阅读说明：本技术 铁水kr脱硫搅拌器用组合式搅拌叶金属芯 (Combined stirring blade metal core for molten iron KR desulfurization stirrer ) 是由 欧阳德刚 杨新泉 邓品团 朱善合 沈继胜 孙伟 朱万军 杨成威 刘婳 于 2020-06-11 设计创作，主要内容包括：本发明公开了铁水KR脱硫搅拌器用组合式搅拌叶金属芯,包括矩形金属厚板、大直径金属圆棒及小直径金属圆棒,大直径金属圆棒沿搅拌器轴向单排间隔均匀的焊接在矩形金属厚板的外侧面上,每个大直径金属圆棒垂直于矩形金属厚板；大直径金属圆棒外端面、前侧面和后侧面均焊接有小直径金属圆棒,最上一根大直径金属圆棒的上侧面和最下一根大直径金属圆棒的下侧面均焊接有小直径金属圆棒。具有服役条件下搅拌叶应力分布均匀、迟滞耐火材料衬的启裂与裂纹发展、遏制搅拌叶结构性损毁等优点,达到大幅度延长搅拌器使用寿命、延迟搅拌器在线起始维护时间、降低搅拌器在线维护量与维护成本、避免搅拌叶金属芯烧蚀、上下角部大块剥落带来的搅拌中途下线。(The invention discloses a combined stirring blade metal core for a KR desulfurization stirrer for molten iron, which comprises a rectangular metal thick plate, large-diameter metal round rods and small-diameter metal round rods, wherein the large-diameter metal round rods are welded on the outer side surface of the rectangular metal thick plate at intervals along the axial direction of the stirrer in a single row, and each large-diameter metal round rod is vertical to the rectangular metal thick plate; the outer end face, the front side face and the rear side face of each large-diameter metal round rod are welded with small-diameter metal round rods, and the upper side face of the uppermost large-diameter metal round rod and the lower side face of the lowermost large-diameter metal round rod are welded with small-diameter metal round rods. The stirrer has the advantages of uniform stress distribution of the stirring blades under service conditions, delayed crack initiation and crack development of refractory material linings, inhibition of structural damage of the stirring blades and the like, and achieves the purposes of greatly prolonging the service life of the stirrer, delaying the online initial maintenance time of the stirrer, reducing the online maintenance amount and the maintenance cost of the stirrer, and avoiding off-line stirring caused by ablation of metal cores of the stirring blades and large stripping of upper and lower corner parts.)

1. The utility model provides a molten iron KR desulfurization agitator is with combination formula stirring leaf metal core which characterized in that: the stirring shaft comprises a plurality of rectangular metal thick plates (4), a plurality of large-diameter metal round rods (5) arranged on each rectangular metal thick plate (4) and a plurality of small-diameter metal round rods (6) arranged on each large-diameter metal round rod (5), wherein the plurality of rectangular metal thick plates (4) are uniformly arranged along the circumferential direction, the inner side surfaces of the rectangular metal thick plates (4) are welded with the outer surface of the lower part of a metal stirring shaft core (2), the plurality of large-diameter metal round rods (5) are uniformly welded on the outer side surfaces of the rectangular metal thick plates (4) at intervals in a single row along the axial direction of a stirrer, and each large-diameter metal round rod (5) is perpendicular to each rectangular metal thick plate (4); in addition, the outer end face, the front side face and the rear side face of each large-diameter metal round rod (5) are welded with small-diameter metal round rods (6), and the upper side face of the uppermost large-diameter metal round rod (5) and the lower side face of the lowermost large-diameter metal round rod (5) are welded with small-diameter metal round rods (6).

2. The combined stirring blade metal core for the molten iron KR desulfurization stirrer as claimed in claim 1, wherein: the metal round bars with the small diameters (6) are vertically and uniformly welded on the front side and the rear side of the metal round bars with the large diameters (5) at intervals, the metal round bars with the small diameters (6) are obliquely welded on the upper side of the metal round bar with the large diameter (5) at the top and the lower side of the metal round bar with the large diameter (5) at the bottom at intervals, and in addition, the metal round bars with the small diameters (6) on the outer end faces of all the metal round bars with the large diameters (5) on each rectangular metal thick plate (4) are arranged in a divergent mode.

3. The combined stirring blade metal core for the molten iron KR desulfurization stirrer as claimed in claim 2, wherein: when the large-diameter metal round rods (5) are odd, the small-diameter metal round rods (6) on the outer end face of the middle large-diameter metal round rod (5) and the large-diameter metal round rods (5) are coaxially arranged, the small-diameter metal round rods (6) on the outer end faces of the other large-diameter metal round rods (5) are symmetrically arranged along the middle small-diameter metal round rod (6) in a divergent mode, and included angles between the small-diameter metal round rods (6) on the outer end faces of every two adjacent large-diameter metal round rods (5) are equal; when major diameter metal pole (5) are the even number, minor diameter metal pole (6) and major diameter metal pole (5) coaxial arrangement of two major diameter metal pole (5) outer terminal surfaces in the middle of, minor diameter metal pole (6) of all the other major diameter metal pole (5) outer terminal surfaces are along the symmetrical central line between two minor diameter metal pole (6) in the middle of and are divergent symmetrical arrangement, and except that minor diameter metal pole (6) of two major diameter metal pole (5) outer terminal surfaces in the middle of, the contained angle between minor diameter metal pole (6) of every other two adjacent major diameter metal pole (5) outer terminal surfaces equals.

