A casting process for a compacted graphite cast iron fully hydraulic load sensing steering gear housing casting

Abstract

The present invention relates to the field of casting production technology, specifically, to a casting process for a vermicular graphite cast iron full hydraulic load sensing steering gear housing casting. It includes step one, mold manufacturing; step two, smelting and impurity removal and vermicular inoculation, using high-quality pig iron as the main raw material, and stirring and smelting with additives, step three, casting and molding, using vibration casting technology for casting; step four, cooling and molding, step five, sand removal and cleaning. In the casting process for the vermicular graphite cast iron full hydraulic load sensing steering gear housing casting, mold manufacturing, smelting and impurity removal and vermicular inoculation, casting and molding, cooling and molding, and sand removal and cleaning are adopted, so as to achieve the homogenization of the creep rate and the improvement of the casting performance, reduce energy consumption and material waste, reduce production costs, and improve the strength and toughness of the vermicular graphite cast iron full hydraulic load sensing steering gear housing, thereby improving its service life and reliability.

Description

Technical Field

[0001] The invention relates to the technical field of casting production, in particular to a casting process for a compacted graphite cast iron full hydraulic load sensing steering gear housing casting. Background Art

[0002] As a fully hydraulic steering gear in the steering system of engineering machinery, it is a steering safety component. It works in a harsh environment and is subjected to irregular alternating impact stress. Its casting quality requires Class I. At present, with the continuous progress of the automotive industry, the performance and quality requirements of automotive parts are becoming more and more stringent. As an important part of the vehicle control system, the fully hydraulic load-sensing steering gear needs to withstand complex and changeable loads and working environments. Vermicular graphite cast iron is a new type of cast iron material that combines the advantages of gray cast iron and ductile iron. Its excellent mechanical properties and thermal conductivity make it an ideal choice for manufacturing such shells.

[0003] The mechanical properties of vermicular graphite cast iron are between those of gray cast iron and ductile iron. For example, its tensile strength, elongation and bending fatigue strength are better than those of gray cast iron, and close to those of ferritic ductile iron. The cross-sectional sensitivity of vermicular graphite cast iron is much smaller than that of ordinary gray cast iron, so its mechanical properties on thick and large cross-sections are still relatively uniform. In addition, its wear resistance is better than that of inoculated cast iron and high-phosphorus wear-resistant cast iron. The outstanding advantage is that its yield strength ratio is the highest among casting alloys, and its thermal conductivity and heat fatigue resistance are much higher than those of ductile iron, which are the outstanding advantages of vermicular graphite cast iron. Its anti-growth and anti-oxidation properties are higher than those of other cast irons, and it also has good process performance.

[0004] However, there are still some deficiencies in the casting process of the compacted graphite cast iron full hydraulic steering gear body shell casting in the prior art.

[0005] The creeping effect of the existing vermicular graphite cast iron casting process will be unstable, which may lead to differences in the creeping rate, mechanical properties, etc. of the castings, which will not only affect the quality and performance of the castings and reduce the thermal conductivity of the castings, but also cause a decline in mechanical properties, increase production costs, cause economic losses, and reduce production efficiency, thereby affecting the application of vermicular graphite cast iron materials in full hydraulic steering gears.

[0006] In view of this, there is an urgent need to improve the deficiencies of the prior art by optimizing the casting process of vermicular graphite cast iron to meet the high performance requirements of the full hydraulic load sensing steering gear housing casting. Summary of the invention

[0007] The object of the present invention is to provide a casting process for a compacted graphite cast iron fully hydraulic load sensing steering gear housing casting to solve the problems raised in the above background technology.

[0008] To achieve the above object, on the one hand, the present invention provides a casting of a fully hydraulic load sensing steering gear housing of a vermicular cast iron, comprising the following steps:

[0009] S1.1, mold manufacturing, adopt the design requirements of the full hydraulic load sensing steering gear housing to manufacture the corresponding precision casting mold;

[0010] S1.2, smelting, impurity removal and vermicular inoculation, using high-quality pig iron as the main raw material, and stirring and smelting with additives, wherein the additives include: impurity remover, vermicular agent, inoculant and spheroidizer;

[0011] S1.3, casting molding, the temperature of molten iron should be within the range of 1200℃~1300℃, and the vibrating casting technology should be used for casting;

[0012] S1.4, cooling molding, let the casting cool naturally to room temperature in the mold;

[0013] S1.5. Remove sand and burrs from the surface of castings by sand removal.

