Method for manufacturing centrifugal permanent mold roll and roll body molding device

Abstract

The present application relates to centrifugal shaped casting roller body modeling device, including several hole type chills for modeling rolling groove which are arranged in parallel along the axial direction in the roller die, the hole type chills are expanded and fixed in the annular structure of the inner wall of the roller die after being combined by at least 8 sector chills to limit the deformation of the sector chills, the hole type chill structure combined by multiple sector chills is adopted to be expanded and fixed in the inner side of the roller die, so that the deformation problem of the hole type chill is effectively solved, the demolding is facilitated, and the industrial production of shaped roller can be effectively realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of roll manufacturing, in particular to a preparation method of centrifugal mold casting roll and a roll body molding device thereof. BACKGROUND

[0002] Since the beginning of hot rolling steel, the roll has been the main working component and tool for continuous plastic deformation of metal on the rolling mill, and the performance of the roll directly affects the production efficiency of rolling and the surface quality of the steel, so the importance of the various physical and mechanical properties of the roll is self-evident. For many years, the roll production industry has actively introduced advanced technologies from related industries, and has made great progress and development in production processes and material properties, greatly promoting and promoting the development of the rolling industry. For example, in the plate and strip rolling industry, new material and new process rolls with excellent performance such as centrifugal casting high speed steel roll and CPC high speed steel roll have been introduced. In the wire and bar rolling industry, centrifugal high speed steel rolls and tungsten carbide rolls with excellent wear resistance for finishing mill stands have been introduced. These rolls produced with new materials and new processes have shown good rolling performance after being put into the market, and have also promoted the development of plate and strip rolling and wire and bar rolling industries.

[0003] However, the roll for rolling section steel has not developed significantly for a long time. Most of the rolls used for rolling section steel today are conventional rolls with poor wear resistance and toughness, and in recent years, a small part of the section steel rolling has introduced centrifugal rolls, but the materials are limited to medium NiCrMo non-limit hardening nodular cast iron rolls, pearlite nodular cast iron rolls and a small number of bainite nodular cast iron rolls. Although the unit rolling amount has increased, the increase is not large. If higher quality and higher hardness rolls are continuously introduced, the difficulty of deep hole machining will be greatly increased, which will inevitably consume huge opening hole cost and lose processing efficiency. At the same time, it also faces the problem of wear resistance reduction caused by the decrease of hardness after deep hole opening.

[0004] The product involved in the present application is a roll used for hot rolling production of large, medium and small section steel, and a roll for rough and medium rolling of bar and wire rod. These rolls have a common feature, that is, they need to open relatively deep grooves (generally the opening depth is 40-150mm, except for individual flat roll rolling of wire and bar rough and medium rolling). The basic structure of these rolls is as follows Figure 1 It includes a transmission end roll neck 1, a transmission end flat head 2, an operation side roll neck 5, a roll ring 4 of the roll body part, a rolling groove 3 of the roll body part and several parts.

[0005] The traditional roll production process in the past is to cast the roll body into a smooth state, process it according to the order drawing (flat roll drawing) and deliver it in the smooth state of the roll body, and then the rolling mill performs slotting according to the groove drawing, such as Figure 1This method has been used for many years (since the rolling steel and wire, bar), in the long-term practice of rolling found that this method has many drawbacks, the most prominent is that these rolls are often deep groove (the more large-scale steel groove deeper), the general depth of 40 ~ 150 mm, or even deeper. This will greatly increase the hardness of the upper and lower parts of the groove, thus greatly reducing the wear resistance of the groove, obviously will shorten the service life of the roll. The final result is that the frequent replacement of the groove, the roll, greatly reducing the rolling mill operating rate, increasing the rolling cost.

[0006] Because the roll body is cast by the inner surface of the cold die (we are used to call the roll die) coated with refractory material, the supercooling degree of the liquid iron closest to the cold die is relatively large during casting, so the microstructure grain of the outer surface of the roll is very fine and the hardness is relatively high, but as it extends to the inner layer of the roll, the supercooling degree becomes smaller and the microstructure grain becomes relatively larger. This is the inevitable result of the solidification process of liquid metal, that is, the microstructure difference from outside to inside is inevitable for the casting of rolls of any material. The difference in microstructure will inevitably result in a change in hardness. That is, the hardness difference from outside to inside will be different for different materials, but the hardness difference is inevitable. Then, using the ordinary flat roll casting method to produce steel rolling rolls, the microstructure of the groove will become larger and the hardness will gradually decrease as the groove extends downward after the groove is deepened, and the hardness at the bottom of the groove will be the lowest when the groove is finished. Thus, a large hardness difference will be formed between the upper surface of the groove and the bottom of the groove, which is called hardness difference. The upper part of the same groove has high wear resistance, while the bottom of the groove has low wear resistance, and the bottom of the groove will be the first to wear and deform when rolling, although the upper part of the groove has good wear resistance. The life of the groove is also ended. As can be seen, the hardness difference between the upper and lower parts of the groove will seriously affect the service effect and service life of the roll due to the characteristics of the deep groove of the steel rolling roll.

[0007] The machining amount of the groove required by the drawing is very large, and the weight loss of the machining is about 20-40% of the weight of the flat roll. As can be seen, the deep groove of the roll will consume a large amount of working hours, and also greatly increase the consumption of turning tools. If the number of grooved rolls is large, more numerical control machining tools need to be added. The cost of grooving machining is very huge, and the processing cycle is also prolonged, increasing the capital occupation.

[0008] When slotting the roll surface, the machining allowance is large, requiring a long time for drilling and turning. In addition, the outer layer of the roll is relatively hard, and the hardness is even higher if it is made of bainitic ductile iron or high-speed steel. Such a hard material will inevitably be subjected to high-intensity extrusion for a long time during the long processing process. Under the action of high-intensity extrusion, a lot of turning heat will be generated. During turning, the iron chips are often red, and the temperature of the iron chips can reach 700-800℃. The temperature of the roll at the turning point can also reach 500-600℃. If a rolling mill roll is subjected to the combined effects of high-intensity extrusion and high temperature for an extended period, the matrix structure will undergo a transformation. This is especially true for high-hardness materials such as bainitic ductile iron or high-speed steel, which often retain a significant proportion of austenite. Under high temperatures, this austenite undergoes a structural transformation, causing volume expansion. If this transformation is compounded by the high-intensity extrusion force, the stress on the outer layer of the roll will increase dramatically. If this stress exceeds the material's inherent toughness limit, stress release will occur, manifesting as a sudden cracking of the rolling groove during processing. Even if the initial stress does not exceed the material's tolerance limit, it will create a significant stress hazard during processing, posing a considerable threat to subsequent rolling operations. It is highly likely that the roll will suddenly release stress during rolling under the combined effects of temperature rise and rolling load, causing cracks or even complete collapse.

