Gray cast iron glass mold and preparation method thereof

Abstract

The invention relates to the technical field of glass molds, in particular to a gray cast iron glass mold and a preparation method thereof.The gray cast iron glass mold is prepared from, by weight, 3.45%-3.65% of C, 1.80%-2.20% of Si, 0.50%-0.70% of Mn, smaller than 0.03% of S, smaller than 0.10% of P, smaller than 0.20% of Ni, 0.25%-0.35% of Mo, 0.15%-0.25% of V and the balance Fe and inevitable impurities. By adding proper elements into the gray cast iron, the oxidation resistance, the wear resistance, the thermal conductivity and the thermal fatigue performance of the glass mold can be improved.

Description

Technical Field

[0001] This application relates to the technical field of glass molds, and in particular to a gray cast iron glass mold and a preparation method thereof. Background Art

[0002] Glass molds are important equipment for the forming of glass products. Taking the forming of glass containers as an example, since the glass container forming mold not only plays the role of restricting the shape of the glass container during the process of forming the glass container, but also serves as a heat exchange medium for the molten glass material, and is frequently in contact with high-temperature glass melt and undergoes oxidation, growth, thermal fatigue, as well as friction and wear with the glass container, it is necessary to require the materials used to manufacture glass molds to have good density, easy machinability, chemical stability, excellent specific heat and thermal conductivity, small thermal expansion coefficient, good thermal crack resistance and excellent wear resistance. Among them, the antioxidant property is an important indicator for considering glass mold materials.

[0003] Since oxygen in the air diffuses along the graphite into the internal cavity of the cast iron, the strength of the cast iron is reduced, the oxidation inside the glass mold is aggravated, the mold material is prone to expansion and growth, resulting in gaps and cracks, and the service life is shortened.

[0004] Therefore, improving the antioxidant property of gray cast iron is of great significance for improving the service life of glass molds. Summary of the Invention

[0005] In order to improve the antioxidant property of gray cast iron glass molds, this application provides a gray cast iron glass mold and a preparation method thereof.

[0006] In the first aspect, this application provides a gray cast iron glass mold, adopting the following technical solution: A gray cast iron glass mold, which is made of the following raw material ratio: C: 3.45 - 3.65 wt%, Si: 1.80 - 2.20 wt%, Mn: 0.50 - 0.70 wt%, S < 0.03 wt%, P < 0.10 wt%, Ni < 0.20 wt%, Mo: 0.25 - 0.35 wt%, V: 0.15 - 0.25 wt%, and the balance is Fe and unavoidable impurities.

[0007] By adopting the above technical solutions, both C and Si are elements that strongly promote the graphitization transformation. The higher the C content, the more favorable it is for graphite nucleation. The addition of Si can increase the activity of C in iron and promote the graphite nucleation effect. In addition, the addition of Si raises the eutectic and eutectoid transformation temperature lines, and the eutectic point and eutectoid point shift to the left, promoting graphite nucleation. An appropriate amount of Mn alloy can refine the grain structure, expand the γ region at the same time, lower the eutectoid temperature, and Mn can react with S to form MnS, weakening the harmful effect of S. Therefore, after Mn reacts with S, Mn can inhibit the second-stage graphitization and promote the formation of pearlite structure. However, the manganese content in cast iron should not be too high, as it increases the tendency of white mouth after exceeding a certain amount. Therefore, adjusting the elements such as C, Si, and Mn in the molten iron can control the structure of cast iron.

[0008] Secondly, V promotes the formation of carbides during the crystallization of cast iron liquid, promotes and refines graphite, homogenizes the graphite distribution, refines the pearlite in the structure, forms a hard phase to strengthen the matrix of the structure, and reduces the ferrite and dendrites in the large cross-section of the material structure; furthermore, adding the Mo alloy element, the chemical property of the Mo element itself is not active, but its function is to refine the graphite in the structure, improve the uniformity of the cross-section structure, enhance the high-temperature stability of the structure, and increase the density of the structure; at the same time, the Mo and V alloy elements form metal compounds with elements such as C and Fe in the cast iron alloy, and at the same time, it also promotes the formation of a metastable Fe-C structure pearlite. The pearlite has a high degree of order and strong anti-deformation ability. The combined action of the three greatly improves the energy barrier of the lattice network deformation slip of the matrix, so as to achieve the effect of improving the matrix strength.

