KR20040012167A - Lance for converter refining - Google Patents

Abstract

PURPOSE: A lance for converter refining is provided to prevent blowout of nozzle by forming protrusion part and groove on inner and outer parts of the nozzle respectively, exclude danger of explosion by blocking inflow of cooling water into molten steel and improve quality and productivity by substantially reducing operation time required for nozzle exchange. CONSTITUTION: In a lance for converter refining comprising a nozzle(30) on which oxygen injection port(33) is formed, and a body(40) comprising an oxygen supply pipe(41) formed on an upper part of the nozzle(30), a cooling water feed pipe(42) for surrounding the oxygen supply pipe(41), and a cooling water return pipe(43) for covering the cooling water feed pipe(42), the lance for converter refining is characterized in that a protrusion part(31) is formed on a central part inside the nozzle(30) positioned under the lance for the converter refining, and a groove(32) having a certain depth is formed at an outer side of the nozzle oppositely directed to the protrusion part(31), wherein widths (W,W') of the protrusion part and groove formed on the inner and outer sides of the lance nozzle for converter refining are 1/4 to 1/3 of width (T) of the lance nozzle for converter refining.

Description

Lance for converter refining}

The present invention relates to a converter refining lance used when the high-pressure oxygen is injected into the molten metal in the refining process of the converter to remove impurities present in the molten metal, and more specifically, the inner / outer side of the converter refining lance nozzle. Protruding portions and grooves are formed in the central portion to solve the problem of puncture caused by the loss of the nozzle portion due to the overheating of the nozzle and to extend the service life.

In general, the oxygen lance used in the converter refining process is used to inject high pressure oxygen into the molten metal of the converter to remove silicon, manganese, phosphorus, carbon, etc. present in the molten metal by oxidation.

As described above, when the oxygen blowing lance which injects high pressure oxygen to remove impurities present in the molten metal of the converter is used, the ignition nozzle is formed at the center of the lance nozzle in the oxygen hole gap (-) pressure, so that it is unignited (scrap and When the oxygen is injected into the molten iron, the molten iron does not react with the molten iron and the scrap iron is scattered. There is a problem that the lance puncture (puncture) is generated by the nozzle portion for the lance nozzle overheat due to this lack.

The converter lance for scouring having the above problems is divided into a body 10 consisting of a triple tube and a nozzle 20 provided at a lower portion thereof, as shown in FIG. 1, and the inner center of the body 10 contains oxygen. The oxygen supply pipe 11 in which the oxygen injection port 21 supplied to the nozzle 20 is formed is provided. In addition, a coolant feed tube 12 is installed outside the oxygen supply tube 11 to receive an oxygen supply tube 11 and to supply coolant to cool the oxygen supply tube 11, and the coolant feed tube 12 is provided. Outside the c), a coolant return pipe 13 for returning the coolant supplied to the coolant feed pipe 12 is provided.

On the other hand, the nozzle 20 which is installed at the lower end of the body 10 and injects oxygen supplied to the oxygen supply pipe 11 into the molten metal of the converter is formed with a plurality of oxygen injection ports 21 as shown in FIG. As oxygen is injected into the oxygen injection port 21, a positive pressure is formed around the oxygen injection port 21, and a gap between the nozzle 20 and the nozzle 20 is formed with a negative pressure.

And the phenomenon in which the puncture 22 is generated in the nozzle 20 can be divided into a phenomenon occurring in the outside and a phenomenon occurring in the inside, as shown in Figure 3, when the outside occurs from the upper side to the lower side of the lance This is because hot molten slag or now flows down and attaches to the center of the lance and erodes the lance nozzle in the middle where heat transfer is poor when the current falls. When moving from the water supply to the drainage, the stagnant section of the coolant is formed on the central tip side, so that the coolant does not flow well. Therefore, in the case of stagnant cooling water, the temperature is increased and the nozzle particles at the center tip become finer, and wear is severe, resulting in a puncture.

