A vertical mill roller and a preparation method thereof

Abstract

The present application relates to a kind of vertical mill roller and its preparation method, and the roller includes roller base body and insert, insert includes longitudinal insert strip and transverse insert strip, longitudinal insert strip and transverse insert strip all have the curvature that is attached to the surface of base body, longitudinal insert strip is evenly distributed in the surface of base body with interval arrangement, there are multiple groups of transverse insert strip evenly distributed between adjacent two longitudinal insert strips, the part of each insert strip that is fused with base body all uses the structure of isosceles trapezoidal longitudinal section, the part that is exposed to the outside of base body, longitudinal insert strip uses the structure of semicircular longitudinal section, transverse insert strip uses the structure of equilateral triangle longitudinal section, the insert part uses medium chromium alloy steel, base body uses high chromium alloy steel.Prepared insert part, insert part is pre-buried in the casting of roller, pours roller base body iron liquid, base body iron liquid is metallurgically combined with insert, obtains roller blank, then after annealing, quenching, tempering obtains finished product.The roller can prolong service life and ensure safe use.

Description

TECHNICAL FIELD

[0001] The present application relates to a grinding roller, belonging to the field of metal material and processing technology. BACKGROUND

[0002] In recent years, the vertical mill (abbreviation: vertical mill) has more and more applications in the cement, thermal power generation and other industries. The grinding roller is the most easily worn, the most easily failed and the most critical component of the vertical mill. Due to the easy wear and failure of the grinding roller, the normal operation of the vertical mill is affected. Due to the serious wear or abnormal failure of the grinding roller, the vertical mill stops running, causing great economic losses. Therefore, it is particularly important to develop a grinding roller with safe use and long service life. A safe grinding roller can avoid frequent failure and improve economic efficiency.

[0003] A large amount of research and development work has been done by researchers and related enterprise producers on the material and process of grinding roller, and various grinding rollers with excellent performance have been developed. For example, patent CN 111590053B discloses a manufacturing method of an easily processed and repairable high-wear-resistant metal ceramic composite grinding roller. First, ceramic particles are surface metallized pretreated, then the ceramic particles are uniformly mixed with a binder and ceramic powder is added to the mixture, the particle mixture is uniformly loaded into a foam ceramic mold and dried, and after drying and demolding, a ceramic preform is obtained. Then, wear-resistant alloy liquid and carbon steel liquid are poured in sequence to obtain a metal ceramic roller skin lining plate with three layers of ceramic preform / wear-resistant alloy / carbon steel vertically downward from the working surface. The working part of the grinding roller uses ceramic material, which has the outstanding feature of high hardness and poor toughness. Compared with the carbon steel used on the non-working surface of the grinding roller, although the hardness is higher than that of the non-working surface, the toughness is much lower than that of the non-working surface, so the safety is not guaranteed during use. The ceramic preform is prone to failure such as falling off or large-area cracking due to its poor toughness. In addition, although the ceramic particles are surface metallized pretreated, it is difficult to ensure that they can be completely fused with the metal liquid. Moreover, the material of the wear-resistant alloy in the patent is high chromium cast iron or high manganese steel, and the initial hardness of high manganese steel is about HB200, which is much lower than that of ceramic (the hardness of ceramic is generally greater than HB600). This combination is very unreasonable. Patent CN 210022447U discloses a wear-resistant roller sleeve for coal mills. The main feature of the roller sleeve is that the roller sleeve body includes an inner lining layer, a ceramic particle layer, and an outer skin layer from inside to outside. This patent mainly applies to coal mills, and the ceramic particle layer fully covers the wear part of the roller sleeve, greatly improving the service life of the roller sleeve. The large area of the wear part of the roller sleeve uses high-hardness and low-toughness ceramic material. Patent CN111185273A provides a metal ceramic composite grinding roller and a preparation method thereof. The ceramic composite roller is composed of a roller core and a high chromium cast iron layer outside the roller core, and a ceramic preform block is embedded in the high chromium cast iron layer. The ceramic preform block is made of zirconia reinforced alumina ceramic. The metal ceramic composite grinding roller provided by the invention is formed by melting and infiltrating the roller core and the ceramic preform block made of a specific ceramic through the high chromium cast iron layer to form an integral structure. The internal roller core is easy to process, and the external ceramic preform block has high hardness and good impact resistance, ensuring wear resistance and impact resistance while saving high-carbon chromium iron. The service life of the metal ceramic composite grinding roller provided by the invention can reach 530h, and during the wear period, the high chromium cast iron is firmly attached to the outside of the carbon steel roller core without cracking or falling off. The ceramic preform block is embedded in the high chromium cast iron layer, which is a brittle material. Embedding a ceramic material with high hardness and poor toughness on the high chromium cast iron layer is undoubtedly brittle on brittle, which is difficult to cope with complex working conditions.Patent CN114939646A discloses "a TiC metal ceramic particle reinforced composite wear-resistant grinding roller and its preparation process", the melting wetting angle of TiC metal ceramic particles and iron matrix in the invention is less than 30 degrees, the thermal expansion coefficient of TiC metal ceramic particles and alloy matrix is close, and the chemical bond polarity is similar, so the bonding strength with the matrix is high, and it is not easy to fall off during use, which is significantly higher than ZTA, and can be applied to working conditions with higher extrusion or impact load. The grinding roller of the invention uses TiC metal ceramic particles and iron matrix, and the use site is ceramic particles.

[0004] Patent CN212943173U proposes a "roller cover with composite wear-resistant nails", the roller cover is characterized in that the surface of the roller cover body is provided with first wear-resistant nails and a plurality of second wear-resistant nails, the outer end face of the first wear-resistant nails is a straight strip structure, the exposed part of the second wear-resistant nails is a cylindrical structure, and the second wear-resistant nails and the first wear-resistant nails are arranged in staggered positions. The patent has the beneficial technical effect that it proposes a roller cover with composite wear-resistant nails, which is provided with wear-resistant nails of two structures, which can effectively improve the structural performance of the roller cover. This technology only designs a roller cover with such a structure, and the material of the wear-resistant nails and the material of the roller cover are not specified. Patent CN110846582A discloses "an extrusion roller cover in a roller press and a preparation method thereof", the extrusion roller cover in the roller press includes a matrix, the outside of the matrix is composed of deposited metal A and deposited metal B hard alloy blocks. The hard alloy blocks are evenly embedded on the outer circle of the matrix and are arranged in a regular interval in the axial direction, the deposited metal A is stacked in the circumferential gap of the hard alloy blocks in the axial direction, the deposited metal B is stacked on the deposited metal A, and the average height of the deposited metal B is greater than the height of the hard alloy blocks. The extrusion roller cover of the invention greatly increases the wear resistance and prolongs the service life, the extrusion roller cover is always in an efficient state, and the cost is saved. The deposited metal B is stacked on the deposited metal A, and the average height of the deposited metal B is greater than the height of the hard alloy blocks, which is difficult to ensure the stability of the deposited metal A and the deposited metal B. In the case of severe working conditions, the deposited metal A and the deposited metal B are easy to fall off, causing the failure of the roller cover and seriously affecting normal production.