[0009] In summary, by adding appropriate elements to gray cast iron in this application, the oxidation resistance, wear resistance, thermal conductivity, and thermal fatigue performance of the glass mold can be improved.

[0010] In a specific feasible implementation scheme, the inner cavity of the gray cast iron glass mold is of A / D type graphite, and the pearlite content is <10%; the core part is AD graphite, and the pearlite content is <10%.

[0011] By adopting the above technical solution, introducing pearlite structure into the cast iron structure is beneficial to improving the matrix strength performance. However, when it is used as a glass mold material, the pearlite content in the structure should be strictly controlled because the service temperature range of the glass mold material is 450 - 850 °C, which exactly covers the pearlite transformation temperature range of 550 - 760 °C. When the mold is installed and in service, the retained pearlite in the structure slowly decomposes, resulting in a change in the structure stress, causing non-uniform deformation of the mold, and thus making the mold warp and unable to be clamped on the workbench, leading to the scrapping of the mold due to aging. At the same time, since Fe3C in the pearlite structure is a metastable phase, it undergoes an oxidation reaction with the oxygen invading from the environment at high temperatures, forming a large number of lamellar ferrite structures in the matrix, exposing a large amount of the surface of the matrix ferrite to the oxidizing atmosphere, strongly promoting the oxidation reaction of the matrix and reducing the oxidation resistance of the matrix.

[0012] In a second aspect, the present application provides a method for preparing a gray cast iron glass mold, adopting the following technical solution: The method for preparing a gray cast iron glass mold includes the following steps: Batch preparation: Prepare the corresponding masses of pig iron, scrap steel, return material, ferromanganese, and ferrosilicon as raw materials according to the proportions of each element; Melting: Place the raw materials in a melting furnace and melt them to obtain molten iron; Inoculation: Add the inoculant and the molten iron into the ladle in sequence to obtain inoculated molten iron; Pouring: Place an inoculation block in the mold cavity, and pour the inoculated molten iron into the mold. After the molten iron cools, a blank is obtained; Annealing: After taking out the blank from the mold, heat it, keep it warm, and then cool it in the furnace and then air-cool to obtain the gray cast iron glass mold.

[0013] By adopting the above technical solution, the preparation method is simple, and at the same time, the prepared gray cast iron glass mold has good oxidation resistance, wear resistance, thermal conductivity, and thermal fatigue performance.

[0014] In a specific feasible embodiment, during the melting, the melting temperature is 1480 - 1530 °C.

[0015] By adopting the above technical solutions, during smelting, the tensile strength continuously increases with the increase of temperature. The tensile strength of the material is mainly affected by the material structure. When the smelting temperature rises, the higher the energy obtained by the short-range ordered atomic clusters of alloying elements in the molten iron, the smaller the diameter of the atomic clusters, and the stronger their migration and diffusion ability in the molten iron. The distribution of alloying elements becomes more uniform, improving the homogenization degree of alloying elements in the molten iron. At the same time, the high temperature makes the diameter of the particulate matter of alloying elements distributed in the molten iron small. When the molten iron rapidly solidifies and cools, the alloying elements in the structure form the second phase and alloy solid solution. When the material is subjected to load and slips and deforms, the pinning of heterogeneous particles in the matrix to the crystal slip lines increases, hindering the rapid increase and movement of the slip lines. Therefore, the tensile strength of the material increases. However, when the smelting temperature exceeds the stable temperature by more than 50 °C, the burn-out rate of carbon increases at this time, and the phenomenon of internal silicon increase occurs in the molten iron, increasing the brittleness and white mouth tendency of the casting. At the same time, too high a smelting temperature will also lead to a large shrinkage cavity tendency in the casting structure and stress cracking of the as-cast structure, etc. Therefore, appropriately increasing the smelting temperature of the molten iron is beneficial to refining the coarse graphite and massive cementite in the raw pig iron, eliminating the tissue heredity of carbon steel in the batching, improving the fluidity of the molten iron, and at the same time is an effective measure to exclude the gas in the molten iron as much as possible to avoid casting porosity due to low molten iron temperature.

