JP4751238B2 - Stave cooler for blast furnace - Google Patents

Description

  The present invention absorbs stress generated by thermal expansion of the stave body and the iron skin, and particularly reduces the stress acting on the welded portion between the water supply / drainage pipe and the stave body as much as possible, and can withstand long-term use. For stave cooler.

  In the current blast furnace operation, a stave cooler (hereinafter sometimes simply referred to as a stave) is widely used as a means for cooling the furnace wall.

  In recent years, with the blast furnace operation aimed at increasing the amount of tapping and improving the efficiency of tapping, the heat load of the blast furnace body has increased more than before, and there is a need for a stave cooler that can cool the furnace body more efficiently. It came to be able to. Under such circumstances, a stave cooler made of copper or copper alloy having a thermal conductivity superior to that of a conventional cast iron stave has recently been developed and applied.

  However, when a copper or copper alloy stave cooler is applied to a blast furnace, new problems that did not exist in conventional cast iron staves have come to the surface. In other words, in the conventional cast iron stave, the cooling pipe is placed in the stave body mold in advance, and then cast to form a structure in which the cooling pipe and the stave body are integrated. It can be set as the structure without the junction part of water supply / drainage pipe.

  On the other hand, for a stave cooler made of copper or copper alloy, after forming a cooling pipe in the stave body, it is necessary to weld and join the water supply / drainage port of the stave body to the water supply / drainage pipe. It becomes the structure which has.

  In the copper or copper alloy stave cooler, the welded part in the vicinity of the stave body is the thermal expansion between the furnace inner side of the stave body exposed to high temperature and the iron side of the stave body that is cooled and radiated in blast furnace operation. When stress is generated due to the displacement due to the difference and the heat shrinkage difference, it becomes a stress concentration part, and a fatigue crack is generated at this part, leading to shortening of the life of the stave cooler.

  As shown in FIG. 6, the normal stave is attached by fixing the stave body 1 to the iron skin 6 with mounting bolts 8 and iron nuts 9 so that the load of the stave body 1 does not act directly on the water supply / drainage extraction pipe 2. The load is distributed.

  Further, as shown in FIG. 3, the water supply / drainage extraction pipe 2 of the stave cooler made of copper or copper alloy is welded to the water supply / drainage opening of the stave body 1, and the opening portion of the iron skin 6 through which the water supply / drainage extraction pipe 2 passes is The furnace water in the blast furnace is prevented from leaking outside the iron skin by welding the water supply / drainage extraction pipe 2 and the iron skin 6 through the seal plate 5.

  In the conventional stave shown in FIG. 3 and FIG. 6, in blast furnace operation, due to the thermal expansion difference between the furnace inner side of the stave body and the iron skin side, and further due to the displacement due to the thermal expansion difference between the iron skin side and the iron skin of the stave body. In this case, although the stress variation occurs, the mounting bolt 8 can share the load of the stave body, but cannot absorb the stress variation due to the difference in thermal expansion.

  For this reason, in a copper or copper alloy stave cooler, due to stress fluctuations due to thermal expansion differences in blast furnace operation, the welded part with the water supply / drainage pipe near the main body of the stave, which is the stress concentration part, is considered to be the site of fatigue cracks. It was.

  Further, the seal plate 5 connecting the water supply / drainage extraction pipe 2 and the iron skin 6 is easily deformed when a displacement due to a difference in thermal expansion occurs between the stave body and the iron skin, and is welded to the water supply / drainage extraction pipe in the vicinity of the stave main body. Although there is an effect of reducing the stress of the part, the seal plate 5 itself may be repeatedly damaged by the deformation due to the stress, and there may be a problem that the gas in the furnace leaks out.

  Conventionally, there is a method of joining the water supply / drainage extraction pipe and the iron skin via a contractible expansion / contraction pipe (for example, see Patent Document 1). In this method, as shown in FIG. 4, an expansion / contraction pipe 7 is disposed so as to surround the water supply / drainage extraction pipe 2, and the water supply / drainage extraction pipe 2 is welded to the iron skin 6 through the expansion / contraction pipe 7.