[0005] Patent CN 104630610B, invented "super wear-resistant composite roller mill sleeve and its manufacturing method". The super wear-resistant composite roller mill sleeve, including the outer layer of super wear-resistant and the inner layer of high toughness double-layer structure, the outer layer is more than 35% of the carbide super wear-resistant cast iron, the inner layer is high toughness medium carbon low alloy steel, the outer layer and the inner layer are combined together by metallurgy, which completely eliminates the failure forms such as dropping and peeling caused by welding micro cracks, and can be maintained for life. It uses carbide super wear-resistant cast iron material with a content of more than 35%, which has high hardness but low toughness, so the design idea is high hardness at the working position, but ignores the decisive factor of toughness. Patent CN 103170392A, invented a kind of vertical mill double metal grinding roller, which is used for vertical mill double metal grinding roller in cement and power industry, including core body and outer hard surface layer, the core body and outer hard surface layer are integrated by centrifugal composite casting, the outer hard surface layer is high speed alloy steel: 0.7%~4.0% carbon, <2% silicon, <2% manganese, 4%~18% chromium, 0.5%~4% nickel, 3%~10% vanadium, 2%~10% molybdenum, 0.5%~7% niobium, 0~2% cobalt, 0.5%~8% tungsten. The technical deficiencies are: first, the core body and outer hard surface layer are integrated by centrifugal composite casting, which is complex, and if not controlled well, it may not get good metallurgical bonding of the casting, second, the outer layer of high speed alloy steel contains a large amount of precious metal materials, which undoubtedly increases the cost, since the outer layer is high speed alloy steel, the carbon content is set to 0.7~4.0% carbon, when the carbon content reaches 4%, it is not in the scope of steel. In addition, the outer structure of the double metal grinding roller is not improved.

[0006] Patent CN 114086068 A, a kind of high wear-resistant grinding roller and its preparation method, high wear-resistant grinding roller includes insert A, insert B and matrix, insert A and insert B are bar structure with thick one end and thin one end, the bar structure is embedded in the matrix, the thin end face of bar structure is exposed on the surface of matrix to form the working surface of grinding roller, and the thin end face of insert A and insert B is evenly staggered on the surface of matrix;Wherein insert A adopts medium high alloy steel, insert B adopts super high alloy cast iron, and matrix adopts medium alloy steel. The grinding roller has good safety and wear resistance, and is widely used, and is not easy to break and easy to recycle. The technical deficiencies are that the working position still uses insert A and insert B two kinds of high hardness materials, which has the risk of abnormal failure under the condition of excessive force or uneven force, and cannot guarantee the safe and normal operation of the grinding roller.

[0007] In summary, the main deficiencies in the current grinding roller technology are as follows:

[0008] (1) In order to improve the wear resistance of the products and extend the service life, most of the existing grinding rollers use preforms in which ceramics or ceramic particles account for the majority of the weight, or preforms similar to ceramics. This type of high-hardness, low-toughness material is used as the preform. Although the inlaid material in this design has high hardness and wear resistance, its toughness is greatly reduced compared to the base material. When the grinding roller and related products are used, they will crack, fall off, fail, etc. due to low toughness, resulting in failure of the grinding roller and other products, and the normal operation of the equipment cannot be guaranteed. The safety of use is not considered enough.

[0009] (2) For the structure that combines metal inserts with metal bases, on the one hand, the combination method is simple physical compound, and the chemical composition, heat treatment process, smelting process, etc. of the materials of the inlaid prefabricated body and the grinding roller base are rarely considered and involved, and there is a risk of separation during use; on the other hand, although some technologies have designed the appearance, shape and related structural dimensions of the inlaid materials, the actual design is highly subjective, and the details such as the structural shape are not accurately designed according to the working conditions of the grinding roller products. During use, the parts often fall off, fall off or crack due to uneven force or insufficient toughness.

[0010] The local stress-bearing parts of the grinding roller require better toughness and hardness than the base of the grinding roller. During use, the local stress-bearing parts often fall off, break off or crack due to uneven stress or insufficient toughness, resulting in abnormal failure of the grinding roller. Therefore, it is particularly important to develop a grinding roller material with excellent local performance. Summary of the Invention

[0011] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a vertical mill roller and a preparation method thereof, which can extend the service life and ensure safe use.

[0012] The technical solution adopted by the present invention is:

[0013] A vertical mill roller comprises a grinding roller base and inserts, wherein the inserts comprise longitudinal insert strips and transverse insert strips, both of which have curvatures that fit the outer surface of the base, the longitudinal insert strips being arranged at intervals and evenly distributed on the base surface, and multiple groups of transverse insert strips being evenly distributed between two adjacent longitudinal insert strips, the portion of each insert strip fused with the base (i.e., the portion embedded in the base) all having a trapezoidal longitudinal cross-section, the portion exposed outside the base having a semicircular longitudinal cross-section for the longitudinal insert strips and an equilateral triangular longitudinal cross-section for the transverse insert strips, the insert portion being made of medium-chromium alloy steel, and the base being made of high-chromium alloy steel.

[0014] The high-chromium alloy steel material used in the base body has the following chemical composition by weight percentage: C: 1.315-1.429%, Si: 0.327-0.465%, Mn: 0.881-0.926%, S≤0.026%, P≤0.028%, Cr: 13.281-15.197%, Ni: 0.621-0.703%, Mo: 0.891-0.923%, Cu: 0.627-0.639%, V: 0.215-0.338%, Ti: 0.0299-0.0415%, Re: 0.132-0.219%, B: 0.0811-0.0953%, Nb: 0.116-0.178%, W: 0.233-0.349%, Zr: 0.0391-0.0456%, Al: 0.0325-0.0449%, N: 0.0018-0.0045%, and the balance of Fe and impurities.

[0015] The medium-chromium alloy steel material used in the insert part has the following chemical composition by weight percentage: C: 0.568-0.617%, Si: 0.325-0.457%, Mn: 0.587-0.751%, S, P≤0.025%, Cr: 6.155-6.338%, Ni: 0.183-0.269%, Mo: 1.115-1.577%, Cu: 0.513-0.628%, V: 1.715-1.747%, Ti: 0.021-0.0315%, Re: 0.03-0.04%, B: 0.0031-0.0039%, Nb: 0.268-0.291%, W: 0.353-0.464%, Al: 0.0355-0.0416%, N: 0.056-0.078%, and the balance of Fe and impurities, and the total amount of impurities is ≤0.038%.

[0016] The longitudinal insert strip and the transverse insert strip are integrally formed with the base body without interface. The part of the insert strip fused with the base body has a longitudinal section in the shape of an isosceles trapezoid. The part of the insert strip exposed outside the base body is in the same height as the part embedded in the base body.

[0017] The part of the longitudinal insert strip exposed outside the base body has a longitudinal section in the shape of a semicircle with a diameter of 9.6-15.8 mm. The part of the transverse insert strip exposed outside the base body has a longitudinal section in the shape of an equilateral triangle with a side length of 9.0-15.8 mm.

