CN118060495A - Core bar structure, sand core, internal fastening device and casting process - Google Patents
Core bar structure, sand core, internal fastening device and casting process Download PDFInfo
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- CN118060495A CN118060495A CN202410501061.XA CN202410501061A CN118060495A CN 118060495 A CN118060495 A CN 118060495A CN 202410501061 A CN202410501061 A CN 202410501061A CN 118060495 A CN118060495 A CN 118060495A
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- 238000005266 casting Methods 0.000 title claims abstract description 54
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 118
- 239000010959 steel Substances 0.000 claims abstract description 118
- 239000004576 sand Substances 0.000 claims abstract description 47
- 239000011347 resin Substances 0.000 claims description 18
- 229920005989 resin Polymers 0.000 claims description 18
- 239000000919 ceramic Substances 0.000 claims description 8
- 239000003795 chemical substances by application Substances 0.000 claims description 8
- 238000000465 moulding Methods 0.000 claims description 4
- 238000010276 construction Methods 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 230000000149 penetrating effect Effects 0.000 claims 1
- 238000013461 design Methods 0.000 abstract description 3
- 238000013467 fragmentation Methods 0.000 abstract description 2
- 238000006062 fragmentation reaction Methods 0.000 abstract description 2
- 238000007689 inspection Methods 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 16
- 238000000034 method Methods 0.000 description 11
- 229910052742 iron Inorganic materials 0.000 description 8
- 230000007547 defect Effects 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005553 drilling Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 241001391944 Commicarpus scandens Species 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000009740 moulding (composite fabrication) Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
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Abstract
The invention relates to a core bar structure, a sand core, an internal fastening device and a casting process, wherein the core bar structure is a combined core bar and comprises a main core bar and a core head core bar which is radially and detachably connected to one side of the main core bar, the main core bar adopts a long round steel pipe with a preset aperture, and the long round steel pipe is provided with a pipe wall threaded hole so as to be connected with the core head core bar; the core head core bar adopts a short round steel pipe with a preset aperture, and one end of the short round steel pipe is provided with an external thread and is connected with a pipe wall threaded hole of the long round steel pipe through the external thread end. The main oil duct sand core can be well fixed in the casting mould, uneven wall thickness caused by shaking of the sand core in the casting process is prevented, and the main core bars can be recycled, so that the cost is saved; the fastening mode is simple and convenient for field operation, greatly saves the box inspection time and improves the working efficiency. The design of the core bar and the fastening device ensures the accurate position of the sand core after being put in, and prevents the problems of deformation of the sand core and fragmentation of surface sand caused by shrinkage of the core bar.
Description
Technical Field
The invention relates to the technical field of casting processes, in particular to a core bar structure, a sand core, an inner fastening device and a casting process, which are suitable for an ultra-long small-size round sand core.
Background
The large diesel engine body casting needs to have enough strength to ensure the normal operation of the engine body in various environments. The two main oil channels of the engine body are distributed on two sides of the casting, and the thickness of the wall is thin, the diameter is small and the length is very long, so that the quality requirement is particularly strict, the wall thickness around the oil channels is required to be uniform, if the process design is improper, the sand core at the main oil channel position of the casting is eccentric, once the main oil channel is eccentric, the integral stress at the oil channel position is uneven due to the fact that the main oil channel is eccentric, sand sticking in the main oil channel is difficult to clean, and finally the engine body is damaged through skin.
In the prior art, the main oil duct of the engine body of the medium and small-sized engine is cast by using the embedded steel pipe, and because the steel pipe is an embedded part, the contact between the steel pipe and molten iron in the casting molding process can generate the casting defect of poor fusion of the steel pipe and the casting, namely, gaps exist between the steel pipe and the casting, meanwhile, the molten iron on the surface of the steel pipe is easy to cool too fast due to the cooling effect of the steel pipe in the molten iron, and the cold insulation phenomenon, namely, the defect that the steel pipe is not completely covered by the molten iron, is easy to occur on the surface of the oil duct due to the low temperature of the molten iron on the surface of the steel pipe. The main oil duct of the engine body can be directly cast by using the sand core, so that the defects of poor fusion, cold insulation and the like can be effectively avoided, but the main oil duct is small in size and long in length, so that the difficulty of directly casting by using the sand core is also faced with technical challenges.
