Ladle KR stirring paddle with semi-spiral paddle blade structure
By adopting a semi-propelled blade structure and a snorkel cooling design in the KR stirring paddle, the problems of low desulfurization efficiency and short service life in traditional stirring technology are solved, and a more efficient desulfurization and safer stirring process is achieved.
Patent Information
- Application Number
- CN202420276615.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-05
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-02-05
AI Technical Summary
In traditional KR mechanical stirring technology, the agglomeration of desulfurizer causes the specific surface area of the reaction to decrease, the reaction rate slows down, and the presence of a stirring dead zone leads to poor desulfurization effect. Traditional straight and spiral stirring paddles are prone to cause molten overflow during high-speed stirring. Safety hazards and short service life.
The iron-clad KR stirring paddle adopts a semi-spiral blade structure, combined with the "upper and downward inclination" design of the upper vertical and lower bent and inclined, reduces the rotational inertia, reduces the vortex height, and reduces the thermal stress of the steel structure through cooling of the ventilator. Enhance the bonding force between the blade and refractory castable to ensure uniformity and safety of stirring.
The stirring time is shortened, the desulfurization agent consumption is reduced, the iron level is controlled, the risk of overflow is avoided, the service life of the stirring paddle is extended, and the desulfurization effect is improved.
Smart Images
Figure CN222250810U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of steel smelting, in particular to a KR stirring paddle for a molten iron ladle with a semi-spiral blade structure. Background Art
[0002] With the continuous progress and development of continuous casting technology, its advanced desulfurization technology has increased the sulfur content requirements of many steel grades, and the sulfur content of some ultra-pure steels must not exceed 0.001%. The traditional blast furnace-converter process can no longer meet the needs of the development of continuous casting technology.
[0003] At present, the desulfurization method commonly used in the pretreatment stage of molten iron is KR mechanical stirring (Kanbara Reactor). This method mainly stirs the molten iron by an immersed stirring paddle. The rotating KR stirring paddle is inserted into the molten iron, and the desulfurizer added from the top is rolled into the molten iron near the paddle and a desulfurization reaction occurs. However, during the mechanical stirring process, the desulfurizer will agglomerate and grow into spherical particles ranging from a few millimeters to tens of millimeters. The increase in the particle size of the desulfurizer will cause the specific surface area of the desulfurization reaction to decrease, and then cause the desulfurization reaction rate to decrease. Due to the agglomeration of the desulfurizer before entering the molten iron, the surface of the desulfurizer reacts with the molten iron to generate CaS, which hinders the further progress of the desulfurization reaction, so that the internal CaO content remains high after the desulfurization is completed. After the desulfurizer is put in, the speed of the stirring paddle is continuously increased to a certain extent, and the desulfurizer is sucked into the molten iron as much as possible to react chemically with [S] in the molten iron. The density of the desulfurizer is lower than that of the molten iron. It is difficult for it to sink to the bottom area when it circulates with the molten iron. At the same time, there is a weak flow area with a low flow rate at the bottom of the blade during the KR stirring process, which is also called the "dead zone". Due to the combined influence of the slow flow rate of the molten iron in the weak flow area and the low density of the desulfurizer, the desulfurization effect in this area is poor. The quality of the molten iron dynamic conditions determines the entrainment and mixing ability of the KR stirring. When the stirring process (rotation speed, immersion depth, eccentricity, pulse, positive and negative stirring, etc.) and structure (molten iron ladle structure, blade size, blade shape, etc.) are different, the molten iron flow characteristics, mixing time, dead zone ratio and forced eddy zone range will also be different. Therefore, the degree of mixing of the desulfurizer and the molten iron in the ladle depends on the quality of the molten iron dynamic conditions, and how to improve the dynamic conditions is the top priority for improving the efficiency of the desulfurization reaction.
[0004] When the ordinary straight-blade KR impeller is stirring, the stirring kinetic energy of the impeller is concentrated near the straight blade, pushing toward the horizontal wall direction, and the flow in the bottom area of the ladle is very gentle. It mainly forms a horizontal circulation flow, and the entire stirring field is in a relatively stable state. The molten iron near the two sides of the blade wall flows actively, and the flow rate in the lower area of the blade is the slowest, forming a stirring dead zone. Therefore, in order to achieve the required desulfurization effect of the entire ladle of molten iron, it is necessary to increase the consumption of desulfurizer and extend the stirring time.