[0018] The method for manufacturing the vertical mill roller comprises the following steps: casting a blank of the insert part and forging the insert part into a designed structure, embedding the insert part into a casting mold of the mill roller according to the designed structure, pouring molten iron into the casting mold to form a base body of the mill roller, metallurgically combining the base body with the insert part to obtain a mill roller blank, and annealing, quenching and tempering the mill roller blank to obtain a finished mill roller.

[0019] The preparation method of the roller mill, specifically comprising the following steps:

[0020] (I) Preparation of insert preform

[0021] (1) Preparation of raw materials

[0022] The waste steel, ferrosilicon, manganese iron, chromium iron, nickel iron, molybdenum iron, copper, vanadium iron, titanium iron, boron iron, niobium iron, tungsten iron, aluminum wire, chromium nitride, rare earth ferrosilicon material are weighed;

[0023] (2) Molding

[0024] Molding is performed using a sand mold;

[0025] (3) Melting of raw materials

[0026] The raw materials are melted, and the melting sequence is in the order of waste steel, ferroalloy, waste steel, and precious metal. When the iron liquid reaches 1506-1557℃, pre-deoxidation treatment is performed. First, 0.55% manganese iron is added, and then 0.25% ferrosilicon is added. The chemical composition of the molten iron is tested, and the chemical composition of the iron liquid is adjusted to meet the requirements of the medium chromium alloy steel. When the temperature of the iron liquid in the furnace reaches 1635-1646℃, 0.028% aluminum wire is inserted, and then the furnace is tapped;

[0027] (4) Inoculation pouring

[0028] The obtained iron liquid is poured into a ladle for modification and inoculation. After the molten iron is inoculated, it is poured into a mold and cooled to room temperature to obtain a blank;

[0029] (5) Forging forming

[0030] The obtained blank is polished and cleaned, and then placed in a heating furnace for heating. The heating temperature is controlled at 1066-1168℃, and the holding time is 2-2.5 hours. After holding, the blank is placed in a mold for forging forming. The initial forging temperature is 1065-1155℃, and the final forging temperature is ≥898℃. After forging, the insert preform is obtained. The forged preform is cleaned and polished again and then used;

[0031] (II) Preparation of composite grinding roller

[0032] (1) Preparation of raw materials

[0033] The waste steel, ferrosilicon, manganese iron, low-carbon chromium iron, nickel iron, molybdenum iron, copper, electrolytic vanadium, titanium iron, rare earth ferrosilicon, boron iron, niobium iron, tungsten iron, zirconium iron, aluminum wire, chromium nitride material are weighed;

[0034] (2) Molding

[0035] The insert preform is put into the mold forming process to ensure that the insert preform is evenly distributed in the mold, and the insert preform is preheated to 196-265°C before pouring;

[0036] (3) Melting of raw materials

[0037] The raw materials are melted, and the melting sequence is in the order of scrap steel, ferroalloy, scrap steel, and precious alloy. When the molten iron reaches 1548-1565°C, pre-deoxidation treatment is performed. First, 0.43% manganese iron is added, and then 0.13% silicon iron is added. The chemical composition of the molten iron is tested, and the chemical composition of the molten iron is adjusted to meet the requirements of the high chromium alloy steel. When the temperature of the molten iron in the furnace reaches 1628-1635°C, 0.023% aluminum wire is inserted, and then the furnace is tapped;

[0038] (4) Modification and inoculation pouring

[0039] The obtained molten iron is poured into a ladle for modification and inoculation. The modification and inoculation agent is dried in advance before tapping, and is put into the ladle. Pouring is performed into the mill roll mold, and the mold is cooled to room temperature and unpacked;

[0040] (5) Cleaning and grinding

[0041] The obtained casting is removed from the sprue and then cleaned and ground to obtain a composite cast mill roll blank;

[0042] (Three) Mill roll heat treatment

[0043] (1) Annealing: the obtained mill roll blank is loaded into the furnace for annealing treatment;

[0044] (2) Rough machining: the mill roll obtained after annealing is subjected to rough machining;

[0045] (3) Quenching: the mill roll blank obtained by rough machining is loaded into the furnace for quenching treatment;

[0046] (4) Tempering: the casting after quenching is reloaded into the furnace for tempering treatment;

[0047] (5) The mill roll after tempering is subjected to finishing.

[0048] In the above preparation method, the inoculation modifier used in the inoculation and modification of the insert preform is: 0.263% boron iron, 0.121% aluminum wire, 0.256% rare earth silicon, 0.115% silicon carbide, and 0.138% titanium iron. The inoculation modifier used in the modification and inoculation of the composite mill roll is: 0.453% rare earth silicon iron, 0.252% titanium iron, 0.234% chromium nitride, 0.068% zirconium iron, and 0.245% boron iron.

[0049] In the preparation method, the annealing process in the heat treatment is as follows: the temperature of the cast entering the furnace is controlled to be below 185 DEG C, the temperature of the cast entering the furnace is controlled to be below 300 DEG C, the heating speed is controlled to be 29 DEG C-33 DEG C / hour, the temperature is kept for 1 hour at 300 DEG C, the temperature is kept for 1.5 hours at 650 DEG C, the temperature is kept for 3.5-5.5 hours at 1106 DEG C, and the temperature is kept for 1.5-2.5 hours at 1046-1058 DEG C after the temperature is kept for 3.5-5.5 hours at 1106 DEG C.

[0050] The quenching process is as follows: the temperature of the cast entering the furnace is controlled to be below 189 DEG C, the temperature of the cast entering the furnace is controlled to be below 300 DEG C, the heating speed is controlled to be 38 DEG C-45 DEG C / hour, the temperature is kept for 1 hour at 300 DEG C, the temperature is kept for 1.5 hours at 650 DEG C, the temperature is kept for 3.5-4.5 hours at 1108 DEG C-1110 DEG C, and the temperature is kept for 1.5-2.5 hours at 1046-1058 DEG C after the temperature is kept for 3.5-5.5 hours at 1106 DEG C.

[0051] The tempering process is as follows: the temperature of the cast entering the furnace is controlled to be below 188 DEG C, the heating speed is controlled to be 48 DEG C-51 DEG C / hour, the temperature is kept for 4.5-7.5 hours at 500 DEG C-560 DEG C, and the cast is naturally cooled in the air after the cast is taken out of the furnace.

[0052] The present application has the following advantages:

[0053] (1) The grinding roller of the present application is made of medium alloy steel, and the grinding roller is cast after the medium alloy steel is forged and metallurgically combined with the base body. The base body is made of high chromium alloy steel. The toughness and hardness of the insert are higher than those of the base body. The insert has sufficient toughness, and the design ensures the safety of the use part. The insert has sufficient hardness, and the design also ensures the wear resistance of the use part. The hardness of the insert is close to that of the base body, and the insert or the base body will not be severely worn during use. Therefore, the insert and the base body complement each other, and the material selection and structural design ensure the safety and wear resistance.