4. The combined stirring blade metal core for the molten iron KR desulfurization stirrer as claimed in claim 1, wherein: the length L1 of the rectangular metal thick plate (4) along the radial direction of the stirrer is 50-70 mm, the circumferential thickness b1 is 70-110 mm, and the axial height H1 is 600-700 mm; the diameter d1 of the large-diameter metal round rod (5) is 45-65 mm, the length L2 along the radial direction of the stirrer is 350-450 mm, the ratio of the spacing distance b2 between the central lines of two adjacent large-diameter metal round rods (5) to the diameter d1 of the large-diameter metal round rod (5) is 2-2.5, the ratio of the distance b3 between the central line of the uppermost large-diameter metal round rod (5) and the upper end face of the rectangular metal thick plate (4) to the diameter d1 of the large-diameter metal round rod (5) is 1.0-1.5, and the ratio of the distance b3 between the central line of the lowermost large-diameter metal round rod (5) and the lower end face of the rectangular metal thick plate (4) to the diameter d1 of the large-diameter metal round rod (5) is 1.0-1.5.

5. The combined stirring blade metal core for the molten iron KR desulfurization stirrer as claimed in claim 1, wherein: the ratio of the diameter d2 of the small-diameter metal round rod (6) to the diameter d1 of the large-diameter metal round rod (5) is 1/3-1/2, the small-diameter metal round rods (6) are welded on the upper side surface of the uppermost large-diameter metal round rod (5) and the lower side surface of the lowermost large-diameter metal round rod (5) in an inclined mode at intervals, the inclination angle is 45-75 degrees, and the ratio of the interval distance b4 of every two adjacent small-diameter metal round rods (6) to the radial length L2 of the large-diameter metal round rods (5) is 1/2-1/3.

6. The combined stirring blade metal core for the molten iron KR desulfurization stirrer as claimed in claim 1, wherein: the top of the outer end face of the small-diameter metal round rod (6) on the upper end face of the topmost large-diameter metal round rod (5) is collinear with the top of the outer end face of the small-diameter metal round rod on the outer end face of the large-diameter metal round rod (5), and the line is parallel to the upper end face of the rectangular metal thick plate (4), similarly, the top of the outer end face of the small-diameter metal round rod (6) on the lower end face of the bottommost large-diameter metal round rod (5) is collinear with the top of the outer end face of the small-diameter metal round rod on the outer end face of the large-diameter metal round rod (5), and the line is parallel to the lower end face of the rectangular metal thick plate (4), and the distance from the top of the outer end face of the small-diameter metal round rod (6) on the upper end face of the topmost large-diameter metal round rod (5) to the top of the outer end face of the small-diameter metal round; and the distance L3 between the outer end face of the small-diameter metal round rod (6) coaxially arranged with the large-diameter metal round rod (5) and the surface of the stirring shaft core (2) is 400-520 mm.

7. The combined stirring blade metal core for the molten iron KR desulfurization stirrer as claimed in claim 1, wherein: the V-shaped metal anchoring parts (1) are distributed and welded on the outer surfaces of the rectangular metal thick plate (4), the large-diameter metal round rod (5) and the small-diameter metal round rod (6) at intervals.

Technical Field

The invention relates to the technical field of molten iron pretreatment, in particular to a combined stirring blade metal core for a molten iron KR desulfurization stirrer.

Background

According to the report of related data, the molten iron desulphurization pretreatment is the most economic process for reducing the mass fraction of sulfur in steel in a blast furnace converter-continuous casting process, and is one of important means for improving the operation of a blast furnace and a converter, wherein the molten iron KR stirring desulphurization process becomes the preferred process for efficiently and stably deeply desulphurizing molten iron with excellent stirring and mixing dynamics characteristics, and presents the development trend of gradually replacing the blowing desulphurization process along with the continuous improvement of the quality requirements of users on steel products and the continuous improvement of the molten iron KR stirring desulphurization technology.

The KR stirring desulfurization process of molten iron comprises the steps of enabling a stirrer with a metal stirring core and a rectangular or inverted right trapezoid blade which is lined with refractory materials and is arranged in a single-layer cross mode to vertically immerse molten iron along the center of a molten iron tank to be rotated and stirred, enabling the liquid level of the molten iron to generate a vortex, adding weighed desulfurizer to the surface of the molten iron through a feeder, drawing the desulfurizer floating on the liquid level of the molten iron down by the vortex to be drawn into the molten iron, discharging and floating under the action of centrifugal force and buoyancy lift force, realizing the entrainment, discharge and floating circulation motion of the desulfurizer in the molten iron, and achieving the purpose of molten iron desulfurization through the circulating mixed contact and surface reaction of the desulfurizer and high-temperature molten iron. Due to the downward pulling of the stirring vortex and the buoyancy rising of the self-floating desulfurizer particles, the entrainment and upward floating circulation of the desulfurizer in molten iron and the continuous contact reaction of the desulfurizer and the molten iron are realized; due to strong stirring power and up-and-down stirring circulating flow driving, the fast flow, turbulent flow mixing and shearing dispersion of the molten iron and the desulfurizer multi-phase fluid are realized, the mass transfer speed of reactants and reaction products in the molten iron tank is promoted, and the desulfurization reaction efficiency is improved; thereby greatly improving the dynamic condition of the molten iron desulphurization pretreatment reaction and obviously improving the stability of the desulphurization reaction and the economic index of the desulphurization technology. Therefore, the stirring desulfurization of the molten iron KR has the advantages of excellent desulfurization reaction kinetic condition, full desulfurization reaction, high desulfurization efficiency and the like, but the stirrer serving as the only power source in the stirring desulfurization reactor of the molten iron KR directly relates to the stirring mixing characteristic of the reactor and the degradation of the desulfurization reaction kinetic condition, not only needs to bear the effects of high-temperature heating, molten iron permeation, slag erosion, frequent and alternate change of high temperature and low temperature and the like, but also needs to bear the scouring of high-temperature molten iron, has extremely bad working conditions, is the most easily damaged device in the desulfurization reactor, needs to be maintained on line in large quantity, seriously restricts the exertion of the stirring desulfurization production capacity of the molten iron KR and the technical economy thereof, once becomes a key restriction factor for preventing the popularization and application of the stirring desulfurization technology of the molten iron KR, and therefore, how to delay the damage process of the stirrer and prolong the service life of the stirrer, The reduction of the online maintenance amount and the stable stirring and mixing characteristics become the focus of the consistent attention of scholars at home and abroad.