However, in the case of the center of the tip of the nozzle, the negative pressure is formed at the peak and stagnation zone, and the frequency of the presence of the glowing iron granules is high (time). It is easy to attach and the attached steel grain or slag is severely damaged by the weak cooling ability, and the inner center part is worn out by the water pressure of the coolant falling from the upper part, so the top nozzle part is eroded up and down. Increasing nozzle usage due to replacement, production failures due to nozzle replacement, and explosion of molten steel due to nozzle punctures led to unstable operations that could not exclude large accidents.

Conventional converter lance nozzles include Japanese Patent Application Laid-Open No. 63-69152 or Japanese Patent Application Laid-Open No. 63-206420 provided with a ceramic nozzle in order to prolong the life of the nozzle. 239712 is provided.

According to the structure of Japanese Patent Application Laid-open No. Hei 8-239712, in the converter nozzle for the blowdown blower having a triple tube structure, the sleeve (S) made of Cu-WC alloy having thermal conductivity and excellent heat resistance and abrasion resistance is selected from the oxygen injection port (H). The bar is installed inside, there is an advantage to protect the oxygen injection port (H), but there is a problem that can not protect the nozzle (N) base material, there is a problem that can not prevent puncture occurrence.

The present invention has been invented to solve this problem in view of the above problems, the purpose of the external operation such as the occurrence of unignition and spitting of the phenomenon that the scrap iron is not reacted when oxygen and molten iron is not reacted when the oxygen is injected into the scrap iron and molten iron The present invention aims to provide a converter refining lance that can prevent the puncture of the lance nozzle part by developing a nozzle that can absorb the fluctuation of the condition to the maximum.

In another aspect, the present invention is characterized in that the protrusion is formed in the nozzle and the groove is formed on the outside facing the nozzle, and the coolant flow path is formed in the Laval form, thereby rapidly cooling the coolant center part and recessing the outer center part.

1 is a longitudinal cross-sectional view of a converter lance used in general,

2 is a cross-sectional view of a converter lance used in general,

3 is a cross-sectional view of a state in which puncture occurs in the converter lance nozzle,

Figure 4 is a longitudinal cross-sectional view of a conventional converter refining lance,

5 is a longitudinal cross-sectional view of the converter lance lance in accordance with the present invention;

6A to 6E are shape views of protrusions provided in converter lance nozzles according to the present invention;

Figure 7 is an excerpt of the projection and groove formed in the converter lance nozzle according to the present invention.

※ Explanation of symbols on main parts of drawing ※

10: body 11: oxygen supply pipe

12: coolant feed tube 13: coolant return tube

20: nozzle 21: oxygen injection port

22: protrusion 23: groove

L: Lance W: Width of protrusion

W ': Width of groove T: Width of whole nozzle

The configuration of the present invention for achieving the above object is located in the lower portion of the nozzle 30, the oxygen injection port 33 is formed, and is formed in succession to the upper portion of the nozzle 30 and the oxygen supply pipe sequentially from the inside ( 41) and a coolant feed tube (42) surrounding the oxygen supply pipe and a body (40) consisting of a coolant return tube (43) surrounding the coolant feed tube.

The protrusion 31 is formed in the inner center part of the nozzle 30 located below the converter lance, and the groove 32 of predetermined depth is formed in the outer side of the nozzle which opposes the protrusion.

The widths W and W 'of the protrusions and the grooves formed on the inner and outer sides of the converter refining lance nozzle are 1/4 to 1/3 of the width of the converter refining lance nozzle, and the converter refining lance The protrusions and grooves formed on the inside / outside of the nozzle are any one of a semicircular shape, a semi-elliptical shape, a conical shape, and a triangular shape.

Hereinafter, the converter lance for scouring of the present invention will be described in detail with reference to the accompanying drawings.

The oxygen supply pipe 41 serves to supply oxygen at a high pressure to the molten steel of the converter through the oxygen injection port 33 by supplying oxygen from an already prepared oxygen supplier (not shown). The coolant feed tube 42 is a tube through which coolant is supplied to cool the lance, and the coolant feed tube 43 is a tube 43 for extracting the coolant having cooled the lance. Therefore, when the lance is used, the coolant is continuously cooled while the coolant feed pipe 42 and the coolant return pipe 43 continue.

