Casting process for large four-cylinder diesel engine cylinder head

Abstract

The application discloses a casting process for a large four-cylinder diesel engine cylinder cover, which comprises the following steps: S1, core making; S2, sand core assembling; S3, pouring; and S4, mold opening. In the core making process, each sand core part is perforated, so that the sand amount is reduced, the hollowing process is realized, the overall weight of the sand core is reduced, the gas emission amount during the combustion of the sand core in the pouring process is reduced, and the gas discharge is facilitated; meanwhile, a coating and an asbestos pad are coated on the surface of each sand core, one-way gas discharge is realized, the exhaust passage is effectively prevented from being infiltrated with molten iron and losing effectiveness, and the pouring quality is ensured.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, specifically relating to a casting process for a large four-cylinder diesel engine cylinder head. Background Technology

[0002] Currently, in pursuit of better operating efficiency and mechanical strength, recent developments in diesel engines have largely focused on component integration to enhance strength. For example, parts of components such as the flywheel housing, water chamber, and gear housing are directly cast into the cylinder head, reducing the required thickness while achieving the same or even higher mechanical strength. Simultaneously, more complex and intricate water and exhaust channels are used to improve operating efficiency. For instance, the water jacket design within the cylinder head covers a wider flow area, and the smaller exhaust channels achieve better heat dissipation efficiency and improved casting mechanical properties.

[0003] However, the new designs on these engines necessitate more complex and finer sand core partings in the casting process. In actual production, the old water jacket is usually converted from one sand core into multiple sand cores for composite. The internal exhaust system of the sand core, which is divided into multiple parts, is prone to molten iron seepage during the pouring process, leading to burrs and exhaust system failure. Furthermore, splitting it into multiple sand cores also significantly increases the requirements for assembly precision, making it difficult to produce products that meet customer requirements based on the existing sand core structure with the conventionally designed gating and exhaust systems in casting. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a brand-new casting process for the cylinder head of a large four-cylinder diesel engine.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A casting process for a large four-cylinder diesel engine cylinder head includes the following steps:

[0007] S1, Core Making

[0008] a. Use a hot core machine to manufacture the upper shell core, lower shell core, upper water jacket core, lower water jacket core, air intake core, exhaust core, and oil passage core respectively;

[0009] b. Apply alcohol-based coating to the center of the four cylinder valves on the lower housing core; cover the molding areas of the lower and upper housing cores with water-based coating by atomized spraying; soak the upper water jacket core, lower water jacket core, intake manifold core, and oil passage core in water-based coating.

[0010] c. Dry the upper shell core, lower shell core, upper water jacket core, lower water jacket core, air intake core, and oil passage core to allow the solvent on the surface of the sand core to evaporate and dry.

[0011] d. Drill holes at the mating parts of the upper shell core, lower shell core, upper water jacket core, air intake core, exhaust core, and oil passage core to form exhaust channels;

[0012] S2, Sand Core Assembly

[0013] The upper shell core, lower shell core, upper water jacket core, lower water jacket core, air intake core, exhaust core, and oil passage core are bonded together with sand core adhesive to form a finished sand core. An asbestos gasket is placed between the mating surfaces of the upper water jacket core and the lower water jacket core.

[0014] S3, Pouring

[0015] First, the sand mold required for casting is made, and the finished sand core in S2 is placed into the sand mold; second, the metallurgical raw materials are dissolved and prepared to obtain a qualified casting liquid, which is then poured into the casting ladle; finally, the casting liquid in the casting ladle is poured into the sand mold.

[0016] S4, Mold Opening

[0017] First, the mold is opened and the casting blank is separated; second, the residual sand on the surface of the casting blank is cleaned; finally, the burrs on the casting blank are removed and the ends are ground smooth to obtain the finished blank.

[0018] Preferably, in step S1a, after the hot core machine has produced each part of the sand core, the parting line burrs, vent plug burrs, and sand injection nozzle burrs of all sand cores are removed, and a visual inspection is conducted to check for any parts with shape defects.

[0019] Preferably, in step b of S1, the coating thickness of the alcohol-based coating brushed on the lower shell core corresponding to the center position of the four cylinder valves is 0.3-0.6 mm; and / or, the water-based coating is atomized by a pneumatic spray gun and sprayed to cover the forming parts required for casting the lower shell core and the upper shell core, and the covering thickness is 0.1-0.3 mm.