The molten iron KR desulfurization stirrer is a complex body formed by a metal stirring core and a refractory material lining outside the metal stirring core, wherein the metal stirring core is formed by welding a metal stirring shaft core, a stirring blade metal core thick plate and a metal anchoring piece, and the refractory material lining is integrally cast and molded by adopting a refractory castable. Based on the requirement of long service life of the stirrer, domestic and foreign scholars successively develop a great deal of work from the aspects of the appearance of the stirrer blade, refractory castable of the stirrer, repairing material, repairing and maintenance process thereof and the like, obtain the practical application effect of greatly prolonging the service life of the stirrer, greatly promote the development of the stirring desulfurization technology of the molten iron KR and meet the requirement of large-scale stable production of low-sulfur steel. However, with the continuous improvement of the quality requirement of steel products, the deep desulfurization proportion of molten iron is continuously improved, so that the secondary stirring time of a KR desulfurization single tank is continuously prolonged, and the service condition is continuously deteriorated; in addition, along with the maximization of smelting equipment and the optimization of molten iron conveying process, the temperature of desulfurization pretreatment molten iron is continuously increased, the highest molten iron desulfurization temperature exceeds 1500 ℃, the temperature level of the stirrer under the service condition is further increased, the rotating linear speed of the stirrer blade is increased, the scouring abrasion of the refractory material lining of the stirrer blade is aggravated, and the service life of the stirrer is greatly shortened. Analysis shows that the continuously deteriorated working condition parameters not only aggravate deterioration and abrasion of the lining physical and chemical performance of the refractory material of the stirrer and infiltration and corrosion of slag iron, and cause reduction of the service life of the stirrer, but also increase the heat absorption capacity and further increase the temperature of the stirrer in the stirring process, increase the temperature difference and thermal stress of intermittent stirring in the service process of the stirrer, promote crack initiation and crack development of the refractory material of the stirrer in a concentrated manner, and aggravate crack infiltration and peeling damage of the refractory material lining; meanwhile, the increase of the integral temperature of the stirrer enlarges the internal stress of the joint surface between the metal core and the refractory material lining caused by the difference of thermal expansion performance, so that the internal stress of the joint surface of the refractory material lining is damaged, the integrity of the composite structure of the metal core and the refractory material lining of the stirrer is seriously weakened, the structural peeling of the refractory material lining and the exposed melting loss of the metal core are caused, and the service life of the stirrer is greatly reduced. Therefore, the product quality and the production and management benefits of enterprises are effectively improved due to the continuous improvement of the technical requirements of molten iron desulphurization and the production and management technology, the working condition of molten iron KR stirring desulphurization is seriously deteriorated, the service life of the stirrer is shortened, the stability of the dynamic condition of molten iron KR stirring desulphurization reaction is reduced, and the technical economy of the molten iron KR stirring desulphurization process is restricted. Therefore, a new technology of prolonging the service life of the stirrer, which is suitable for the current KR stirring desulphurization molten iron condition development, is continuously developed.