[0014] As a further improvement of the technical solution, in S1.2, the smelting impurity removal and creep inoculation technology includes the following steps:

[0015] S2.1. Preparation before smelting: first check the medium frequency induction furnace, then prepare the smelting materials, including high-quality pig iron, impurity remover, vermicular agent, inoculant and spheroidizer, and at the same time, preheat the medium frequency induction furnace;

[0016] S2.2, during the smelting process: first add high-quality pig iron, and when the pig iron begins to melt but has not yet completely melted, add a de-impurity agent for de-impurity treatment; when the molten iron melts and the temperature reaches 1460-1500℃, add a vermicular agent; after the vermicular agent is added and stirred for a while, add an inoculant, and finally add a spheroidizing agent;

[0017] S2.3, post-smelting processing, first, take samples from the molten iron for testing, and adjust the composition of the molten iron according to the test results to meet the requirements of the subsequent casting process. Then pour the smelted molten iron into a casting ladle to prepare for the casting operation.

[0018] As a further improvement of the technical solution, in S1.2, the amount of the impurity remover is 0.2% to 0.6% of the mass of the molten iron; the amount of the vermicular agent is 0.8% to 1.4% of the mass of the molten iron; the amount of the inoculant is 0.6% to 1.0% of the mass of the molten iron; and the amount of the spheroidizer is 1.2% to 1.6% of the mass of the molten iron.

[0019] As a further improvement of the technical solution, the impurity remover includes silicon dioxide, aluminum oxide, silicates and alkaline oxides, silicon dioxide and aluminum oxide are main chemical components, and silicates and alkaline oxides are auxiliary chemical components.

[0020] As a further improvement of the technical solution, the creeping agent includes rare earth ferrosilicon, rare earth calcium silicon, rare earth ferrosilicon magnesium alloy and magnesium titanium alloy.

[0021] As a further improvement of the technical solution, the inoculant includes silicate and trace elements, and the silicate is the main chemical component, and the trace elements include calcium, barium, strontium, manganese and zirconium.

[0022] As a further improvement of the technical solution, the spheroidizing agent includes spheroidizing elements, and the spheroidizing elements include Mg, Ce, and Ca.

[0023] As a further improvement of the technical solution, the dosage of the impurity remover is 0.6% of the mass of the molten iron; the dosage of the vermicular agent is 1.4% of the mass of the molten iron; the dosage of the inoculant is 0.8% of the mass of the molten iron; and the dosage of the spheroidizer is 1.3% of the mass of the molten iron.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. In the casting process of the vermicular graphite cast iron full hydraulic load sensing steering gear housing casting, the steps of mold manufacturing, smelting and impurity removal and vermicular inoculation, casting molding, cooling molding and sand removal cleaning are adopted to achieve the uniformity of the vermicular rate and the improvement of casting performance, reduce energy consumption and material waste, reduce production costs, and improve the strength and toughness of the vermicular graphite cast iron full hydraulic load sensing steering gear housing, thereby improving its service life and reliability.

[0026] 2. In the casting process of the vermicular graphite cast iron full hydraulic load sensing steering gear housing casting, by adding impurity remover, vermicular agent, inoculant, and spheroidizer to stir with molten iron, impurities in the molten iron can be effectively removed, the purity of the molten iron can be improved, the uniformity of the creep rate can be increased, the mechanical properties of the cast iron can be improved, the fluidity of the cast iron can be improved, the shrinkage holes inside the casting can be reduced, the quality of the casting can be improved, the creep of graphite can be controlled, the creep range can be expanded, the performance of the vermicular graphite cast iron can be improved, the creep rate can reach 95%, the production cost can be reduced, the production efficiency can be improved, and the economic loss can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall flow chart of Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. Example 1

[0029] according to Figure 1 As shown, the embodiment of the present invention also provides a method for preparing the above-mentioned compacted graphite cast iron full hydraulic load sensing steering gear housing casting, and the specific steps are as follows:

