling water is supplied from the passage of the cooling water inner pipe 2, and the water guiding holes 7a, 7b, 7c.
The outer peripheral portion of the blowing oxygen blowing hole 5 is cooled by passing through.
At the same time, a large amount of cooling water flow can be supplied to the heat receiving surface 6, and is finally discharged through the passage of the cooling water pipe 1.

At this time, as shown in FIG. 5, the tip portion of the oxygen blowing hole 5 for blowing is repeatedly heated by radiant heat or the like.
Deformation part 13 and corner damage part 14 due to being cooled
Occurs. In particular, in the deforming portion 13, the blowing oxygen blowing hole has a flat or elliptical shape, and the gaseous oxygen jet stream 12 has its jetting direction component refracted. Therefore, stable operation during molten steel refining is hindered, and the iron yield is reduced. As a known technique in this field, Japanese Utility Model Publication No. 63-69152 discloses that
A lance head nozzle mounting hole having a cooling water passage formed therein is provided, and a plurality of grooves or holes inclined with respect to the mounting hole longitudinal direction are provided on the peripheral wall of the mounting hole, and the mounting hole has a predetermined length. As a lance for blowing oxygen into which a hollow ceramics nozzle is inserted, a technique is disclosed in which a shielding effect is provided by an oxygen flow ejected while swirling. However, the conventional ceramic tube is insufficient in the effect of preventing oxygen hole deformation due to cracking due to heat load during use.

[0005]

As a result of various analyzes on the generation of the deformed portion 13 and the corner damaged portion 14 of the blown oxygen blowing hole 5, it has become clear that the deformation is caused by a certain pattern. It was That is, repeated heating by radiant heat or the like and cooling by waiting at the end of blowing generate residual compressive strain in the lance nozzle, which is accumulated and added together with the heating / cooling cycle to expand the deformation. In the initial stage, the one-end deformed portion 13 bulges outward and contracts inward on the opposite side due to the difference in thermal expansion, and eventually changes from the initial shape to a shape with a residual deformation of about 10 mm. become.

Macroscopically, this deformation causes the components of the oxygen jet flow 12 to be bent inward, so that the jet flow as a whole is bent inward, and the jet collision path deviates from the steady position. For this reason, the fire point position, which is the oxygen jet collision position on the molten steel surface, may be displaced, which hinders steady operation. The present invention, for the purpose of preventing the above-mentioned deformation in the oxygen blowing hole for blowing, examines a reinforcing material for the oxygen blowing hole for blowing, and realizes steady stabilization in one generation of the lance nozzle for blowing. In addition, the present invention provides a lance nozzle for blowing a converter, which can extend the life of the lance nozzle and reduce the time and cost burden due to the replacement.

[0007]

Means for Solving the Problems The present invention is intended to solve the above problems, and its gist is to: (1) have a plurality of oxygen blowing holes for blowing and a cooling water passage,
In the lance nozzle made of metal with excellent thermal conductivity,
A circular cross-section of the blowing oxygen blowing hole that blows gaseous oxygen at a high speed is provided with a reinforcing member that supports the inner wall of the blowing oxygen blowing hole against the stress of deforming into a flat or elliptical shape, A lance nozzle for blowing of a converter, wherein a reinforcing material is engaged and extends in a length direction of the blowing oxygen blowing hole.

(2) At least one supporting plate for the reinforcing material has a diameter of at least one of the oxygen blowing holes for blowing, or two having a radial length fastened inside the oxygen blowing holes for blowing. The lance nozzle for converter blowing as described in (1) above.

(3) The lance nozzle for blowing a converter according to (1), wherein the reinforcing material is made of stainless steel, copper or a copper alloy.

(4) The converter lance nozzle for blowing of converter as described in (1), wherein the shape of the reinforcing material is I type, three-arrow type or cross type. The operation of the present invention will be described below.

[0011]

In a normal lance nozzle, due to repeated heat loads from molten steel, the oxygen holes as shown by reference numeral 13 in FIG. This deformation progresses with the number of times the nozzle is used, and when the deformation amount increases, the oxygen jet flow cannot maintain the predetermined characteristics.

Therefore, a rib 8 supported by a mounting member 9 fixed to the inner wall of the oxygen hole with a bolt or the like is provided in the hole void formed by the inner wall of the oxygen blowing hole for blowing, which is cooled by the cooling water of the cooling water flow 4. Set up. If there is no rib above, the thermal stress toward the center generated in the oxygen blowing hole wall for blowing due to the radiant heat from the molten steel will be entirely taken up by the oxygen blowing hole wall for blowing, and the amount of deformation of the entire hole will be large. Becomes On the other hand, when the rib 9 is provided on the wall of the oxygen blowing hole for blowing, most of the thermal stress toward the center is absorbed by the rib, the stress generated on the wall of the hole is reduced, and the deformation amount is also small. The cross section of the rib is shown in FIG. 1 and FIG.
The shape may be a cross shape as shown in FIG. 1, or an I shape and other shapes. Further, the ribs may be fastened by welding or another joining method such as caulking.

Further, if the number of ribs is increased, the degree of progress with respect to deformation is reduced, but there are problems that the production becomes complicated, the oxygen hole diameter becomes large, and the entire lance nozzle becomes large. The present invention, by providing a rib that absorbs thermal stress to the oxygen blowing hole for blowing,
Prevents deformation of oxygen blowing holes for blowing and realizes longer life of lance. The present invention will be further detailed with reference to the accompanying drawings of the embodiments.