According to the tracking record of the damage course of the stirrer in the service process in the molten iron KR desulfurization process of multiple domestic iron and steel enterprises, the damage of the stirrer is mainly concentrated at the radial outer side part of the stirring blade, the main damage forms are longitudinal and transverse cracks, crack penetration erosion, crack stripping, erosion abrasion and the like of a blade refractory material lining, and finally the stirrer is used after being burnt, damaged and eroded by a thick metal core plate of the stirring blade. Analysis shows that in the rotary stirring desulfurization process of the stirrer, along with the increase of the radial extension distance of the stirring blades, the rotating linear speed of the stirring blades is increased, the molten iron scouring and surface heat exchange are enhanced, the surface temperature, the temperature gradient and the temperature difference thermal stress are increased, the mechanical property of the refractory material lining is reduced, and particularly the radial outer side face of the stirring blade with the largest rotating radius is formed; in addition, to the edges and corners of the stirring blades, because a plurality of surfaces are in contact with molten iron for heat exchange, the heat exchange specific surface area is large, the working temperature is higher, the performance of the refractory material is reduced more quickly, and erosion wear and cracking are easier. The stirring blade is composed of a refractory material lining wrapped stirring blade metal core thick plate, and as the thermal expansion coefficient of the refractory material is lower than that of the metal material, the thermal expansion and contraction quantities of the stirring blade metal core thick plate and the wrapped refractory material lining are different in the intermittent stirring service process of the stirrer, so that huge interface internal stress is formed, and along with the increase of the radial extension distance of the stirring blade, the working temperature of the stirring blade is continuously increased, and the structural stress in the interface of the stirring blade metal core and the refractory material lining is sharply increased; due to the integrity of the thick metal plate with the metal core of the stirring blade and the unconstrained structural characteristics of the outer side surface of the stirring blade, the internal structural stress and the external thermal stress in the longitudinal middle part and the transverse middle part of the refractory lining of the stirring blade are concentrated and crack is initiated, and under the synergistic action of the scouring penetration of the stirring molten iron and the internal and external stresses, cracks rapidly develop and run through, particularly longitudinal cracks, are more seriously scoured by stirring circumferential flow, the online repair and maintenance effect is extremely poor, and finally the cracking peeling of the refractory lining of the stirring blade and the ablation and melting loss of the metal core of the stirring blade are caused and the off-line use is stopped. Therefore, the service life of the KR stirrer for the present molten iron is shortened due to not only increase of the desulfurized molten iron, but also crack damage caused by stress concentration in the structural interface of the thick metal plate core composite wrapped by the refractory material of the stirring blade.

Aiming at the problem of prolonging the service life of the stirrer, scholars at home and abroad develop a great deal of research work from two aspects of refractory materials of the stirrer and the appearance structure of the stirrer, and related documents of the problem of crack damage caused by concentrated internal stress of the stirring blades are not reported and pay less attention, such as: chinese patent "low stress molten iron desulphurization stirrer", grant bulletin number: CN107904348B discloses a low-stress stirrer consisting of a combined stirring blade core, a heat-insulating buffer coating and a refractory lining of the stirring blade core. Through the structural design of the combined stirring blade core, the combined stirring blade core formed by arranging a plurality of strip-shaped or cylindrical stirring blade cores at intervals of 5-100 mm in a layered mode along the axial direction of the stirring shaft is adopted, so that the accumulation of the thermal expansion amount of a conventional single plate-shaped metal stirring blade core structure is avoided, the thermal expansion amount of the stirring blade core along the direction of the stirring shaft is obviously reduced, the axial pulling crack damage of a refractory material lining of the stirring blade is effectively restrained, and the high-temperature melting damage resistance of the stirring blade core and the comprehensive integrity of the stirring blade are greatly improved; the thermal insulation buffer coating is sprayed on the surface of the combined stirring blade core, so that on one hand, the thermal expansion difference between the refractory material lining and the stirring blade core is absorbed and relieved, on the other hand, the thermal insulation of the stirring blade core is realized, the working temperature of the stirring blade core is reduced, and the thermal expansion amount of the stirring blade core is reduced; by the design of the formula of the heat-insulating spray coating, the excellent heat-insulating property, deformation capability and high-temperature resistance of the heat-insulating coating are ensured, and the heating and cooling speeds of the metal core of the stirring blade and the interface internal stress caused by the metal core in the service process are reduced; by the optimized design of the formula of the refractory castable for the stirring blade core refractory material lining, the limitation of the highest service temperature of steel fibers is avoided, the service temperature of the stirring blade core refractory material lining is greatly increased, and adverse effects caused by high-temperature oxidation and corrosion of the steel fibers in the conventional stirrer castable are avoided. Through industrial tests and popularization and application, the initial forming time of longitudinal and transverse cracks on the radially outer side surface of the stirring blade is prolonged, the development speed of longitudinal and transverse main cracks in the middle is delayed, the initial repairing and using times of the outer side surface of the stirring blade are delayed to about 200 from a conventional furnace of 20-30, the crack damage process of the refractory material lining on the outer side surface of the stirring blade is well inhibited, the service life of the stirrer is prolonged by about 0.5 time, and meanwhile, the online maintenance workload and the maintenance cost of the stirrer are obviously reduced. However, with the increase of the service life, the thickness of the erosion wear on the outer surface of the stirring blade is continuously increased, especially the blade extension part with large rotation radius and high linear velocity, so that the thickness of the refractory material lining for protecting the strip-shaped or cylindrical metal core is rapidly reduced, the temperature rise and reduction speed of the metal core in the service process is rapidly increased, the internal stress of the combination interface of the refractory material lining and the metal core is rapidly increased, the crack damage and the metal core ablation of the refractory material lining at the outer end surface of the strip-shaped or cylindrical metal core are caused, in addition, the large stripping of the upper corner part and the lower corner part at the outer side of the stirring blade is frequently caused. Analysis shows that the strip-shaped or cylindrical metal stirring core structure realizes the dispersion of the expansion with heat and contraction with cold of the metal stirring core of the whole metal thick plate, and reduces the damage degree caused by the concentration of internal and external stress of the stirring blade, but in order to ensure the sufficient strength and rigidity of the stirring blade, the dimension of the strip-shaped or cylindrical metal core is larger, when the refractory lining is seriously worn, the end face of the strip-shaped or cylindrical metal core still forms local internal stress concentration and local stress crack damage of the refractory lining because the heat insulation protection function of the refractory lining is reduced; meanwhile, because the strip-shaped or cylindrical metal core is arranged in parallel to the upper surface and the lower surface of the stirring blade, although the rotating linear speed of the upper surface and the lower surface of the stirring blade is reduced along with the reduction of the rotating radius, and the radial internal stress concentration phenomenon is not prominent, the service life of the stirrer is greatly prolonged, the abrasion of the refractory material linings of the upper end surface and the lower end surface of the stirring blade is serious, the radial stress concentration of the interface of the strip-shaped or cylindrical metal core of the upper surface and the lower surface is continuously intensified, the peripheral cracks are formed in the outer side areas of the upper end surface and the lower end surface of the stirring blade and longitudinally develop along the front surface and the rear surface of the stirring blade, and finally the large blocks at the upper; in addition, the reliability and the bonding compactness of the separated welding connection between the strip-shaped or cylindrical metal rod and the surface of the metal shaft center of the stirrer are difficult to keep consistent, and the welding operation is difficult to be large, so that the difference of the cooling effect of the metal shaft center of the stirrer on each metal rod of the stirring blade is large, and the cooling effect is also one of important factors causing the local internal stress concentration of the metal core of the stirring blade and the interface of the refractory material lining. Therefore, how to further reduce the concentration of internal stress in the interface between the metal core of the stirring blade composite body and the refractory lining is the key point for further prolonging the service life of the stirrer.