  In this case, the gas in the blast furnace is sealed so as not to leak to the outside of the iron shell by the seal plate 5 welded to the end of the expansion and contraction pipe 7 and the outer periphery of the water supply / drainage extraction pipe 2.

  According to this method, when the displacement due to the thermal expansion difference between the stave body and the iron skin occurs, the expansion tube 7 is deformed in the direction of thermal expansion or thermal contraction, so that stress can be absorbed. The effect which suppresses the fatigue fracture of the welding part with the water supply / drainage extraction pipe | tube near the stave main body by the stress resulting from a thermal expansion difference, and the seal plate 5 is acquired.

  However, as shown in FIG. 4, the expansion tube 7 is a structure that can be easily expanded and contracted, such as a bellows structure. On the other hand, the corrosion progresses rapidly due to the adhesion of dust due to long-term use, and is easily damaged by fatigue. There is a problem in terms of sex.

  For this reason, it is necessary to periodically replace the expansion tube 7 so that the gas in the furnace does not leak to the outside due to a breakage or crack in the expansion tube 7 or to simply repair the broken hole or crack in the expansion tube 7 Therefore, there is a problem that a great deal of labor is required, and productivity is lowered due to the cessation of the blast furnace.

  In addition, if a stave load is applied to the welded portion between the stave body and the water supply / drainage pipe due to deformation of the stave mounting bolts, the welded part between the stave body and the water supply / drainage discharge pipe will cause fatigue failure, and cooling water will flow from that location. There is a risk of leaking and causing major troubles such as flooding in the furnace.

Further, as a method of attaching the conventional cast iron stave to the iron skin, the purpose is to perform the quick stave replacement by omitting the mounting bolt 8 and the nut 9 of the stave body 1, and as shown in FIGS. stave arranged protective tube 3 so as to surround the plumbing take-out pipe 2 to the main body, further, place the combing box so as to surround the protective tube 3 around the steel shell opening, plumbing take-out tube 2 and the protective tube 3, and, between the combing box protective tube 3, a method of fixing is known by each packing 10 and the fixed block 11 (for example, Patent Document 2, see).

According to this method, to improve the rigidity of the plumbing take-out tube 2 by fixing the like packing 10 to the plumbing removing tube 2 and the protective tube 3, further protective tube 3 and the combing boxes and packing 10 such as By fixing with, by supporting the load of the stave body, as shown in FIG. 7, the mounting bolt 8 and the nut 9 of the stave body 1 are omitted.

This method can also be applied to a stave made of copper or copper alloy. However, in this method, since the supply and drain take-out tube 2 and the protective tube 3 and the combing box is a structure formed by integrating, it can not absorb the stress which is displaced by the difference in thermal expansion between the stave body and Tetsugawa 6, On the contrary, there is a high possibility that stress concentration occurs in the welded portion between the stave body 1 and the water supply / drainage extraction pipe 2 and fatigue failure occurs.

  As described above, in recent years, with the increase in the thermal load of the blast furnace furnace body in blast furnace operation, the difference in thermal expansion between the furnace inner side and the iron skin side of the stave body, and the iron skin side and the iron skin of the stave body As a result, the possibility of fatigue failure occurring at the welded portion of the stave body and the water supply / drainage pipe, and at the welded portion of the water supply / drainage discharge pipe and the iron skin has increased. Then, the present condition is that the sufficient effect for improving the lifetime of a stave is not acquired.

JP 52-8553 A JP-A-8-225813

  In view of the above-described conventional state of the art, the present invention absorbs the stress caused by the difference in thermal expansion between the stave body and the iron skin caused by the increase in the thermal load of the blast furnace furnace body in the blast furnace operation. Providing a blast furnace stave cooler that has a highly reliable structure that can withstand long-term use by suppressing the occurrence of fatigue failure at the weld between the main body and the water supply / drainage pipe and the weld between the iron skin and the water supply / drainage pipe The purpose is to do.

