High-strength nodular cast iron injection molding machine template

Abstract

The invention provides a high-strength nodular cast iron injection molding machine template, and relates to the technical field of injection molding machine templates, the proportion and formula of rare earth La (lanthanum), Ce (cerium) and Y (yttrium) in a rare earth magnesium spheroidizing agent are accurately regulated and controlled to effectively control the form of graphite nodules, the blooming tendency of the graphite nodules at the thick and large part of the template and the water inlet part is thoroughly eliminated, and the high-strength nodular cast iron injection molding machine template is obtained. Wherein the content proportion range of the rare earth La (lanthanum) in the rare earth magnesium spheroidizing agent is 8%-15%, the content proportion range of the rare earth Ce (cerium) in the rare earth magnesium spheroidizing agent is 15%-25%, the content proportion range of the rare earth Y (yttrium) in the rare earth magnesium spheroidizing agent is 3%-10%, and the formula of the rare earth magnesium spheroidizing agent further comprises other auxiliary components, and the blooming tendency of the graphite nodules at the thick and large part and the water inlet part of the template of the high-strength nodular cast iron injection molding machine is successfully eliminated, so that the uniformity of the internal structure of the material is remarkably improved, the dimensional deviation of the graphite nodules is controlled within + / -5% through microstructure detection, and the distribution uniformity reaches more than 95%.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molding machine templates, and more specifically, particularly relates to a high-strength ductile iron injection molding machine template. Background Art

[0002] In the field of injection molding machine template manufacturing, traditional ductile iron templates are difficult to effectively control the graphite ball shape, and graphite ball blooming frequently occurs in thick and large parts and water inlet parts. In actual production, after a large number of sampling tests, it was found that the probability of graphite ball blooming in these key parts of templates manufactured by traditional processes is as high as 30%-50%. This problem seriously weakens the overall strength and service life of the template. Graphite ball blooming will cause serious unevenness in the internal structure of the material, which will greatly reduce the mechanical properties of the material. For example, its tensile strength will be reduced by 20%-30%, yield strength will be reduced by 15%-25%, and elongation will be reduced by 30%-40%. This makes the template very prone to defects such as cracks and deformation when it is subjected to high pressure and complex stress during the injection molding process, which not only affects the working stability of the injection molding machine, but also increases the product size deviation and scrap rate, and increases the maintenance cost and downtime of the equipment, seriously restricting the efficiency and quality of injection molding production, and increasing the production cost and operation risk of the enterprise. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a high-strength ductile iron injection molding machine template to solve the above problems.

[0004] A high-strength ductile iron injection molding machine template achieves effective control of the morphology of graphite balls by precisely adjusting the ratio and formula of rare earth La (lanthanum), Ce (cerium), and Y (yttrium) in a rare earth magnesium nodularizer, and completely eliminates the tendency of graphite balls to bloom in thick and large parts of the template and at a water inlet. The content ratio of rare earth La (lanthanum) in the rare earth magnesium nodularizer ranges from 8% to 15%.

[0005] Preferably, the content ratio of rare earth Ce (cerium) in the rare earth magnesium spheroidizer is in the range of 15%-25%, and the content ratio of rare earth Y (yttrium) in the rare earth magnesium spheroidizer is in the range of 3%-10%. The formula of the rare earth magnesium spheroidizer also includes other auxiliary components, such as magnesium oxide, calcium, etc., and their total content ratio in the spheroidizer is 5%-10%, and the auxiliary components have a specific ratio relationship, and the ratio of magnesium oxide to calcium is 2:1-3:1.

[0006] A method for preparing a high-strength ductile iron injection molding machine template comprises the steps of preparing a rare earth magnesium spheroidizer according to a specific ratio. During the preparation process, the raw materials need to be fully melted in a high temperature environment of 1400-1600°C for 30-60 minutes to ensure that the components are evenly mixed.

[0007] Preferably, the temperature when preparing the rare earth magnesium spheroidizer is controlled at 1450°C-1550°C. In this temperature range, the reaction activity of the rare earth element and the molten iron is optimal, and the spheroidization effect can be maximized. During the spheroidization process, the spheroidizer is added by using a special spiral adding device, and is evenly added to the molten iron at a speed of 10-20 g / s to ensure that the spheroidizer is evenly dispersed in the molten iron to avoid the local concentration being too high or too low to affect the spheroidization effect. In the inoculation step after the spheroidization treatment, the type of inoculant is ferrosilicon inoculant, and the amount added is 1.2%-1.8% of the weight of the molten iron. The particle size of the inoculant is controlled at 0.5-1.5 mm to ensure that it can be quickly melted and diffused in the molten iron, and promote the refinement and uniform distribution of graphite balls.