Aiming at further weakening stress concentration of the stirring blades and overcoming the problem of influence of different materials of the stirring blade complex on the structural integrity of the complex, the Chinese patent 'a long-life molten iron desulphurization stirrer', authorization notice number: CN107937655B discloses a long-life molten iron desulphurization stirrer with stirring blades composed of combined stirring blade cores and refractory material linings of the stirring blade cores. Through the structural design of the combined stirring blade core, the combined stirring blade core formed by arranging a plurality of refractory anchoring brick stirring blade cores at intervals of 10-50 mm in a layered mode along the axial direction of the stirring shaft is adopted, the accumulation of the thermal expansion amount of a conventional single plate-shaped metal stirring blade core structure is avoided, the thermal expansion amount of the stirring blade core along the direction of the stirring shaft is obviously reduced, the axial pulling and cracking damage of the refractory material lining of the stirring blade is effectively inhibited, particularly, the refractory anchoring brick and the refractory material lining of the stirring blade core are made of the same material, the internal stress caused by the thermal expansion difference between the stirring blade core and the refractory material lining of the stirring blade core is thoroughly avoided, and meanwhile, the high-temperature melting resistance of the stirring blade core and the comprehensive integrity of the stirring blade are greatly improved. According to the description, the refractory anchoring bricks are used as the stirring blade cores to realize the same material of the stirring blades, so that the problem of internal stress caused by different materials of the metal cores of the conventional stirring blades and the refractory lining is thoroughly solved, the purpose of greatly delaying the thermal stress damage process of the stirring blades can be theoretically achieved, but how to ensure the reliable connection of the refractory anchoring bricks and the axes of the stirring metals and continuously and stably bear the strong stirring force and molten iron impact force of the stirring blades in the high-temperature stirring process is realized, the potential equipment safety hazard caused by the sudden damage of the stirring blades is avoided, further research is needed, and the research is verified in an industrial test; meanwhile, due to the adoption of the non-standard refractory anchoring bricks, the customization and processing period of a small amount of anchoring bricks is long, the cost is high, and the industrial implementation of the technology is restricted, which is also the main reason that the patent technology has no reports of industrial tests and application effects.

In conclusion, for the stirring blade with the structure that the refractory material lining wraps the metal core complex body, which is simple to prepare and firm and reliable to combine, the problem of internal stress damage caused by the difference of physical and chemical properties of different materials of the stirring blade is effectively reduced, corresponding research has been carried out in China, and part of research results have better application effects in the aspects of prolonging the service life of the stirrer, reducing online maintenance and repair, reducing the production cost of stirring and desulfurizing molten iron KR and the like in actual production, however, a large research space is still left in the aspects of further restraining stress crack damage of the stirring blade, reliably preparing the stirrer, continuously stabilizing the using effect, avoiding potential safety hazard, prolonging the service life of the stirrer and the like, and particularly, the temperature and the stress distribution rule of the stirring blade under the service condition and the crack damage of local stress concentration caused by the temperature and the stress distribution rule of the stirring blade under the service condition are directly influenced by the metal stirring core structure.

Disclosure of Invention

The invention aims to provide a combined stirring blade metal core for a molten iron KR desulfurization stirrer, which has the advantages of uniform stress distribution of the stirring blades, retardation of crack initiation and crack development of a refractory material lining and inhibition of structural damage of the stirring blades, and aims to overcome the defects of the prior art.

In order to achieve the purpose, the combined stirring blade metal core for the molten iron KR desulfurization stirrer comprises a plurality of rectangular metal thick plates, a plurality of large-diameter metal round rods arranged on each rectangular metal thick plate and a plurality of small-diameter metal round rods arranged on each large-diameter metal round rod, wherein the plurality of rectangular metal thick plates are uniformly arranged along the circumferential direction, the inner side surfaces of the rectangular metal thick plates are welded with the outer surface of the lower part of the metal stirring shaft core, the plurality of large-diameter metal round rods are uniformly welded on the outer side surfaces of the rectangular metal thick plates at intervals in a single row along the axial direction of the stirrer, and each large-diameter metal round rod is perpendicular to the rectangular metal thick plates; in addition, the outer end face, the front side face and the rear side face of each large-diameter metal round rod are welded with small-diameter metal round rods, and the upper side face of the uppermost large-diameter metal round rod and the lower side face of the lowermost large-diameter metal round rod are welded with small-diameter metal round rods.