[0009] Existing technologies also include methods for achieving integral casting of molded rolls. For example, Chinese invention patent CN100404172C discloses a method for producing centrifugally cast grooved composite rolls. This method involves setting several metal rings inside a metal mold, cutting the metal rings into two semicircles using wire cutting, and fixing the metal rings inside the metal mold with bolts after drilling holes in the metal mold for casting. However, in practice, it has been found that when using this method for casting, after casting and cooling, the chills are deformed and cannot be used. They can only be used after being repaired on a lathe. However, it is troublesome to perform machining repairs after each use. More importantly, the dimensions of the repaired chills have changed, which will seriously affect the assembly of the chills and the fit of the inner hole of the roll mold. It will also affect the machining allowance of the chills. If the machining allowance is too large, the cooling effect of the die will be lost, and the performance of the groove will decrease. Meanwhile, the threaded connection is not conducive to opening the mold. During centrifugal casting, the roller mold will experience hot and cold changes, resulting in a large temperature difference. At the same time, the high-speed centrifugal rotation will also change the angle of the threaded connection position. Under the influence of thermal expansion and contraction, the difficulty of opening the mold will be increased dramatically. The difficulty of opening the mold will also affect the roundness of the metal mold and the deformation of the metal mold box during the opening and preparation process. Therefore, it was found during the trial production that this solution could not meet the requirements of industrial production and there are many technical problems that need to be solved. Summary of the Invention

[0010] (I) Technical problems to be solved

[0011] In order to solve the above problems of the prior art, the present application provides a preparation method of centrifugal profiled casting roll and a roll body modeling device, which realizes the centrifugal casting of profiled roll and effectively solves the deformation problem of the hole type cold iron, can adapt to batch production, effectively reduces the production and processing cost, and greatly increases the service life of the profiled roll.

[0012] (II) Technical solutions

[0013] In order to achieve the above purpose, the main technical solutions adopted by the present application include:

[0014] The centrifugal profiled casting roll body modeling device comprises a plurality of hole type cold irons for modeling rolling grooves arranged in parallel along the axial direction in the roll mold; the hole type cold iron is an annular structure composed of at least 8 fan-shaped cold irons expanded and arranged in the inner wall of the roll mold to limit the deformation of the fan-shaped cold iron.

[0015] Further, the metal mold is a roll mold or a roll mold inner mold arranged in the roll mold for changing the inner diameter of the roll mold.

[0016] Further, the hole type cold iron is cut into 12 fan-shaped cold irons by a metal ring wire.

[0017] Further, the planar end of the fan-shaped cold iron is provided with a positioning hole for positioning with an adjacent fan-shaped cold iron; a positioning pin is arranged in the positioning hole; the positioning hole is arranged close to the outer circular arc of the fan-shaped cold iron; the distance between the positioning hole and the outer circular arc of the fan-shaped cold iron is 25-35mm.

[0018] Further, at least two adjacent fan-shaped cold irons are provided with an expansion groove for expanding the hole type cold iron; an expansion pin is arranged in the expansion groove.

[0019] Further, the inner side of the fan-shaped cold iron is provided with a groove for reinforcing the refractory coating; the cross section of the groove is inverted triangular, and the bottom angle is arc-shaped.

[0020] A preparation method of centrifugal profiled casting roll, specifically comprising the following steps:

[0021] S1: Preparation and installation of hole-type cooling iron, referring to the roll hole pattern, according to the number and size of the rolling groove distributed on the same roll surface and the inner diameter of the roll die, a corresponding number of metal rings are made, the metal rings are cut into at least 8 fan-shaped cooling irons of the same size by wire cutting, positioning holes are opened in the plane end of two adjacent fan-shaped cooling irons, and an expansion groove for expanding the hole-type cooling iron is arranged between at least two adjacent fan-shaped cooling irons; referring to the design size on the paper, mark the installation position of the hole-type cooling iron on the roll die inner hole; place the positioning pin in the positioning hole in sequence to assemble the hole-type cooling iron, and finally expand the expansion pin into the expansion groove after expansion to complete the installation of the hole-type cooling iron;

[0022] S2: Roll die preheating, the roll die assembled with the hole-type cooling iron is put into the preheating kiln for preheating, and the preheating temperature is 70±5℃;

[0023] S3: Hole-type cooling iron brush coating, the roll die after preheating is hoisted out of the preheating kiln and placed horizontally on a special parallel anvil for safe rotation;

[0024] A layer of previously prepared clay water is brushed on the hole-type cooling iron after preheating to facilitate bonding of the coating;

[0025] The prepared paste-like refractory coating is quickly applied to the hole-type cooling iron and evenly scraped, compacted and polished;

[0026] The coating paste is diluted with water in a clean container, and the hole-type cooling iron is further brushed smooth with a clean brush;

[0027] The hole-type cooling iron is dried to half dry, and then brushed again with diluted coating, and the coating is absolutely uniform and smooth;

[0028] S4: End cap modeling, the sand and impurities on the corresponding end cap are cleaned;

[0029] The end cap is brushed with clay water;

[0030] The end cap is placed on the end cap modeling base of the corresponding type;

[0031] The end cap modeling sample is placed in the positioning groove of the end cap modeling sample in the end cap inner hole;

[0032] The modeling sand is filled between the end cap and the modeling sample, and tamped;

[0033] The protruding modeling sand on the upper surface of the end cap is scraped flat, and the modeling sample is removed;

[0034] The circular arc and plane of the modeling sample are repaired according to the process requirements;

[0035] The end cap is brushed with special refractory coating;

[0036] When the first coat of paint is dry, use a spoon to press the paint and keep the surface smooth;

[0037] Brush the second coat of paint again;

[0038] When the second coat of paint is dry, press it again as above;

[0039] The third coat of paint is placed in a clean and uncontaminated container, and the paint is brushed again to ensure that the surface is smooth and completely brushed;

[0040] When the third coat of paint is dry, the end cap is installed on both sides of the roller mold with the end cap expansion pin, and the pin is installed, and at least six end cap expansion pins are installed on each end cap;

[0041] S5: drying and preheating, the roller mold combination with the cold iron and the end cap is lifted to the drying kiln trolley, and the sand mold is dried and the cold mold is preheated;

[0042] S6: roller mold coating, the roller mold combination after drying and preheating is pulled out of the drying kiln, and the roller mold combination is lifted to the centrifuge;

[0043] Start the centrifuge at a speed of 800-1100 rpm as required by the process;

[0044] Place the coated sand in a strictly positioned paint tank, and extend it into the hole of the end cap on both sides of the roller mold;

[0045] Uniformly and slowly tilt the paint tank to accurately and uniformly pour the paint onto the inner surface of the roller mold in the gap;

[0046] Keep the centrifuge rotating for 1 minute and stop, and the paint is complete;

[0047] After checking that the paint is completely qualified without defects, wait for pouring.