[0008] Preferably, the pouring temperature during the casting process is controlled at 1300°C-1400°C, and the pouring rate is 5-10 kg / second. Under this pouring condition, the molten iron can flow smoothly in the mold cavity and fill it completely, avoiding defects such as cold shut and pores. After the casting is completed, the template needs to be heat treated, heated to 800°C-900°C, kept warm for 2-4 hours, and then cooled to below 500°C with the furnace and taken out of the furnace. The heat treatment can further improve the organizational properties of the template and improve its comprehensive mechanical properties.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] 1. The tendency of graphite balls to bloom in the thick and large parts of the template and the water inlet of the high-strength ductile iron injection molding machine has been successfully eliminated, which significantly improves the uniformity of the internal structure of the material. After microstructure testing, the size deviation of the graphite balls is controlled within ±5%, and the distribution uniformity reaches more than 95%.

[0011] 2. The overall strength of the ductile iron injection molding machine template has been greatly improved. Its tensile strength has been increased by 30%-40% compared with the traditional process, and its yield strength has been increased by 25%-35%. It has effectively enhanced the bearing capacity of the template during the injection molding process, reduced the probability of defects such as cracks and deformation, and greatly guaranteed the reliability and stability of the template.

[0012] 3. The service life of the injection molding machine template has been significantly extended. In the accelerated fatigue test simulating the actual working conditions, the life of the new template is 2-3 times that of the traditional template, which reduces the maintenance frequency and replacement cost of the equipment, improves the working efficiency and product quality of the injection molding machine, and brings significant economic and production benefits to the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the graphite morphology of the template before improvement;

[0014] Figure 2 It is a schematic diagram of the key morphology of the improved template graphite of the present invention;

[0015] Figure 3 It is a schematic diagram of the external morphology structure of the improved template graphite of the present invention. DETAILED DESCRIPTION

[0016] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0017] See also Figure 1-Figure 3 The present invention provides a high-strength ductile iron injection molding machine template. By accurately adjusting the ratio and formula of rare earth La (lanthanum), Ce (cerium), and Y (yttrium) in the rare earth magnesium nodularizer, the morphology of graphite balls can be effectively controlled, and the tendency of graphite balls to bloom in thick and large parts of the template and the water inlet part can be completely eliminated. The content ratio of rare earth La (lanthanum) in the rare earth magnesium nodularizer is in the range of 8%-15%.

[0018] The content ratio of rare earth Ce (cerium) in the rare earth magnesium spheroidizer is in the range of 15%-25%, and the content ratio of rare earth Y (yttrium) in the rare earth magnesium spheroidizer is in the range of 3%-10%. The formula of the rare earth magnesium spheroidizer also includes other auxiliary components, such as magnesium oxide, calcium, etc., and the total content ratio of them in the spheroidizer is 5%-10%, and there is a specific ratio relationship between the auxiliary components, and the ratio of magnesium oxide to calcium is 2:1-3:1.

[0019] A method for preparing a high-strength ductile iron injection molding machine template comprises the steps of preparing a rare earth magnesium spheroidizer according to a specific ratio. During the preparation process, the raw materials need to be fully melted in a high temperature environment of 1400-1600°C for 30-60 minutes to ensure that the components are evenly mixed.

[0020] The temperature when preparing the rare earth magnesium spheroidizer is controlled at 1450°C-1550°C. In this temperature range, the reaction activity of the rare earth element and the molten iron is optimal, and the spheroidization effect can be maximized. In the spheroidization process, the spheroidizer is added by using a special spiral adding device, and is evenly added to the molten iron at a speed of 10-20 g / s to ensure that the spheroidizer is evenly dispersed in the molten iron to avoid the local concentration being too high or too low to affect the spheroidization effect. In the inoculation step after the spheroidization treatment, the type of inoculant is ferrosilicon inoculant, and the addition amount is 1.2%-1.8% of the weight of the molten iron. The particle size of the inoculant is controlled at 0.5-1.5 mm to ensure that it can be quickly melted and diffused in the molten iron, and promote the refinement and uniform distribution of graphite balls.