[0054] (2) The invention designs the insert block structure, inserts the insert block on the base body, and the longitudinal insert block strips and the transverse insert block strips are evenly distributed on the surface of the base body, the longitudinal insert block strip is designed as a semicircle in longitudinal section, the design of the longitudinal insert block strip facilitates the extrusion of the material into the groove formed between the longitudinal insert block strips; the transverse insert block strip is designed as an equilateral triangle in longitudinal section, and the design of the transverse insert block strip can extrude and crush the material after entering the groove, thereby improving the grinding and crushing efficiency. When the equipment is running, the material is extruded into the groove of the grinding roller, and the material extruded into the groove is also extruded and crushed. This special design structure, on the one hand, reduces the direct wear of the base body material of the grinding roller by extruding the material into the groove, and on the other hand, improves the production efficiency and reduces the wear by setting the transverse insert block strip in the groove as a crushing mechanism to crush the material twice, thereby prolonging the service life of the grinding roller.

[0055] (3) The grinding roller of the invention is entirely made of metal materials, the base body of the grinding roller is high alloy steel, and the alloy steel in the inlay is selected, compared with the current ceramic metal composite, the invention can effectively avoid the fracture and block falling caused by poor composite. The toughness index of the selected material and process is much higher than that of ceramic materials, so the absolute safety of the working part is ensured, and the ceramic composite will not fall off or crack. At the same time, all metal materials are used, which is more convenient for recycling and reuse of the old grinding roller. The ceramic metal composite grinding roller is not easy to recycle and utilize due to the large amount of ceramic in the base body, which causes waste of resources.

[0056] (4) The grinding roller of the invention has good safety and wear resistance after heat treatment, the insert block preform is selected from medium chromium alloy steel (Cr6 series), the preform is forged, and then combined with the base body by metallurgical bonding, and after heat treatment, the performance of the insert block preform reaches: the hardness of the base body reaches HRC61-63, and the impact performance reaches (sample without notch) 18-26j / cm 2 . The insert block preform as the main working part ensures sufficient toughness and hardness, and ensures the safety of the grinding roller in use. The base body is selected from high chromium cast steel (Cr15 series), and after casting and heat treatment, the mechanical properties reach: hardness: HRC58-61, and impact toughness 10-16j / cm 2 . The hardness is sufficient to improve the wear resistance of the grinding roller. The wear resistance of the grinding roller of the invention is 2.5-3 times that of a single high chromium cast iron material grinding roller, has good market prospects, and can create considerable economic benefits.

[0057] The composite grinding roller material is reasonable in selection, the structure design is scientific, the inlay has excellent toughness and hardness, so under the working condition of high stress and hard material, the composite grinding roller can normally and safely run, the accident frequency is greatly reduced, so the service life of the grinding roller is prolonged.

[0058] Table 1 is the comparison of indexes of several common grinding rollers

[0059]

[0060] BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 It is a distribution diagram of the grinding roller inlay of the application;

[0062] Figure 2 It is a sectional view of the grinding roller of the application;

[0063] Figure 3 It is a structure diagram of the inlay of the application;

[0064] Figure 4 It is a metallographic structure diagram (100 times) of the grinding roller inlay of the application (martensite + a small amount of residual austenite) after heat treatment, 4% nitric acid alcohol etching;

[0065] Figure 5 It is a metallographic structure diagram (100 times) of the grinding roller base body of the application (martensite + carbide + a small amount of residual austenite) after heat treatment, 4% nitric acid alcohol etching;

[0066] Wherein, 1. longitudinal inlay strip, 2. transverse inlay strip. DETAILED DESCRIPTION

[0067] The application will be further described below in combination with the drawings and specific embodiments.

[0068] Embodiment 1

[0069] A vertical mill grinding roller, comprising a grinding roller base body and an inlay, the inlay part comprises longitudinal inlay strips 1 and transverse inlay strips 2, the longitudinal inlay strips 1 and the transverse inlay strips 2 both have an arc that is attached to the outer surface of the base body, the longitudinal inlay strips are uniformly distributed on the surface of the base body in an interval, a plurality of groups of transverse inlay strips are uniformly distributed between the two adjacent longitudinal inlay strips, the part of each inlay strip that is fused with the base body all adopts a structure with an isosceles trapezoidal longitudinal section, the part of the longitudinal inlay strip that is exposed outside the base body adopts a structure with a semicircular longitudinal section, and the part of the transverse inlay strip that is exposed outside the base body adopts a structure with an equilateral triangular longitudinal section, the inlay part adopts medium chromium alloy steel, and the base body adopts high chromium alloy steel. The part of the inlay that is exposed outside the base body is consistent in height with the part that is embedded in the base body.

[0070] The preparation method steps are as follows:

[0071] (I) Preparation of the insert preform

[0072] (1) Preparation of raw materials

[0073] The waste steel, ferrosilicon, ferromanganese, ferrochrome, ferronickel, ferromolybdenum, copper, ferrovanadium, ferrotitanium, ferroboron, ferro niobium, ferrotungsten, aluminum wire, chromium nitride, and rare earth ferrosilicon are weighed according to the calculated weight percentage;

[0074] Among them, the modifier raw materials used for smelting the insert preform are ferroboron, aluminum wire, rare earth ferrosilicon, silicon carbide, and ferrotitanium.

[0075] (2) Molding

[0076] The molding is performed using a resin sand mold.

[0077] (3) Melting of raw materials

[0078] The raw materials of the first step are melted, and the melting sequence is in the order of waste steel, ferroalloy, waste steel, and precious metal. The precious metal is added in the later stage to avoid burning loss. When the iron liquid reaches 1556°C, pre-deoxidation treatment is performed. First, 0.55% ferromanganese is added, and after 8 minutes, 0.25% ferrosilicon is added. The chemical composition of the molten iron is tested, and the chemical composition of the iron liquid is adjusted. When the temperature of the iron liquid in the furnace reaches 1638°C, 0.028% aluminum wire is inserted, and then the furnace is tapped.

[0079] (4) Inoculation and modification pouring

[0080] The obtained iron liquid is poured into a ladle for modification and inoculation. The inoculation modifier is 0.263% ferroboron, 0.121% aluminum wire, 0.256% rare earth ferrosilicon, 0.115% silicon carbide, and 0.138% ferrotitanium. Before the molten iron is tapped, these modifiers are dried in advance, mixed uniformly, and placed at the bottom of the ladle. After the molten iron is inoculated, it is poured into the mold and cooled to room temperature to obtain a blank.

[0081] (5) Forging into shape

[0082] The obtained blank is polished and cleaned, and then placed in a heating furnace for heating. The heating temperature is controlled at 1168°C, and the holding time is 2-2.5 hours. After holding, the blank is placed in a mold for forging into shape. The initial forging temperature is 1155°C, and the final forging temperature is ≥968°C. After forging, the insert preform is obtained. The forged preform is cleaned and polished again and then used.

[0083] The prepared insert preform has the following chemical composition in mass percentage: C: 0.617%, Si: 0.365%, Mn: 0.731%, S: 0.021, P: 0.025%, Cr: 6.338%, Ni: 0.259%, Mo: 1.577%, Cu: 0.593%, V: 1.747%, Ti: 0.0315%, Re: 0.04%, B: 0.0039%, Nb: 0.291%, W: 0.464%, Al: 0.0416%, N: 0.066%, and the balance of Fe and impurities, and the total amount of impurities is 0.028%.