The present invention solves the above technical problem, and the gist of the invention is that
(1) In a blast furnace stave cooler in which a water supply / drainage extraction pipe is welded to a copper or copper alloy stave body, and the stave body and a blast furnace core are fixed by a plurality of steel mounting bolts, a water supply / drainage extraction pipe is connected to the stave body. A protective tube is welded to surround the protective tube, and a combing box is provided to surround the protective tube on the outer peripheral surface of the opening formed in the iron skin, and the side plate and the seal plate of the combing box are can be contracted in the direction of displacement due to thermal expansion difference, and the plate thickness have a sufficient strength required for the seal and one of the side plate end portion is welded to the steel shell, the other of the side plate end through the seal plate A blast furnace stave cooler which is welded to the outer peripheral surface of the protective tube ,
(2) In a blast furnace stave cooler in which a water supply / drainage extraction pipe is welded to a copper or copper alloy stave body, and the stave body and a blast furnace core are fixed by a plurality of steel mounting bolts, the water supply / drainage pipe is connected to the stave body. A protective plate is welded so as to surround, and a side plate having a thickness of 8 to 10 mm and a seal plate having a thickness of 5 to 7 mm so as to surround the protective tube on the outer peripheral surface of the opening formed in the iron skin. A combing box comprising: one end of the side plate of the combing box is welded to the iron shell, and the other end of the side plate is welded to the outer peripheral surface of the protective tube via the seal plate. This is a blast furnace stave cooler .

  According to the blast furnace stave cooler of the present invention, when adopting a copper or copper alloy stave cooler with excellent cooling capacity for the furnace body or bottom of the blast furnace, the heat load of the blast furnace furnace body in high output blast furnace operation is reduced. Absorbs stress due to the difference in thermal expansion between the stave body and the iron skin that accompanies the increase, and causes fatigue failure in the welded portion between the stave body and the water supply / drainage extraction pipe, and the weld between the iron skin and the water supply / drainage extraction pipe Thus, a blast furnace furnace cooling stave having a highly reliable structure that can withstand long-term use can be provided.

  FIG. 1 shows the joining state of the blast furnace furnace cooling stave of the present invention and the iron skin, and FIG. 2 shows the joining of the stave body, water supply / drainage pipe, protective tube, combing box, and iron skin of the present invention. A state is shown typically.

  As shown in FIGS. 1 and 2, the blast furnace stave cooler according to the present invention has a water supply / drainage pipe 2 welded to a copper or copper alloy stave body 1, and the stave body 1 and the blast furnace iron skin 6 are made of a plurality of steels. It is fixed with a mounting bolt 9 made of steel. By making the stave body made of copper or copper alloy, heat conductivity is increased compared to the conventional cast iron stave body, and cooling water circulating in the cooling water piping in the stave body is used from the inside of the stave body to the furnace. Heat can be efficiently removed.

  The load of the stave body 1 is supported by a plurality of steel mounting bolts 9. The steel mounting bolt 9 can share the load of the stave body 1, but cannot absorb the stress fluctuation due to the difference in thermal expansion between the stave body 1 and the iron skin 6.

Therefore, in the present invention, as shown in FIGS. 1 and 2, in the blast furnace stave cooler, the protective tube 3 is welded to the stave body 1 so as to surround the water supply / drainage extraction tube 2, and the opening formed in the iron skin. iron skin surface of the outer peripheral parts, the combing box so as to surround the protective tube 3 provided the one side plate 4 ends of the combing box welded to Tetsugawa 6, the other seal of the side plate 4 ends The structure is welded to the outer periphery of the water supply / drainage pipe 2 through the plate 5.

  In the above stave structure, since the protective tube 3 is welded to the stave body 1 so as to surround the water supply / drainage extraction pipe 2, the welded portion between the water supply / drainage port of the stave body 1 and the water supply / drainage extraction pipe 2, which is a stress concentration site. By increasing the cross-sectional area in the vicinity and sharing the load at this portion by the protective tube, the stress at the welded portion of the water supply / drainage extraction tube 2 can be reduced when displacement due to the difference in thermal expansion occurs.