[0020] Preferably, in step b of S1, the upper water jacket core, lower water jacket core, air intake core, and oil passage core are soaked in a water-based coating with a Baume degree of 31-33 for 3-8 seconds.

[0021] Preferably, the upper water jacket core includes a first upper water jacket core and a second upper water jacket core, the lower water jacket core includes a first lower water jacket core, a second lower water jacket core, a third lower water jacket core, and a fourth lower water jacket core assembled sequentially, and the oil passage core includes a first oil passage core and a second oil passage core installed on the lower shell core, and a third oil passage core installed on the upper shell core. This arrangement further breaks down the complex sand core and assembles it step by step, reducing the assembly difficulty and improving the manufacturing accuracy of the sand core.

[0022] Specifically, in S2, the first upper water jacket core, the second upper water jacket core, the first lower water jacket core, the second lower water jacket core, the third lower water jacket core, the fourth lower water jacket core, the air intake core, the exhaust core, the first oil passage core, and the second oil passage core are first bonded together and assembled into the first semi-finished sand core; then the upper shell core and the third oil passage core are bonded together and assembled into the second semi-finished sand core; finally, the first semi-finished sand core and the second semi-finished sand core are assembled together to obtain the finished sand core.

[0023] Preferably, an alcohol-based coating is also applied to the outside of the first semi-finished sand core to increase its refractoriness.

[0024] Preferably, the exhaust duct core is provided with multiple through-pins arranged side-by-side at intervals, with the through-pins protruding upwards from the upper shell core. This design simplifies operation and facilitates exhaust.

[0025] Preferably, an exhaust column is provided at the assembly position of the air intake core and the exhaust core. The sand core exhaust channel is arranged with a needle and exhaust column to implement a hollowing process, thereby reducing the gas generated by the combustion of the sand core during casting, and the gas generated by the combustion can be discharged through the exhaust channel to avoid the formation of porosity defects in the casting.

[0026] Preferably, in step S3, an electric furnace is used to dissolve the metallurgical raw materials, and after the temperature inside the electric furnace rises to 1480℃~1500℃, the casting liquid is poured into the casting ladle, and the temperature of the casting liquid in the casting ladle is measured. When the temperature reaches 1400℃~1420℃, the casting is carried out.

[0027] Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0028] This invention reduces the amount of sand and achieves a hollowing process by drilling holes in each sand core during the core-making process. This reduces the overall weight of the sand core, decreases the amount of gas generated during sand core combustion during casting, and facilitates gas discharge. At the same time, by coating each sand core surface with a coating and asbestos pads, one-way venting is achieved, effectively preventing the venting channels from failing due to molten iron seepage, thus ensuring casting quality. Attached Figure Description

[0029] Figure 1 This is a three-dimensional structural diagram of the upper shell core in this invention;

[0030] Figure 2 This is a three-dimensional structural diagram of the lower shell core in this invention;

[0031] Figure 3 This is a three-dimensional structural diagram of the first water supply sleeve core in this invention;

[0032] Figure 4 This is a three-dimensional structural diagram of the first semi-finished sand core in this invention;

[0033] Figure 5 This is a three-dimensional structural diagram of the second semi-finished sand core in this invention;

[0034] Figure 6 This is a three-dimensional structural diagram of the finished sand core in this invention;

[0035] The components are: 1. Upper shell core; 2. Lower shell core; 3. Upper water jacket core; 31. First upper water jacket core; 4. Lower water jacket core; 41. First lower water jacket core; 42. Second lower water jacket core; 43. Third lower water jacket core; 44. Fourth lower water jacket core; 5. Intake duct core; 6. Exhaust duct core; 7. Oil passage core; 71. First oil passage core; 72. Second oil passage core; 73. Third oil passage core. Detailed Implementation

[0036] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0037] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0040] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0041] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0042] like Figures 1 to 6 As shown, the casting process for the cylinder head of a large four-cylinder diesel engine in this embodiment includes the following steps: S1, core making; S2, sand core assembly; S3, pouring; S4, mold opening.

