JP4300995B2 - Construction method for lining refractory bricks for steelmaking containers - Google Patents

Description

  The present invention relates to a method for constructing a refractory brick of a molten metal refining or transporting container whose side walls are lining with a refractory brick, and in particular, a swirl stirring method (KR method) in hot metal pretreatment, The present invention relates to a spiral construction method capable of extending the life of a lining refractory brick of a steelmaking container used for a swirl stirring method (electromagnetic stirring) in promoting the inclusion inclusion.

  It is important to mix the hot metal and the reactants well in order to efficiently perform desulfurization and desulfurization during the hot metal pretreatment. For this reason, a refractory lance is inserted deeply into the hot metal to inject the reactants with the gas, or a refractory impeller is immersed in the hot metal and swirled to allow the reactants to be swirled. The method of entraining is often used.

  In addition, in order to efficiently desulfurize and remove inclusions even during refining of molten steel, a refractory lance is immersed in the molten steel and the reactant is injected with gas, or the molten steel is rotated up and down by RH. Or, a method of turning the molten steel laterally with an electromagnetic stirrer is often used.

  However, due to these agitation, the wear of the refractory in the hot metal ladle and ladle containing hot metal and molten steel tends to become severe, extending the life of the refractory from the standpoint of enhancing the reaction and reducing the refractory cost. Countermeasures are strongly desired.

  By the way, as a brick used for the lining of the hot metal ladle, as shown in FIG. 7, the side (the upper side of the paper surface in FIG. 7B) that is in contact with the inner peripheral surface of the container is long, and the side facing the side (FIG. 7 (b), the squeezed brick 1 (JIS R 2103 62) having a trapezoidal shape in plan view is the mainstream, but in order to efficiently perform hot metal desulfurization / desulfurization, it is more severe. In order to perform lining that can withstand stirring and extend the life, there are the following problems.

1) In construction using the approaching brick 1, as shown in FIG. 8, in order to pile up in a ring shape step by step, an attack brick is required for each step. Further, the thermal stress in the circumferential direction approaches between the bricks, and the joint portion having a low strength is melted, and the joint portion 2 becomes concave as shown in FIG. 9, and the shape of the squeezed brick 1 is kamaboko. It becomes a shape.

2) Recently, the KR impeller agitation method is more often used than the injection method, so in addition to 1) above, the friction and wear between the rotating KR impeller and the side bricks cause Brick chipping and wear have progressed, and it has become impossible to obtain a sufficient life as before.

Therefore, in order to solve the problem in the previous stage of 1) above, in order to shorten the construction time by eliminating the need for bricks at each stage, the starter bricks having different shapes are sequentially placed on the bottom of the furnace when building the ladle. A technique is set in which the standard shaped squeezed bricks are spirally stacked on these starter bricks to build a furnace.
JP-A-5-305423

Moreover, the refractory which has the same curved surface on both end surfaces is also disclosed.
Japanese Patent Laid-Open No. 2-175067

  However, even in the spiral furnace construction method described in Patent Document 1 described above, the thermal stress in the circumferential direction approaches between the bricks, the weak joints are melted, and the joints become concave, The conventional problem that the shape becomes kamaboko cannot be solved.

  In addition, the refractory disclosed in Patent Document 2 is characterized in that it extends the life, and the shape of the brick is disclosed in detail, such as by providing a corner cut to absorb thermal strain during use. There is no mention about the construction method at the time of construction.

  The problem to be solved by the present invention is that the construction method using the conventional squeeze brick cannot extend the life of the refractory brick when, for example, a stirring method using a KR impeller is adopted.

  The inventor presumed that the wear of the lining bricks was intense at the joints between the bricks adjacent in the circumferential direction, so the wear mechanism was assumed to be due to the thermal expansion of the bricks, suppressing the generation of stress due to the thermal expansion, and In order to reduce the stress value per unit area, investigations and experiments were repeated.

  As a result, by utilizing the features of spiral construction, and by making the gap between the bricks adjacent in the circumferential direction curved, it also takes advantage of the curved brick that makes it difficult to insert molten metal into the gap, and It was found that the brick life could be extended by absorbing the thermal strain during use by devising the construction method, rather than prescribing the brick shape intricately.

The present invention has been made based on the above findings,
The construction method of the lining refractory brick of the steelmaking container of the present invention,
A brick having a convex curved surface on one end surface and a concave curved surface matching the convex curved surface on the other end surface is fitted so that the convex curved surface and the concave curved surface of the adjacent bricks fit together, and the mating surface is made of steel. It is most important to pile up spirally in the direction of the rotational flow of the molten metal injected into the container from the lower side to the upper side of the side wall of the container so as to be curved in the direction from the inside to the outside of the container. Features.