[0084] (II) Preparation of the composite grinding roller

[0085] (1) Preparation of raw materials

[0086] The raw materials include scrap steel, ferrosilicon, ferromanganese, low-carbon ferrochrome, ferro-nickel, ferro-molybdenum, copper, electrolytic vanadium, ferro-titanium, rare earth ferrosilicon, ferro-boron, ferro-niobium, ferro-tungsten, ferro-zirconium, aluminum wire, and chromium nitride.

[0087] Among them, the modifier raw materials used in the smelting of the grinding roller body are rare earth ferrosilicon, ferro-titanium, chromium nitride, ferro-zirconium, and ferro-boron.

[0088] (2) Molding

[0089] The insert preform is placed in the casting mold, wherein the insert body that needs to be exposed outside the working surface finally needs to be buried inside the casting sand, and the other part does not need to be buried in the casting mold. The purpose is that after pouring the alloy liquid, the part that does not need to be exposed is wrapped by the alloy liquid and is integrated with the grinding roller body alloy liquid. During the molding process, it is ensured that the insert preform is uniformly distributed inside the casting mold. Before pouring, the insert preform is preheated to 265℃.

[0090] (3) Smelting of raw materials

[0091] The raw materials are smelted, and the smelting sequence is in the order of scrap steel, ferroalloy, scrap steel, and precious alloy. When the iron liquid reaches 1560℃, pre-deoxidation treatment is performed. First, 0.43% ferromanganese is added, and then 0.13% ferrosilicon is added after 10 minutes. The chemical composition of the molten iron is tested, and the chemical composition of the iron liquid is adjusted. When the temperature of the iron liquid in the furnace reaches 1629℃, 0.023% aluminum wire is inserted, and then the furnace is discharged.

[0092] (4) Inoculation and modification pouring

[0093] The obtained iron liquid is poured into a pouring ladle for modification and inoculation. The inoculation modifier is 0.453% rare earth ferrosilicon, 0.252% ferro-titanium, 0.234% chromium nitride, 0.068% ferro-zirconium, and 0.245% ferro-boron. Before discharging, the inoculation modifier is dried in advance and placed in the pouring ladle. The pouring is performed into the grinding roller casting mold, and the cooling is performed to room temperature and the mold is opened.

[0094] (5) cleaning and polishing

[0095] The obtained casting is removed from the pouring and riser, and then cleaned and polished to obtain a composite casting grinding roller blank;

[0096] The chemical composition of the prepared grinding roller base is as follows in mass percent: C: 1.428%, Si: 0.435%, Mn: 0.881%, S: 0.021%, P: 0.023%, Cr: 15.197%, Ni: 0.703%, Mo: 0.923%, Cu: 0.639%, V: 0.338%, Ti: 0.0415%, Re: 0.219%, B: 0.0953%, Nb: 0.178%, W: 0.349%, Zr: 0.0456%, Al: 0.0325%, N: 0.0045%, and the balance of Fe and impurities.

[0097] (Three) heat treatment of the grinding roller

[0098] (1) annealing

[0099] The obtained grinding roller blank is loaded into a furnace for annealing treatment, and the annealing treatment process is as follows: the temperature of the casting entering the furnace is controlled to be below 185°C, the temperature is controlled to be below 300°C, the heating rate is controlled to be 33°C / hour, the temperature is kept at 300°C for 1 hour, the temperature is raised from 300°C to 650°C at a rate of 53°C / hour, the temperature is kept at 650°C for 1.5 hours, the temperature is raised from 650°C to 1106°C at a rate of 75°C / hour, the casting is kept at 1106°C for 5.5 hours, and then cooled in the furnace after the temperature is kept at 1106°C;

[0100] (2) rough machining

[0101] The grinding roller obtained after annealing is rough machined according to the drawing;

[0102] (3) quenching

[0103] The rough machined grinding roller blank is loaded into a furnace for quenching treatment, and the quenching treatment process is as follows: the temperature of the casting entering the furnace is controlled to be within 189°C, the temperature is controlled to be within 300°C, the heating rate is controlled to be 45°C / hour, the temperature is kept at 300°C for 1 hour, the temperature is raised from 300°C to 650°C at a rate of 53°C / hour, the temperature is kept at 650°C for 1.5 hours, the temperature is raised from 650°C to 1020°C at a rate of 75°C / hour, the casting is kept at 1110°C for 4.5 hours, and the holding time is adjusted according to the wall thickness of the casting; after the holding, the power is turned off, and the furnace is cooled; when the temperature in the furnace drops to 1058°C, the holding is performed for 2.5 hours, the furnace is discharged, and the quenching is performed by air cooling and spraying (water mist); after the casting is discharged, the air cooling and spraying are started; when the temperature of the casting drops to below 685°C, the spraying is stopped, and the air cooling is continued; when the temperature drops to below 550°C, the air blowing is stopped, and the air cooling is performed in the air;

[0104] (4) Tempering

[0105] After quenching, the castings are put back into the furnace for tempering. The tempering process is as follows: the casting temperature is controlled below 188℃, the heating rate is controlled at 51℃ / hour, and the casting is kept at 560℃ for 7.5 hours. After the holding time is up, the castings are taken out of the furnace, cooled naturally in the air, and tempered twice.

[0106] (5) Finishing

[0107] Finish the tempered grinding roller according to the drawing requirements;

[0108] (6) Quality inspection

[0109] Conduct hardness, impact toughness and ultrasonic flaw detection tests on the finished grinding rollers;

[0110] The sample was heat treated together with the casting. The mechanical properties of the grinding roller matrix are as follows: Impact performance (sample without notch): 11j / cm 2 , HRC59.5. The mechanical properties of the insert are: impact toughness (sample without notch) 23.5j / cm 2 ,HRC62;

[0111] (7) Packaging and storage

[0112] Finished grinding rollers that meet the drawing requirements are packaged and put into storage.

[0113] Example 2

[0114] A vertical mill roller comprises a roller base and inserts. The inserts comprise longitudinal insert strips 1 and transverse insert strips 2. Each longitudinal insert strip 1 and transverse insert strip 2 has a curvature that conforms to the outer surface of the base. The longitudinal insert strips are spaced and evenly distributed on the base surface. Multiple groups of transverse insert strips are evenly distributed between adjacent longitudinal insert strips. The portion of each insert strip fused with the base has an isosceles trapezoidal longitudinal cross-section. The portion exposed outside the base has a semicircular longitudinal cross-section for the longitudinal insert strips and an equilateral triangular longitudinal cross-section for the transverse insert strips. The inserts are made of medium-chromium alloy steel, while the base is made of high-chromium alloy steel. The portion of the insert exposed outside the base is of the same height as the portion embedded in the base.