[0043] S1, Core Making

[0044] a. Using a hot core machine, the upper shell core 1, lower shell core 2, upper water jacket core 3, lower water jacket core 4, air intake core 5, exhaust core 6, and oil passage core 7 are manufactured separately. The upper water jacket core 3 includes a first upper water jacket core 31 and a second upper water jacket core. The lower water jacket core 4 includes a first lower water jacket core 41, a second lower water jacket core 42, a third lower water jacket core 43, and a fourth lower water jacket core 44, which are assembled in sequence. The oil passage core 7 includes a first oil passage core 71 and a second oil passage core 72 installed on the lower shell core 2, and a third oil passage core 73 installed on the upper shell core 1. After the hot core machine has manufactured each sand core, the parting line burrs, exhaust plug burrs, and sand injection nozzle burrs of all sand cores are removed, and a visual inspection is performed to check for any parts with shape defects.

[0045] b. Apply alcohol-based coating to the center of the four cylinder valves on the lower shell core 2, with a coating thickness of 0.6mm. Apply water-based coating to the required forming parts of the lower shell core 2 and upper shell core 1 using a pneumatic spray gun, with a coating thickness of 0.3mm. Soak the upper water jacket core 3, lower water jacket core 4, intake core 5, and oil passage core 7 in water-based coating with a Baume degree of 31-33 for 3-8 seconds, ensuring that the coating thickness on the surface of each sand core is 0.2mm after soaking.

[0046] c. Dry the upper shell core 1, lower shell core 2, upper water jacket core 3, lower water jacket core 4, air intake core 5, and oil passage core 7. Place the above-mentioned sand cores in an oven and bake at 140-160℃ for 30-60 minutes to allow the moisture, alcohol, and other solvents on the surface of the sand cores to evaporate and dry.

[0047] d. Drill holes at the interlocking parts of the upper shell core 1, lower shell core 2, upper water jacket core 3, air intake core 5, exhaust core 6, and oil passage core 7 to form exhaust channels. No holes are drilled on the lower water jacket core 4.

[0048] In other words, the part of the upper shell core 1 that mates with the first upper water jacket core 31 is drilled with a 5mm drill bit to create an exhaust channel; the part of the upper shell core 1 that mates with the third oil passage core 73 is drilled with a 3mm drill bit to create an exhaust channel; the part of the lower shell core 2 that mates with the first upper water jacket core 31 is drilled with a 5mm drill bit to create an exhaust channel; the three core heads on the first upper water jacket core 31 that connect to the upper shell core 1 and the lower shell core 2 are drilled with a 3mm drill bit, and the drilling depth is such that a 10mm sand core thickness is reserved on the opposite side of the drilling to form a one-way hole to ensure that molten iron will not enter; the eight core heads on the air inlet core 5 that mate with the lower shell core 2 are drilled with a 3mm drill bit, and the drilling depth is such that a 10mm sand core thickness is reserved on the opposite side of the drilling to form a one-way hole. Leave a 10mm sand core thickness to form a one-way hole to ensure that molten iron will not enter; drill holes with a 3mm drill bit at eight core heads at the assembly points of the exhaust channel core 6 and the lower shell core 2, with the drilling depth being 10mm sand core thickness reserved on the opposite side of the hole to form a one-way hole to ensure that molten iron will not enter; drill holes with a 3mm drill bit at four Y-shaped parts on the exhaust channel core 6, with the drilling depth being 10mm before the Y-shaped bifurcation to make them one-way holes to ensure that molten iron will not enter; drill holes with a 3mm drill bit at two core heads at the assembly points of the first oil channel core 71, the second oil channel core 72, and the third oil channel core 73 at the assembly points of the lower shell core 2, with the drilling depth being 10mm sand core thickness reserved on the opposite side of the hole to form a one-way hole to ensure that molten iron will not enter.

[0049] S2, Sand Core Assembly

[0050] The upper shell core 1, lower shell core 2, upper water jacket core 3, lower water jacket core 4, air intake core 5, exhaust core 6, and oil passage core 7 are bonded together with sand core adhesive to form a finished sand core. An asbestos gasket is provided between the mating surfaces of the upper water jacket core 3 and the lower water jacket core 4.

