JP2012180579A - Protective structure for throat part of blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective structure for a throat part of a blast furnace, which has an anchor link for preventing falling and shift of a protective plate of the throat even when excessive tensile stress acts, and is capable of maintaining a throat shape such that a furnace inner surface practically keeps roundness.SOLUTION: An anchor link 25 includes: an anchor rod 29 which is inserted into a cylindrical body 27 of a steel shell joint 26 from the side of a throat protective plate 3, and whose threaded rod 29a passes through a rod passing hole 28a; a washer 34 extrapolated from the outer side of a blast furnace steel shell 1 to the threaded rod part; and a nut 33 for abutting the washer to the peripheral edge of the rod passing hole 28a of an anchor link connection member 28 by being screwed to the threaded rod. When the tensile stress acting on the anchor link becomes almost as large as the tensile strength of the anchor rod, the washer mitigates the tensile stress by plastic deformation.

Description

  The present invention relates to a blast furnace furnace port protection structure, and more particularly, to a connection structure of an anchor link for fixing a furnace port protection plate covering a furnace inside of a stave to a blast furnace iron skin.

The inner wall of the blast furnace near the furnace mouth is impacted or slipped by a charge charged from a bell-type or bell-less type furnace top charging device, so that wear resistance of the furnace wall is required.
As shown in FIG. 5, the blast furnace core 1 near the blast furnace mouth is covered with a stave 2 which is a cooling wall, and the inner peripheral surface of the stave 2 is shaped like a plate. The structure covered with the furnace port protection plate 3 is known (for example, patent document 1).

  In the structure of FIG. 5, the anchor base portion 4 protrudes from the back surface of the furnace port protection plate 3, and the coupling portion 5 is provided above the furnace port protection plate 3. The stave 2 is provided with a through hole 6 into which the anchor base 4 is fitted. A cylindrical body 7 made of a heat-resistant material communicating with the inside and outside of the blast furnace core 1 is fixed to the blast furnace core 1, and an anchor link is connected to the outer end of the blast furnace core 1 of the cylindrical body 7. The member 8 is fixed.

  Then, the furnace port protection plate 3 is arranged so that the anchor base 4 and the coupling part 5 face the blast furnace core 1 side, and the anchor base 4 is fitted into the through hole 6 of the stave 2. Then, one end of the anchor link 9 is connected to the anchor base portion 4 and the coupling portion 5, and the other end of the anchor link 9 inserted into the cylindrical body 7 is connected to the anchor link connecting member 8, so that the furnace port protection plate 3 is The blast furnace iron skin 1 is fixed via an anchor link 9. The opening of the cylinder 7 is closed with a cap 10.

  According to the structure of FIG. 5, even if the high temperature gas flowing in the blast furnace flows between the back surface of the furnace port protection plate 3 and the stave 2, the anchor base portion 4 of the furnace port protection plate 3 enters the through hole 6 of the stave 2. By being inserted, it is possible to prevent the joint portion of the anchor base 4 and the anchor link 9 from coming into contact with the high temperature gas, and to prevent the anchor link 9 from being deformed or broken due to an increase in thermal load. Moreover, since the anchor link 9 connected to the joint portion 5 of the furnace port protection plate 3 is housed in the cylindrical body 7 formed of a heat resistant material, damage due to contact with the high temperature gas can be prevented.

Japanese Patent No. 4122899

  By the way, the high-temperature gas flow preferentially passes through a portion having a low airflow resistance, so that the gas flow on the front and back sides of the furnace port protection plate 3 is unstable depending on how the charge is charged. As a result, the temperature state of the protective plate repeatedly fluctuates such that the inside of the furnace is high or the iron side is high. Depending on this temperature state, the furnace port protection plate 3 may be deformed into a convex shape or a concave shape in a direction away from the stave 2.

When the furnace port protection plate 3 is deformed into a convex shape or a concave shape, an excessive tensile stress acts on the anchor link 9 that fixes the furnace port protection plate 3 to the blast furnace iron skin 1. There is a possibility that the anchor link 9 not provided is broken. In particular, when a portion near the anchor base portion 4 of the anchor link 9 is broken, the repair is not easy.
If the furnace link protection plate 3 is dropped or misaligned due to the breakage of the anchor link 9, the roundness of the furnace port furnace wall cannot be maintained, and the distribution of the charge in the furnace becomes unstable. Deteriorating gas flow distribution results in reduced productivity in blast furnace operation.