[0030] Step 1: Mold manufacturing: adopt the design requirements of the full hydraulic load sensing steering gear housing to manufacture the corresponding precision casting mold to ensure the dimensional accuracy and surface quality of the casting;

[0031] Step 2: Smelting, impurity removal and vermicular inoculation, using high-quality pig iron as the main raw material, and stirring and smelting with additives, wherein the additives include: impurity remover, vermicular agent, inoculant and spheroidizer;

[0032] Step 3: Casting. The temperature of the molten iron should be within the range of 1200℃~1300℃. Vibration casting technology is used for casting to ensure that the molten iron flows evenly in the mold and reduce the generation of pores and inclusions. Moreover, this temperature range is determined based on the physical and chemical properties of the molten iron and the requirements of the casting process, which can ensure that the casting has a dense structure and good mechanical properties.

[0033] Step 4: Cooling and molding: Allow the casting to cool naturally to room temperature in the mold, and control the cooling rate and cooling time to avoid cracks and deformation of the casting, so as to obtain uniform microstructure and good mechanical properties;

[0034] Step 5: Sand removal and cleaning to remove sand and burrs on the surface of the casting, eliminate residual stress, improve the strength and toughness of the casting, and also to ensure the dimensional accuracy, surface quality and mechanical properties of the casting.

[0035] The additives used in the present invention include the following ingredients:

[0036] The dosage of impurity remover is 0.2% to 0.6% of the mass of molten iron; the impurity remover includes silicon dioxide, aluminum oxide, silicates and alkaline oxides. Silicon dioxide and aluminum oxide are the main chemical components, and silicates and alkaline oxides are auxiliary chemical components. They can effectively remove impurities and dirt, reduce harmful elements, protect products, improve process efficiency and environmental safety, etc., providing important support for product production.

[0037] The dosage of vermicular agent is 0.8% to 1.4% of the mass of molten iron; vermicular agent includes rare earth ferrosilicon, rare earth calcium silicon, rare earth ferrosilicon magnesium alloy and magnesium titanium alloy, and its main purpose is to extend the service life of the mold and die, and reduce the loss and cost in the production process. At the same time, the vermicular agent can stably produce vermicular graphite cast iron, improve the overall performance and quality of the casting, and the vermicular agent can also increase the creep rate and narrow the range of the creep rate. The produced vermicular iron parts have a small tendency to white cast iron, the length-to-thickness ratio of the vermicular graphite is small, and the plastic toughness of the vermicular iron parts is good.

[0038] The dosage of inoculant is 0.6% to 1.0% of the mass of molten iron; the inoculant includes silicate and trace elements, with silicate as the main chemical component and trace elements including calcium, barium, strontium, manganese and zirconium. The main function of using inoculant is to eliminate or reduce the tendency of white cast iron, so that the graphite form in cast iron is mainly fine and evenly distributed A-type graphite, thereby improving the mechanical properties of cast iron; in addition, it can also avoid the occurrence of overcooling structure and reduce the wall thickness sensitivity of cast iron parts.

[0039] The dosage of spheroidizer is 1.2% to 1.6% of the mass of molten iron; the spheroidizer includes spheroidizing elements, including Mg, Ce, and Ca. The main function of using spheroidizer is to add it into the molten iron to obtain spheroidal graphite cast iron. Spheroidal graphite makes the strength of cast iron much higher than that of gray cast iron, and its toughness is better than that of malleable cast iron, while maintaining a series of advantages of gray cast iron. In summary, adding spheroidizer not only improves the performance and quality of castings, but also improves the wear resistance and corrosion resistance of materials, increases the service life of materials, optimizes the working environment, and reduces production costs.