The oil duct of the conventional machine body is a whole steel pipe, two sides of the steel pipe are fixed on the sand core during core setting, a specific fastening device is not needed, and the steel pipe can be directly poured because of small short dead weight deformation. The whole oil duct of the large diesel engine body casting is longer in length and smaller in diameter, and under the action of dead weight, the sand core is deformed extremely due to dead weight only when the end faces at two sides are fixed, so that the surface skin thickness of the oil pipe is seriously affected.
Disclosure of Invention
The present invention is directed to solving the various problems mentioned above, and further to providing a core bar structure, a sand core, an in-mold fastening device and a casting process suitable for an ultra-long small-sized round sand core.
In a first aspect, the present invention provides a core structure, characterized in that,
The core bar structure is a combined core bar and comprises a main core bar and a core head core bar which is radially and detachably connected to one side of the main core bar, wherein the main core bar adopts a long round steel pipe with a preset aperture, and a pipe wall threaded hole is formed in the long round steel pipe so as to be connected with the core head core bar; the core head core bar adopts a short round steel pipe with a preset aperture, and one end of the short round steel pipe is provided with an external thread and is connected with a pipe wall threaded hole of the long round steel pipe through the external thread end.
Further, a plurality of through holes are formed in the whole body of the long round steel pipe so as to realize exhaust and strengthen the molding firmness of the sand core.
Further, the core-head core bars are provided with 2, and 2 core-head core bars are connected to the main core bar at a predetermined interval.
Further, the long round steel pipe as the main core bar and the short round steel pipe as the core head core bar each have a hollow pipe cavity.
Further, the main core bar is sized to fit the main oil gallery of a large diesel engine block.
In a second aspect, the present invention provides a sand core, which is characterized in that the sand core is prepared and formed in a core box based on the core bar structure, and further includes:
Filling sand with resin in the pipe, and filling and curing the resin in the hollow pipe cavities of the long round steel pipe and the short round steel pipe of the core bar structure;
and the ceramsite sand layer outside the pipe is coated and formed on the outer pipe wall surfaces of the long round steel pipe and the short round steel pipe of the core bar structure.
Further, the sand core is a main oil duct sand core of a large diesel engine body with a core bar structure.
In a third aspect, the present invention provides an internal fastening device for implementing internal fastening of the above-mentioned sand core; the special feature is that the fastening device comprises:
in the core bar structure, a threaded detachable connection structure is arranged between the long round steel pipe and the short round steel pipe;
in the core bar structure, an internal thread is arranged at the other end of the short round steel tube; and
The screw rod and the nut are mutually matched, one end of the screw rod is provided with external threads and is connected with the internal threads at the end part of the short round steel pipe of the core rod, and the other end of the screw rod is used for installing the nut.
Further, the nut is locked on the gasket.
In a fourth aspect, the invention provides a casting process of a large diesel engine body casting, comprising the following steps:
S1: core bar is designed and core box is designed based on core bar structure
The core bars are designed into combined core bars, and comprise a main core bar and two core-head core bars radially arranged on one side of the main core bar, wherein the main core bar adopts a long round steel pipe with a preset aperture, a plurality of through holes are formed in the whole body of the long round steel pipe so as to realize air exhaust and sand core forming firmness enhancement, and two pipe wall threaded holes are formed in the long round steel pipe so as to be respectively connected with the two core-head core bars; the core head core bar adopts a short round steel pipe with a preset aperture, one end of the short round steel pipe is provided with external threads and is connected with a pipe wall threaded hole of the long round steel pipe through the external thread end, the other end of the short round steel pipe is provided with internal threads, and the obtained core bar structure is used as a main oil duct core bar of a large diesel engine body.
S2: core making
And filling resin sand into hollow tube cavities of the long round steel tube and the short round steel tube of the main oil duct core bar, then placing the main oil duct core bar into a core box for core making, injecting the ceramic sand and the resin curing agent mixed according to a preset proportion, and coating the ceramic sand doped with the resin curing agent outside the core bar Zhou Chengxing to form a ceramic sand layer, so as to obtain the main oil duct sand core of the large diesel engine body.
S3: lower core
The prefabricated cylinder body sand core, the water channel sand core and the camshaft sand core are sequentially put into the sand mould according to the technological construction requirement, and finally the main oil duct sand core is put into the sand mould, then the main oil duct sand core and the camshaft sand core are fastened and connected through the internal fastening device, the internal fastening device comprises a screw rod, a gasket and a nut, and the fastening and connecting mode is as follows: the screw rod penetrates through the reserved through hole of the cam shaft sand core, the inner end of the screw rod is connected with an inner screw hole at the outer end of the core rod short round steel pipe in a screwed mode, the outer end of the screw rod extends to the outer side of the cam shaft sand core, and then the gasket is tightly pressed on the side wall of the cam shaft sand core and locked through the nut.