[0115] The preparation method comprises the following steps:

[0116] (1) Preparation of insert preform

[0117] (1) Prepare raw materials

[0118] Weigh scrap steel, ferrosilicon, ferromanganese, ferrochrome, ferronickel, ferromolybdenum, copper, ferrovanadium, ferrotitanium, ferroboron, ferroniobium, ferrotungsten, aluminum wire, chromium nitride, rare earth ferrosilicon and other materials according to the calculated weight percentage;

[0119] Wherein, the modifier raw material used in smelting the inlay preform: boron iron, aluminum wire, rare earth silicon, silicon carbide, titanium iron;

[0120] (2) Molding

[0121] Molding is performed using resin sand mold;

[0122] (3) Melting of raw materials

[0123] The raw materials are smelted, and the smelting sequence is in the order of scrap steel, ferroalloy, scrap steel, and precious metal, which is added in the later stage to avoid burning loss. When the iron liquid reaches 1550℃, pre-deoxidation treatment is performed, 0.55% manganese iron is first added, and 0.25% silicon iron is added after 8 minutes. The chemical composition of the molten iron is tested, and the chemical composition of the iron liquid is adjusted. When the temperature of the iron liquid in the furnace reaches 1630℃, 0.028% aluminum wire is inserted, and then the furnace is discharged;

[0124] (4) Inoculation pouring

[0125] The obtained iron liquid is poured into a ladle for modification and inoculation. The modifiers are: 0.263% boron iron, 0.121% aluminum wire, 0.256% rare earth silicon, 0.115% silicon carbide, and 0.138% titanium iron. Before the molten iron is discharged, these modifiers are dried in advance, mixed uniformly, and placed at the bottom of the ladle. After the molten iron is inoculated, it is poured into the mold and cooled to room temperature to obtain the blank;

[0126] (5) Forging

[0127] The obtained blank is polished and cleaned, then placed in a heating furnace for heating, with the heating temperature controlled at 1118℃ and the holding time of 2.5 hours. After holding, the blank is placed in a mold for forging, with the initial forging temperature of 1110℃ and the final forging temperature ≥988℃. After forging, the inlay preform is obtained. The forged preform is cleaned and polished again before use;

[0128] The chemical composition of the prepared inlay preform is as follows: C: 0.598%, Si: 0.425%, Mn: 0.628%, S: 0.021%, P: 0.021%, Cr: 6.238%, Ni: 0.239%, Mo: 1.437%, Cu: 0.528%, V: 1.726%, Ti: 0.0235%, Re: 0.031%, B: 0.0036%, Nb: 0.288%, W: 0.398%, Al: 0.0395%, N: 0.066%, and the balance is Fe and impurities.

[0129] (II) Preparation of composite grinding roller

[0130] (1) Preparation of raw materials

[0131] Scrap, ferrosilicon, ferromanganese, low-carbon ferrochrome, nickel iron, ferromolybdenum, copper, electrolytic vanadium, ferrotitanium, rare earth ferrosilicon, boron iron, ferro-niobium, ferrotungsten, zirconium iron, aluminum wire, chromium nitride and other materials;

[0132] Among them, the modifier raw material used for smelting the grinding roller base is: rare earth ferrosilicon, ferrotitanium, chromium nitride, zirconium iron, boron iron;

[0133] (2) Molding

[0134] Put the insert preform into the mold, wherein the insert that needs to be finally exposed outside the working surface needs to be buried inside the mold sand, and the other part does not need to be buried in the mold; the purpose is that after pouring the alloy liquid, the part that does not need to be exposed is wrapped by the alloy liquid and is integrated with the alloy liquid of the grinding roller base; during the molding process, ensure that the insert preform is uniformly distributed inside the mold; before pouring, preheat the insert preform to 245℃;

[0135] (3) Smelting of raw materials

[0136] Smelt the raw materials, and the smelting sequence is in the order of scrap, ferroalloy, scrap and precious alloy; when the iron liquid reaches 1550℃, perform pre-deoxidation treatment; first add 0.43% ferromanganese, then add 0.13% ferrosilicon after 10 minutes; test the chemical composition of the molten iron, and adjust the chemical composition of the iron liquid; when the temperature of the iron liquid in the furnace reaches 1630℃, insert 0.023% aluminum wire, and then pour out;

[0137] Pour the obtained iron liquid into a pouring ladle for modification and inoculation; the modification and inoculation agent is 0.453% rare earth ferrosilicon, 0.252% ferrotitanium, 0.234% chromium nitride, 0.068% zirconium iron and 0.245% boron iron; before pouring out, dry the modification and inoculation agent in advance, put it into the pouring ladle, pour it into the grinding roller mold, and cool to room temperature to open the box;

[0138] (5) Cleaning and grinding

[0139] Remove the pouring riser from the obtained casting, and then clean and grind to obtain a composite cast grinding roller blank;

[0140] The chemical composition of the prepared grinding roller base is as follows: C: 1.315%, Si: 0.327%, Mn: 0.881%, S: 0.022%, P: 0.023%, Cr: 13.281%, Ni: 0.621%, Mo: 0.891%, Cu: 0.627%, V: 0.215%, Ti: 0.0299%, Re: 0.132%, B: 0.0811%, Nb: 0.116%, W: 0.233%, Zr: 0.0391%, Al: 0.0325%, N: 0.0018%, and the balance is Fe and impurities.

[0141] (III) Heat treatment of grinding roller

[0142] (1) Annealing

[0143] The obtained grinding roller blank is loaded into a furnace for annealing treatment. The annealing treatment process is as follows: the temperature of the casting into the furnace is controlled below 185°C, the temperature below 300°C, the temperature rising speed is controlled at 33°C / hour, at 300°C, the temperature is kept for 1 hour, between 300°C and 650°C, the temperature rising speed is controlled at 53°C / hour, the temperature is kept at 650°C for 1.5 hours, between 650°C and 1100°C, the temperature rising speed is controlled at 75°C / hour, the casting is kept at 1100°C for 5.5 hours. After the temperature keeping at 1100°C, the furnace is cooled in the furnace;

[0144] (2) Rough machining

[0145] The grinding roller obtained after annealing is rough machined according to the drawing;

[0146] (3) Quenching

[0147] The rough machined grinding roller blank is loaded into a furnace for quenching treatment. The quenching treatment process is as follows: the temperature of the casting into the furnace is controlled within 189°C, the temperature below 300°C after entering the furnace, the temperature rising speed is controlled at 45°C / hour, at 300°C, the temperature is kept for 1 hour, between 300°C and 650°C, the temperature rising speed is controlled at 53°C / hour, the temperature is kept at 650°C for 1.5 hours, between 650°C and 1110°C, the temperature rising speed is controlled at 75°C / hour, the casting is kept at 1110°C for 4.5 hours, and the temperature keeping time is adjusted according to the wall thickness of the casting; after the temperature keeping, the power is turned off, and the furnace is cooled, and the temperature in the furnace is kept at 1056°C for 2.5 hours, then the casting is taken out of the furnace, quenched, and quenched by air cooling + spraying (water mist). After the casting is taken out of the furnace, air cooling + spraying is started, and when the temperature of the casting is below 685°C, the spraying is stopped, and the air cooling is continued. When the temperature is below 550°C, the air blowing is stopped, and the air cooling is continued in the air;

[0148] (4) Tempering

[0149] The quenched casting is reloaded into a furnace for tempering. The tempering process is as follows: the temperature of the casting into the furnace is controlled below 188°C, the temperature rising speed is controlled at 51°C / hour, at 555°C, the temperature is kept for 7.5 hours, and after the temperature keeping time reaches, the casting is taken out of the furnace, and naturally cooled in the air. The tempering is performed twice;

[0150] (5) Finishing

[0151] The tempered grinding roller is finished according to the requirements of the drawing;

[0152] (6) Quality detection

[0153] The finished grinding roller is detected for hardness, impact toughness, and ultrasonic flaw detection;

[0154] The sample is heat treated together with the casting. The mechanical properties of the grinding roller base are: impact performance (sample without notch): 12 j / cm 2 , HRC 60. The mechanical properties of the insert are: impact toughness (sample without notch): 22.5 j / cm 2 , HRC 61.5.