Furthermore, the small-diameter metal round rods are vertically and uniformly welded on the front side and the rear side of the large-diameter metal round rods at intervals, the small-diameter metal round rods are obliquely welded on the upper side of the uppermost large-diameter metal round rod and the lower side of the lowermost large-diameter metal round rod at intervals, and the small-diameter metal round rods on the outer end faces of all the large-diameter metal round rods on each rectangular metal thick plate are arranged in a divergent manner.

Further, when the number of the large-diameter metal round rods is odd, the small-diameter metal round rods on the outer end face of the middle large-diameter metal round rod and the large-diameter metal round rods are coaxially arranged, the small-diameter metal round rods on the outer end faces of the other large-diameter metal round rods are symmetrically arranged along the middle small-diameter metal round rod in a divergent mode, and included angles between the small-diameter metal round rods on the outer end faces of every two adjacent large-diameter metal round rods are equal; when major diameter metal pole is the even number, the minor diameter metal pole and the major diameter metal pole coaxial arrangement of two major diameter metal pole outer terminal surfaces in the middle of, the minor diameter metal pole of the outer terminal surface of all the other major diameter metal poles is along the symmetrical central line between two minor diameter metal poles in the middle of and disperses symmetrical arrangement, and except that the minor diameter metal pole of two major diameter metal pole outer terminal surfaces in the middle of, the minor diameter metal pole of every other two adjacent major diameter metal pole outer terminal surfaces is parallel arrangement, the contained angle between the minor diameter metal pole of all the other major diameter metal pole outer terminal surfaces equals.

Further, the radial length L1 of the rectangular metal thick plate along the stirrer is 50-70 mm, the circumferential thickness b1 is 70-110 mm, and the axial height H1 is 600-700 mm; the diameter d1 of the large-diameter metal round rod is 45-65 mm, the length L2 of the stirrer along the radial direction is 350-450 mm, the ratio of the spacing distance b2 between the central lines of two adjacent large-diameter metal round rods to the diameter d1 of the large-diameter metal round rod is 2-2.5, the ratio of the distance b3 between the central line of the uppermost large-diameter metal round rod and the upper end face of the rectangular metal thick plate to the diameter d1 of the large-diameter metal round rod is 1.0-1.5, and the ratio of the distance b3 between the central line of the lowermost large-diameter metal round rod and the lower end face of the rectangular metal thick plate to the diameter d1 of the large-diameter metal round rod is 1.0-1.5.

Furthermore, the ratio of the diameter d2 of the small-diameter metal round rods to the diameter d1 of the large-diameter metal round rods is 1/3-1/2, the small-diameter metal round rods are welded on the upper side surface of the uppermost large-diameter metal round rod and the lower side surface of the lowermost large-diameter metal round rod at intervals in an inclined mode, the inclination angle is 45-75 degrees, and the ratio of the interval distance b4 of every two adjacent small-diameter metal round rods to the radial length L2 of the large-diameter metal round rods is 1/2-1/3.

Further, the top of the outer end face of the small-diameter metal round rod on the upper end face of the uppermost large-diameter metal round rod is collinear with the top of the outer end face of the small-diameter metal round rod on the outer end face of the large-diameter metal round rod and the line is parallel to the upper end face of the rectangular metal thick plate, similarly, the top of the outer end face of the small-diameter metal round rod on the lower end face of the lowermost large-diameter metal round rod is collinear with the top of the outer end face of the small-diameter metal round rod on the outer end face of the large-diameter metal round rod and the line is parallel to the lower end face of the rectangular metal thick plate, and the distance from the top of the outer end face of the small-diameter metal round rod on the upper end face of the uppermost large-diameter metal round rod to the top of the outer end face of the small-diameter metal round rod; and the distance L3 between the outer end face of the small-diameter metal round rod coaxially arranged with the large-diameter metal round rod and the surface of the stirring shaft core is 400-520 mm.

Furthermore, V-shaped metal anchoring parts are distributed and welded on the outer surfaces of the rectangular metal thick plate, the large-diameter metal round rod and the small-diameter metal round rod at intervals.

Compared with the prior art, the invention has the following advantages: the combined stirring blade metal core for the molten iron KR desulfurization stirrer has the advantages of simple and reliable metal core processing and preparation under service conditions, uniform stress distribution of the stirring blades, delayed crack initiation and crack development of a refractory material lining, inhibition of structural damage of the stirring blades and the like, and achieves the comprehensive purposes of greatly prolonging the service life of the stirrer, delaying the online initial maintenance time of the stirrer, reducing the online maintenance amount and the maintenance cost of the stirrer, avoiding the ablation of the metal core of the stirring blades and the adverse influence of large stripping of upper and lower corner parts on the production rhythm during the offline stirring process and greatly improving the economic indexes of the molten iron KR desulfurization technology and the like.

Drawings

FIG. 1 is a schematic structural view of a metal core of a thick plate of a stirring blade of a conventional stirrer;

FIG. 2 is a schematic sectional view taken along line A-A of FIG. 1;

FIG. 3 is a schematic structural diagram of a combined stirring blade metal core for a KR desulfuration stirrer for molten iron according to the present invention;

FIG. 4 is a schematic sectional view taken along line B-B of FIG. 3

The components in the figures are numbered as follows: the device comprises a V-shaped metal anchoring piece 1, a stirring shaft core 2, a metal core thick plate 3 of a conventional stirring blade, a rectangular metal thick plate 4, a large-diameter metal round rod 5 and a small-diameter metal round rod 6.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments.