[0014]

EXAMPLE As an example of the present invention, the oxygen flow rate is 60,000 Nm3.
For a lance nozzle with 5 oxygen holes per hour, a thickness of 10
mm, a stainless steel reinforcing plate was provided. In this embodiment, after the oxygen holes and the like are finished to a predetermined size with a lance formed by ordinary casting, tap holes are drilled in the inner wall of the oxygen holes by drilling, and stainless steel mounting brackets 9 are made by using stainless steel bolts. Installed. The reinforcing plate 8 that has been assembled in advance is inserted from the outside toward the inside of the oxygen hole, and is fastened to the above-mentioned mounting bracket using the tap hole formed in the upper portion of the reinforcing plate.

The diameter of the oxygen hole was determined so as to have the same cross-sectional area as that of the conventional nozzle.
Conventionally, the amount of deformation was 12 mm after 120 uses,
It could be 1 mm or less. The rib shape, the material, and the inlet side and outlet side diameters of the blowing oxygen blowing holes of this example are shown in FIG. Also, regarding the various ribs in FIG.
After confirming the effect on the oxygen jet itself by inserting the rib into the oxygen blowing hole for blowing, it was also confirmed that the oxygen jets coalesce after leaving the lance nozzle and the same oxygen flow as the conventional lance nozzle is obtained. did. In addition, it was confirmed that the product had a life of three times or more when it was used until the amount of deformation became a standard that required conventional replacement.

The rib as the reinforcing material of the present invention is provided on the inner wall of the oxygen blowing hole for blowing, and has a function different from that of the conventional general rib for reinforcing or cooling. When the oxygen jet for blowing is provided inside the oxygen jet hole as described above, the oxygen jet itself is divided by the ribs, and a corresponding oxygen jet flow is generated in each section. The oxygen jet shock wave visualized by a shadow graph is shown in FIG. 4 as a schematic diagram. In this figure, in the normal nozzle, the oxygen jet flow forms a single uniform jet, but in the deformed nozzle described above, the jet becomes non-uniform and the convergence is disturbed. Further, as an example of the present invention, as a result of investigating the state of the jet by the cross-shaped nozzle, the jets are divided at a very short distance from the nozzle, but they are mixed and uniform at a distance of about 5 times or more of the hole diameter. It became clear that a single jet stream was formed. This means that in the converter operation, the distance from the nozzle to the molten steel surface is usually about 1 m, so that the influence of the jetting of the jet by the reinforcing material does not pose any problem.

The rib material is preferably a non-oxidizing material such as the above-mentioned stainless steel or heat resistant steel. This is because an oxidizing material such as Al that reacts with oxygen is unsuitable, and ceramics with excellent heat resistance can be heated at a temperature of 25 ° C.
Since it is repeated at 400 ° C, it breaks and cannot be used. On the other hand, the rib length does not necessarily need to extend to the entire length of the blowing oxygen blowing hole, and it is sufficient if the rib extends at a position near the heat receiving surface, at least about 500 mm from the tip. The reinforcement effect is obtained. The tip portion means a position of 40 to 50 mm from the tip on the oxygen output side, which corresponds to the deformed portion. Further, if the rib is too thick, it will impede the oxygen jet flow. Therefore, if the thickness is preferably about 10 mm, the adverse effect does not occur and it does not hinder the operation.

[0018]

As is apparent from the above embodiments, the present invention reduces the thermal stress generated in the oxygen blowing hole for blowing by the rib inside the oxygen hole, and deforms the entire oxygen blowing hole for blowing. Can be prevented and the oxygen jet flow can be maintained at a predetermined flow. Further, it is possible to reduce the progress of deformation of the blowout oxygen blowing hole for a long period of time, and it is possible to extend the life of the lance nozzle.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline in which ribs are provided in oxygen blowing holes for blowing according to the present invention.

FIG. 2 is a diagram showing an outline in which a cross-shaped rib is provided in an oxygen blowing hole for blowing according to the present invention.

FIG. 3 is a diagram showing various ribs according to the present embodiment.

FIG. 4 is a diagram showing an oxygen jet flow with various nozzle shapes according to the present invention.

FIG. 5 is a diagram showing an outline of a conventional lance nozzle.

FIG. 6 is a view of the conventional lance nozzle taken along the line AA in FIG.

[Explanation of symbols]

 1 ... Cooling water outer pipe 2 ... Cooling water inner pipe 3 ... Oxygen supply pipe 4 ... Cooling water flow 5 ... Blowing oxygen blowing hole 6 ... Heat receiving surface 7a, 7b, 7c ... Water guide hole 8 ... Rib 9 ... Mounting bracket 10 ... Rib mounting part 11 ... Cooling water passage 12 ... Oxygen jet flow 13 ... Deformation part 14 ... Corner damage part

Claims (4)

[Claims] 1. A lance nozzle, which has a plurality of blowing oxygen blowing holes and a cooling water passage and is made of a metal having excellent thermal conductivity, has a blowing oxygen blowing hole for blowing gaseous oxygen at a high speed. A reinforcing member for supporting the inner wall of the blowing oxygen blowing hole is provided against the stress of deforming the circular cross section into a flat or elliptical shape, and the reinforcing member is provided in the longitudinal direction of the blowing oxygen blowing hole. A lance nozzle for converter blowing that is worn and extended. 2. The supporting plate of the reinforcing material has at least one of the diameter length of the blowing oxygen blowing hole or two or more of the radial length fastened inside the blowing oxygen blowing hole. The lance nozzle for blowing a converter as claimed in claim 1, which comprises: 3. A converter blowing lance nozzle according to claim 1, wherein the reinforcing material is made of stainless steel, copper or a copper alloy. 4. The converter blowing lance nozzle according to claim 1, wherein the shape of the reinforcing material is an I-shape, a three-arrow shape, or a cross shape.