[0040] In order to further improve the creeping effect and casting quality and increase the creeping rate, in step 2, the smelting impurity removal and creeping inoculation technology includes the following steps:

[0041] (1) Before smelting, first check the medium frequency induction furnace to ensure that the equipment can work stably, and then prepare the smelting materials, including high-quality pig iron, impurity remover, vermicular agent, inoculant and spheroidizer. At the same time, preheat the medium frequency induction furnace to ensure uniform temperature in the furnace and improve smelting efficiency;

[0042] (2) During the smelting process: first, high-quality pig iron is added as the main raw material for smelting. When the pig iron begins to melt but has not yet completely melted, a de-impurifying agent is added for de-impurizing treatment. The addition of the de-impurifying agent helps to remove impurities in the molten iron and improve the purity of the molten iron. When the molten iron melts and the temperature reaches 1460-1500°C, a vermicularizing agent is added. The addition of the vermicularizing agent helps to improve the microstructure and properties of the cast iron, making it have fine and evenly distributed graphite. After the vermicularizing agent is added and stirred for a while, an inoculant is added. The addition of the inoculant can further refine the grains, improve the organizational properties of the material, and improve the mechanical properties of the cast iron. Finally, a spheroidizing agent is added. The function of the spheroidizing agent is to help the carbon element in the pig iron form spherical graphite particles, thereby producing ductile cast iron.

[0043] The high-quality pig iron and additives are melted and stirred in proportion to uniformly prepare molten iron;

[0044] (3) Post-smelting processing: First, samples are taken from the molten iron for testing to ensure that the purity of the molten iron meets the requirements. Based on the test results, the composition of the molten iron is adjusted to meet the requirements of the subsequent casting process. The smelted molten iron is then poured into a casting ladle in preparation for the casting operation.

[0045] In the present invention, firstly, adding an impurity remover is helpful to remove impurities in molten iron and improve the purity of molten iron. Then, adding a vermicularizing agent and an inoculant can not only improve the microstructure and performance of cast iron, but also improve the mechanical properties of cast iron. Then, adding a spheroidizing agent and mixing the spheroidizing agent and the vermicularizing agent can result in that magnesium in the spheroidizing agent reacts with sulfur in molten iron to generate magnesium sulfide (MgS), and this process is called a desulfurization reaction. At the same time, magnesium can also react with oxygen and nitrogen in molten iron to play a role of deoxidation and denitrification. Moreover, the rare earth elements and magnesium in the vermicularizing agent will also participate in the above chemical reaction, but their main role is to stabilize the vermicularizing effect and allow the original sulfur content of molten iron to fluctuate within a certain range. The elements (such as RE, Mg, Si, etc.) in the vermicularizing agent will interact in the molten iron to jointly affect the morphology and distribution of graphite, thereby forming vermicular graphite cast iron or ductile iron with an ideal morphology, and effectively improving the strength, toughness and wear resistance of the cast iron.

[0046] By adopting the steps of mold manufacturing, smelting and impurity removal and creep inoculation, casting molding, cooling molding and sand removal cleaning, the creep rate is homogenized and the performance of the casting is improved, energy consumption and material waste are reduced, production costs can be reduced, and the strength and toughness of the vermicular graphite cast iron full hydraulic load sensing steering gear housing are improved, thereby improving its service life and reliability.

[0047] By adding impurity removers, vermicularizing agents, inoculants, and spheroidizing agents to the molten iron and stirring them, impurities in the molten iron can be effectively removed, the purity of the molten iron can be improved, the uniformity of the creep rate can be increased, the mechanical properties of the cast iron can be improved, the fluidity of the cast iron can be improved, the internal shrinkage holes of the castings can be reduced, and the quality of the castings can be improved. The creep of graphite can also be controlled, the creep range can be expanded, and the performance of vermicular graphite cast iron can be improved, so that the creep rate can reach 95%, reducing production costs, improving production efficiency, and reducing economic losses.

[0048] According to different raw material dosages, the casting of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting provided by the present invention is further described through the following specific embodiments. Example 2

[0049] The purpose of this embodiment is to provide a casting smelting with low additive data. The additives in this embodiment include the following raw materials:

[0050] The amount of impurity remover added is 0.2% of the mass of molten iron; the amount of vermicular agent added is 0.8% of the mass of molten iron; the amount of inoculant added is 0.7% of the mass of molten iron; the amount of spheroidizer added is 1.2% of the mass of molten iron.

[0051] Molten iron is obtained by melting, stirring and mixing the above-mentioned high-quality pig iron and additives in proportion.