  If the thickness of the protective tube is less than 5 mm, sufficient strength cannot be obtained, and if it exceeds 7 mm, the distance from the water supply / drainage tube becomes narrow and welding becomes difficult, so that sufficient strength can be obtained and welding can be easily performed. Therefore, 5 to 7 mm is preferable. The material of the protective tube is preferably carbon steel for high-temperature piping because it maintains strength even when exposed to high temperatures and can be easily welded.

Further, the opening formed in the steel shell, the combing box so as to surround the protective tube 3 is arranged, plumbing removing tube 2 and the protective tube 3, without directly welding the steel shell, due to thermal expansion the displacement state capable, the plumbing removing tube 2 and the protective tube 3 is welded to the furnace shell through a combing box, if the displacement due to thermal expansion difference occurs, by combing box is deformed in the displacement direction The stress of the welded portion of the water supply / drainage extraction pipe 2 can be reduced.

Also, the iron skin surface of one and the opening periphery of the side plate 4 ends combing box is welded, and the other the protective tube 3 the outer peripheral surface of the side plate 4 ends combing box, via the seal plate 5 because it is welded, blast furnace gas is shielded by the side plate 4 and the seal plate 5 of the combing boxes, it is prevented from leaking out of the steel shell.

  Note that the opening of the iron skin 6 is freely displaced without contact with the iron skin even if the water supply / drainage extraction pipe 2 and the protective pipe 3 are slightly deformed when a displacement due to a difference in thermal expansion occurs in blast furnace operation. Therefore, it is preferable to have a sufficiently large opening diameter as compared with the outer diameter of the protective tube 3.

Further, the side plate 4 and the seal plate 5 constituting the combing box, when the displacement due to thermal expansion difference in blast furnace operation has occurred, to allow shrinkage to the displacement direction, a metal plate such as the plate thickness is thin steel plate preferable.

When the thickness of the side plate 4 is less than 8 mm, it is too thin and difficult to weld, and when it exceeds 10 mm, it is not easily deformed and cannot absorb the difference in thermal expansion, so that sufficient strength is maintained and easy. The thickness of the side plate 4 is preferably 8 to 10 mm.

  Further, the plate thickness of the seal plate 5 is too thin when it is less than 5 mm, and welding becomes difficult, and when it exceeds 7 mm, it is not easily deformed and cannot absorb the thermal expansion difference, so that sufficient strength is maintained, and The thickness of the seal plate 5 is preferably 5 to 7 mm because it can be easily welded.

  Moreover, the material of these side plates and the seal plate is preferably ordinary carbon steel because it has sufficient strength and can be easily welded.

  Moreover, the manufacturing method of the copper or copper alloy stave of the present invention is not particularly limited, but can generally be manufactured as follows. First, one wooden piece of the same shape as the stave is manufactured inside and outside the furnace. Secondly, the wooden mold is placed in each metal frame corresponding to the furnace inside and outside of the stave, and then sand is put. Third, after the sand is hardened, the wooden mold is pulled out to make a sand mold. As for the water channel, a sand mold in which sand is hardened is separately manufactured and installed at a fixed position of the sand mold.

  Fourth, the sand molds on the inside and outside of the furnace are aligned up and down, and a molten copper or copper alloy is injected from the inlet. Fifth, the sand mold is removed after solidification, and the sand hole is fitted and welded with a plug of the same material as the copper stave body. Weld the water supply / drainage pipe to the water supply / drainage port, and weld the protective pipe to surround the water supply / drainage extraction pipe.

  Also, a water channel is drilled in the rolled copper plate or rolled copper alloy plate of the same shape as the stave, unnecessary holes are fitted with a plug of the same material as the stave body and welded, and the water supply / drainage pipe is welded to the water supply / drainage port. There is also a manufacturing method in which a protective tube is welded so as to surround it.