[0005] When the spiral KR impeller is stirring, the stirring kinetic energy generated by the spiral impeller extends to the bottom of the ladle. The flow in the bottom area of the ladle is more intense than that of the original straight impeller, mainly forming a vortex. The entire stirring field vibrates greatly. The spiral impeller can generate a large vortex during the transportation process, which can significantly enhance the downward suction effect and improve the flow field dynamics conditions in the lower half of the ladle to a great extent, thereby shortening the stirring time and reducing the consumption of desulfurizers. However, during high-speed stirring, as the stirring time and stirring speed increase, the vortex height will increase, which can easily cause the problem of increased molten iron level. The vortex will overflow the molten iron, bringing safety hazards, thus bringing about the problem of reduced molten iron loading level and limited stirring speed of the spiral KR impeller.
[0006] The ordinary straight-blade KR stirring paddle and the spiral KR stirring paddle have a single structure. Although rotation and vortex are formed in the initial stage of stirring, inertial rotation and vortex are formed during long-term high-speed rotation, which affects the uniformity of stirring. It is necessary to extend the stirring time and increase the addition of desulfurizer to achieve the desulfurization purpose. Utility Model Content
[0007] The utility model provides a KR stirring paddle for a molten iron ladle with a semi-spiral blade structure, which directly changes the existing KR stirring paddle steel structure and is easy to operate on site. Specifically, the stirring paddle blade of the utility model adopts a "straight up and inclined down" structure with a vertical upper part and a bent and inclined lower part, forming a semi-spiral stirring paddle. The structure is designed in advance to flush the molten iron with an inclined path to buffer the stirring resistance of the molten iron. During use, the lower spiral structure blade can make the molten iron rotate and vortex, and the upper straight blade can break the vortex to form a horizontal circulation flow. The two structures are combined to reduce the rotational inertia at high speed, which can reduce the height of the molten iron vortex and make the entire molten iron stir violently, thereby shortening the stirring time, reducing the addition of desulfurizer, achieving rapid desulfurization, controlling the height of the molten iron liquid level, ensuring that the molten iron does not overflow, and achieving safety in use. The utility model can also prevent the steel structure from being deformed and twisted due to high temperature, ensure the strength of the blade and the integrity of the refractory material, thereby increasing the service life of the stirring paddle.
[0008] The specific technical solutions are as follows:
[0009] A KR stirring paddle for a molten iron ladle with a semi-helical blade structure comprises a KR stirring paddle steel structure and a refractory castable wrapped outside the KR stirring paddle steel structure, wherein the KR stirring paddle steel structure comprises a stirring paddle main shaft and a plurality of stirring paddle blades uniformly welded circumferentially to the bottom of the stirring paddle main shaft, wherein the stirring paddle blades consist of an upper blade and a lower blade, wherein the upper blade is vertical, and the back side of the lower blade in the rotation direction forms an angle of 160 to 170 degrees with the upper blade.
[0010] During high-temperature stirring, the viscosity of the molten iron is very high. When the stirring paddle is used, the rotating stirring paddle is inserted into the high-temperature molten iron. In the process of entering the molten iron, the right angle is easily washed, worn, and broken. This is also the main reason for the short life of the straight stirring paddle. The semi-spiral blade structure of this scheme forms an angle of 160-170° between the back of the lower blade in the direction of rotation and the upper blade, which is the preset molten iron rotation path. The lower spiral design can alleviate the impact force when the stirring paddle is inserted into the molten iron, reduce the right-angle wear of the bottom of the stirring paddle, and slow down the fracture, thereby increasing the service life of the stirring paddle. At the same time, the 160-170° angle structure causes a vortex to form at the bottom of the stirring paddle when stirring. When the angle is large, there is no vortex effect. When the angle is small, the vortex is large. The larger the vortex, the greater the risk of overflow or the lower level of the molten iron loading liquid. There is a risk of cracking between the stirring paddle blade and the refractory castable. To avoid cracking, the utility model designs the back of the lower blade in the direction of rotation to form an angle of 160-170° with the upper blade.
[0011] In one embodiment, a stopper is provided at the bottom of the main shaft of the KR stirring paddle of the ladle with a semi-spiral blade structure.