S4: and after core setting, carrying out mold closing pouring according to conventional operation.
S5: box disassembling
After sand removal, the main oil gallery core bar structure is disassembled in the following way: and removing the short round steel pipe from the long round steel pipe of the main core bar, and finally taking the long round steel pipe of the main core bar out of the casting mold to obtain a complete engine body casting, wherein the wall thickness of the main oil duct at two sides of the engine body casting is uniform.
Compared with the prior art, the invention has the main technical advantages that:
1. The engine body oil duct does not need to consider the fusion problem of the steel pipe and the oil duct, the cold insulation problem and the like;
2. The thin sand on the surface of the core bar can be well fixed, the exhaust of the sand core is facilitated, and the problems that sand inclusion and more mantles are difficult to clean in a main oil duct caused by the breakage of the surface of the sand core in the casting process are prevented;
3. The main oil duct sand core can be well fixed in the casting mould in a fastening mode, so that uneven wall thickness caused by shaking of the sand core in the casting process is prevented, and meanwhile, the main core bar can be recycled, so that the cost is saved;
4. The fastening mode is simple and convenient for field operation, can greatly save the box inspection time and improve the working efficiency.
5. The core bar fixing and fastening method is designed, so that the position of the sand core after being put in is accurate, and the problems of deformation of the main oil duct sand core and surface sand fragmentation caused by shrinkage of the core bar in the heating and cooling processes are prevented.
Drawings
Fig. 1: the main oil gallery core bar structure of the first embodiment is schematically shown;
Fig. 2: a schematic diagram of a main oil gallery sand core structure in the second embodiment;
Fig. 3: the internal fastening device of the third embodiment is a schematic structural view;
fig. 4: schematic diagram of the internal fastening position state structure of the main oil duct sand core;
fig. 5: a casting mould structure schematic diagram of a large diesel engine body in the fourth embodiment;
In the figure, 10, a main oil duct core bar structure, 11, a long round steel pipe, 11a, a through hole, 11b, a pipe wall threaded hole, 12, a short round steel pipe, 12a, external threads, 12b, internal threads, 20, a main oil duct sand core, 21, in-pipe resin sand filling, 22, an out-pipe ceramsite sand layer, 30, an in-fastening device, 31, a screw rod, 31a, a screw rod external thread, 32, a nut, 33, a gasket, 40, a casting mould, 41, a cylinder body sand core, 42, a water channel sand core, 43 and a camshaft sand core.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings.
The following examples relate to a main oil duct core bar structure, sand core, internal fastening device and casting process of a body casting of a large diesel engine, wherein the body casting of the large diesel engine has a weight of 11000Kg, a casting weight of 40000Kg, a material HT350 and a maximum external dimension 4471 x 1808 x 1372. The wall thickness of the main part is in the range of 21-116. The two main oil channels are distributed on two sides of the casting, the aperture of the main oil channel is 80mm, the wall thickness is 31mm, the length is 4153mm, and the thickness of the tile shaft part is 116mm.
Example 1
The present embodiment relates to a main oil duct core bar structure 10 of a body casting of a large diesel engine, as shown in fig. 1, the core bar structure 10 adopts a combined core bar, which comprises a long round steel pipe 11 as a main core bar and two short round steel pipes 12 as core print core bars, and the two core print core bars can be detachably connected with the main core bar. The long round steel pipe 11 and the short round steel pipe 12 are hollow steel pipes having a predetermined pore diameter. The whole body of the long round steel pipe 11 is provided with a plurality of through holes 11a for realizing the functions of exhausting air and enhancing the molding firmness of the sand core. In addition, two pipe wall threaded holes 11b are formed in the long round steel pipe 11 to connect the two short round steel pipes 12; one end of the short round steel pipe 12 is provided with an external thread 12a and is connected with a pipe wall threaded hole 11b of the long round steel pipe through the external thread end.
Example two
The present embodiment relates to a main oil gallery sand core 20 of a body casting of a large diesel engine, as shown in fig. 2, where the main oil gallery sand core 20 is formed in a core box based on the core bar structure 10 of the first embodiment. The structure comprises a combined core bar structure formed by assembling a long round steel pipe 11 and two short round steel pipes 12 together, further comprises resin sand filling 21 filled and solidified in hollow pipe cavities of the long round steel pipe 11 and the short round steel pipes 12, and an outside ceramsite sand layer 22 coated and molded on the outer pipe wall surfaces of the long round steel pipe 11 and the short round steel pipes 12.