As shown in fig. 1 and 2, the combined stirring blade metal core for the molten iron KR desulfurization stirrer shown in fig. 3 and 4 comprises three or four rectangular metal thick plates 4, a plurality of large-diameter metal round rods 5 mounted on each rectangular metal thick plate 4, and a plurality of small-diameter metal round rods 6 mounted on each large-diameter metal round rod 5, wherein the three or four rectangular metal thick plates 4 are uniformly arranged along the circumferential direction, the inner side surfaces of the rectangular metal thick plates 4 are welded to the outer surface of the lower part of the metal stirring shaft core 2, the plurality of large-diameter metal round rods 5 are welded to the outer side surfaces of the rectangular metal thick plates 4 at uniform intervals in a single row along the axial direction of the stirrer, and each large-diameter metal round rod 5 is perpendicular to the rectangular metal thick plates 4; in addition, the outer end face, the front side face and the rear side face of each large-diameter metal round rod 5 are welded with the small-diameter metal round rods 6, the upper side face of the uppermost large-diameter metal round rod 5 and the lower side face of the lowermost large-diameter metal round rod 5 are welded with the small-diameter metal round rods 6, and the V-shaped metal anchoring parts 1 are welded on the outer surfaces of the rectangular metal thick plate 4, the large-diameter metal round rods 5 and the small-diameter metal round rods 6 at intervals.

Wherein, in the front and back directions of the metal core of the stirring blade, the small-diameter metal round bars 6 are vertically and evenly welded on the front side surface and the back side surface of the large-diameter metal round bar 5 at intervals, in the upper and lower surface directions of the metal core of the stirring blade, the small-diameter metal round rods 6 are obliquely welded on the upper side surface of the uppermost large-diameter metal round rod 5 and the lower side surface of the lowermost large-diameter metal round rod 5 at intervals, in addition, the small-diameter metal round rods 6 on the outer end faces of all the large-diameter metal round rods 5 on each rectangular thick metal plate 4 are arranged in a divergent manner, that is, if the number of the large diameter metal round rods 5 is odd, the small diameter metal round rod 6 on the outer end face of the large diameter metal round rod 5 is coaxially arranged with the large diameter metal round rod 5, the small-diameter metal round rods 6 on the outer end faces of the other large-diameter metal round rods 5 are arranged along one small-diameter metal round rod 6 in a divergent symmetrical mode, and the included angles between the small-diameter metal round rods 6 on the outer end faces of every two adjacent large-diameter metal round rods 5 are equal; if major diameter metal pole 5 is when the even number, the minor diameter metal pole 6 and the major diameter metal pole 5 coaxial arrangement of two middle major diameter metal pole 5 outer terminal surfaces, the minor diameter metal pole 6 of the other major diameter metal pole 5 outer terminal surfaces is along the symmetrical central line between two middle minor diameter metal poles 6 and is the symmetrical arrangement that diverges, and except that the minor diameter metal pole 6 of two middle major diameter metal pole 5 outer terminal surfaces is parallel arrangement, the contained angle between the minor diameter metal pole 6 of the other every two adjacent major diameter metal pole 5 outer terminal surfaces equals.

The radial length L1 of the rectangular metal thick plate 4 along the stirrer is 50-70 mm, the circumferential thickness b1 is 70-110 mm, and the axial height H1 is 600-700 mm; the diameter d1 of the large-diameter metal round rod 5 is 45-65 mm, the length L2 along the radial direction of the stirrer is 350-450 mm, the ratio of the spacing distance b2 between the central lines of two adjacent large-diameter metal round rods 5 to the diameter d1 of the large-diameter metal round rod 5 is 2-2.5, the ratio of the distance b3 between the central line of the uppermost large-diameter metal round rod 5 and the upper end face of the rectangular metal thick plate 4 to the diameter d1 of the large-diameter metal round rod 5 is 1.0-1.5, and the ratio of the distance b3 between the central line of the lowermost large-diameter metal round rod 5 and the lower end face of the rectangular metal thick plate 4 to the diameter d1 of the large-diameter metal round rod 5 is 1.0-1.5.

The ratio of the diameter d2 of the small-diameter metal round rod 6 to the diameter d1 of the large-diameter metal round rod 5 is 1/3-1/2, the small-diameter metal round rods 6 are welded on the upper side surface of the uppermost large-diameter metal round rod 5 and the lower side surface of the lowermost large-diameter metal round rod 5 in an inclined mode at intervals, the inclination angle is 45-75 degrees, and the ratio of the interval distance b4 of every two adjacent small-diameter metal round rods 6 to the radial length L2 of the large-diameter metal round rod 5 is 1/2-1/3; the top of the outer end face of the small-diameter metal round rod 6 on the upper end face of the topmost large-diameter metal round rod 5 is collinear with the top of the outer end face of the small-diameter metal round rod on the outer end face of the large-diameter metal round rod 5 and the line is parallel to the upper end face of the rectangular metal thick plate 4, and similarly, the top of the outer end face of the small-diameter metal round rod 6 on the lower end face of the bottommost large-diameter metal round rod 5 is collinear with the top of the outer end face of the small-diameter metal round rod on the outer end face of the large-diameter metal round rod 5 and the line is parallel to the lower end face of the rectangular metal thick plate 4, and the distance from the top of the outer end face of the small-diameter metal round rod 6 on the upper end face of the topmost large-diameter metal round rod 5 to the top of the outer end face of the small; the distance L3 between the outer end face of the small-diameter metal round rod 6 coaxially arranged with the large-diameter metal round rod 5 and the surface of the stirring shaft core 2 is 400-520 mm. The structure of other metal cores and the number of stirring blades of the stirrer are the same as those of a conventional stirrer.