  Therefore, the present invention has been made in view of the above circumstances, and includes an anchor link that prevents the furnace port protection plate from falling off or slipping even when excessive tensile stress acts, and the furnace inner surface is substantially round. It is an object of the present invention to provide a blast furnace furnace port protection structure capable of maintaining the furnace mouth shape so as to maintain the above.

  In order to achieve the above object, the blast furnace furnace port protection structure according to the present invention covers the inner peripheral surface of the stave installed in the furnace port part of the blast furnace with the furnace port protection plate, and One end of the anchor link is fixed to the back surface facing the stave, the anchor link passes through a through hole formed in the stave, and the other end of the anchor link is fixed to the iron core joint portion of the blast furnace iron skin. In the protective structure of the blast furnace furnace port portion that holds the protective plate, a tensile stress acts on the anchor link due to thermal deformation due to a temperature state change of the furnace port protective plate, and the anchor structural member constituting the anchor link is pulled. A tensile stress relaxation member is provided that relaxes the tensile stress by its own deformation when the tensile stress increases to near strength.

  According to a second aspect of the present invention, in the protective structure for a blast furnace core portion according to the first aspect, the iron skin coupling portion is fixed to an opening hole formed in the blast furnace iron skin, and the inside and outside of the blast furnace iron skin A cylindrical body communicating with the disk, and a disk-shaped anchor link connecting member fixed to an end of the cylindrical body outside the blast furnace iron skin and provided with a rod passage hole, and the anchor link is connected to the furnace port Inserted into the cylinder from the protective plate side, the anchor rod as the anchor constituent member through which the threaded rod passes through the rod passage hole, and extrapolated from the outside of the blast furnace iron skin to the threaded rod portion The anchor link comprising: a washer as the tensile stress relaxation member; and a nut that abuts the washer on a peripheral edge of the rod passage hole of the anchor link connecting member by being screwed to the threaded rod. Tensile stress acts, when increased until the tensile strength near the anchor rod, the washer is so as to relieve the tensile stress by plastic deformation.

  According to a third aspect of the present invention, in the protective structure of the blast furnace furnace port portion according to the second aspect, the diameter of the rod passage hole of the anchor link connecting member is α, the inner diameter of the washer is β1, and the washer When the outer diameter of the washer is β2, the relation of β1 <α <β2 is established, and when the tensile stress acting on the anchor link becomes close to the tensile strength of the anchor rod, the peripheral portion of the inner diameter of the washer The washer is plastically deformed so as to enter the rod passage hole.

  According to the protection structure of the blast furnace mouth portion of the present invention, tensile stress acts on the anchor link due to deformation of the furnace mouth protection plate due to temperature change in the blast furnace, and the tensile stress is close to the tensile strength of the anchor constituent members constituting the anchor link. Since the tensile stress relaxation member that relaxes the tensile stress due to its own deformation when it becomes large, the anchor component member is prevented from breaking, and the furnace port protection plate does not fall off or shift. The furnace port shape can be maintained so that the inner surface maintains roundness.

It is a figure which shows the anchor link which concerns on this invention, and an iron-skin coupling | bond part. The 1st thermal deformation pattern of the furnace port protection plate at the time of operating a blast furnace is shown. The 2nd thermal deformation pattern of the furnace port protection plate at the time of operating a blast furnace is shown. It is a figure which shows the tensile stress relaxation member which relieves a tensile stress by its own plastic deformation. It is a side view which shows the protection structure of the conventional blast furnace furnace port part.

Hereinafter, an embodiment of a blast furnace furnace port protection structure according to the present invention will be described with reference to the drawings.
The furnace port protection plate 3 partially shown in FIG. 1 has the same shape as the furnace port protection plate 3 shown in FIG. 5, is resistant to aging embrittlement even when used at high temperatures for a long time, and has excellent wear resistance. It is a member.