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, around the welded plumbing take-out pipe 2 to a copper stave body 1 according to the present invention, with placing the protective tube 3 and combing boxes copper stave coolers, staves four places of the main body Was fixed to the iron core of the blast furnace body with copper mounting bolts and nuts.

  In order to confirm the effect of the copper stave according to the present invention, a conventional copper stave cooler in which the water supply / drainage pipe 2 welded to the conventional copper stave body 1 is welded to the iron skin via the seal plate 5 is similarly used. Attached to the iron core of the blast furnace furnace body, when the blast furnace operation is performed using the copper stave cooler according to the present invention and the conventional copper stave cooler, the damaged state of the welded portion of the stave body and the water supply / drainage discharge pipe 2 and the seal plate 5 Simulated.

  In the copper stave cooler according to the present invention, plain carbon steel having a thickness of 9 mm was used for the combing box, and plain carbon steel having a thickness of 6 mm was used for the seal plate.

  According to the simulation results, in the copper stave cooler according to the present invention, no damage was observed in the welded portion of the stave body 1 and the water supply / drainage pipe 2 and the seal plate 5.

  On the other hand, in the conventional copper stave cooler, a thermal stress of about twice the allowable stress acts on the welded portion between the stave body 1 and the water supply / drainage extraction pipe 2 and the iron skin of the seal plate 5. It became clear that the plate could break.

It is a figure which shows the aspect which has arrange | positioned the stave by this invention to the blast furnace wall. It is a figure which shows the joining condition of the stave main body and iron skin through the protection pipe | tube of a stave water supply / drainage extraction pipe | tube by this invention, and a combing box. It is a figure which shows the joining condition of the stave main body and iron skin without passing through the conventional stave expansion-contraction pipe | tube. It is a figure which shows the joining condition of the stave main body and iron skin through the conventional stave expansion-contraction pipe | tube. It is a figure which shows the joining condition of the stave main body and iron skin through the protection pipe | tube of the conventional stave water supply / drainage extraction pipe, the combing box, and a filler. It is a figure which shows the aspect which has arrange | positioned the stave through the conventional attachment bolt to the blast furnace wall. It is a figure which shows the aspect which has arrange | positioned the stave to the blast furnace wall without using the conventional attachment bolt.

Explanation of symbols

1 stave body 2 plumbing take-out pipe 3 protective tube 4 (combing box) side plate 5 (combing Box) seal plate 6 furnace shell 7 telescopic tube 8 mounting bolt 9 nuts 10 packing 11 fixed block

Claims (2)

In a blast furnace stave cooler in which a water supply / drainage extraction pipe is welded to a copper or copper alloy stave body, and the stave body and the blast furnace iron shell are fixed by a plurality of steel mounting bolts, the water supply / drainage extraction pipe is surrounded by the stave body A protective tube is welded, and a combing box is provided to surround the protective tube on the outer peripheral surface of the opening formed in the core, and the side plate and the seal plate of the combing box have a thermal expansion difference. can be in the displacement direction due to shrinkage, and the plate thickness have a sufficient strength required for the seal, one of the side plate end portion is welded to the steel shell, the protective other side plate end through the seal plate A blast furnace stave cooler which is welded to the outer peripheral surface of a pipe. In a blast furnace stave cooler in which a water supply / drainage extraction pipe is welded to a copper or copper alloy stave body, and the stave body and a blast furnace core are fixed by a plurality of steel mounting bolts, the stave body surrounds the water supply / drainage pipe. A protective tube is welded to the outer shell, and a combing plate comprising a side plate having a thickness of 8 to 10 mm and a seal plate having a thickness of 5 to 7 mm so as to surround the protective tube on the outer peripheral surface of the opening formed in the core. A box is provided, one end of the side plate of the combing box is welded to an iron skin, and the other end of the side plate is welded to the outer peripheral surface of the protective tube via the seal plate. Stave cooler for blast furnace.

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