[0048] S7: outer layer pouring, after completing the furnace-side smelting according to the chemical composition required by the process, take the furnace-side test sample for analysis;

[0049] After the chemical composition test is qualified, the temperature is raised to the required alloy temperature;

[0050] The crane lifts the pre-prepared and preheated alloy water ladle to the furnace for tapping;

[0051] After tapping, slagging and setting, measure the temperature;

[0052] After reaching the pouring temperature, immediately lift the ladle to the centrifuge gate position;

[0053] After the centrifuge speed reaches the required speed, pour;

[0054] Keep the flow stable during pouring, and slow down the flow in the later stage until the pouring is completed;

[0055] Pour the middle layer, and after the outer layer is poured, use the overhead crane to hoist the middle layer pouring alloy ladle with appropriate size and sufficient preheating to the furnace front to prepare for tapping;

[0056] After tapping, slagging and setting, hoist to the centrifuge pouring port;

[0057] Pour the middle layer alloy water into the inner surface of the outer layer when the temperature of the inner surface of the outer layer approaches the solidus temperature;

[0058] Pour the inner layer, when the inner surface of the middle layer runs to just reach the liquidus temperature, the outer layer and the middle layer just reach complete solidification, and it is required that the centrifuge is completely stopped at this time;

[0059] Hoist the roll die to the bottom box placed in advance to combine the box;

[0060] Combine the riser box and the pouring cup on the roll die;

[0061] Hoist the inner layer molten iron with qualified temperature and chemical composition to the pouring cup position for core pouring;

[0062] The core pouring requires stable flow pouring, and slow pouring when pouring into the riser box until the pouring is completed;

[0063] Cooling, the roll after pouring is naturally cooled in the pouring pit;

[0064] After the cooling time and temperature meet the requirements, hot opening of the box and sand cleaning are carried out;

[0065] After the cooling time of 3-7 hours and the temperature of 650-700 DEG C meet the requirements, hot opening of the box is carried out, and immediately hoisted into the 700 DEG C heat treatment kiln for uniform temperature, heat preservation and subsequent annealing treatment;

[0066] Transport the blank roll to machining or heat treatment.

[0067] (Three) beneficial effects

[0068] The beneficial effects of the present application are: the deformation problem of the pass cold iron is effectively solved by the split structure pass cold iron positioning and the expansion structure, and the pass cold iron can be used stably and for a long time, the production is facilitated, and the service life and mechanical properties of the roll are effectively improved by improving and optimizing the preparation method. DETAILED DESCRIPTION

[0069] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope, and other related drawings can also be obtained by those of ordinary skill in the art without any creative effort based on these drawings.

[0070] Figure 1 is a schematic diagram of the profile roll structure;

[0071] Figure 2 is an exploded view of the upper roll body shaping device of the present application;

[0072] Figure 3 is an exploded view of the lower roll body shaping device of the present application;

[0073] Figure 4 is a sectional view of the upper roll overall cavity assembly structure of the present application;

[0074] Figure 5 is a sectional view of the lower roll overall cavity assembly structure of the present application;

[0075] Figure 6 is a sectional view of the upper roll solid structure after pouring and solidification of the present application;

[0076] Figure 7 is a sectional view of the lower roll solid structure after pouring and solidification of the present application;

[0077] Figure 8 is a sectional view of the hole type cold iron of the present application;

[0078] Figure 9 is an A-A sectional view of the hole type cold iron of the present application;

[0079] Figure 10 is an enlarged view of the I part of the hole type cold iron of the present application;

[0080] Figure 11 is an enlarged view of the II part of the hole type cold iron of the present application;

[0081] Figure 12 is a schematic diagram of the paint tank structure of the present application;

[0082] Figure 13 is a photograph of the upper roll demolding of the present application;

[0083] Figure 14 is a photograph of the demolded upper roll of the present application;

[0084] Figure 15 is a photograph of the rough machining of the upper roll of the present application;

[0085] Explanation of reference signs

[0086] 1. drive end neck, 2. drive end head, 3. groove, 4. roll ring, 5. operating side neck;

[0087] 10. roll die, 101. roll die runway, 102. end cap pin hole; 20. groove cold iron, 201. expansion groove, 202. expansion pin; 21. fan-shaped cold iron, 211. positioning hole, 212. positioning pin, 213. groove, 30. end cap, 301. end cap expansion pin, 302. end cap sand mold;

[0088] 103. roll die inner die; 40. bottom box, 401. bottom box sand mold; 50. riser box, 501. riser box sand mold;

[0089] 60. upper roll blank, 601. upper roll core upper neck, 602. upper roll core lower neck, 603. upper roll outer layer, 604. upper roll intermediate layer, 605. upper roll core roll body;

[0090] 70. lower roll blank, 701. lower roll core upper neck, 702. lower roll core lower neck, 703. lower roll outer layer, 704. lower roll intermediate layer, 605. lower roll core roll body;

[0091] 800. paint tank, 801. partition; DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work under the premise that the embodiments fall within the scope of protection of the present application. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work under the premise that the embodiments fall within the scope of protection of the present application.

[0093] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0094] In the description of the present application, it should be noted that unless otherwise expressly specified and limited, the terms "mounting", "provided with", "connected" and the like should be interpreted broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0095] Embodiment one, please refer to Figures 1-11 The figure shows:

[0096] The centrifugal sand casting roller body molding device comprises a plurality of hole-type chills 20 for molding the rolling groove 3 arranged in the roller die 10 along the axial direction. The hole-type chills 20 are composed of at least 8 fan-shaped chills 21, which are expanded and tightly arranged on the inner wall of the roller die 10 to limit the deformation of the fan-shaped chills 21. The hole-type chills 20 are used to set in the roller die 10 to form the rolling groove 3. It not only facilitates demolding, but also needs to have close surface contact with the inner wall of the roller die 10 to avoid gaps. The purpose is to prevent molten iron from entering the gap during centrifugal casting and affecting product quality. During centrifugal casting, if the gap is not closed, the molten iron will enter the gap and affect the quality of the product. Figure 1The roll die 10 in the roll die 10 will be placed horizontally, and the roll die runway 101 will be in contact with the side supporting wheel on the centrifugal machine, and the roll die 10 will be driven to rotate at high speed by the rotation of the centrifugal machine side supporting wheel, if there is a gap, the high-speed rotating molten iron will enter the gap under the action of centrifugal force, and after cooling and solidification, it will be adhered to the inner wall of the roll die 10, which will affect the demolding and easily damage the roll die 10, so it is not suitable to use the way of destroying the overall structure of the roll die 10 to fix the hole type cooling iron 20, such as opening a threaded hole for fixing and the like, and the special process requirement of centrifugal casting also needs to ensure the uniformity of the mass distribution during high-speed rotation, so that the roll die 10 can rotate uniformly and stably, which also increases the difficulty of fixing the hole type cooling iron 20. The hole type cooling iron 20 is cut into at least 8 small fan-shaped cooling irons 21 and is expanded and arranged in the inner wall of the roll die 10, which can realize close fitting with the inner wall of the roll die 10, and at the same time, the overall consistency of the roll die 10 is not damaged, and the weight of the gas fixing part is not increased, which ensures the uniform distribution of the overall mass, thereby effectively realizing the forming of the profiled roll. At the same time, the purpose of dividing the at least 8 fan-shaped cooling irons 21 can also effectively reduce the deformation of the fan-shaped cooling iron 21 during centrifugal casting by the way of expansion and arrangement. Since the fan-shaped cooling iron 21 will expand and shrink when heated and cooled during centrifugal casting, the repeated process will cause the deformation of the fan-shaped cooling iron 21, which is not allowed. On the one hand, it will affect the final quality of the roll forming, and on the other hand, it will cause the hole type cooling iron 21 to become a consumable product. In order to ensure that the hole type cooling iron 20 can realize the demolding effect, it is a common means of the prior art to cut it into two or three pieces, but this method can only realize demolding, but the prior art does not consider more serious technical problems such as cooling iron deformation, and cannot actually solve the practical problems of casting and cost control, which is also the reason why the related technology has not been mass-produced in the prior art. By reducing the size of the fan-shaped cooling iron 21, the deformation amount of the fan-shaped cooling iron 21 can be effectively reduced to meet the needs of industrial production. Since the arc length occupied by the fan-shaped cooling iron 21 in the circle is shortened, it can realize smaller deformation under the same strength, and in combination with the special expansion structure of the present application, sufficient supporting force is provided to ensure that the fan-shaped cooling iron 21 is expanded and pressed against each other in the early stage of centrifugal casting of molten iron, thereby further avoiding the formation of gaps. Under the limitation of the roll die 10, the original ring structure is maintained, and during the cooling and shrinking process, on the one hand, the supporting force provided during expansion can reduce the deformation of the fan-shaped cooling iron 21, and on the other hand, due to the smaller length of the fan-shaped cooling iron 21, the contact surface of the adjacent two fan-shaped cooling irons 21 can also provide friction to prevent deformation, and the contact surface of the fan-shaped cooling irons 21 is wedge-shaped, which can further resist the fan-shaped cooling iron 21 to prevent its deformation, thereby fundamentally solving the problem of deformation.