A ring-shaped pin engaging portion 22a is formed integrally with the anchor base portion 4 that is formed so as to protrude from the lower back of the furnace port protection plate 3. A through hole 6 is formed in the lower portion of the stave 2 so as to penetrate the front and back.
The furnace port protection plate 3 is disposed so as to cover the inner periphery of the stave 2 by fitting the anchor base portion 4 into the through hole 6 of the stave 2.

The anchor base portion 4 provided at the lower back portion of the furnace port protection plate 3 is fixed to the iron skin coupling portion 26 of the blast furnace iron skin 1 via an anchor link 25.
As shown in FIG. 1, the iron skin coupling portion 26 is fixed to the inner periphery of the opening hole 1 a provided in the blast furnace iron skin 1, and a cylindrical body 27 made of a heat resistant material communicating with the inside and outside of the blast furnace iron skin 1 A disc-shaped anchor link connecting member 28 is provided which is fixed to an end portion of the cylindrical body 27 outside the blast furnace iron shell 1 and has a rod passage hole 28a which coincides with the axial center position of the cylindrical body 27.

The anchor link 25 is pinned to an anchor rod 29 having a threaded rod portion 29a and a ring-shaped pin engaging portion 29b, and a pin engaging portion 29b of the anchor rod 29 and a pin engaging portion 22a of the anchor base portion 4. And a link member 32 connected through 30 and 31.
Then, the threaded rod portion 29a of the anchor rod 29 coupled to the pin engaging portion 22a of the anchor base portion 4 via the link member 32 is loosely inserted into the rod passage hole 28a of the anchor link coupling member 28, and the threaded rod portion 29a is inserted. By inserting the inserted flat plate washer 34 between the nut 33 screwed into the threaded rod portion 29 a and the side surface of the anchor link connecting member 28, the furnace port protection plate 3 is connected to the blast furnace iron core via the anchor link 25. 1 is fixed to the iron skin coupling portion 1.

Here, assuming that the diameter of the rod passage hole 28a of the anchor connecting member 28 is α, the inner diameter of the washer 34 is β1, and the outer diameter of the washer is β2 (see FIG. 4A),
β1 <α <β2 (1)
Have the relationship.
The washer 34 is made of a general structural rolled steel (SS400), and has dimensions of a plate thickness of 9 mm, an outer diameter (β2) of 135 mm, and an inner diameter (β1) of 32 mm. Further, the diameter (α) of the rod passage hole 28a of the anchor connecting member 28 is set to 105 mm.

Here, when a large tensile stress acts on the anchor link 25 from the furnace port protection plate 3, the washer 34 of the anchor link 25 is plastically deformed to relieve the large tensile stress and prevent the anchor rod 29 from being broken. It has become.
That is, the washer 34 of the anchor link 25 is plastically deformed when the tensile stress acting on the anchor link 25 from the furnace port protection plate 3 increases to near the tensile strength of the anchor rod 29.

The configuration of such a part was determined by confirming by experiments that the washer 34 was deformed before the anchor rod 29 was broken when a tensile force was applied to the anchor rod 29. Deformation analysis can also be used to determine such specifications.
Here, FIG.2 and FIG.3 shows the deformation | transformation pattern of the furnace port protection plate 3 at the time of using for blast furnace operation.

In the operation of the blast furnace, the atmosphere temperature T1, the furnace port protection plate 3 and the stave 2 are caused by the passage path of the in-furnace gas which is blown from the tuyere and passes through the charge S deposited inside the furnace port protection plate 3. A difference occurs in the ambient temperature T2.
As shown in FIG. 2, when the atmospheric temperature T1 becomes higher than the atmospheric temperature T2 of the furnace gas between the furnace port protection plate 3 and the stave 2, the furnace port protection plate 3 circles the contact surface with the stave 2. A1 to A4 are deformed into a convex shape in a direction away from the stave 2.