[0012] Furthermore, the semi-spiral blade structure of the ladle KR stirring paddle has a vent pipe inside the stirring paddle main shaft, and gaps are left between the vent pipe and the inner wall of the stirring paddle main shaft and the block. Cooling gas can enter from the vent pipe, and after being dispersed by the block at the bottom of the stirring paddle main shaft, it flows out from the gap between the vent pipe and the inner wall of the stirring paddle main shaft, thereby cooling the stirring paddle steel structure, reducing the thermal stress generated by the steel structure, slowing down the stress deformation of the steel structure caused by high temperature, alleviating the problems of cracking and peeling of the castable, and improving the service life of the ladle stirring paddle.
[0013] In one embodiment, the ladle KR stirring paddle with a semi-spiral blade structure may be a four-blade structure, with four stirring paddle blades. The upper blades of the four stirring paddle blades may be uniformly welded to the bottom of the stirring paddle main shaft in a "cross" shape.
[0014] In one embodiment, the ladle KR stirring paddle with a semi-spiral blade structure has concave notches on the top and side surfaces of the upper blades and the bottom and side surfaces of the lower blades, which can enhance the tightness of the connection between the refractory castable and the steel structure and increase the connection strength.
[0015] In one embodiment, the ladle KR stirring paddle with a semi-helical blade structure has through holes on both the upper blade and the lower blade. When pouring refractory castables, the through holes are filled with refractory castables, so that the refractory castables on both sides of the stirring paddle blades are connected to maintain the integrity of the refractory castables.
[0016] In one embodiment, the ladle KR stirring paddle of the semi-spiral blade structure has a plurality of first V-shaped anchors with two arms in the shape of wavy lines welded horizontally and vertically on the surface of the stirring paddle blade. Compared with V-shaped anchors with two arms in the shape of straight lines arranged in the same direction, the utility model adopts the first V-shaped anchors with two arms in the shape of wavy lines and combines the horizontal and vertical staggered welding method, which can further enhance the bonding force between the stirring paddle blade and the refractory castable.
[0017] In one embodiment, the upper blade and the lower blade of the stirring paddle blade of the ladle KR stirring paddle with a semi-spiral blade structure can be integrally formed. For example, the lower part of the stirring paddle blade can be bent to a certain extent to form an upper blade and a lower blade with a certain angle, and when the stirring paddle blade is welded to the stirring paddle main shaft, the bending direction of the lower blade is kept opposite to the designed rotation direction of the stirring paddle. In addition, the upper blade and the lower blade of the stirring paddle blade can also be combined and fixed by welding or other methods.
[0018] In one embodiment, the ladle KR stirring paddle with the semi-helical blade structure has a plurality of second V-shaped anchors welded on the surface of the stirring paddle main shaft to enhance the bonding tightness between the stirring paddle main shaft and the refractory castable.
[0019] In one embodiment, the bottom end of the lower blade of the ladle KR stirring paddle with a semi-helical blade structure may be 50 to 100 mm higher than the bottom end of the stirring paddle main shaft.
[0020] In one embodiment, the ladle KR stirring paddle with a semi-spiral blade structure has an upper blade and a lower blade with the same width.
[0021] In one embodiment, the length ratio of the upper blade to the lower blade of the ladle KR stirring paddle with a semi-spiral blade structure can be 1:1 to 3. Under the above length ratio, the spiral structure of the lower blade enables the lower molten iron to form a vortex, and the molten iron with the vertical structure of the upper blade forms a horizontal circulation flow, breaking or relieving the vortex, reducing the height of the molten iron vortex, stirring the entire molten iron vigorously, and controlling the height of the molten iron liquid level to ensure that the molten iron does not overflow, thereby achieving safety in use.
[0022] In one embodiment, the thickness of the refractory castable of the ladle KR stirring paddle with a semi-helical blade structure may be 80 to 120 mm.
[0023] In one embodiment, the stirring paddle of the ladle KR with the semi-helical blade structure is a steel plate with a thickness of 80 to 100 mm.