Example III
The present embodiment relates to an internal fastening device 30 for fastening a main oil gallery sand core 20 of a body casting of a large diesel engine in a core manufacturing process, as shown in fig. 3-4, the internal fastening device 30 is designed and formed based on a main oil gallery core bar structure 10 of the first embodiment, and the structure includes, in the main oil gallery core bar structure 10, a designed detachable connection structure of threads between a long round steel pipe 11 and a short round steel pipe 12; in the main oil gallery core structure 10, an internal thread 12b is provided at the other end of the short round steel pipe 12; the screw rod 31 is provided with screw rod external threads 31a at one end, and is used for being connected with internal threads 12b arranged at the end part of the short round steel pipe 12 of the core rod, the other end of the screw rod 31 is used for installing the screw rod 32, the gasket 33 penetrates through the screw rod 31 and is abutted to a stress surface, and the screw rod 32 is locked on the gasket 33. In this embodiment, the bearing surface is a camshaft sand core 43 of a body casting of a large diesel engine.
Example IV
The embodiment relates to a casting process of a large diesel engine body casting, which comprises the following steps of:
S1: the main oil gallery core structure 10 is designed and the core box is designed based on the core structure
Designing a main oil duct core bar structure 10, a core box core punching mode and a core box splitting mode according to a casting structure;
In this embodiment, the main oil gallery core structure 10 is designed as a combined core, where the combined core includes a main core and two core-head cores connected to the main core, the main core adopts a long round steel pipe 11, and the whole body of the main core is uniformly provided with a plurality of through holes 11a and two pipe wall threaded holes 11b for connecting the core-head cores. The two core-head core bars adopt two short round steel pipes 12, one ends of the two short round steel pipes 12 are connected with two pipe wall threaded holes 11b formed in the long round steel pipe 11 through external threads 12a, so that the two core-head core bars are radially connected to one side of the main core bar.
In designing the main oil gallery core structure 10, the key considerations of this embodiment include: how to avoid the defects of sand inclusion air holes and the like formed in the casting oil passage and how to optimize the casting process based on the main oil passage core bar structure 10.
For the first aspect, since the whole sand core is wrapped in molten iron in the casting process, the temperature of the molten iron is higher, a large amount of gas is generated in the sand reaction process, if the gas is not smoothly discharged, the surface of the sand core is damaged, sand inclusion air holes are easily formed in an oil duct of a casting, and the like, therefore, when designing a main oil duct core bar, consideration is needed to be given to how to discharge the gas, for the embodiment, a plurality of through holes 11a are processed on a long round steel pipe 11 selected for the main core bar, two through holes 11a are used for the purpose, one through hole can discharge the gas generated in the sand core, and the other through holes 11a can better fix the sand attached to the surface of the long round steel pipe 11, prevent the sand on the surface of the long round steel pipe 11 from falling, and further enable the sand core coated on the periphery of the steel pipe to be molded more firmly.
In addition, based on the specific assembly structure of the main core bar and the core print core bar in the main oil gallery core bar structure 10 of this embodiment, in order to ensure that the main oil gallery core bar 10 can be more conveniently assembled and disassembled and taken out, this embodiment designs an internal fastening device 30, and meanwhile, this embodiment performs a scheme exploration and a simulation test on the connection mode of the core print core bar and the main core bar, and the first scheme that is preselected is: and welding nuts at the positions of the side surfaces of the main core bars for installing the core head core bars, reserving bolt holes in the centers of the core head core bars, and connecting the core head core bars by using screws after core setting. The second pre-selected option is: drilling and tapping, namely the pipe wall threaded holes, are processed on the core head installation position of the main core bar and are used for connecting the core head core bar.