[0097] In an embodiment of the present application, the hole type cooling iron 20 is cut into 12 fan-shaped cooling irons 21 by a metal ring wire. The flat end of the fan-shaped cooling iron 21 is provided with a positioning hole 211 for positioning with an adjacent fan-shaped cooling iron 21; the positioning hole 211 is provided with a positioning pin 212; the positioning hole 211 is arranged close to the outer circular arc of the fan-shaped cooling iron 21; the distance between the positioning hole 211 and the outer circular arc of the fan-shaped cooling iron 21 is 25-35 mm. At least two adjacent fan-shaped cooling irons 21 are provided with an expansion groove 201 for expanding the hole type cooling iron 20; the expansion groove 201 is provided with an expansion pin 202, and the expansion groove 201 is wedge-shaped; the expansion pin 202 is a wedge-shaped pin. By arranging the fan-shaped cooling iron 21 into 12 pieces, the fan-shaped cooling iron 21 can hardly deform, and can be repeatedly used for a long time. The positioning problem of the multiple fan-shaped cooling irons 21 is solved by the positioning pin 212. The positioning pin 212 can not only facilitate positioning, but also effectively prevent the inward shrinkage of the two ends of the fan-shaped cooling iron 21 from deforming when cooled. The positioning pin 212 is arranged at a position away from the center, which is close to the outer circular arc position while ensuring sufficient supporting force. By this design, the positioning pin 212 is away from the high-temperature iron (steel) water, and the heating is alleviated, and the temperature rise time is prolonged, so that the positioning pin 212 can fully play a role in limiting the deformation of the cooling iron. When cooled, the positioning pin 212 located on the outside is cooled first. Since it is straight, it can also ensure the straight characteristics after current cooling. When the fan-shaped cooling iron 21 is gradually cooled to the inner layer, it will deform inward. At this time, the positioning pin 212 cooled first will not be affected by the inward deformation of the fan-shaped cooling iron 21 and will not deform together, but can limit the inward deformation of the fan-shaped cooling iron 21, thereby further reducing the deformation of the fan-shaped cooling iron 21. The inward deformation refers to the deformation of the two ends of the fan-shaped cooling iron due to its arc structure and the cooling from the outside to the inside, which causes the two ends to shrink inward toward the center of the circular arc. This deformation will change the shape of the rolling groove of the roller, causing difficult-to-repair problems, and the deformed cooling iron is also difficult to be repeatedly used.

[0098] In an embodiment of the present application, the inner side of the fan-shaped cooling iron 21 is provided with a groove 213 for reinforcing the refractory coating. The cross section of the groove 213 is inverted triangular, and the bottom angle is circular arc. The groove 213 can facilitate the brushing of the coating and improve the connection stability of the coating, avoiding the problem of coating separation during centrifugal casting.

[0099] In an embodiment of the present application, the roll die 10 is provided with a roll die inner die 103 for changing the inner diameter of the roll die 10; the roll die inner die 103 is provided with a plurality of hole type cooling irons 20 for shaping the rolling groove 3 inside the roll die 10 in parallel along the axial direction. The roll die inner die 103 can use the same roll die 10 for casting the upper roll and the lower roll, saving the number of molds.

[0100] It is found through analysis that the main reason for the deformation of the hole-type cooling iron 20 is that the high-temperature metal liquid wraps the hole-type cooling iron 20 completely after the outer layer iron (steel) of the roll is water-grouted, at which time the cooling iron is suddenly and sharply heated, the temperature rises to about 900-1000 DEG C, and under the action of high temperature, the temperature continues for about 30 minutes, and then the temperature begins to slowly decrease. During the high-temperature period, the hole-type cooling iron expands, and the hole-type cooling iron is tightly expanded on the inner surface of the roll die. After grouting is completed, the temperature begins to slowly decrease as the heat of the metal liquid is continuously absorbed by the hole-type cooling iron and the roll die, and the temperature of the roll die is continuously dissipated to the air, and the temperature of the whole grouting body slowly decreases. During the process that the temperature of the metal liquid and the hole-type cooling iron in the roll die continuously decreases, their volumes also gradually shrink. The hole-type cooling iron combined by two single blocks shrinks in volume, and the outer side of the arc-shaped structure of the cooling iron first shrinks after heat dissipation, and the inner side temperature decreases more slowly and is still in a high-temperature state. When the outer side shrinks and deforms inward, the inner side is more likely to shrink inward due to the high temperature, and the arc of the single cooling iron is relatively long in order to realize positioning and fixing in the prior art, which results in a large shrinkage of the whole, and then the final result is that the hole-type cooling iron has a large shrinkage deformation. The single deformation of the hole-type cooling iron leads to that the combined hole-type cooling iron cannot form a complete circular hole, and if the hole-type is restored to a circular shape by mechanical processing repair, there are some other serious problems: (1) the hole-type cooling iron combination cannot be firmly combined without the roll die, and the whole cannot be repaired on a lathe, and the single block repair is almost infeasible. (2) After the first repair, the size of the hole-type cooling iron is somewhat deviated and can be barely accepted, but the problem is that the hole-type cooling iron is deformed every time, and the hole-type cooling iron needs to be repaired every time, and a large size deviation is generated in the second repair, which seriously affects the assembly of the hole-type cooling iron and the quenching effect of the rolling groove, not to mention the deformation and repair after the second time.

[0101] Through the above trial found problems, after careful analysis and research to decide to continue to decompose the hole type cold iron into more blocks, by reducing the arc of each cold iron to reduce the deformation of single cold iron method to control or basically eliminate the deformation of the whole hole type cold iron assembly. In the subsequent trial period has tried 4, 6, 8 and many other ways to try to solve the deformation of the hole type cold iron, but all ended in failure, the overall deformation of the hole type cold iron assembly cannot meet the production requirements. And with the increase of the number of cold iron, the positioning and installation difficulty of cold iron increases sharply, with the increase of the number, its installation and positioning in the roll die 10 are more difficult, how to ensure that the cold iron can be stably and accurately positioned and installed in the roll is also a difficulty. In the original scheme, after decomposing into several blocks, the roll is placed horizontally, and then placed in a circle in sequence, and the positioning is realized by using the small gap of the cold iron itself and the mutual extrusion. When rotating, the cold iron will tightly fit the inner wall of the roll due to the centrifugal force. However, with the increase of the number of cold iron, the positioning of this method is difficult to realize, and the gap is not easy to control. In the present application, the expansion pin 202 is extruded to make the fan-shaped cold iron 21 fit more tightly, and the installation method is changed to vertically place the roll die 10 to install the hole type cold iron 20, and the positioning pin 212 is added for positioning and reinforcement, effectively solving the problem of difficult installation.