[0051] In other words, firstly, the lower shell core 2, the first upper water jacket core 31, the second upper water jacket core 32, the first lower water jacket core 41, the second lower water jacket core 42, the third lower water jacket core 43, the fourth lower water jacket core 44, the air intake core 5, the exhaust core 6, the first oil passage core 71, and the second oil passage core 72 are bonded and assembled to form the first semi-finished sand core; secondly, the upper shell core 1 and the third oil passage core 73 are bonded and assembled to form the second semi-finished sand core; finally, the first semi-finished sand core and the second semi-finished sand core are assembled to obtain the finished sand core.

[0052] Meanwhile, an alcohol-based coating is applied to the outer side of the first semi-finished sand core to increase its refractoriness; multiple through-holes are inserted side-by-side at intervals on the venting core 6, with several through-holes protruding upwards from the upper shell core 1; venting columns are provided at the assembly and mating positions of the air inlet core 5 and the venting core 6. The sand core venting channels are arranged with through-holes and venting columns to implement a hollowing-out process, thereby reducing the gases generated during sand core combustion during casting, and allowing the combustion gases to escape through the venting channels, preventing the formation of porosity defects in the casting.

[0053] S3, Pouring

[0054] First, an automatic molding machine is used to create the sand mold required for casting, and the finished sand core in S2 is lowered into the sand mold through a core-setting machine. Second, an electric furnace is used to melt the metallurgical raw materials to obtain a qualified casting liquid. When the temperature in the electric furnace rises to 1480℃~1500℃, the casting liquid is poured into the casting ladle. Finally, the temperature of the casting liquid in the casting ladle is measured. When the temperature reaches 1400℃~1420℃, the casting liquid in the casting ladle is poured into the sand mold.

[0055] S4. Mold opening.

[0056] After 2.5 hours of pouring, the mold is opened. First, the casting blank is removed and separated. Then, steel balls are used to clean the residual sand on the surface of the casting blank. Finally, the burrs on the casting blank are removed and the ends are ground smooth to obtain the finished blank.

[0057] In summary, this embodiment has the following advantages:

[0058] 1. By drilling holes in each sand core during the core-making process, the amount of sand is reduced and a hollowing process is achieved, which reduces the overall weight of the sand core, reduces the amount of gas generated when the sand core burns during the casting process, and facilitates the exhaust of gas; at the same time, by coating each sand core surface with a coating and asbestos pads, one-way venting is achieved, and the venting channel is effectively prevented from failing due to the seepage of molten iron, thus ensuring the casting quality.

[0059] 2. Use extraction needles and venting columns to arrange sand core venting channels to implement a hollowing process, thereby reducing the gas generated by sand core combustion during casting, and allowing the combustion gas to be discharged through the venting channels to avoid the formation of porosity defects in the casting.