[0021] The pouring temperature during the casting process is controlled at 1300℃-1400℃, and the pouring speed is 5-10 kg / second. Under this pouring condition, the molten iron can flow smoothly in the mold cavity and fill it completely, avoiding defects such as cold shut and air holes. After the casting is completed, the template needs to be heat treated, heated to 800℃-900℃, kept warm for 2-4 hours, and then cooled to below 500℃ with the furnace. The heat treatment can further improve the organizational properties of the template and improve its comprehensive mechanical properties.

[0022] Embodiment 1:

[0023] Formula of rare earth magnesium spheroidizer: rare earth La (lanthanum) content is 10%, Ce (cerium) content is 20%, Y (yttrium) content is 5%, magnesium oxide content is 4%, calcium content is 2%, and the rest are conventional spheroidizer ingredients.

[0024] Manufacturing process: The raw materials are smelted at 1500℃ for 45 minutes to prepare the spheroidizing agent, which is evenly added to the molten iron at a speed of 15 g / s using a special spiral adding device for spheroidizing treatment. After spheroidization, ferrosilicon inoculant with a particle size of 1 mm is added, and the addition amount is 1.5% of the weight of the molten iron. The pouring temperature is controlled at 1350℃ and the pouring speed is 8 kg / s. After casting, it is heated to 850℃ and kept warm for 3 hours, then cooled to below 500℃ with the furnace and taken out of the furnace.

[0025] Effect: The phenomenon of graphite ball blooming in the thick parts and water inlet parts of the injection molding machine template has been effectively improved. Only a very small number (about 2%-3%) of graphite balls show slight abnormalities. The template strength is increased by 32% compared with the traditional process. After 1000 cycles of loading test under simulated injection molding conditions, the template has no obvious cracks and deformation, and the product size deviation is controlled within ±0.05 mm.

[0026] Embodiment 2:

[0027] Formula of rare earth magnesium spheroidizer: rare earth La (lanthanum) content is 12%, Ce (cerium) content is 18%, Y (yttrium) content is 8%, magnesium oxide content is 3%, calcium content is 2%, and the rest are conventional spheroidizer ingredients.

[0028] Manufacturing process: smelt at 1550℃ for 30 minutes to prepare the spheroidizer, add the spheroidizer in batches for spheroidization treatment, each addition amount is 1 / 3 of the total amount, the interval time is 10 seconds, add ferrosilicon inoculant with a particle size of 0.8 mm after spheroidization, the addition amount is 1.3% of the weight of the molten iron, the pouring temperature is controlled at 1380℃, the pouring speed is 7 kg / s, after casting is completed, heat to 880℃, keep warm for 2.5 hours, and then cool to below 500℃ with the furnace and take out of the furnace.

[0029] Effect: There is basically no graphite ball blooming in the thick parts of the template and the water inlet, and the overall strength is improved by 38% compared with the traditional process. In the durability test under simulated injection molding conditions, after 1500 cycles of loading, the template still maintains good mechanical properties, the product dimensional accuracy is stable, and the scrap rate is reduced by 40% compared with the traditional process.

[0030] Embodiment 3:

[0031] Formula of rare earth magnesium spheroidizer: rare earth La (lanthanum) content is 8%, Ce (cerium) content is 22%, Y (yttrium) content is 6%, magnesium oxide content is 5%, calcium content is 3%, and the rest are conventional spheroidizer ingredients.

[0032] Manufacturing process: smelting at 1480℃ for 60 minutes to prepare the spheroidizer, using a special injection device to add the spheroidizer, the injection pressure is 0.5MPa, after spheroidization, add ferrosilicon inoculant with a particle size of 1.2mm, the addition amount is 1.6% of the weight of the molten iron, the pouring temperature is controlled at 1320℃, the pouring speed is 9kg / s, after casting is completed, heat to 820℃, keep warm for 3.5 hours, and then cool to below 500℃ with the furnace and take out of the furnace.

[0033] Effect: The blooming of graphite balls is effectively suppressed, and only a small amount (about 1%-2%) of graphite balls have a slight deviation in shape. The strength of the template is increased by 30%. In terms of cost, due to the adjustment of some raw materials and process optimization, it is reduced by 12% compared with the traditional manufacturing method. In actual production, 100 products were produced continuously, and the product qualification rate reached more than 98%, and the appearance quality of the template was good without obvious defects.

[0034] Comparison of embodiments:

[0035] In terms of strength improvement: Example 2 has the most outstanding strength improvement effect, which is 38% higher than the traditional process, thanks to its reasonable ratio of rare earth elements and unique spheroidizing agent addition method and process parameter control. Example 1 increased by 32%, and Example 3 increased by 30%. The higher La (lanthanum) and Y (yttrium) content and the shorter spheroidizing agent addition interval in Example 2 promote the refinement and uniform distribution of graphite balls, thereby effectively enhancing the strength of the material.