[0102] The hole type cold iron 20 is made of heat-resistant metal material to ensure that the cold iron does not deform for a long time. In the subsequent trial verification, a 12-block combination method is adopted, which completely achieves the expected effect of realizing the purpose of basically no deformation of the hole type cold iron combination.

[0103] In production practice, it is found that although the design method of 12-block combination hole type cold iron solves the problem of shrinkage deformation of hole type cold iron, a new problem arises, that is, the assembly difficulty greatly increases after the number of cold iron increases to 12 blocks. Therefore, we try to solve the problems of assembly, inlaying and fixing.

[0104] If it is 2 or 4 blocks, the assembly difficulty will be small, but the assembly difficulty of 12 blocks will greatly increase. Therefore, after many attempts and careful research, positioning holes are designed on the connecting end face of single hole type cold iron, and positioning pins are installed in the positioning holes, so that adjacent single hole type cold iron can be connected together to prevent single cold iron from falling down when suspended during installation. The specially made hoisting tool for hole type cold iron combination is used to hoist the previously combined hole type cold iron into the inner hole of the roll die, and the expansion pin is tightened at the positioned position to complete the installation of the hole type cold iron.

[0105] Through repeated trial production, it is proved that the design of the 12-piece combined hole-type cooling iron can effectively solve the deformation problem of the hole-type cooling iron. After many failures and improvements, the positioning pin hole is designed between the single-piece hole-type cooling iron, and the positioning pin is used to connect the single-piece cooling iron during assembly. After the assembly of all single-piece hole-type cooling irons in the circumferential direction is completed, a 3% wedge expansion groove 201 is designed between the last two cooling irons (without positioning pin between the two cooling irons), and a 3% wedge wedge is punched into the expansion groove 201 for expansion. In this way, the assembly of the 12-piece hole-type cooling iron is perfectly completed.

[0106] It is particularly noted here that the purpose of designing the single-piece cooling iron positioning hole and positioning pin is to facilitate the assembly of the 12-piece cooling iron, and at the same time, they also play another crucial role, i.e. limiting expansion and contraction during heating and cooling of the hole-type cooling iron, and preventing deformation of the hole-type cooling iron. Because the hole and pin belong to a small gap fit, they need to be made on site, and the fit gap is about 0.10mm. In this way, the deformation of the hole-type cooling iron assembly after assembly is controlled within a very small range. In addition, the positioning hole is designed to be located at a position of 25-35mm from the outer circle of the hole-type cooling iron (the mating surface with the inner hole of the roll die) towards the center. This position is far away from the high-temperature iron (steel) water, and the heating is relieved, and the temperature rise time is prolonged. In this way, the positioning pin can fully play a role in limiting the deformation of the cooling iron.

[0107] The hole-type cooling iron adopts heat-resistant cast iron material. In the selection of the material of the hole-type cooling iron, the minimum deformation is achieved. Through the trial of various materials, the material with the smallest deformation, i.e. high-chromium cast iron, is finally determined.

[0108] The problem of coating hanging of the hole-type cooling iron and the inner surface of the roll die. The refractory coating is a necessary refractory barrier between the metal mold and the high-temperature iron (steel) water in the metal cavity, and it has strict requirements on the coating: 1) The refractory degree of the coating should be high. The pouring temperature of the outer layer of the roll is 1350-1500℃ (the pouring temperature of the iron water is the lower limit temperature, and the pouring temperature of the steel water is the lower limit temperature). Therefore, only the coating with high refractory degree can withstand the high-temperature iron (steel) water. 2) The strength of the coating should be high. During centrifugal pouring, the iron (steel) water is poured into the high-speed rotating mold cavity through a special pouring gate (the general mold rotating speed is 800-1100r / min). At this time, the roll die inner hole and the cooling iron will be subjected to a large iron (steel) water erosion under the action of centrifugal force. If the coating strength is low, it will fall off during centrifugal pouring, causing the iron (steel) water to directly contact the mold or the cooling iron and cause adhesion, ultimately damaging the mold and causing the roll to be scrapped. After many failures, the coating ratio and hanging method are determined.

[0109] Coating ratio:

[0110]

[0111] The brushing method of the coating: the coating is brushed by adopting the method of turning grooves on the cold iron. When the hole type cold iron is machined, the helical grooves with the width of 4mm and the depth of 2.5mm are turned on the inner side of the cold iron to reinforce the refractory coating. When the coating is brushed, the coating is first applied on the surface with the grooves, then the diluted coating is brushed with a brush after the surface is smooth, the coating is brushed again after the surface is dried, and the surface is kept smooth without sand and pits. After the hole type cold iron is brushed with the coating, the hole type cold iron is put into the drying kiln to be preheated and dried, and then the coating is applied on the inner surface of the roll die. Thus, the coating of the whole cavity is applied, and the cavity is waiting for pouring.

[0112] The above design is obtained through trial production and exploration for more than ten years, and the centrifugal compound centrifugal mold casting roll can be successfully mass produced.

[0113] The use of the process for producing the roll for section steel also brings great benefits in the following aspects:

[0114] 1. Because the roll hole type produced by the centrifugal compound centrifugal mold casting roll process is formed by the method of chilling and cooling, the cooling speed of the upper and lower parts of the hole type tends to be consistent, so that the grains of the upper and lower parts of the hole type tend to be consistent, and there is basically no difference in the grain size, so that the hardness of the upper and lower parts of the hole type is basically the same, and the wear resistance is basically the same. This makes the overall wear resistance of the whole roll groove consistent. This effectively eliminates the difference in wear resistance of the upper and lower parts of the roll groove, and improves the overall wear resistance of the whole roll groove.

[0115] In addition, the use of the process also improves the cooling speed of the metal liquid, and makes the overall roll grain tend to be refined, and further improves the wear resistance of the roll groove.

[0116] According to the previous trial production records, under the premise of maintaining the same chemical composition of the material (pearlitic ductile cast iron), the roll produced by the centrifugal compound centrifugal mold casting roll process can increase the steel passing amount by 200-250% when used for rolling the plain carbon 4# angle steel compared with the roll produced by the ordinary centrifugal compound casting roll process.

[0117] 2. The use of the process can greatly save the amount of outer high alloy iron (steel) liquid. In order to improve the wear resistance of the roll, the outer layer of the centrifugal roll often uses a material with high alloy content, and the valuable metals for cast iron rolls include nickel and molybdenum, and the material cost of the outer iron liquid is about 10000-13000 yuan / ton. The valuable metals for high speed steel rolls include nickel, molybdenum, niobium, vanadium and tungsten, and the material cost of the outer steel liquid is about 30000-35000 yuan / ton. The use of the process can save the amount of outer iron (steel) liquid by about 20-40%.

