RU2115745C1 - Tip of oxygen-converter lance - Google Patents

Abstract

FIELD: ferrous metallurgy, in particular, designs of devices for blowing of liquid melt with oxygen in converter. SUBSTANCE: tip has upper plate, separator, blowing nozzles and lower copper plate provided with adapting steel ring with supporting unit on which separator of internal hollows for supply and discharge of cooling agent is freely mounted. Supporting unit is made in the form of projection on lower part of adopting ring. Projection is made with through passage channels communicating tip internal hollows with one another. Through passage channels may be made in projection body to form in plan a row of uniformly spaced over circumference alternating projections and depressions. EFFECT: simplified manufacture, higher stability, maintainability and reliability of lance. 2 cl, 3 dwg

Description

 The invention relates to ferrous metallurgy, in particular to the design of devices for purging a liquid melt with oxygen in converters.

 Known tuyere for blowing cast iron in the converter, containing three concentric pipes, the inner of which has a metal hose compensator, and the separation pipe is a compensator of a pair of telescopic sleeves. A nozzle is attached to the pipes, including nozzles, an end plate-shaped plug of the central pipe, a cooler flow separator with stops and a bottom plate. Lances of this type have found wide application mainly for large-capacity converters, since they provide maintainability by repeatedly mounting new tips to the old tail end of the lance (ed. Certificate of the USSR N 857270, C 21 C 5/48, 1981).

 The disadvantage of the tip of such a lance is the large mechanical load on the nozzles and bottom plate arising from the oxygen pressure in the pipeline, which leads to low resistance of welds between the plate and nozzles made of technically pure copper. Moreover, the weld between the copper bottom plate and the steel outer pipe, on which all power loads from oxygen and cooling water are closed, is also not reliable enough. For oxygen tuyeres of 370-ton converters, the load on the external weld reaches 16 tons. Destruction of this weld can lead to separation of the head and a major accident.

 A lance head is known, including a base, oxygen pipes and a shell fixed to the base by means of blow nozzles. The shell is additionally attached to the base of the oxygen pipe with at least one rod placed in the inter-nozzle space mainly along its axis. The presence of a rod tie allows you to hold the bottom of the lance head from thermal deformation when welding it with nozzles, and also increases the rigidity of the central part of the bottom. A similar idea was also used in autosvid. USSR N 1652358, C 21 C 5/48, 1991.

 However, these tips also have low resistance to welds between the copper shell and the mating parts due to high mechanical stresses from oxygen and water, as well as from thermal stresses associated with fluctuations in the temperature of the walls of the nozzles. Moreover, the thermal stresses in the joints in the presence of screeds increase.

 Closest to the proposed invention, selected as a prototype of the invention, is an oxygen converter lance tip containing an upper plate, a cooler flow divider, blast nozzles and a lower copper plate equipped with a transition steel ring to which hook-shaped pendants are evenly spaced around the ring circumference ( RF patent N 2051974, class C 21 C 5/48, 1995). On the cantilevered protrusions of the hook-shaped suspensions, a common seating surface is made on which a separator is mounted.

 The disadvantage of the prototype is the welded joint of the most critical node of the tip - hook-shaped suspensions with a transitional steel ring, on which the separator, which accepts the main static and dynamic load, is supported, as well as the relatively high complexity of the manufacture of the tip, which is a determining factor for large volumes of production of such tips. In addition, welds have lower thermal conductivity than the material of the parts connected by these seams, which impairs its cooling during operation.

 In the prototype, the main power welds between the transition steel ring and hook-shaped suspensions, on which the divider rests, are subject to increased requirements, and therefore, welding is carried out with special care and with mandatory control tests of the finished product and monitoring the state of the tip during operation tuyeres.

 In the practice of steelmaking, due to major accidents, tuyeres that have worked out their maximum standard resistance are removed, as a rule, from service while their performance is still quite satisfactory.