[0016] In a specific feasible implementation, during inoculation, the addition amount of the inoculant is 0.3-0.5 wt% of the molten iron.

[0017] By adopting the above technical solutions, with the increase of the inoculant amount, the service life of the mold is extended; the hardness value of the working surface in the inner cavity area also has a certain upward and downward trend, but the increase amplitude is very small. With the increase of the inoculant amount, the graphite structure is refined, and the graphite structure changes from ordinary A-type graphite to fine D-type graphite. When the inoculant is appropriate, in addition to the fine needle-shaped D-type graphite formed by inoculation, a large number of A-type primary graphite are also scattered. When the inoculant is excessive, carbon atoms at the solidification front of the molten iron adsorb on a large number of free carbon and silicon groups and grow rapidly. Inoculation treatment enhances the graphitization of the molten iron, effectively reduces the white mouth tendency; refines the graphite size and eutectic cell; improves the tissue uniformity of different cross-sections; improves the mechanical properties of the casting, and rationally coordinates the inoculation treatment in terms of both strength performance and machining performance.

[0018] In a specific feasible implementation, the inoculant is a silicon-barium inoculant.

[0019] By adopting the above technical solution, in order to enhance the mechanical properties of cast iron, it is necessary to control the growth of graphite. An inoculant composed of ferrosilicon and a small amount of calcium-silicon alloy is poured into the molten iron with the flow when pouring the molten iron ladle, so that a large number of tiny silicon enrichment areas are added to the molten iron, increasing the compositional fluctuations in the local area. At the same time, the melting of the inoculant particles consumes the heat in the particle micro-region, so that the temperature of the particle region is lower than the overall temperature to form a supercooled region, which is conducive to the attachment, nucleation and growth of free C atoms in the molten iron, refining the graphite, and the matrix is in pearlite structure, thus improving the strength and hardness of the cast iron.

[0020] In a specific feasible implementation, the inoculant is a silicon-calcium-rare earth and silicon-barium inoculant composite.

[0021] By adopting the above technical solution, the inoculant introduces Ca, which can form CaC2 with free carbon atoms and is also conducive to the similar attachment, nucleation and growth of C atoms; at the same time, rare earths form rare earth sulfides with S in the molten iron, promoting the nucleation of graphite; in short, using a silicon-calcium-rare earth and silicon-barium inoculant composite for in-furnace inoculation treatment, it is found that the inoculation effect of such an inoculant is several times higher than that of the traditional silicon-barium inoculant in application, greatly reducing the tendency of the workpiece to become white-mouthed, homogenizing the cross-sectional structure, improving the maturity of the molten iron, resisting inoculation decay and stabilizing the production of castings.

[0022] In a specific feasible implementation, during pouring, the addition amount of the inoculation block is 2-3 wt% of the molten iron.

[0023] By adopting the above technical solution, gray cast iron is basically a eutectic alloy composed of iron, carbon and silicon. Among them, carbon mainly exists in the form of graphite. To produce high-quality castings, it is crucial to control the morphology of graphite and the matrix metal structure formed during the solidification of cast iron. And good inoculation treatment can make gray cast iron have a microstructure that meets the requirements, thus ensuring the mechanical properties and machining properties of the castings. Adding an inoculant to the liquid cast iron can form a large number of submicroscopic nuclei, promoting the formation of eutectic clusters in the liquid phase. When approaching the eutectic solidification temperature, fine graphite flakes are first formed at the nucleation sites and grow into eutectic clusters from this, improving the mechanical properties of the cast iron. The inoculated cast iron has good fluidity, reduced shrinkage of the castings, improved machining properties and reduced residual stress. This application controls the morphology of graphite and the matrix metal structure formed during the solidification of cast iron, controls the fiber structure of the gray cast iron produced, improves the mechanical properties of the cast iron, and improves the physical properties of the glass mold through the inoculation method combining inoculation during tapping and inoculation during pouring.