[0036] Graphite ball blooming inhibition effect: Example 2 almost completely eliminated the graphite ball blooming, while Example 1 and Example 3 performed better but still had a small amount of abnormality. The batch addition of spheroidizing agent and the appropriate selection of inoculant particle size in Example 2 made it more accurate and effective in controlling the growth morphology of graphite. In comparison, the spiral addition device in Example 1 and the injection device in Example 3 were slightly inferior in uniformity and stability.

[0037] Cost: Example 3 has obvious advantages in cost control, which is 12% lower than the traditional manufacturing method, mainly due to the optimized selection of raw materials and the simplification of some processes. Although Examples 1 and 2 are excellent in performance improvement, the cost is relatively high. In practical applications, if the enterprise has extremely high requirements for product strength and quality, and cost is not the primary consideration, Example 2 is the best choice; if the enterprise pays attention to cost control while pursuing certain performance improvements, Example 3 is more suitable; Example 1 has achieved a certain balance between performance and cost, and can be flexibly selected according to specific production needs and the economic conditions of the enterprise.

[0038] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A high-strength ductile iron injection molding machine template, characterized in that: By precisely controlling the ratio and formula of rare earth La (lanthanum), Ce (cerium), and Y (yttrium) in the rare earth magnesium nodulizer, effective control of the morphology of graphite balls can be achieved, and the tendency of graphite balls to bloom in thick and large parts of the template and the water inlet can be completely eliminated. The content ratio of rare earth La (lanthanum) in the rare earth magnesium nodulizer is in the range of 8%-15%.

2. A high-strength ductile iron injection molding machine template as claimed in claim 1, characterized in that: The content ratio of rare earth Ce (cerium) in the rare earth magnesium spheroidizer ranges from 15% to 25%.

3. A high-strength ductile iron injection molding machine template as claimed in claim 2, characterized in that: The content ratio of rare earth Y (yttrium) in the rare earth magnesium spheroidizer ranges from 3% to 10%.

4. A high-strength ductile iron injection molding machine template as claimed in claim 3, characterized in that: The formula of the rare earth magnesium spheroidizer also includes other auxiliary components, such as magnesium oxide, calcium, etc., the total content ratio of which in the spheroidizer is 5%-10%, and there is a specific ratio relationship between the auxiliary components, and the ratio of magnesium oxide to calcium is 2:1-3:

1.

5. A method for manufacturing the high-strength ductile iron injection molding machine template according to claim 1, comprising the step of preparing a rare earth magnesium spheroidizer according to a specific ratio. During the preparation process, the raw materials need to be fully melted in a high temperature environment of 1400°C-1600°C for 30-60 minutes to ensure that the components are evenly mixed.

6. The manufacturing method according to claim 5, characterized in that: The temperature when preparing the rare earth magnesium spheroidizer is controlled at 1450℃-1550℃. In this temperature range, the reaction activity between the rare earth element and the molten iron is optimal, and the spheroidization effect can be maximized.

7. The manufacturing method according to claim 5, characterized in that: During the spheroidizing process, the spheroidizing agent is added into the molten iron at a rate of 10-20 g / s by a special spiral adding device to ensure that the spheroidizing agent is evenly dispersed in the molten iron to avoid local concentration being too high or too low and affecting the spheroidizing effect.

8. The manufacturing method according to claim 5, characterized in that: In the inoculation step after spheroidization, the type of inoculant is ferrosilicon inoculant, and its addition amount is 1.2%-1.8% of the weight of the molten iron. The particle size of the inoculant is controlled at 0.5-1.5 mm to ensure rapid melting and diffusion in the molten iron, promoting the refinement and uniform distribution of graphite nodules.

9. The manufacturing method according to claim 5, characterized in that: The pouring temperature during the casting process is controlled at 1300℃-1400℃, and the pouring speed is 5-10 kg / s. Under this pouring condition, the molten iron can flow smoothly in the mold cavity and fill it completely, avoiding defects such as cold shut and air holes.

10. The manufacturing method as claimed in claim 5, after casting is completed, the template needs to be heat treated, heated to 800°C-900°C, kept warm for 2-4 hours, and then cooled to below 500°C before being taken out of the furnace, and the microstructure and properties of the template are further improved by heat treatment, thereby improving its comprehensive mechanical properties.

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