[0118] Table 1: Comparison of advantages of the centrifugal composite rolling roller for rough rolling of profiled steel and wire, rod with traditional centrifugal flat roller casting and rolling

[0119] Table 1

[0120]

[0121] A preparation method of a centrifugal profiled casting roller, specifically comprising the following steps:

[0122] S1: Preparation and installation of the hole type chills 20, referring to the roller hole type drawing, according to the number and size of the rolling grooves 3 distributed on the same roller surface and the inner diameter of the roller die 10, a corresponding number of metal rings are made, the metal rings are cut into at least 8 fan-shaped chills 21 of the same size by wire cutting, positioning holes 211 are opened at the plane ends of two adjacent fan-shaped chills 21, and expansion grooves 201 for expanding the hole type chills 20 are arranged between at least two adjacent fan-shaped chills 21; referring to the drawing design size, the installation position of the hole type chills 20 is marked on the inner hole of the clean roller die 10; the positioning pins 212 are placed in the positioning holes 211 in sequence to assemble the hole type chills, and finally the expansion pins 202 are punched into the expansion grooves 201 to expand and complete the installation of the hole type chills; as shown in Figure 2 the figure, the upper roller is made, two hole type chills 20 are installed in the roller die 10, the hole type chills 20 are tightly attached to the inner wall of the roller die 10 after being expanded by the expansion pins 202 cooperating with the expansion grooves 201, end covers 30 are fixed at both ends of the roller die 10, the end covers 30 are provided with end cover type sand 302, the end covers 30 are fixed by punching the tapered end cover expansion pins 301 into the end cover pin holes 102 uniformly arranged on the circumference of the end of the roller die 10, and the roller die runway 101 on the roller die 10 is used to cooperate with the centrifuge to enable the roller die 10 to rotate;

[0123] S2: Preheating of the roller die 10, the roller die with assembled hole type chills is put into the preheating kiln for preheating, and the preheating temperature is 70±5℃;

[0124] S3: Hole type chill 20 brush coating, the roller die after preheating is lifted out of the preheating kiln and placed horizontally on a special parallel anvil for safe rotation;

[0125] A layer of previously prepared clay water is brushed on the preheated hole type chill to facilitate the bonding of the coating;

[0126] The prepared paste-like refractory coating is quickly applied to the hole type chill and evenly scraped, compacted and polished;

[0127] The coating paste is diluted with water in a clean container, and the hole type chill is further brushed smooth with a clean brush;

[0128] When the chill is semi-dry, brush the chill with the diluted coating again, and make sure the coating is even and smooth;

[0129] S4: mold the end cap, clean the sand and debris on the corresponding end cap;

[0130] Brush the end cap with clay water;

[0131] Place the end cap on the corresponding end cap molding base;

[0132] Place the end cap molding pattern in the positioning groove of the end cap;

[0133] Fill the molding sand between the end cap and the molding pattern, and tamp it;

[0134] Scrape the protruding molding sand on the surface of the end cap, and remove the molding pattern;

[0135] According to the process requirements, repair the arc and plane of the molding pattern;

[0136] Brush the end cap with special refractory coating;

[0137] When the first coating is semi-dry, press the coating with a spatula, and make sure the surface of the coating is smooth after pressing;

[0138] Brush the second coating;

[0139] When the second coating is semi-dry, press the coating again as above;

[0140] For the third coating, use a clean and uncontaminated container to hold clean and sand-free coating, and brush the coating again with a clean brush to ensure that the coating surface is completely and smoothly coated;

[0141] When the third coating is semi-dry, install the well-molded end cap with the end cap expansion pin on both sides of the roll mold, and make sure there are at least 6 end cap expansion pins for each end cap;

[0142] S5: drying and preheating, hoist the roll mold assembly with the downed chill and the upped end cap to the drying kiln trolley, and pull it into the drying kiln for sand mold drying and cold mold preheating;

[0143] S6: roll mold coating, pull out the drying and preheated roll mold assembly from the drying kiln, and hoist it to the centrifuge;

[0144] Start the centrifuge at a speed of 800-1100 rpm as required by the process;

[0145] The coated sand coating is placed in a strictly positioned coating groove and extends into the hole of the end cover on both sides of the roll die; the coating groove 800 is a semicylinder consistent with the length of the roll die, the two ends are closed, the top is open, and a partition plate 801 is added in the middle to isolate the position provided with the profiled chill, so that the area without the profiled chill forms the coating groove 800 accommodating the coated sand coating; as shown in Figure 12

[0146] The coating groove is uniformly and slowly tilted to accurately and uniformly pour the coating into the inner surface of the roll die in the gap between the profiles;

[0147] The centrifuge is kept rotating for 1 minute and then stopped, and the coating is completed;

[0148] After the coating is completely qualified without defects, the pouring is waited.

[0149] S7: outer layer pouring, after the furnace-side smelting is completed according to the chemical composition required by the process, the furnace-side test sample is taken for test analysis;

[0150] After the chemical composition test is qualified, the temperature is increased to the required temperature of the alloy;

[0151] The crane lifts the previously prepared and preheated alloy ladle to the furnace side to prepare for tapping;

[0152] After the tapping, slagging and calming are completed, the temperature is measured;

[0153] After the pouring temperature requirement is reached, the ladle is lifted to the centrifuge pouring position;

[0154] After the centrifuge speed reaches the requirement, pouring is performed;

[0155] During pouring, fast and stable flow pouring is maintained, and slow flow pouring is performed in the later stage of pouring until it is filled;

[0156] Middle layer pouring, after the outer layer pouring is completed, the crane lifts the middle layer pouring alloy ladle with appropriate size and sufficient preheating to the furnace side to prepare for tapping; the preheating temperature requirement is 700-800℃;

[0157] After the tapping, slagging and calming are completed, the ladle is lifted to the centrifuge pouring position;

[0158] When the inner surface temperature of the outer layer approaches the solidus temperature, the middle layer alloy water is poured;

[0159] High-speed steel, bainite, pearlite III, pearlite II, pearlite I and other materials of the roll need to be poured with a middle layer, and the main purpose of pouring the middle layer is:

[0160] The main purposes of pouring the middle layer for high-speed steel rolls are two:

[0161] ​1) Because the outer layer of high speed steel roller contains a high content of chromium (Cr), generally 3-8%, if the intermediate layer is not poured to separate, the inner layer will dissolve a large amount of chromium in the outer layer during core pouring, because chromium is a strong carbide forming element, a large amount of carbide will be formed in the core, which will greatly reduce the tensile strength of the core, and serious problems such as roller breakage and cracking will occur during subsequent heat treatment process, and serious problems such as breakage and cracking will also occur during rolling on the rolling mill.

[0162] 2) Because the outer layer of high speed steel roller contains a large amount of elements such as molybdenum (Mo: 3-5%), niobium (Nb: 1-2%), vanadium (V: 3-9%), tungsten (W: 2-8%) and other elements, a large amount of corresponding ferroalloy needs to be added to ensure the content, and the value of these ferroalloy is very valuable, therefore the cost of the outer layer metal of high speed steel roller is also very high, reaching 25000-30000 yuan / ton. Therefore, the thickness of the working layer needs to be strictly controlled, both to ensure the need of rolling and not to waste. The method of pouring the intermediate layer can precisely control the back-dissolution amount of the outer layer, and on the basis of ensuring the precise connection of the small head of the end cover and the large head of the bottom box, reduce unnecessary working layer thickness and reduce production cost.