[0024] Compared with the prior art, the utility model has the following beneficial effects:
[0025] 1. The straight structure of the upper part of the KR stirring paddle blade of the utility model can stir the molten iron, and the oblique structure of the lower part can reduce and buffer the resistance of the molten iron during stirring. The lower oblique structure is similar to the spiral type, and is combined with the upper straight structure to form a "straight on top and oblique on the bottom" structure, becoming a semi-spiral stirring paddle. The structure is designed in advance to flush the molten iron with an oblique path, which ensures that the molten iron is stirred evenly while buffering the resistance of the molten iron. The stirring kinetic energy of the original straight stirring paddle is concentrated near the straight blade, and is pushed toward the horizontal direction of the package wall. The flow in the bottom area of the package is very gentle, and the vortex is relatively gentle; the stirring kinetic energy generated by the semi-spiral stirring paddle of the utility model extends to the bottom of the package, and the flow in the bottom area of the package is more intense than that of the original straight stirring paddle, and the degree of vortex generated is more obvious.
[0026] 2. During use, the KR stirring paddle of the utility model can be introduced with cooling gas through the vent pipe, thereby reducing the temperature of the KR stirring paddle steel structure and its supporting refractory materials, reducing the thermal stress generated by the steel structure, avoiding deformation and distortion of the steel structure due to high temperature, and alleviating the cracking and peeling problems of the castable.
[0027] 3. The KR stirring paddle of the iron ladle with a semi-helical blade structure of the utility model can enhance the bonding strength between the stirring paddle steel structure and the refractory castable by means of the concave notch on the edge of the stirring paddle blade, the through hole in the middle, a plurality of first V-shaped anchors with wavy arms welded horizontally and vertically on the surface, and a plurality of second V-shaped anchors welded on the surface of the stirring paddle main shaft. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 The overall structure schematic diagram of the ladle KR stirring paddle with a semi-helical blade structure in a specific embodiment, the top of the figure shows the rotation direction, that is, the direction is clockwise when viewed from above;
[0029] Figure 2 It is a schematic diagram of the cross-sectional structure of a ladle KR stirring paddle with a semi-helical blade structure in a specific implementation manner;
[0030] Figure 3 It is a schematic structural diagram of a stirring paddle blade of a ladle KR stirring paddle with a semi-helical blade structure in a specific implementation manner;
[0031] Figure 4 It is an enlarged schematic diagram of the bottom structure of the stirring paddle main shaft of the KR stirring paddle of the molten iron ladle with a semi-helical blade structure in a specific implementation manner. DETAILED DESCRIPTION
[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0033] See also Figure 1, a semi-spiral blade structure KR stirring paddle 100 for molten iron ladle, a four-blade paddle structure, combined with Figure 2 The ladle KR stirring paddle 100 of the semi-helical blade structure includes a KR stirring paddle steel structure and a refractory castable 3 wrapped outside the KR stirring paddle steel structure. The thickness of the refractory castable can be 80 to 120 mm. The KR stirring paddle steel structure includes a stirring paddle main shaft 1 and four stirring paddle blades 4 uniformly welded to the bottom of the stirring paddle main shaft 1 in the circumferential direction. Figure 3 The stirring paddle blade 4 is composed of an upper blade 11 and a lower blade 10, wherein the upper blade 11 is vertical, that is, the upper blades 11 of the four stirring paddle blades 4 can be evenly welded to the bottom of the stirring paddle main shaft 1 in a "cross" shape, and the back of the lower blade 10 in the rotation direction forms an angle of 160 to 170 degrees with the upper blade 11 (i.e. Figure 3 The angle α in the stirring blade is 160-170°, specifically 165°). The width of the upper blade 11 and the lower blade 10 are the same, and the length ratio is 1:1-3, specifically 1:2. The stirring blade 4 is a steel plate with a thickness of 80-100 mm. Further, as Figure 2 As shown, the bottom end of the lower blade 10 is 50 to 100 mm higher than the bottom end of the stirring paddle main shaft 1.
[0034] Combination Figure 2 , Figure 4 , a stopper 5 is provided at the bottom of the stirring paddle main shaft 1. A vent pipe 2 is provided inside the stirring paddle main shaft 1, and gaps are left between the vent pipe 2 and the inner wall of the stirring paddle main shaft 1 and the stopper 5. The cooling gas can enter from the vent pipe 2, and after being dispersed by the stopper 5 at the bottom of the stirring paddle main shaft 1, it flows out from the gap between the vent pipe 2 and the inner wall of the stirring paddle main shaft 1, thereby cooling the stirring paddle steel structure, reducing the thermal stress generated by the steel structure, slowing down the stress deformation of the steel structure caused by high temperature, alleviating the problems of cracking and peeling of the castable, and improving the service life of the stirring paddle of the ladle.