[0155] (7) Packaging and storage

[0156] The finished grinding roller that meets the drawing requirements is packaged and stored.

[0157] Example 3

[0158] The structure and preparation method steps are the same as in Example 2, except that the chemical composition of the grinding roller base is different.

[0159] (1) The chemical composition of the grinding roller base has the following weight percentage contents: C: 1.388%, Si: 0.427%, Mn: 0.893%, S: 0.021%, P: 0.021%, Cr: 14.281%, Ni: 0.665%, Mo: 0.891%, Cu: 0.629%, V: 0.225%, Ti: 0.0415%, Re: 0.182%, B: 0.0811%, Nb: 0.156%, W: 0.349%, Zr: 0.0391%, Al: 0.0325%, N: 0.0028%, and the balance is Fe and impurities.

[0160] (2) The mechanical properties of the grinding roller base after heat treatment are: impact performance (sample without notch): 13 j / cm 2 , HRC 59.5.

[0161] (3) The chemical composition and mechanical properties of the insert are the same as in Example 2.

[0162] Example 4

[0163] The preparation method steps are the same as in Example 2, except that the chemical composition of the grinding roller base is different.

[0164] (1) The chemical composition of the grinding roller base has the following weight percentage contents: C: 1.355%, Si: 0.427%, Mn: 0.889%, S: 0.021%, P: 0.021%, Cr: 14.556%, Ni: 0.671%, Mo: 0.923%, Cu: 0.637%, V: 0.338%, Ti: 0.0299%, Re: 0.136%, B: 0.0811%, Nb: 0.136%, W: 0.233%, Zr: 0.0391%, Al: 0.0375%, N: 0.0038%, and the balance is Fe and impurities.

[0165] (2) The mechanical property indexes of the grinding roller base after heat treatment: impact performance (the sample has no notch): 10.5 j / cm 2 , HRC 61.

[0166] (3) The chemical composition and mechanical property of the insert are the same as those of Example 2.

[0167] Example 5

[0168] The preparation method steps are the same as those of Example 2, except that the chemical composition of the grinding roller base is different.

[0169] (1) The weight percentage content of the chemical composition of the grinding roller base is: C: 1.365%, Si: 0.455%, Mn: 0.886%, S: 0.022%, P: 0.023%, Cr: 15.111%, Ni: 0.621%, Mo: 0.923%, Cu: 0.637%, V: 0.265%, Ti: 0.0299%, Re: 0.219%, B: 0.0953%, Nb: 0.116%, W: 0.233%, Zr: 0.0391%, Al: 0.0325%, N: 0.0035%, and the balance is Fe and impurities.

[0170] (2) The mechanical property indexes of the grinding roller base after heat treatment: impact performance (the sample has no notch): 12.5 j / cm 2 , HRC 60.

[0171] (3) The chemical composition and mechanical property of the insert are the same as those of Example 2.

[0172] Example 6

[0173] The preparation method steps are the same as those of Example 2, except that the chemical composition of the grinding roller base and the chemical composition of the insert are different.

[0174] (1) The weight percentage content of the chemical composition of the grinding roller base is: C: 1.386%, Si: 0.442%, Mn: 0.899%, S: 0.021%, P: 0.023%, Cr: 14.355%, Ni: 0.699%, Mo: 0.911%, Cu: 0.628%, V: 0.331%, Ti: 0.0299%, Re: 0.136%, B: 0.0811%, Nb: 0.166%, W: 0.349%, Zr: 0.0456%, Al: 0.0325%, N: 0.0018%, and the balance is Fe and impurities.

[0175] (2) The insert has the following chemical composition by weight percentage: C: 0.611%, Si: 0.421%, Mn: 0.588%, S: 0.021%, P: 0.024%, Cr: 6.186%, Ni: 0.198%, Mo: 1.115%, Cu: 0.513%, V: 1.726%, Ti: 0.029%, Re: 0.031%, B: 0.0031%, Nb: 0.268%, W: 0.353%, Al: 0.0355%, N: 0.056%, and the balance of Fe and impurities.

[0176] (3) The mechanical property index of the grinding roller base after heat treatment is as follows: impact property (sample without notch): 13.5 j / cm 2 , HRC 60.5.

[0177] (4) The mechanical property index of the insert after heat treatment is as follows: impact property (sample without notch): 19.5 j / cm 2 , HRC 62.

[0178] The above is a detailed introduction to the present application in combination with specific embodiments, and the protection scope of the present application is not limited thereto.

Claims

1. A vertical mill roller, comprising a grinding roller base and an insert, characterized in that: The inserts include longitudinal insert strips and transverse insert strips, each of which has an arc that fits the outer surface of the substrate. The longitudinal insert strips are spaced and evenly distributed on the surface of the substrate. There are multiple groups of transverse insert strips evenly distributed between adjacent longitudinal insert strips. The portion of each insert strip that is fused with the substrate adopts a trapezoidal longitudinal cross-section structure. The portion exposed outside the substrate adopts a semicircular longitudinal cross-section structure, and the transverse insert strip adopts a triangular longitudinal cross-section structure. The insert portion is made of medium-chromium alloy steel, and the substrate is made of high-chromium alloy steel. The preparation method includes first casting a blank of the insert portion and forging it into a shape, pre-embedding the insert portion into a casting mold of the grinding roller according to the designed structure, pouring molten iron of the grinding roller substrate, metallurgically combining the molten iron of the substrate with the insert, obtaining a grinding roller blank, and annealing, quenching, and tempering the grinding roller blank to obtain a finished grinding roller. The substrate adopts high chromium alloy steel material, and its chemical composition by weight percentage is as follows: C: 1.315-1.429%, Si: 0.327-0.465%, Mn: 0.881-0.926%, S≤0.026%, P≤0.028%, Cr: 13.281-15.197%, Ni: 0.621-0.703%, Mo: 0.891-0.923%, Cu: 0.627-0.639%, V: 0.215-0.338%, Ti: 0.0299-0.0415%, Re: 0.132-0.219%, B: 0.0811-0.0953%, Nb: 0.116-0.178%, W: 0.233-0.349%, Zr: 0.0391-0.0456%, Al: 0.0325-0.0449%, N: 0.0018-0.0045%, the balance is Fe and impurities; The insert part adopts the medium chromium alloy steel material, and its chemical composition weight percentage is: C: 0.568-0.617%, Si: 0.325-0.457%, Mn: 0.587-0.751%, S, P ≤ 0.025%, Cr: 6.155-6.338%, Ni: 0.183-0.269%, Mo: 1.115-1.577%, Cu: 0.513-0.628% , V: 1.715~1.747%, Ti: 0.021~0.0315%, Re: 0.03~0.04%, B: 0.0031~0.0039%, Nb: 0.268~0.291%, W: 0.353~0.464%, Al: 0.0355~0.0416%, N: 0.056~0.078%, the balance is Fe and impurities, and the total amount of impurities is ≤0.038%.