[0024] In a specific feasible implementation, during pouring, the pouring temperature is 1370-1380 °C.

[0025] By adopting the above technical solution, when the pouring temperature is lower than 1370 °C, the viscosity of the molten iron is high and the fluidity is poor, and the shrinkage cavities and porosity in the mold are obvious and the mold gradually becomes scrapped. When the pouring temperature exceeds 1380 °C, the surface defects of the casting increase due to overburning and sand inclusion, and the chill in the casting undergoes remelting, and the chill in the casting cannot be demolded and is scrapped. As the pouring temperature increases, the service life of the test mold first increases and then decreases, and the hardness value increases slowly and gradually levels off.

[0026] In a specific feasible embodiment, during the annealing, the blank is heated to 955 °C and held for 10 h, and then cooled in the furnace to 500 °C and then taken out of the furnace for air cooling.

[0027] By adopting the above technical solution, the annealing treatment can remove the internal stress of the material matrix, improve the plasticity and toughness of the material, and improve the machining performance of the material; optimizing the temperature and time during annealing, promoting graphite nucleation and refining graphite, and forming a protective film on the surface of the matrix with alloying elements having good oxidation resistance are all beneficial to improving the oxidation resistance of the structure.

[0028] In summary, the present application includes at least one of the following beneficial technical effects: 1. By adding appropriate elements, the present application improves the oxidation resistance, wear resistance, thermal conductivity and thermal fatigue performance of the glass mold. 2. The inner cavity of the gray cast iron glass mold of the present application is A / D type graphite, and the pearlite content is <5%; the core part is AD graphite, and the pearlite content is <10%; a small amount of pearlite is contained in the structure of the gray cast iron glass mold of the present application, which can avoid the oxidation reaction of Fe3C with the oxygen intruded from the environment at high temperature, form a large number of lamellar ferrite structures in the matrix, expose a large amount of the surface of the matrix ferrite to the oxidizing atmosphere, strongly promote the oxidation reaction of the matrix, and reduce the oxidation resistance of the matrix. 3. The inoculant of the present application adopts a complex of silicon-calcium-rare earth and silicon-barium inoculant. Among them, Ca can form CaC2 with free carbon atoms, which is also beneficial to the similar attachment nucleation growth of C atoms; at the same time, rare earths form rare earth sulfides with S in the molten iron, promote the nucleation of graphite and refine graphite, which is beneficial to improving the oxidation resistance of the structure. Detailed implementation manners

[0029] The present application will be further described in detail below through examples. Examples

[0030] Example 1 This example discloses a gray cast iron glass mold, including the following raw materials: C: 3.45 wt%, Si: 1.80 wt%, Mn: 0.50 wt%, S: 0.02 wt%, P: 0.05 wt%, Ni: 0.10 wt%, Mo: 0.25 wt%, V: 0.15 wt%, and the balance is Fe and unavoidable impurities.

[0031] This embodiment also discloses a preparation method of a gray cast iron glass mold, which includes the following steps: S1, batching: Select pig iron, scrap steel, return scrap, ferromanganese, and ferrosilicon as raw materials; S2, melting: Place the above raw materials in a melting furnace, heat to 1480 °C, and control the melting time to 2 min to obtain molten iron; S3, inoculation: Add 3 g of silicon-barium inoculant to the ladle, then pour the above 1000 g of molten iron into the hanging ladle. The inoculation temperature is 1430 °C, and inoculate for 2 min. The particle size of the silicon-barium inoculant is 1-3 mm, and it is purchased from Henan Jin'ao Metallurgy Co., Ltd.; S4, pouring: Put 20 g of inoculation blocks into the mold cavity, and then pour the molten iron after the above inoculation into the mold. The molten iron cools to obtain a blank. Control the pouring temperature to 1370 °C. The inoculation blocks are purchased from QINBLOC of Xi'an Qinli Alloy Materials Technology Co., Ltd., and the average particle size is 25.4 mm; S5, annealing: Take out the obtained blank from the mold and place it in an annealing furnace to heat to 955 °C, and then keep it warm for 10 h; Cool the annealed blank in the furnace to 500 °C and then take it out of the furnace and air-cool it to room temperature to obtain a gray cast iron glass mold with A / D type graphite in the inner cavity, pearlite content < 5%, AD graphite in the core part, and pearlite content < 10%.