 The objective of the invention is to simplify the manufacture, as well as increase the durability, maintainability and reliability of the lance.

 The solution to this problem is ensured by the fact that the tip of the oxygen-converter tuyere contains an upper plate, a separator, blast nozzles and a lower copper plate equipped with a transition steel ring with a support assembly, on which the separator of the internal cavities for supplying and removing the cooler is freely mounted, according to the invention, the support assembly made in the form of a protrusion on the lower part of the transition ring, while the protrusion is made with through passage channels, through which the internal cavity of the tip communicated between at home. Through passage channels can be made in the body of the protrusion with the formation in terms of a number of evenly spaced alternating protrusions and depressions.

 In FIG. 1 shows the proposed tip of the oxygen-converter tuyere; in FIG. 2 is a view of FIG. 1 on top; figure 3 conditionally shows an embodiment (a fragment of the transition ring with shaped in terms of the shape of the passage channels).

 The tip contains an upper plate 1, a separator 2, blast nozzles 3, a lower copper plate 4, a transition steel ring 5 with an annular bead 6 and intermediate elements 7. The protrusion 6 of the transition steel ring 5 is provided with a seating surface 8 under the bearing surface of the separator 2. By means of the separator 2 the internal cavities of the tip are divided into the inlet and outlet (for the cooler) cavities. In the body of the shoulder 6 are made (by drilling, milling, etc.) pass-through channels 9, designed to pass the cooler.

 The proposed device operates as follows.

 The tip is welded to the tail of the oxygen lance, which has metal-hose and telescopic compensators on the inner pipes, the lance is connected to the supply and exhaust pipes of cooling water and oxygen, lowered into the converter and the melt is purged with oxygen. During the purge from the pressure of oxygen on the plate 1 and water on the plate 4, an axial force arises, which is mainly perceived by the ring 5 through the protrusion 6. The number of holes or alternating protrusions and depressions (channels) 9 for passing the cooler is selected from the conditions of strength and thermal conductivity. In practice, in the manufacture of tips, they are guided by the conditions of strength with a minimum thickness of jumpers between holes (or alternating protrusions).

 The presence of support in the form of a single part, perceiving the main load, improves the reliability of the device. Quite complete unloading of the welds on the nozzles and lower plate from mechanical forces, as well as from thermal stresses arising from temperature fluctuations, is practicable. Moreover, the design provides free radial expansion of the outer ring 5 relative to the separator 2 at thermal deformations, which unloads the outer circumferential seams from this type of load. As a result, the resistance of the tuyeres increases. Due to the fact that the transition steel ring is made with a protrusion 6, the axial loads are uniformly distributed around the circumference of the steel transition ring 5, while the conditions of heat transfer are improved and the danger of separation of the copper plate 4 is completely eliminated.

 In addition, the complexity of manufacturing the tips of oxygen-converter tuyeres was reduced and the reliability of their operation was increased, since there was no danger of the tip breaking off due to the destruction of the welds under the action of axial loads, since these loads are perceived mainly through the protrusion 6 by a steel ring 5 and transferred to the outside lance steel pipe (not conventionally shown in the drawing).

The practical resistance of the proposed tips on converters with a cage of 370 tons and a purge intensity of 1400 m ³ / min is over 250 heats on the best samples and 200 heats on average per converter campaign.

Claims (2)

 1. The tip of the oxygen-converter form, comprising an upper plate, a separator, blast nozzles and a lower copper plate equipped with a transition steel ring with a support unit, on which the separator of the internal cavities for supplying and removing the cooler is freely installed, characterized in that the support unit is made in a protrusion on the lower part of the transition ring, while the protrusion is made with through passage channels, through which the internal cavity for supplying and removing the cooler communicated with each other.  2. The tip according to claim 1, characterized in that the through passage channels are made in the body of the protrusion with the formation in terms of a number of evenly spaced around the circumference, alternating protrusions and depressions.

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