2. A vertical mill roller according to claim 1, characterized in that: The longitudinal insert strips and the transverse insert strips are integral structures without interfaces in the base body and in the parts exposed outside the base body. The parts where the insert strips are fused with the base body adopt a structure with an isosceles trapezoidal longitudinal section.

3. A vertical grinding roller according to claim 1 or 2, characterized in that: For the part exposed outside the base body, the longitudinal insert strip adopts a semicircular longitudinal section structure with a semicircular diameter of 9.6 to 15.8 mm, and the transverse insert strip adopts an equilateral triangle longitudinal section structure with a side length of 9.0 to 15.8 mm.

4. The method for preparing a vertical mill roller according to any one of claims 1 to 3, characterized in that: The specific steps are as follows: (1) Preparation of insert preform (1) Prepare raw materials Weigh scrap steel, ferrosilicon, ferromanganese, ferrochrome, ferronickel, ferromolybdenum, copper, ferrovanadium, ferrotitanium, ferroboron, ferroniobium, ferrotungsten, aluminum wire, chromium nitride, and rare earth ferrosilicon materials; (2) Modeling Use sand molds for shaping; (3) Melting of raw materials The raw materials are smelted in the order of scrap steel, ferroalloy, scrap steel, and precious metals. When the molten iron reaches 1506° C. to 1557° C., a pre-deoxidation treatment is performed, 0.55% ferromanganese is added, and then 0.25% ferrosilicon is added. The chemical composition of the molten iron is tested and the weight percentage of the chemical composition of the molten iron is adjusted to meet the requirements of the medium chromium alloy steel. When the temperature of the molten iron in the furnace reaches 1635° C. to 1646° C., 0.028% aluminum wire is inserted, and the molten iron is then taken out of the furnace. (4) Inoculation and pouring The obtained molten iron is poured into a ladle for modification and inoculation. After inoculation, the molten iron is poured into a mold and cooled to room temperature to obtain a blank; (5) Forging The obtained blank is polished and cleaned, and then placed in a heating furnace for heating. The heating temperature is controlled at 1066-1168°C and the holding time is 2-2.5 hours. After holding, the blank is placed in a mold for forging. The initial forging temperature is 1065-1155°C and the final forging temperature is ≥898°C. After forging, an insert preform is obtained. The forged preform is cleaned and polished again and then set aside for use. (2) Preparation of composite grinding roller (1) Prepare raw materials Weigh scrap steel, ferrosilicon, ferromanganese, low carbon ferrochrome, ferronickel, ferromolybdenum, copper, electrolytic vanadium, ferrotitanium, rare earth ferrosilicon, ferroboron, ferroniobium, ferrotungsten, ferrozirconium, aluminum wire, and chromium nitride materials; (2) Modeling Place the preform insert into the mold and ensure that the preform insert is evenly distributed inside the mold before pouring. Preheat the insert preform to 196°C to 265°C; (3) Melting of raw materials The raw materials are smelted in the order of scrap steel, ferroalloy, scrap steel, and precious alloy. When the molten iron reaches 1548° C. to 1565° C., a pre-deoxidation treatment is performed, 0.43% ferromanganese is added, and then 0.13% ferrosilicon is added. The chemical composition of the molten iron is tested and the weight percentage of the chemical composition of the molten iron is adjusted to meet the requirements of the high chromium alloy steel. When the temperature of the molten iron in the furnace reaches 1628° C. to 1635° C., 0.023% aluminum wire is inserted, and then the molten iron is taken out of the furnace. (4) Metamorphic inoculation casting The obtained molten iron is poured into a ladle for modification and inoculation. The modified inoculant is dried in advance before being taken out of the furnace, placed in a ladle, poured into a grinding roller mold, and cooled to room temperature before unpacking; (5) Cleaning and polishing The obtained casting is removed from the pouring and riser, and then cleaned and polished to obtain a composite casting grinding roller blank; (3) Grinding roller heat treatment (1) Annealing: The obtained grinding roller blank is loaded into a furnace and annealed; (2) Rough machining: The grinding roller obtained after annealing is rough machined according to the drawing; (3) Quenching: The grinding roller blank obtained by rough processing is loaded into the furnace and quenched; (4) Tempering: After quenching, the casting is reloaded into the furnace for tempering treatment; (5) The grinding roller is finely processed after tempering.

5. The method for preparing a vertical mill roller according to claim 4, wherein: The inoculating modifiers used in the inoculation casting for preparing the insert preform are: 0.263% ferrosibron, 0.121% aluminum wire, 0.256% rare earth silicon, 0.115% silicon carbide, and 0.138% ferrotitanium; the inoculating modifiers used in the modification inoculation casting for preparing the composite grinding roller are: 0.453% rare earth ferrosilicon, 0.252% ferrotitanium, 0.234% chromium nitride, 0.068% ferrozirconium, and 0.245% ferroboron.

6. The method for preparing a vertical mill roller according to claim 4, wherein: The annealing process described in the heat treatment is: the casting entering the furnace temperature is controlled below 185°C and below 300°C, the heating rate is controlled at 29°C to 33°C / hour, at 300°C, it is kept warm for 1 hour, between 300°C and 650°C, the heating rate is controlled at 41°C to 53°C / hour, at 650°C it is kept warm for 1.5 hours, between 650°C and 1006°C, the heating rate is controlled at 62°C to 75°C / hour, the casting is kept warm at 1106°C for 3.5 to 5.5 hours, and the temperature is adjusted appropriately according to the wall thickness of the casting. After keeping warm at 1106°C, it is cooled in the furnace.

7. The method for preparing a vertical mill roller according to claim 4, wherein: The quenching process is as follows: the casting temperature is controlled within 189 ° C, within 300 ° C, the heating rate is controlled at 38 ° C ~ 45 ° C / hour, at 300 ° C, keep warm for 1 hour, between 300 ° C ~ 650 ° C, the heating rate is controlled at 41 ° C ~ 53 ° C / hour, keep warm at 650 ° C for 1.5 hours, between 650 ° C ~ 1110 ° C, the heating rate is controlled at 62 ° C ~ 75 ° C / hour, the casting is kept warm at 1108 ° C ~ 1110 ° C Keep warm for 3.5 to 4.5 hours, and the holding time should be adjusted appropriately according to the wall thickness of the casting; after keeping warm, turn off the power and cool with the furnace. Wait until the temperature in the furnace drops to 1046 to 1058℃ and keep warm for 1.5 to 2.5 hours. Then take the casting out of the furnace and quench. The quenching is done by air cooling + spraying. After the casting is taken out of the furnace, start air cooling + spraying. Stop spraying when the casting temperature drops below 685℃ and continue air cooling. Stop blowing when the casting temperature drops below 550℃ and let it cool naturally in the air.

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