[0035] Combination Figure 2 , Figure 3 The top and side surfaces of the upper blade 11 and the bottom and side surfaces of the lower blade 10 are provided with concave notches 7. The upper blade 11 and the lower blade 10 are provided with square or rectangular through holes 6. The surface of the stirring paddle 4 is welded with a plurality of first V-shaped anchors 8 with two arms in the shape of wavy lines in a staggered manner horizontally and vertically. Figure 2 , a plurality of second V-shaped anchors 9 are welded on the surface of the stirring paddle main shaft 1. The concave notch 7, the through hole 6, the plurality of first V-shaped anchors 8 with wavy arms welded horizontally and vertically on the stirring paddle blade 4, and the plurality of second V-shaped anchors 9 welded on the surface of the stirring paddle main shaft 1 can enhance the bonding strength between the stirring paddle steel structure and the refractory castable.
[0036] In this embodiment, the upper blade 11 and the lower blade 10 in the stirring paddle blade 4 can be integrally formed, that is, the lower portion of the stirring paddle blade 4 (for example, starting from 1 / 3 of the distance from the top in the length direction of the stirring paddle blade 4) is bent to a certain extent to form the upper blade 11 and the lower blade 10 with a certain angle, and when the stirring paddle blade 4 is welded to the stirring paddle main shaft 1, the bending direction of the lower blade 10 is kept opposite to the designed stirring paddle rotation direction. In addition, the upper blade 11 and the lower blade 10 in the stirring paddle blade 4 can also be combined and fixed by welding or other methods.
[0037] The semi-spiral KR stirring paddle of the utility model is designed with comprehensive consideration of the characteristics of the straight KR stirring paddle and the spiral KR stirring paddle. According to the actual stirring effect, the proportion of the straight structure and the spiral structure is adjusted and integrated, so that the liquid level of the upper part of the molten iron ladle is relatively balanced when the stirring paddle is stirring, and there is no molten iron overflow, and the lower part is stirred evenly without "dead corners". The actual example is used on a 350-ton molten iron ladle. Compared with the ordinary straight stirring paddle, the desulfurizer can be reduced by 100-300Kg / furnace when the semi-spiral stirring paddle is used, and the reduction is 3%-8%, and the stirring time is shortened by 1-2min, which is about 5%-10%.
[0038] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.
Claims
1. A ladle KR stirring paddle with a semi-helical blade structure, comprising a KR stirring paddle steel structure and a refractory castable (3) wrapped outside the KR stirring paddle steel structure, wherein the KR stirring paddle steel structure comprises a stirring paddle main shaft (1) and a plurality of stirring paddle blades (4) uniformly welded to the bottom of the stirring paddle main shaft (1) in a circumferential direction, characterized in that: The stirring paddle blade (4) consists of an upper blade (11) and a lower blade (10), wherein the upper blade (11) is vertical, and the back side of the lower blade (10) in the rotation direction forms an angle of 160 to 170 degrees with the upper blade (11).
2. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: A stopper (5) is provided at the bottom of the stirring paddle main shaft (1); A vent pipe (2) is arranged inside the stirring paddle main shaft (1), and gaps are left between the vent pipe (2) and the inner wall of the stirring paddle main shaft (1) and the stopper (5).
3. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: The ladle KR stirring paddle with a semi-spiral blade structure is a four-blade structure, and the number of the stirring paddle blades (4) is four.
4. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: The top surface and side surfaces of the upper blade (11) and the bottom surface and side surfaces of the lower blade (10) are all provided with concave notches (7).
5. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: The upper blade (11) and the lower blade (10) are both provided with through holes (6).
6. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: A plurality of first V-shaped anchor pieces (8) with two arms in the shape of wavy lines are welded in a staggered manner horizontally and vertically on the surface of the stirring paddle blade (4).
7. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: The upper blade (11) and the lower blade (10) of the stirring paddle blade (4) are integrally formed.
8. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: A plurality of second V-shaped anchors (9) are welded to the surface of the stirring paddle main shaft (1).
9. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: The bottom end of the lower blade (10) is 50 to 100 mm higher than the bottom end of the stirring paddle main shaft (1).
10. The ladle KR stirring impeller with a semi-helical blade structure according to claim 1, characterized in that: The widths of the upper blade (11) and the lower blade (10) are consistent, and the ratio of their lengths is 1:1-3.