And in the above-mentioned method of the present invention ,
Convex curved surface formed on one end face of the front Symbol bricks, or construction so as to face the rotational flow of the molten metal,
It is desirable to use the brick having a thickness of 150 to 250 mm and convex and concave curved surfaces formed at both ends of the brick which are arcs having a radius of 160 to 180 mm.

  In the present invention, by making the contact surface in the circumferential direction between adjacent bricks into a curved shape, the contact area is expanded as compared with the case of a flat surface, and the stress value per unit area of joint between adjacent bricks is reduced. Can do. In particular, if it is curved in the thickness direction of the brick after construction (the direction from the inside to the outside of the container), the joint length in the thickness direction becomes long, so that the intrusion of the molten metal is suppressed and the erosion rate of the brick is increased. It can be reduced and the life can be extended.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
In the construction method of the lining refractory brick of the steelmaking container of the present invention, since it is necessary to pile bricks continuously, the brick 11 to be used has one end face (FIG. 1 (a)) as shown in FIG. A convex curved surface 11a on the left end surface of the paper surface, and a concave curved surface 11b having the same size as the convex curved surface 11a on the other end surface (right side surface of the paper surface in FIG. 1B). It is necessary to have.

Then, the brick 11 is curved so that the convex curved surface 11a and the concave curved surface 11b of the adjacent brick 11 are fitted, and the fitting surface is curved in a direction from the inside to the outside of the container 12. As shown in FIG. 2, starting from the lowest position of the side wall 12b on the starter brick 3 set on the bottom 12a of the container 12, it gradually piles up spirally and reaches the top of the lining. The attack brick 4 is used to attack.

  Thus, by stacking the bricks 11 in a spiral manner from the lower part to the upper part of the side wall 12b, the stress of the brick 11 and the bricks 11 due to thermal expansion is long from the lower part to the upper part of the side wall 12b along the spiral. Will be distributed over distance. In addition, the starting point of the spiral which piles up the said brick 11 may not be one place of the lining lower part of the container 12, but may be from several places.

  In the conventional construction method shown in FIG. 8, in which the bricks are competing due to thermal expansion in each stage, a large stress is generated in each stage. However, in the present invention, by making the spiral construction, the extension length of each brick 11 accompanying the brick expansion can be finally absorbed by the uppermost attacking portion. It becomes possible to suppress damage to the joint.

  By the way, in the case of the container 12 used for the molten metal swirl type treatment such as the KR type hot metal desulfurization method, the direction in which the bricks 11 are spirally loaded is as shown in FIG. The direction is preferably the same as the direction indicated by the arrow in FIG.

  The reason is that when the brick 11 is stacked in the same direction as the direction of the swirl flow of the molten metal, the thermal stress of the brick and the mechanical energy of the swirl flow advance in the direction of the swirl flow, contrary to gravity, and spiral. It is because it is dispersed in a shape. On the other hand, when piled in the direction opposite to the swirling flow of the molten metal, the gravity of the brick 11 and the mechanical energy of the swirling flow act on the brick 11 and collide with the thermal stress of the brick 11, and the joint portion of the brick 11. From 2 etc., it becomes easy to cause damage such as cracks, corner chipping and peeling.

  Moreover, in the case of the container 12 used for the molten metal swirl type treatment such as the KR type hot metal desulfurization method, the direction in which the bricks 11 are stacked is one of the bricks 11 adjacent to the circumferential direction of the container 12 as shown in FIG. If the convex curved surface 11a formed on the end surface is stacked so as to face the swirling flow of the molten metal, the joint portion 2 is more effectively prevented from being worn. In such a case, the molten metal flows smoothly even if it hits the joint portion 2, and physical wear can be reduced.

  By the way, the curved surface shape of the both end faces of the brick 11 is such that when the thickness of the brick 11 (the length in the vertical direction in FIG. 1A) is 150 to 250 mm, as shown in FIG. It is desirable that R is an arc shape of 160 to 180 mm.

  In the case where the thickness of the brick 11 is 150 to 250 mm, when the radius R is less than 160 mm, the length of the joint portion 2 is increased and the stress value per unit area of the joint portion 2 is reduced. This is because the corner of the formed concave curved surface 11b becomes an acute angle and corner breakage is likely to occur.

  Further, when the radius R exceeds 180 mm, the length of the joint portion 2 is shortened and the bonding area of the bricks 11 adjacent in the circumferential direction of the container 12 is narrowed, so that the competitive stress increases and the joint portion 2 is damaged. This is because the effect of preventing the molten metal from entering also decreases.