[0052] The proportion of the additives in this embodiment is relatively low, so that the wear resistance, tensile strength, yield strength and creep rate of the casting of the present invention have good mechanical properties and creep effect compared with those of traditional castings. Example 3

[0053] The purpose of this embodiment is to provide a casting smelting with additive data mixing. The additives in this embodiment include the following raw materials:

[0054] The amount of impurity remover added is 0.6% of the mass of molten iron; the amount of vermicular agent added is 1.4% of the mass of molten iron; the amount of inoculant added is 0.8% of the mass of molten iron; the amount of spheroidizer added is 1.3% of the mass of molten iron.

[0055] Molten iron is obtained by melting, stirring and mixing the above-mentioned high-quality pig iron and additives in proportion.

[0056] The additives in this embodiment are mixed in proportion, using a high dose of creeping agent and a medium dose of spheroidizing agent, so that there is no interference between the creeping agent and the spheroidizing agent. At the same time, good mechanical properties and creeping effects can be significantly obtained, which is more suitable for casting production. Example 4

[0057] The purpose of this embodiment is to provide a casting smelting with additive data mixing. The additives in this embodiment include the following raw materials:

[0058] The amount of impurity remover added is 0.6% of the mass of molten iron; the amount of vermicular agent added is 1.4% of the mass of molten iron; the amount of inoculant added is 1.0% of the mass of molten iron; the amount of spheroidizer added is 1.6% of the mass of molten iron.

[0059] Molten iron is obtained by melting, stirring and mixing the above-mentioned high-quality pig iron and additives in proportion.

[0060] The proportion of additives in this embodiment is relatively high. A medium dose of creeping agent and a high dose of spheroidizing agent are used, so that there is no interference between the creeping agent and the spheroidizing agent, the quality of the casting is improved, and the strength, toughness and wear resistance of the cast iron are effectively improved.

[0061] Table 1 Amount of each raw material used in Examples 2-4 (parts)

[0062] Example 2 Example 3 Example 4 De-impurities agent 0.2% 0.6% 0.6% Vermicular agent 0.8% 1.4% 1.4% Inoculant 0.7% 0.8% 1.0% Spheroidizing agent 1.2% 1.3% 1.6%

[0063] In order to verify that the casting produced by the embodiment of the present invention has good mechanical properties and creeping effect, the casting process of the vermicular graphite cast iron full hydraulic load sensing steering gear housing casting provided by the embodiment of the present invention is described through the following test examples.

[0064] Test example

[0065] The purpose of this test example is to test the production of castings prepared in Examples 2-4;

[0066] Test objectives: to detect the wear resistance, tensile strength, yield strength and creep rate of the casting of the present invention, select the castings prepared in the above embodiments 2-4 and ordinary castings on the market, use the back and forth friction method to detect the wear resistance of the castings (i.e., wear amount: mg), use a tensile testing machine to detect the tensile strength (MPa) of the castings, use a yield strength testing machine to detect the yield strength (MPa) of the castings, and use ultrasonic sound velocity to detect the creep rate (%) of the castings;

[0067] Test method: Experimental group 1 uses the composition of Example 2 with additives for casting production, experimental group 2 uses the composition of Example 3 with additives for casting production, and experimental group 3 uses the composition of Example 4 with additives for casting production.

[0068] Test and detection: The wear resistance, tensile strength, yield strength and creep rate of the casting of the present invention are tested.

[0069] Specific detection indicators are shown in Table 2.

[0070] Table 2 Test indicators of each sample

[0071] Experiment 1 Experiment 2 Experiment 3 Control group Wear amount mg 12 5 5 20 Creep rate% 86 95 92 75 Yield strength MPa 400 480 460 280 Tensile strength MPa 460 600 560 320

[0072] As shown in Table 2, Experiments 2 and 3 use the method of adding creeping agent and spheroidizing agent in a phase difference, so that there is no interference between the creeping agent and spheroidizing agent, and the composition of impurity remover and inoculant is high, which effectively improves the strength, toughness and wear resistance of cast iron, and achieves the effect of homogenizing creeping rate and improving casting performance. Compared with Experiment 1, the creeping rate and casting performance obtained by the control group are much better. On the contrary, the control group uses low additives, and the wear resistance, tensile strength, yield strength and creeping rate are low, which not only affects the service life of castings, but also increases production costs and reduces production efficiency, thereby causing economic losses;

[0073] It can be concluded that Experiment 2 is the optimal data, and the dosage of the impurity remover is 0.6% of the mass of the molten iron; the dosage of the creeping agent is 1.4% of the mass of the molten iron; the dosage of the inoculant is 0.8% of the mass of the molten iron; and the dosage of the spheroidizing agent is 1.3% of the mass of the molten iron, so that the creepage rate reaches 95%, reducing production costs, improving production efficiency, and reducing economic losses.