[0163] The intermediate layer of high speed steel roller is made of graphite steel material.

[0164] The purpose of pouring the intermediate layer of the roller made of bainite, pearlite III, pearlite II, pearlite I and other materials is the same as the second point of the high speed steel roller, which is to reduce the production cost of the outer layer.

[0165] Bainite, pearlite III, pearlite II, pearlite I and other materials all belong to nodular cast iron, so the intermediate layer can be made of the same nodular cast iron material as the core.

[0166] Pour the inner layer, when the inner surface of the intermediate layer runs to just reach the liquidus temperature, the outer layer and the intermediate layer just reach complete solidification, and the centrifuge is required to be completely stopped at this time;

[0167] Lift the roller mold 10 to the bottom box 40 placed in advance to combine the boxes;

[0168] Combine the riser box 50 and the sprue cup on the roller mold 10;

[0169] Lift the inner layer molten iron with qualified temperature and chemical composition to the sprue cup position for core pouring;

[0170] The core pouring requires rapid and stable flow pouring, and slows down when pouring into the riser box 50, until it is full;

[0171] Cooling, the poured roller is naturally cooled in the pouring pit;

[0172] After the cooling time and temperature reach the requirements, hot unpacking and sand cleaning are performed;

[0173] After the cooling time 3-7 hours and temperature reach the requirements 650-700℃, hot unpacking is performed, and the roll is immediately hoisted into a heat treatment kiln at 700℃ for temperature equalization, heat preservation and subsequent annealing treatment;

[0174] The roll blank is transported to machining or heat treatment.

[0175] As shown in Figure 2 is an exploded view of the upper roll body modeling device of the present application, Figure 3 is an exploded view of the lower roll body modeling device of the present application, since the main difference between the upper roll and the lower roll in modeling is the diameter of the roll and the difference in the pass, the same set of roll molds 10 can be used for casting the upper roll and the lower roll, the inner diameter of the roll mold 10 is changed to meet the size requirements of the lower roll by setting the roll mold inner mold 103 in the roll mold, and the corresponding pass chill 20 is set in the roll mold inner mold 103 to model the rolling groove 3 on the lower roll, the pass chill 20 in the lower roll body modeling device is also divided into 12 parts for assembly, and the installation method is the same as that in the upper roll, after the outer layer pouring and the intermediate layer pouring are completed, the roll mold 10 is hoisted onto the bottom box 40 placed in advance for closing, the bottom box 40 is provided with a bottom box sand mold 401, the roll mold 10 is closed with the riser box 50, the riser box 50 is provided with a riser box sand mold 501, and then the pouring of the lower roll is performed.

[0176] As shown in Figure 4 and Figure 5 shown, since the structures of the upper roll and the lower roll are slightly different, two pass chills 20 are set in the roll mold 10 when the upper roll is modeled, and three pass chills 20 matching the diameter of the roll mold inner mold 103 are set in the roll mold inner mold 103 when the lower roll is modeled.

[0177] As shown in Figure 6 shown, after pouring is completed, the upper roll is located in the modeling device to form an upper roll blank 60, which includes symmetrical upper roll necks 601 and lower roll necks 602 of the upper roll core part, and a middle part of the upper roll core part roll body 605, the outer of which is sequentially provided with an upper roll intermediate layer 604 and an upper roll outer layer 603, and two rolling grooves 3 formed on the upper roll outer layer 603 are formed by pass chill modeling.

[0178] As shown in Figure 7 shown, after pouring is completed, the lower roll is located in the modeling device to form a lower roll blank 70, which includes symmetrical upper roll necks 701 and lower roll necks 702 of the lower roll core part, and a middle part of the lower roll core part roll body 705, the outer of which is sequentially provided with a lower roll intermediate layer 704 and a lower roll outer layer 703, and three rolling grooves 3 formed on the lower roll outer layer 703 are formed by pass chill modeling.

[0179] As Figures 8-11 shown, it is a cross-sectional view of the hole type cold iron, which includes 12 pieces of fan-shaped cold iron 21 formed by circular ring line cutting, and the flat end between the adjacent two fan-shaped cold iron 21 is provided with a positioning pin 212 for connection and fixation. After connecting 10 pieces of fan-shaped cold iron 21 in turn, the last two pieces of fan-shaped cold iron 21 are provided with an expansion groove 201 for expanding the hole type cold iron 20, and the other flat end of the two pieces of fan-shaped cold iron 21 is provided with a positioning hole 211 matched with the positioning pin 212, so that the remaining 10 pieces of fan-shaped cold iron 21 can continue to be connected to form a circular ring, and finally the hole type cold iron 20 is expanded by driving the expansion pin 202 into the expansion groove 201 to tightly fit inside the roll die 10. The expansion groove 201 is formed by combining the half expansion grooves respectively formed on the adjacent two pieces of fan-shaped cold iron 21, and the expansion groove 201 is formed by recessing inward from the outer circle of the fan-shaped cold iron. The expansion groove 201 can also be arranged between more adjacent fan-shaped cold irons 21. If the expansion groove 201 is arranged, the positioning hole 211 arranged at the flat end and the positioning pin 212 at the corresponding position are cancelled. However, although the number of expansion grooves 201 can theoretically provide stronger expansion effect, it is not conducive to fixation, and the operation of driving the expansion pin 202 multiple times will also affect the roundness of the hole type cold iron 20 in the roll die 10, affect the uniform stress of the roll die 10 inside, because the expansion pin 202 is driven from the axial direction of the roll die 10, and is perpendicular to the radial direction of the hole type cold iron 20. During the expansion process, if the expansion pin 202 is repeatedly driven, the hole type cold iron 20 is easy to deviate from the original positioning position and move along the axial direction, and the stress of the hole type cold iron 20 is also complicated, which cannot be theoretically only extruded between the roll die 10. When the stress of the hole type cold iron 20 is simpler, the roundness of the hole type cold iron 20 can be better maintained when it is tightly fitted in the roll die 10, the stress of each part of the fan-shaped cold iron 21 is uniform, and during centrifugal casting, each fan-shaped cold iron 21 can be better limited and the deformation degree is reduced to meet the process requirements and be repeatedly used. If the number of expansion pins 202 is too large, the fan-shaped cold iron 21 will move slightly along the axial direction, and the movement will be limited by the positioning pin 212. The hole type cold iron 20 is equivalent to being inclinedly arranged inside the roll die 10, so the fan-shaped cold iron 21 will also be subjected to axial friction, and the force is mainly offset by the positioning pin 212, so that the fan-shaped cold iron 21 is subjected to stress before centrifugal casting, and the cold and hot changes during the casting process will amplify the influence, so that the deformation of the fan-shaped cold iron 21 is difficult to effectively control, causing positioning and deformation limitation failure, and the positioning pin 212 also has more obvious plastic deformation, which increases the difficulty of demolding.

[0180] The inner side of the perforated chill 20 is provided with several grooves 213. The cross-section of each groove 213 is an inverted triangle with rounded corners. The grooves 213 facilitate the application of coating and improve the adhesion stability of the coating, thus preventing coating detachment during centrifugal casting.