After the two alternative schemes are determined, the outside sand core of the main oil duct is printed through 3D, and the core setting process and the sand core fastening mode of the sand core of the main oil duct are simulated. In the simulation process of the first scheme, when the welding nut is used for the main core bar, and the screw is used for connection after the sand core of the reserved bolt hole of the core nose core bar is used for core setting, the screw is difficult to directly align the nut of the main core bar and rotationally connect with the nut, meanwhile, due to the angle problem, the core nose core bar is easy to break in the fastening process, the problem of molten iron drilling in the pouring process is easy to cause, the core bar cannot be taken out from a casting, the main core bar steel pipe is deformed in the welding process due to the fact that the pipe wall is heated in the welding process, the core bar is easy to adhere to the wall of the casting, the core bar cannot be taken out directly, and the core bar is scrapped. The first option is eventually abandoned. When the second scheme is simulated, the core bars for processing and drilling are used for coring, the short round steel pipes of the two core heads are screwed into the threaded holes of the two pipe walls of the main core bars in advance, then the core is manufactured, the manufactured oil duct core is tightly connected with the core heads, the oil duct core is not easy to break and damage, and meanwhile, the outer sides of the core steel pipes used by the core heads are exposed, so that a screw rod can be well used for being fastened and connected with the core steel pipes in the core setting fastening process.
Test results: when the second connecting scheme is used, the core bars can be manufactured to effectively prevent the core bars from deforming during hot processing and manufacturing, and further the sand cores are prevented from deforming during core manufacturing. Meanwhile, the core bar of the connecting scheme can be easily taken out from the casting, and the core bar can be reused.
S2, core making
And filling resin sand into the hollow tube cavities of the long round steel tube 11 and the short round steel tube 12 of the main oil duct core bar structure 10, putting the whole main oil duct core bar structure 10 into a core box for core making, and after sand injection, cladding and forming core sand on the periphery of the core bars to form the main oil duct sand core 20 with the core bars. After the main oil duct sand core 20 is molded, the main oil duct sand core needs to be placed on a template with special follow-up support, and each support point needs to be large in width and cannot be far away from the support point, so that surface sand cracks caused by deformation of the main oil duct sand core 20 are effectively prevented.
In this step, in order to ensure the strength of the sand coated on the surface of the steel pipe, the type of the sand used is determined through a comparison experiment, two kinds of sand, one kind of resin sand and one kind of ceramic sand are used in the experiment, when the same resin curing agent is used in the experiment comparison, the strength of the ceramic sand is higher, and the proper resin and curing agent addition is finally determined through the comparison of various resins and curing agent addition. And selecting the sand used on the surface of the final steel pipe as ceramsite sand, and using the determined proportion of the resin curing agent.
S3: lower core
The cylinder body sand core 41, the water channel sand core 42 and the cam shaft sand core 43 which are manufactured in advance are sequentially put into a sand mould according to the technological construction requirement, the main oil duct sand core 20 manufactured in S2 is finally put into the sand mould, then the main oil duct sand core 20 and the cam shaft sand core 43 are fastened and connected through the internal fastening device 30, and the internal fastening device 30 comprises a screw rod 31, a gasket 33 and a nut 32, and the fastening and connecting modes are as follows: the screw 31 penetrates through the cam shaft sand core 43 and then the inner end is screwed to the inner screw hole 12b at the outer end of the core-head core bar short round steel pipe 12, the outer end of the screw extends to the outer side of the cam shaft sand core 43, and then the gasket 33 is tightly pressed on the side wall of the cam shaft sand core 43 and locked by the nut 32, as shown in fig. 5;
S4: and after core setting, carrying out mold closing pouring according to conventional operation.
S5: box disassembling
After sand removal, the short round steel pipe 12 with the screw 31, the gasket 33 and the nut 32 is removed from the long round steel pipe 11 of the main core bar, and finally the long round steel pipe 11 of the main core bar is taken out from the casting mould 40, so that a complete machine body casting is obtained, and the wall thickness of the main oil duct distributed on two sides of the machine body casting is uniform.
Claims (10)
1. A core bar structure is characterized in that,
The core bar structure is a combined core bar and comprises a main core bar and a core head core bar which is radially and detachably connected to one side of the main core bar, wherein the main core bar adopts a long round steel pipe with a preset aperture, and a pipe wall threaded hole is formed in the long round steel pipe so as to be connected with the core head core bar; the core head core bar adopts a short round steel pipe with a preset aperture, and one end of the short round steel pipe is provided with an external thread and is connected with a pipe wall threaded hole of the long round steel pipe through the external thread end.
2. The core structure of claim 1, wherein the core structure,
A plurality of through holes are formed in the whole body of the long round steel pipe so as to realize exhaust and strengthen the molding firmness of the sand core.
3. The core structure of claim 1 or 2, wherein,
The core-head core bars are provided with 2, and the 2 core-head core bars are connected to the main core bar at a predetermined interval.
4. The core structure of claim 1, wherein the core structure,
The long round steel pipe serving as the main core bar and the short round steel pipe serving as the core head core bar are provided with hollow cavities.