In addition, the reason why the protrusions 31 are formed in the inner center portion of the nozzle 30 is to improve cooling ability, and the thickness, that is, the width W of the protrusions 31 is equal to the overall width T of the nozzle 30. The groove 32, which is formed between 1/4 and 1/3, and is formed in the outer center portion of the nozzle 30, also has a width W 'similar to the protrusion 31, and has a width W' of 1/4 to 1/3 of the entire width T. Form between 3 In addition, the protrusions 31 and the grooves 32 may be formed by selecting any one of a semi-circle, a semi-ellipse, a cone, and a three-corner shape, so that the protrusions have the same shape when the center portion is cut at right angles. Formed.

The reason why the width W of the protruding portion 31 is regulated to 1/4 to 1/3 of the width T of the entire nozzle 30 is less than 1/4 if the cooling capacity is similar to that of the conventional art and is larger than 1/3. The cooling ability of the protrusion is great, but the cooling ability of the nozzle of the center portion of the outer tip, which is the original purpose, is inferior to the conventional art.

And the groove 32 is formed in the outer center of the nozzle is the iron granules attached to the gap of the oxygen injection port 33 and even if the iron granules and scattering is attached to give a space so that they can go away immediately without heat transfer to the central center portion Since the film is formed inside, it prevents adhesion again and delays or stops the process of melting.

Hereinafter, the converter lance for scouring of the present invention will be described with reference to Examples.

(Example)

As a result of the experiment on the three-hole nozzle in the 100Ton converter, the cooling water pressure was supplied at 16kg / m ³ and the flow rate at 160Ton.

Nozzle Depression depth (mm) Protrusion thickness (mm) Depression area (mm) Protrusion area (mm) Coolant Flow Cooling water pressure Cooling water passage Conventional example 3 ball none none none none 150 15 Normal Invention 3 ball 11 20 22 25 160 16 Laval Comparative Example 1 3 ball 9 15 18 20 150 17 integrated Comparative Example 2 3 ball 13 23 25 28 150 16 integrated Comparative Example 3 3 ball 6 16 15 17 160 15 integrated

In addition, the comparative example and the present invention were found to be a significant improvement in the lance life as a result of practical application and it was found that the nozzle thickness is good after erosion as shown in Table 2 below.

Center Tip Lance Structure Lance Life (Number of Uses) Nozzle central crystal structure Residual thickness after use for 100 companies Conventional example Upper and lower square 131 Fine grain 7 mm (initial 22 mm) Comparative example Groove forming 148 Fine grain 5 mm (15 mm initial) Comparative example Protrusion Formation Lance 142 Coarse grain 21 mm (initial 28 mm) The present invention Groove and protrusion formation lance 195 Coarse grain 21 mm (initial 22 mm)

The present invention as described above, by forming the protrusions and grooves in the inside and outside of the nozzle to prevent puncture of the nozzle to extend the service life, as well as to prevent the inflow of the coolant in the molten steel due to the prevention of the nozzle central puncture explosion There is an effect that can exclude the risk of, and also due to the drastically reduced work time due to the replacement of the nozzle to the puncture of the nozzle has the effect of improving the quality as well as the yield.

Claims (3)

A nozzle 30 having an oxygen injection port 33 formed thereon, a cooling water feed pipe 42 which is connected to an upper portion of the nozzle and surrounds the oxygen supply pipe 41 and the oxygen supply pipe, and a cooling water return pipe surrounding the cooling water feed pipe ( In the converter refining lance consisting of a body 40 consisting of 43), A converter 31 is formed in the inner central portion of the nozzle 30 positioned below the converter lance, and a groove 32 having a predetermined depth is formed outside the nozzle facing the protrusion. Refining Lance. According to claim 1, wherein the width (W, W ') of the protrusions and grooves formed on the inside / outside of the converter refining lance nozzle is 1/4 to 1/3 of the width of the converter refining lance nozzle (T). Converter lance lance. The converter refining lance according to claim 1, wherein the protrusions and the grooves formed on the inside / outside of the converter refining lance nozzle are any one of a semicircular shape, a semi-elliptical shape, a conical shape, and a triangular shape.