Also, as shown in FIG. 3, when the ambient temperature T1 becomes lower than the ambient temperature T2 between the furnace port protection plate 3 and the stave 2, the furnace port protection plate 3 sets the contact surface with the stave 2 as a circle A5. It deforms into a concave shape in a direction away from the stave 2.
As described above, when the furnace port protection plate 3 is repeatedly deformed into a concave shape or a convex shape, the anchor link 25 that connects the anchor base portion 4 provided at the lower back of the furnace port protection plate 3 and the iron skin coupling portion 26 becomes large. Tensile stress acts.

When the tensile stress acting on the anchor link 25 increases to near the tensile strength of the anchor rod 29 due to the deformation of the concave shape or the convex shape of the furnace port protection plate 3, the washer 34 of the anchor link 25 is shown in FIG. ), Plastic deformation is performed so as to enter the rod passage hole 28a of the anchor link connecting member 28.
Accordingly, the plastically deformed washer 34 relieves a large tensile stress acting on the anchor link 25, thereby preventing the anchor rod 29 from being broken and preventing the furnace port protection plate 3 from falling off or being displaced. The shape of the furnace port can be maintained so as to substantially maintain roundness.

  Further, in the above embodiment, the washer 34 is exclusively deformed by the tensile stress acting on the anchor rod 29, so that the anchor rod 29 can be prevented from being broken, and at the time of maintenance, the outside of the blast furnace Thus, the shape of the washer 34 can be confirmed, and only the washer 34 can be replaced as necessary, so that maintenance can be easily performed.

DESCRIPTION OF SYMBOLS 1 ... Blast furnace iron shell, 1a ... Opening hole, 2 ... Stave, 3 ... Furnace port protection plate, 4 ... Anchor base part, 5 ... Coupling part, 6 ... Through-hole, 22a ... Pin engaging part, 25 ... Anchor link, 26 DESCRIPTION OF SYMBOLS ... Iron skin coupling part, 27 ... Cylindrical body, 28 ... Anchor link connection member, 28a ... Rod passage hole, 29 ... Anchor rod, 29a ... Threaded rod part, 29b ... Pin engaging part, 30, 31 ... Pin, 32 ... Link member, 33 ... Nut, 34 ... Washer, 35 ... Cap, S ... Load

Claims (3)

Cover the inner peripheral surface of the stave installed at the furnace port of the blast furnace with a furnace port protection plate, fix one end of the anchor link to the back of the furnace port protection plate facing the stave, and attach this anchor link to the stave In the protective structure of the blast furnace furnace port portion that passes through the formed through-hole and holds the furnace port protection plate by fixing the other end of the anchor link to the iron shell joint of the blast furnace iron skin,
When the tensile stress acts on the anchor link due to the thermal deformation due to the temperature state change of the furnace port protection plate, and the tensile stress increases to near the tensile strength of the anchor constituent member constituting the anchor link, it deforms itself. A blast furnace furnace port protection structure comprising a tensile stress relaxation member that relaxes the tensile stress. The iron skin coupling portion is fixed to an opening formed in the blast furnace iron skin, and is fixed to a cylindrical body communicating with the inside and outside of the blast furnace iron skin, and an end portion of the cylindrical body outside the blast furnace iron skin, A disk-shaped anchor link connecting member provided with a rod passage hole,
The anchor link is inserted into the cylinder from the furnace port protection plate side, and the anchor rod as the anchor component member through which the threaded rod passes through the rod passage hole, and the outside of the blast furnace iron skin, A washer as the tensile stress relaxation member extrapolated to the threaded rod portion, and a nut that abuts the washer on the periphery of the rod passage hole of the anchor link connecting member by screwing to the threaded rod. Prepared,
2. The blast furnace furnace opening according to claim 1, wherein when the tensile stress acting on the anchor link increases to near the tensile strength of the anchor rod, the washer relaxes the tensile stress by plastic deformation. Protection structure. When the diameter of the rod passage hole of the anchor link connecting member is α, the inner diameter of the washer is β1, and the outer diameter of the washer is β2, the relation of β1 <α <β2 is satisfied.
When the tensile stress acting on the anchor link increases to a value close to the tensile strength of the anchor rod, the washer is plastically deformed so that the peripheral edge of the inner diameter of the washer enters the rod passage hole. The protection structure of the blast furnace furnace opening part of Claim 2 to do.

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