[0032] Example 2 This example is basically the same as Example 1, except that: This example discloses a gray cast iron glass mold, including the following raw materials: C: 3.65 wt%, Si: 2.20 wt%, Mn: 0.70 wt%, S: 0.02 wt%, P: 0.05 wt%, Ni: 0.10 wt%, Mo: 0.35 wt%, V: 0.25 wt%, and the balance is Fe and unavoidable impurities.

[0033] Example 3 This example is basically the same as Example 1, except that: S2, melting: Place the above raw materials in a melting furnace, heat to 1530 °C, and control the melting time to 2 min to obtain molten iron.

[0034] Example 4 This example is basically the same as Example 1, except that: S2, melting: Place the above raw materials in a melting furnace, heat to 1550 °C, and control the melting time to 2 min to obtain molten iron.

[0035] Example 5 This embodiment is basically the same as Embodiment 1, except that: S3, inoculation: Add 5 g of silicon-barium inoculant into the ladle, and then pour the above 1000 g of molten iron into the suspended ladle. The inoculation temperature is 1430 °C, and inoculation is carried out for 2 min.

[0036] Embodiment 6 This embodiment is basically the same as Embodiment 1, except that: S3, inoculation: Add 3 g of silicon-barium inoculant and 2 g of silicon-calcium-rare earth into the ladle, and then pour the above 1000 g of molten iron into the suspended ladle. The inoculation temperature is 1430 °C, and inoculation is carried out for 2 min; among them, the silicon-calcium-rare earth is purchased from Shaanxi Xinfengfan Technology Materials Co., Ltd., and the particle size is 10 mm.

[0037] Embodiment 7 This embodiment is basically the same as Embodiment 1, except that: S4, pouring: Put 30 g of inoculation blocks into the mold cavity, and then pour the molten iron after the above inoculation into the mold. The molten iron is cooled to obtain a blank part, and the pouring temperature is controlled at 1370 °C.

[0038] Embodiment 8 This embodiment is basically the same as Embodiment 1, except that: S4, pouring: Put 30 g of inoculation blocks into the mold cavity, and then pour the molten iron after the above inoculation into the mold. The molten iron is cooled to obtain a blank part, and the pouring temperature is controlled at 1380 °C.

[0039] Embodiment 9 This embodiment is basically the same as Embodiment 1, except that: S4, pouring: Put 30 g of inoculation blocks into the mold cavity, and then pour the molten iron after the above inoculation into the mold. The molten iron is cooled to obtain a blank part, and the pouring temperature is controlled at 1400 °C.

[0040] Comparative example Comparative example 1 The difference between this comparative example and Embodiment 1 is that the gray cast iron glass mold disclosed in this comparative example includes the following raw materials: C: 3.25 wt%, Si: 1.60 wt%, Mn: 0.30 wt%, S: 0.05 wt%, P: 0.2 wt%, Ni: 0.30 wt%, Mo: 0.15 wt%, V: 0.05 wt%, and the balance is Fe and unavoidable impurities.

[0041] Comparative example 2 The difference between this comparative example and Embodiment 1 is that the gray cast iron glass mold disclosed in this comparative example includes the following raw materials: C: 3.85 wt%, Si: 2.40 wt%, Mn: 0.90 wt%, S: 0.05 wt%, P: 0.2 wt%, Ni: 0.30 wt%, Mo: 0.35 wt%, V: 0.35 wt%, and the balance is Fe and unavoidable impurities.