[0074] Therefore, it can be explained that the casting process of the vermicular graphite cast iron full hydraulic load sensing steering gear housing provided by the present invention can not only achieve the uniformity of the creep rate and the improvement of the casting performance, but also improve the strength and toughness of the vermicular graphite cast iron full hydraulic load sensing steering gear housing.

[0075] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A casting process for a fully hydraulic load sensing steering gear housing made of vermicular cast iron, characterized in that: The following steps are involved: S1.1, mold manufacturing, adopt the design requirements of the full hydraulic load sensing steering gear housing to manufacture the corresponding precision casting mold; S1.2, smelting, impurity removal and vermicular inoculation, using high-quality pig iron as the main raw material, and stirring and smelting with additives, wherein the additives include: impurity remover, vermicular agent, inoculant and spheroidizer; S1.3, casting molding, the temperature of molten iron should be within the range of 1200℃~1300℃, and the vibrating casting technology should be used for casting; S1.4, cooling molding, let the casting cool naturally to room temperature in the mold; S1.5, sand removal cleaning, remove sand and burrs on the surface of castings; In S1.2, the dosage of the impurity remover is 0.2% to 0.6% of the mass of the molten iron; the dosage of the vermicular agent is 0.8% to 1.4% of the mass of the molten iron; the dosage of the inoculant is 0.6% to 1.0% of the mass of the molten iron; and the dosage of the spheroidizer is 1.2% to 1.6% of the mass of the molten iron.

2. The casting process of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting according to claim 1 is characterized in that: In S1.2, the smelting impurity removal and creep inoculation technology includes the following steps: S2.

1. Preparation before smelting: first check the medium frequency induction furnace, then prepare the smelting materials, including high-quality pig iron, impurity remover, vermicular agent, inoculant and spheroidizer, and at the same time, preheat the medium frequency induction furnace; S2.2, during the smelting process: first add high-quality pig iron, and when the pig iron begins to melt but has not yet completely melted, add a de-impurity agent for de-impurity treatment; when the molten iron melts and the temperature reaches 1460-1500℃, add a vermicular agent; after the vermicular agent is added and stirred for a while, add an inoculant, and finally add a spheroidizing agent; S2.3, post-smelting processing, first, take samples from the molten iron for testing, and adjust the composition of the molten iron according to the test results to meet the requirements of the subsequent casting process. Then pour the smelted molten iron into a casting ladle to prepare for the casting operation.

3. The casting process of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting according to claim 1, characterized in that: The impurity remover comprises silicon dioxide, aluminum oxide, silicate substances and alkaline oxides, wherein silicon dioxide and aluminum oxide are main chemical components, and silicate substances and alkaline oxides are auxiliary chemical components.

4. The casting process of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting according to claim 1, characterized in that: The creeping agent includes rare earth ferrosilicon, rare earth calcium silicon, rare earth ferrosilicon magnesium alloy and magnesium titanium alloy.

5. The casting process of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting according to claim 1, characterized in that: The inoculant comprises silicate and trace elements, wherein the silicate is a main chemical component, and the trace elements comprise calcium, barium, strontium, manganese and zirconium.

6. The casting process of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting according to claim 1, characterized in that: The spheroidizing agent includes spheroidizing elements, and the spheroidizing elements include Mg, Ce, and Ca.

7. The casting process of the compacted graphite cast iron full hydraulic load sensing steering gear housing casting according to claim 1, characterized in that: The dosage of the impurity remover is 0.6% of the mass of the molten iron; the dosage of the vermicular agent is 1.4% of the mass of the molten iron; the dosage of the inoculant is 0.8% of the mass of the molten iron; and the dosage of the spheroidizer is 1.3% of the mass of the molten iron.

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