[0181] like Figures 13-15 As shown in the photo, the upper roll is a physical object immediately after demolding. The roll, cast using a die-cast chill structure, has no obvious defects, allowing for easy demolding. This significantly reduces the machining dimensions required for subsequent processing, greatly shortening the processing cycle. The upper roll is immediately after demolding from... Figure 13 As can be seen, the upper end of the die chill remains intact, without obvious gaps or deformation, effectively solving the problem of chill deformation and allowing for repeated use. A small shrinkage gap appears in the lower die chill, the size of which is within the machining allowance and does not affect the roundness of the roll groove. The deformation of the die chill is within a controllable range, and the die chill can also be used multiple times. When used for the second time, only one expansion pin 202 needs to be re-machined to achieve the tensioning effect of the die chill, effectively reducing deformation and improving the finished product quality of centrifugal casting rolls.

[0182] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A centrifugal permanent mold roll body molding apparatus characterized by comprising: The metal mold is a roller die or a roller die inner die arranged in the roller die for changing the inner diameter of the roller die.

2. A centrifugal mold roll body molding apparatus according to claim 1, characterized by: The hole type cold iron is cut into 12 fan-shaped cold irons by a metal ring wire.

3. The centrifugal mold roll body molding apparatus according to claim 1, characterized by: The inner side of the fan-shaped cold iron is provided with a groove for reinforcing the refractory coating; the cross section of the groove is inverted triangular, and the bottom angle is arc-shaped.

4. The centrifugal mold roll body molding apparatus according to claim 1, characterized by: Specifically includes the following steps:

5. A method of producing a centrifugal mold cast roll according to any one of claims 1 to 4, characterized in that: S1: preparation and installation of hole type cold iron, referring to the roll hole type drawing, according to the number and size of the rolling groove distributed on the same roll surface and the inner diameter of the roller die, the corresponding number of metal rings is made, the metal rings are cut into 12 fan-shaped cold irons of the same size by wire cutting, positioning holes are opened at the plane end of the adjacent two fan-shaped cold irons, and expansion grooves for expanding the hole type cold iron are arranged between at least two adjacent fan-shaped cold irons; according to the design size of the drawing, mark the installation position of the hole type cold iron on the inner hole of the clean roller die; put the positioning pin in the positioning hole in sequence to assemble the hole type cold iron, and finally expand the expansion pin into the expansion groove in the axial direction of the roller die to complete the installation of the hole type cold iron; S2: roller die preheating, the roller die assembled with the hole type cold iron is put into the preheating kiln for preheating, and the preheating temperature is 70±5℃; S3: hole type cold iron brush coating; S4: end cover molding, installing the molded end cover on both sides of the roller die; S5: drying and preheating, hoisting the roller die assembly with the cold iron and the end cover to the drying kiln trolley, and pulling into the drying kiln for sand mold drying and cold type preheating; S6: roller die coating, uniformly pouring the coated sand coating onto the inner surface of the roller die between the hole type cold irons; S7: sequentially performing outer layer pouring, intermediate layer pouring, inner layer pouring, cooling, and opening the box. The step S3 is specifically that the roller die after preheating is hoisted out of the preheating kiln and horizontally placed on the special parallel pad iron, so as to facilitate safe rotation; 6. A method of making a centrifugal shell mold roll according to claim 5 wherein: A layer of previously prepared clay water is brushed on the preheated hole type cold iron, so as to facilitate the bonding of the coating; The prepared paste refractory coating is quickly applied on the hole type cold iron and evenly scraped and smoothed; The coating paste is diluted with water in a clean container, and the hole type cold iron is further brushed smooth with a clean brush. The hole type cold iron is dried to half dry, and then brushed again with diluted coating, and the coating is absolutely uniform and smooth. The step S4 is specifically that the sand sticking and impurities on the corresponding shaped end cover are cleaned; 7. A method of making a centrifugal permanent mold roll according to claim 5, wherein: The end cover is brushed with clay water; The end cover is placed on the end cover molding base of the corresponding type; ​ Put the end cover modeling appearance in the positioning groove of the end cover modeling appearance in the end cover hole; Fill the molding sand between the end cover and the modeling appearance and tamp it; Scrape the protruding molding sand on the end cover upper surface and lift the modeling appearance; According to the process requirements, repair the circular arc and plane of the modeling appearance; Brush the special refractory coating for the end cover; When the first coating is dried to half, press the coating with a spatula and keep the surface smooth; Brush the second coating; When the second coating is dried to half, press the coating again with the same operation; The third coating is put in a clean container without sand and is brushed with a clean brush to ensure the surface is completely and smoothly coated; When the third coating is dried to half, install the end cover with the end cover expansion pin on both sides of the roll die and make sure there are at least 6 end cover expansion pins for each end cover.

8. A method of making a centrifugal permanent mold roll according to claim 5, characterized in that: The step S6 is specifically: pull out the roll die combination from the drying kiln, and hoist the roll die combination to the centrifuge; Start the centrifuge at the required speed; Put the coated sand coating in the strictly positioned coating groove and extend it into the end cover hole on both sides of the roll die; Slowly tilt the coating groove to accurately and uniformly pour the coating into the roll die inner surface in the gap; Keep the centrifuge rotating for 1 minute and then stop, and the coating is completed; After checking that the coating is completely qualified, wait for pouring.

9. A method of making a centrifugal permanent mold roll according to claim 5, characterized in that: The step S7 is specifically: outer layer pouring, after completing the on-site smelting according to the required chemical composition, take the on-site sample for analysis; After the chemical composition analysis is qualified, increase the temperature to the required temperature of the alloy; Hoist the prepared and preheated alloy ladle to the on-site preparation position; After the pouring, slagging and setting are completed, measure the temperature; Immediately after reaching the required pouring temperature, hoist the ladle to the centrifuge pouring position; After the centrifuge speed reaches the required value, pour; Keep the flow stable during pouring, and slow down the flow in the later stage until the pouring is completed; Middle layer pouring, after the outer layer pouring is completed, hoist the middle layer pouring alloy ladle with appropriate size and sufficient preheating to the on-site preparation position; the preheating temperature is required to be 700-800℃; After the pouring, slagging and setting are completed, hoist the ladle to the centrifuge pouring position; When the inner surface temperature of the outer layer approaches the solidus temperature, pour the middle layer alloy; Inner layer pouring, when the inner surface of the middle layer rotates to just reach the liquidus temperature, the outer layer and the middle layer just reach complete solidification, and it is required that the centrifuge is completely stopped at this time; Hoist the roll die to the previously placed bottom box for combination; Combine the riser box and the pouring cup on the roll die; Hoist the inner layer molten iron with qualified temperature and chemical composition to the pouring cup position for core pouring; Core pouring requires stable flow, and slow down the flow when pouring into the riser box until the pouring is completed; Cooling, the poured roll is naturally cooled in the pouring pit; After the cooling time and temperature reach the required value, perform hot opening of the box and sand cleaning; After the cooling time is 3-7 hours and the temperature reaches the required value of 650-700℃, perform hot opening of the box and immediately hoist it into the 700℃ heat treatment kiln for uniform temperature, holding and subsequent annealing treatment; Transport the blank roll to the machining or heat treatment.

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