5. The core structure of claim 1, wherein the core structure,
The main core bar is used for adapting to the main oil duct of the large diesel engine body.
6. A sand core, characterized in that it is prepared in a core box based on the core bar structure according to any one of the preceding claims 1-5, further comprising:
Filling sand with resin in the pipe, and filling and curing the resin in the hollow pipe cavities of the long round steel pipe and the short round steel pipe of the core bar structure;
and the ceramsite sand layer outside the pipe is coated and formed on the outer pipe wall surfaces of the long round steel pipe and the short round steel pipe of the core bar structure.
7. The sand core of claim 6 wherein,
The sand core is a main oil duct sand core of a large diesel engine body with a core bar structure.
8. An in-mold fastening device for in-mold fastening of the sand core according to any one of claims 6 to 7; characterized in that the fastening means comprise:
in the core bar structure, a threaded detachable connection structure is arranged between the long round steel pipe and the short round steel pipe;
in the core bar structure, an internal thread is arranged at the other end of the short round steel tube; and
The screw rod and the nut are mutually matched, one end of the screw rod is provided with external threads and is connected with the internal threads at the end part of the short round steel pipe of the core rod, and the other end of the screw rod is used for installing the nut.
9. The internal fastening device of claim 8, wherein,
The nut is locked on the gasket.
10. A casting process involving the use of an in-mold fastening device according to any one of claims 8 to 9 for in-mold fastening of a sand core according to any one of claims 6 to 7, comprising the steps of:
S1: core bar is designed and core box is designed based on core bar structure
The core bars are designed into combined core bars, and comprise a main core bar and two core-head core bars radially arranged on one side of the main core bar, wherein the main core bar adopts a long round steel pipe with a preset aperture, a plurality of through holes are formed in the whole body of the long round steel pipe so as to realize air exhaust and sand core forming firmness enhancement, and two pipe wall threaded holes are formed in the long round steel pipe so as to be respectively connected with the two core-head core bars; the core head core bar adopts a short round steel pipe with a preset aperture, one end of the short round steel pipe is provided with external threads and is connected with a pipe wall threaded hole of the long round steel pipe through the external thread end, the other end of the short round steel pipe is provided with internal threads, and the obtained core bar structure is used as a main oil duct core bar of a large diesel engine body;
S2: core making
Filling resin sand into hollow tube cavities of long round steel tubes and short round steel tubes of a main oil duct core bar, then placing the main oil duct core bar into a core box for core making, injecting ceramic sand and a resin curing agent mixed according to a preset proportion, and coating the ceramic sand doped with the resin curing agent outside the core bar Zhou Chengxing to form a ceramic sand layer, so as to obtain a main oil duct sand core of a large diesel engine body;
s3: lower core
The prefabricated cylinder body sand core, the water channel sand core and the camshaft sand core are sequentially put into the sand mould according to the technological construction requirement, and finally the main oil duct sand core is put into the sand mould, then the main oil duct sand core and the camshaft sand core are fastened and connected through the internal fastening device, the internal fastening device comprises a screw rod, a gasket and a nut, and the fastening and connecting mode is as follows: penetrating a screw rod through a reserved through hole of a cam shaft sand core, screwing the inner end of the screw rod into an inner screw hole at the outer end of a core rod short round steel pipe of a core head, extending the outer end of the screw rod to the outer side of the cam shaft sand core, and tightly pressing a gasket on the side wall of the cam shaft sand core and locking the gasket through a nut;
s4: after core setting, carrying out mold closing casting according to conventional operation;
S5: box disassembling
After sand removal, the short round steel pipe is removed from the long round steel pipe of the main core bar, and finally the long round steel pipe of the main core bar is taken out from the casting mould, so that a complete machine body casting is obtained, and the wall thickness of the main oil duct at two sides of the machine body casting is uniform.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410501061.XA CN118060495A (en) | 2024-04-25 | 2024-04-25 | Core bar structure, sand core, internal fastening device and casting process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202410501061.XA CN118060495A (en) | 2024-04-25 | 2024-04-25 | Core bar structure, sand core, internal fastening device and casting process |
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| CN118060495A true CN118060495A (en) | 2024-05-24 |
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| CN202410501061.XA Pending CN118060495A (en) | 2024-04-25 | 2024-04-25 | Core bar structure, sand core, internal fastening device and casting process |
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- 2024-04-25 CN CN202410501061.XA patent/CN118060495A/en active Pending
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