[0042] Performance detection 1. Antioxidant test The gray iron glass molds prepared in each example and each comparative example were placed in an oven at 120 °C and dried for 2 h, taken out and cooled to room temperature in a desiccator, weighed and recorded as m1, and then kept in a box-type resistance furnace at 700 °C for 16 h, and then cooled to 300 °C in the furnace and taken out, and air-cooled to room temperature and weighed and recorded as m2. According to the formula v = (m1 - m2) / (s·t), where t is the oxidation time and s is the surface area of the specimen, the test results were recorded in Table 1.

[0043] 2. Thermal fatigue performance test In the resistance furnace in the laboratory, simulate its working conditions, heat the gray iron glass molds prepared in each example and each comparative example to 600 °C and keep them warm for 10 min, take them out and quickly cool them in cold water, and repeat the cycle 50 times, measure the crack length, and record the test results in Table 1.

[0044] 3. Abrasion resistance test The gray iron glass molds prepared in each example and each comparative example were dragged and polished with steel wool 6000 times under the condition of a load force of 350 gf, calculate their wear amount, and record the test results in Table 1.

[0045] 4. Thermal conductivity test The thermal conductivity of the gray iron glass molds prepared in each example and each comparative example was tested with a laser thermal conductivity tester, and the test results were recorded in Table 1.

[0046] 5. Service life test Determine the number of uses when the gray iron glass molds prepared in each example and each comparative example are scrapped, and record the test results in Table 1.

[0047] Table 1 Performance detection data table of Examples 1-9 and Comparative Examples 1-2 Referring to Table 1, in combination with Examples 1-2 and Comparative Examples 1-2, it can be seen that by adding a certain amount of Mn, Mo, V and other elements to the gray cast iron, the oxidation resistance, wear resistance, thermal conductivity and thermal fatigue performance of the glass mold can be improved; among them, C and Si are both elements that strongly promote graphitization transformation, and the higher the C content, the more conducive to graphite nucleation. The addition of Si can increase the activity of C in iron and promote the graphite nucleation effect; in addition, the addition of Si pulls up the eutectic and eutectoid transformation temperature lines, and the eutectic point and the eutectoid point shift to the left, promoting graphite nucleation. An appropriate amount of Mn alloy has the function of refining the grain structure, expanding the γ zone, and reducing the eutectoid temperature. Mn can react with S to generate MnS, weakening the harmful effect of S. Therefore, after Mn reacts with S, Mn can inhibit the second stage of graphitization and promote the formation of pearlite structure. However, the manganese content in cast iron should not be too high, and it increases the tendency of white cast iron after exceeding a certain amount. In summary, the C, Si, Mn and other elements in the molten iron are adjusted to control the cast iron structure; secondly, V promotes the formation of carbides in the crystallization of cast iron liquid, promotes and refines graphite, uniformly distributes graphite, refines the structure pearlite, forms a hard phase to strengthen the structure matrix, and reduces the large-section ferrite and dendrite of the material structure; thirdly, Mo alloy elements are added. The chemical properties of Mo element itself are not active, but its role is to refine the structure graphite, improve the uniformity of the cross-sectional structure, enhance the high-temperature stability of the structure, and increase the density of the structure; at the same time, Mo and V alloy elements form metallic compounds with C, Fe and other elements in the cast iron alloy, and at the same time, they also promote the formation of a metastable Fe-C structure pearlite. Pearlite has a high degree of order and strong deformation resistance. The three work together to greatly improve the matrix lattice network deformation slip energy barrier, thereby achieving the effect of improving the strength of the matrix and increasing the service life of the glass mold.

[0048] With reference to Table 1, in combination with Examples 1, 3-4, it can be seen that controlling the temperature during smelting can improve the comprehensive performance of the glass mold. This is because appropriately increasing the smelting temperature of the molten iron is conducive to refining the coarse graphite and large cementite structures in the raw material pig iron, eliminating the hereditary structure of carbon steel in the ingredients, and improving the fluidity of the molten iron. It is also an effective measure to exclude the gas in the molten iron as much as possible to avoid the pores in the castings caused by the low molten iron temperature.