[0060] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A casting process for a large four-cylinder diesel engine cylinder head, characterized in that: It includes the following steps: S1, Core Making a. The upper shell core, lower shell core, upper water jacket core, lower water jacket core, air intake core, exhaust core, and oil passage core are manufactured separately using a hot core machine. The upper water jacket core includes a first upper water jacket core and a second upper water jacket core. The lower water jacket core includes a first lower water jacket core, a second lower water jacket core, a third lower water jacket core, and a fourth lower water jacket core that are spliced ​​together in sequence. The oil passage core includes a first oil passage core and a second oil passage core installed on the lower shell core, and a third oil passage core installed on the upper shell core. b. Apply alcohol-based coating to the lower housing core corresponding to the center position of the four cylinder valves, with a coating thickness of 0.3-0.6mm; use a pneumatic spray gun to atomize water-based coating and spray it to cover the molding parts required for casting the lower and upper housing cores, with a coverage thickness of 0.1-0.3mm; immerse the upper water jacket core, lower water jacket core, intake manifold core, and oil passage core in water-based coating with a Baume degree of 31-33 for 3-8 seconds. c. Dry the upper shell core, lower shell core, upper water jacket core, lower water jacket core, air intake core, and oil passage core to allow the solvent on the surface of the sand core to evaporate and dry. d. Drill holes at the mating points of the upper shell core, lower shell core, upper water jacket core, air intake core, exhaust core, and oil passage core to form exhaust channels; drill through the part of the upper shell core that mates with the first upper water jacket core with a 5mm drill bit to create an exhaust channel, and drill through the part of the upper shell core that mates with the third oil passage core with a 3mm drill bit to create an exhaust channel; drill through the part of the lower shell core that mates with the first upper water jacket core with a 5mm drill bit to create an exhaust channel; drill through the three core ends of the first upper water jacket core that connect to the upper and lower shell cores with a 3mm drill bit, and drill to a depth equal to the 10mm sand core thickness reserved on the opposite side of the drilled hole to form a one-way hole to ensure that molten iron does not enter; drill through the eight core ends at the assembly point of the air intake core and the lower shell core. The head is drilled with a 3mm drill bit, and the drilling depth is such that a 10mm sand core thickness is reserved on the opposite side of the drilled hole to form a one-way hole, ensuring that molten iron cannot be poured in; the eight core heads at the assembly part of the exhaust channel core and the lower shell core are drilled with a 3mm drill bit, and the drilling depth is such that a 10mm sand core thickness is reserved on the opposite side of the drilled hole to form a one-way hole, ensuring that molten iron cannot be poured in; the four Y-shaped parts on the exhaust channel core are drilled with a 3mm drill bit, and the drilling depth is such that 10mm before the Y-shaped bifurcation is formed to make it a one-way hole, ensuring that molten iron cannot be poured in; the two core heads at the assembly part of the first oil channel core, the second oil channel core, and the third oil channel core are each drilled with a 3mm drill bit, and the drilling depth is such that a 10mm sand core thickness is reserved on the opposite side of the drilled hole to form a one-way hole, ensuring that molten iron cannot be poured in; S2, Sand Core Assembly First, the first upper water jacket core, the second upper water jacket core, the first lower water jacket core, the second lower water jacket core, the third lower water jacket core, the fourth lower water jacket core, the air intake core, the exhaust core, the first oil passage core, and the second oil passage core are bonded and assembled to form the first semi-finished sand core, wherein an asbestos gasket is placed between the mating surfaces of the upper water jacket core and the lower water jacket core; second, the upper shell core and the third oil passage core are bonded and assembled to form the second semi-finished sand core; finally, the first semi-finished sand core and the second semi-finished sand core are assembled to obtain the finished sand core; S3, Pouring First, the sand mold required for casting is made, and the finished sand core in S2 is placed into the sand mold; second, the metallurgical raw materials are dissolved and prepared to obtain a qualified casting liquid, which is then poured into the casting ladle; finally, the casting liquid in the casting ladle is poured into the sand mold. S4, Mold Opening First, the mold is opened and the casting blank is separated; second, the residual sand on the surface of the casting blank is cleaned; finally, the burrs on the casting blank are removed and the ends are ground smooth to obtain the finished blank.

2. The casting process for the cylinder head of a large four-cylinder diesel engine according to claim 1, characterized in that: In step S1a, after the hot core machine has produced all the sand cores, the parting line burrs, vent plug burrs, and sand injection nozzle burrs of all the sand cores are removed, and the parts with shape defects are visually inspected.

3. The casting process for the cylinder head of a large four-cylinder diesel engine according to claim 1, characterized in that: An alcohol-based coating is also applied to the outside of the first semi-finished sand core to increase its refractoriness.

4. The casting process for the cylinder head of a large four-cylinder diesel engine according to claim 1, characterized in that: The exhaust duct core is provided with multiple through-pins arranged side by side at intervals, wherein the multiple through-pins protrude upward from the upper shell core.

5. The casting process for the cylinder head of a large four-cylinder diesel engine according to claim 1 or 4, characterized in that: An exhaust column is provided at the position where the intake core and the exhaust core are assembled.

6. The casting process for the cylinder head of a large four-cylinder diesel engine according to claim 1, characterized in that: In S3, an electric furnace is used to dissolve metallurgical raw materials. After the temperature inside the electric furnace rises to 1480℃~1500℃, the casting liquid is poured into the casting ladle. The temperature of the casting liquid in the casting ladle is measured, and casting is carried out when the temperature reaches 1400℃~1420℃.

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