Hereinafter, the implementation results performed to confirm the effect of the present invention will be described.
The construction method and effect of the present invention were confirmed under the condition that the KR type desulfurization treatment was performed in a hot metal ladle having a hot metal amount of 230 tons. The hot metal desulfurization treatment conditions were performed by charging quick lime and turning at 120 rpm for 12 minutes.

  In the method of the present invention, an arcuate convex curved surface having a radius R of 178 mm is formed on one end face and an arcuate concave shape having a radius R of 178 mm on the other end face as shown in FIG. Using bricks with a curved surface, from the two lowermost portions of the side wall toward the rotating direction of the KR impeller, that is, the rotating flow direction of the hot metal, and so that the convex curved surface faces the rotating flow direction of the hot metal Then, construction was started in a spiral shape, and two spirals were stacked up to the top of the side wall. For comparison, an experiment was also carried out in the case of a conventional method in which a squeezed brick made of the same material as described above was applied in a ring shape for each stage.

  In this construction, the thickness of the lining bricks is the same at 200 mm, but the joint length is 200 mm in the conventional method, whereas in the method of the present invention, both ends of the brick are circles having a radius of 178 mm. Since what was made into the arc shape was used, the length of 236 mm and 18% joint part is long.

The effect is shown in FIGS.
In the method of the present invention, bricks are piled up in a spiral shape in the circumferential direction, and the attack is stored in the upper part. Therefore, the colliding stress between bricks rises in a spiral shape in the circumferential direction, and the lower and upper side walls are long. After being used 1172 times, the stress is relieved, and the contact with the molten metal flow is relieved during KR treatment, so that the entry of the metal into the joint can be suppressed. However, as shown in FIG. 4 and FIG. 5 (b), the damage form of the brick 11 and the joint portion 2 is not melted into a semi-cylindrical shape, the joint becomes smooth, and damage such as spalling is also caused. It became clear that it would disappear.

  On the other hand, in the construction using the conventional looming brick 1, the pressure is high in the collision (circumferential direction) between the bricks because the steps are stacked in a ring shape (the attack is stored in each step). The corners of the brick between the joints 2 were missing, and after 1046 uses, as shown in FIG. 4 and FIG.

  FIG. 6 shows the original unit price index and the brick life in the above experimental results. In the method of the present invention, the brick life increased by 12% and the original unit price decreased by 18% compared to the conventional method.

  The method of the present invention is not limited to the above-described embodiment, and the embodiment can be arbitrarily changed within the scope of the technical idea described in each claim. For example, the convex curved surface or concave curved surface of the lining brick to be used is not necessarily limited to an arc shape as long as it is a curved surface.

  The present invention as described above can also be applied to the construction of lining refractory bricks for containers other than the swirl stirring method.

It is the figure which showed the lining refractory brick used for this invention method, (a) is the figure seen from the plane, (b) is the figure seen from the front. It is explanatory drawing of the construction method of this invention. It is detail drawing of the construction method of this invention. It is the figure which showed the state after use, (a) shows a conventional method and (b) shows the method of this invention. (A) and (b) are the figures which showed typically Drawing 4 (a) and (b), respectively. It is the figure which compared the original unit price index and brick life of the method of this invention and the conventional method. It is a figure which shows the compression brick used as a lining refractory brick, (a) is the figure seen from the side surface, (b) is the figure seen from the plane. It is the figure which showed the example of construction using the conventional squeeze-shaped brick, (a) is a front view, (b) is a side view. It is a figure explaining the problem of construction using the conventional squeeze brick.

Explanation of symbols

2 Joint part 11 Brick 11a Convex curved surface 11b Concave curved surface 12 Container 12a Bottom part 12b Side wall

Claims (3)

A brick having a convex curved surface on one end surface and a concave curved surface matching the convex curved surface on the other end surface is fitted so that the convex curved surface and the concave curved surface of the adjacent bricks fit together, and the mating surface is made of steel. The container is spirally stacked in the direction of the rotational flow of the molten metal injected into the container from the lower side to the upper side of the side wall of the container so as to be curved in the direction from the inside to the outside of the container. The construction method of the lining refractory brick of the long-life steel-making container. Convex curved surface formed on one end face of the brick, the construction method of the refractory lining brick for steelmaking vessel according to claim 1, construction be characterized Rukoto so as to face the rotational flow of the molten metal. The thickness of the brick is 150 to 250 mm, the convex and concave curved surface formed at both ends of the brick, steel container according to claim 1 or 2 radius, wherein the arc der Rukoto of 160~180mm How to install lining refractory bricks.