[0049] Referring to Table 1 and combining with Examples 1, 5 - 6, it can be seen that by changing the addition amount of the inoculant added during inoculation within an appropriate range, the prepared glass mold has a relatively high service life. At the same time, in this application, a silicon - calcium - rare earth and silicon - barium inoculant composite is used as the inoculant. The silicon - barium inoculant refines graphite, and the matrix is in a pearlite structure, which improves the strength and hardness of the cast iron. The silicon - calcium - rare earth introduces Ca, which can form CaC2 with free carbon atoms and is also conducive to the nucleation and growth of C atoms by similar attachment. At the same time, the rare earth forms rare earth sulfides with S in the molten iron, promoting the nucleation of graphite. Under the synergistic effect of the two, the comprehensive performance of the prepared glass mold is improved.

[0050] Referring to Table 1 and combining with Examples 1, 8 - 9, it can be seen that controlling the pouring temperature can improve the comprehensive performance of the prepared glass mold. This is because when the pouring temperature is lower than 1370 °C, the viscosity of the molten iron is high and the fluidity is poor, and obvious shrinkage cavities and porosity in the mold gradually lead to scrapping. When the pouring temperature exceeds 1380 °C, there are more over - burned and sand - inclusion defects on the surface of the casting, and the chill cores of the casting show remelting phenomena, and the chill of the casting cannot be demolded and is scrapped. As the pouring temperature increases, the service life of the test mold first increases and then decreases, and the hardness value increases slowly and gradually tends to be stable.

[0051] This specific embodiment is only an explanation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A gray cast iron glass mold, characterized in that: It is made from the following raw material ratios: C: 3.45 - 3.65 wt%, Si: 1.80 - 2.20 wt%, Mn: 0.50 - 0.70 wt%, S < 0.03 wt%, P < 0.10 wt%, Ni < 0.20 wt%, Mo: 0.25 - 0.35 wt%, V: 0.15 - 0.25 wt%, and the balance is Fe and unavoidable impurities.

2. The gray cast iron glass mold according to claim 1, characterized in that: The inner cavity of the gray cast iron glass mold is of A / D type graphite, and the pearlite content is < 10%; the core part is AD graphite, and the pearlite content is < 10%.

3. The preparation method of the gray cast iron glass mold according to any one of claims 1-2, characterized in that: It includes the following steps: Batch preparation: Prepare corresponding masses of pig iron, scrap steel, return scrap, ferromanganese, and ferrosilicon as raw materials according to the proportions of each element; Melting: Place the above raw materials in a melting furnace and melt to obtain molten iron; Inoculation: Add the inoculant and molten iron into the ladle in sequence to obtain inoculated molten iron; Pouring: Add an inoculation block into the mold cavity, and pour the inoculated molten iron into the mold. After the molten iron cools, a blank part is obtained; Annealing: Take out the blank part from the mold, heat it, keep it warm, cool it in the furnace, and then air-cool it to obtain the gray cast iron glass mold.

4. The preparation method of the gray cast iron glass mold according to claim 3, characterized in that: During the melting, the melting temperature is 1480 - 1530 °C.

5. The preparation method of the gray cast iron glass mold according to claim 3, characterized in that: During the inoculation, the addition amount of the inoculant is 0.3 - 0.5 wt% of the molten iron.

6. The preparation method of the gray cast iron glass mold according to claim 5, characterized in that: The inoculant is a silicon-barium inoculant.

7. The preparation method of the gray cast iron glass mold according to claim 5, characterized in that: The inoculant is a composite of silicon-calcium-rare earth and silicon-barium inoculant.

8. The preparation method of the gray cast iron glass mold according to claim 3, characterized in that: During the pouring, the addition amount of the inoculation block is 2 - 3 wt% of the pouring liquid.

9. The preparation method of the gray cast iron glass mold according to claim 3, characterized in that: During the pouring, the pouring temperature is 1370 - 1380 °C.

10. The preparation method of the gray cast iron glass mold according to claim 3, characterized in that: During the annealing, heat the blank part to 955 °C, keep it warm for 10 h, cool it in the furnace to 500 °C, and then take it out of the furnace and air-cool it.

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