According to the combined stirring blade metal core for the molten iron KR desulfurization stirrer, the combined structure design formed by the rectangular metal thick plate, the large-diameter metal round rod, the small-diameter metal round rod and the like provides convenience for implementation of a combined structure formed by metal components such as the whole body, the separating body, the dispersing body and the like of the stirring blade metal core; through the connection combination mode of the rectangular metal thick plate, the large-diameter metal round bar and the small-diameter metal round bar, wherein the rectangular metal thick plate is connected with the outer surface of the lower part of the metal core of the stirring shaft in a welding way, one end of the large-diameter metal round bar is vertical to the outer side surface of the rectangular metal thick plate and is connected with the outer side surface of the rectangular metal thick plate in a single row at intervals along the axial direction of the stirrer, one end of the small-diameter metal round bar is connected with the outer end surface or the side surface of the large-diameter metal round bar in a welding way, and the V-shaped metal anchoring parts are uniformly distributed and welded on the outer surface of the metal core of the stirring blade at intervals, the firm connection among all metal components of the combined metal core of the stirring blade is ensured, the preparation difficulty of the metal core of the stirring blade is reduced, the internal stress dispersion effect of the, thereby providing an effective inhibiting means for the internal stress damage of the interface of the stirring blade of the refractory material wrapped metal core composite structure. Through the structural design that other metal core structures of the stirrer and the quantity of the stirring blades are the same as those of the conventional stirrer, the use requirements of online replacement, installation and stable operation of the stirrer are met.

According to the combined stirring blade metal core for the molten iron KR desulfurization stirrer, the structural dimensions of the rectangular metal thick plate are 50-70 mm along the radial length L1 of the stirrer, and the circumferential thickness b1 and the axial height H1 of the rectangular metal thick plate are the same as the circumferential thickness b0 and the axial height H0 of the conventional stirring blade metal core thick plate, so that the reliability and firmness of the surface welding connection of the combined stirring blade metal core and the metal stirring shaft are ensured, the uniform cooling effect of the air-cooled stirring shaft metal core on the combined stirring blade metal core is improved, and the problem of internal stress concentration caused by the fact that the rectangular metal thick plate is too long along the radial length L1 of the stirrer is avoided; the strength and rigidity of the metal core of the combined stirring blade are ensured through the optimized design of the structural size of the large-diameter metal round bar and the welding arrangement mode, and the split dispersion effect of medium-strength internal stress in the radial middle section of the stirring blade is achieved; through the structural dimension of the small-diameter metal round bar and the optimized design of the welding arrangement mode, the reliable transmission of the stirring torque is ensured, and the divergent dispersion of the internal stress of the area, close to the outer surface, of the stirring blade is realized.

In conclusion, the combined stirring blade metal core for the molten iron KR desulfurization stirrer ensures the strength and rigidity of the stirring blade metal core and improves the preparation reliability and the service performance through the reasonable design of each metal component and the combination mode; based on the rule that the internal stress of the stirring blade is increased from inside to outside, the internal stress split dispersion and the divergent dispersion of the metal core of the combined stirring blade greatly reduce the stress and the stress concentration degree in the interface between the refractory material lining of the stirring blade and the metal core, thereby effectively inhibiting the internal stress damage and the crack spalling damage of the stirring blade, and meeting the comprehensive technical requirements of further prolonging the service life of the stirrer, reducing the online maintenance amount, reducing the manufacturing difficulty and the like.

By adopting the combined stirring blade metal core structure, other conventional stirrer metal core structures and refractory material lining casting materials, one KR desulfurization stirrer is respectively used for a 200-ton hot metal ladle and a 300-ton hot metal ladle which are respectively manufactured in a trial mode, and the online installation and the industrial test of the stirrer are carried out through the stirrer connecting flange 1. In order to facilitate the sampling analysis and the damage mechanism research after the stirrer is taken off line, the termination tests are respectively carried out in the 721 furnace and the 601 furnaceCreating a historical maximum life record; according to the tracking and recording result of the test process, the stirrer is not cracked and damaged in the whole stirrer test process, the effect of dispersing the segmented and divergent internal stress of the stirring blades is achieved, online repair and maintenance are not carried out when the stirrer is used in a 400 furnace, the stirring power is slowly attenuated until the stirring rotating speed is still lower than the set highest rotating speed when the test is stopped, the one-time hit rate of molten iron desulphurization is stabilized to be more than 95%, and the average desulfurizer consumption is reduced by 0.5Kg/t_Iron(ii) a The appearance of the stirrer is observed when the stirrer is off line and after the stirrer is off line, the structure of the stirrer is finished, and the stirrer can still be used continuously. The method achieves the expected test purposes of restraining stress concentration crack damage of the stirring blades, prolonging the service life of the stirrer and improving the molten iron desulfurization effect.