CN112808941B

CN112808941B - Sand core of exhaust pipe casting and casting method thereof

Info

Publication number: CN112808941B
Application number: CN202011597365.9A
Authority: CN
Inventors: 李�诚; 纳建虹; 田鑫
Original assignee: Kocel CSR Foundry Ltd
Current assignee: Kocel CSR Foundry Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2023-05-30
Anticipated expiration: 2040-12-30
Also published as: CN112808941A

Abstract

The sand core comprises a bottom core, a middle core and a cover core, wherein the bottom core and the cover core are used for forming the outer contour of the exhaust pipe casting, and the middle core is used for forming the inner cavity structure of the exhaust pipe casting; the bottom core, the middle core and the cover core are printed by a 3DP printing technology. The upper and lower mold closing modeling no-chill direct production process of the wood mold process in the prior art is improved into the mode of integrally casting the inner cavity structure of the exhaust pipe in the technical scheme, namely, the inner cavity structure of the exhaust pipe is integrally formed by the middle layer, so that the cloak on the inner cavity is avoided, and the surface quality and the dimensional accuracy of the inner cavity of the exhaust pipe are improved through the 3DP printing technology. Meanwhile, the chilling blocks are arranged on the end faces of the flanges at the two ends of the main pipeline of the exhaust pipe, so that the compactness of the pipeline wall is improved, and the use level of the exhaust pipe is from civil level to military level.

Description

Sand core of exhaust pipe casting and casting method thereof

Technical Field

The invention relates to the technical field of casting, in particular to a casting method of an exhaust pipe.

Background

The exhaust pipe is one of important parts of the medium-speed diesel engine, and has the functions of exhausting and guiding exhaust gas after combustion in the combustion chamber according to the working sequence of each cylinder of the diesel engine. Because of direct contact with high-temperature waste gas, the working environment is bad, and in order to ensure that the air flow discharge does not affect the power of a diesel engine, high-temperature-resistant vermicular graphite cast iron is often adopted for casting. However, the assembly flange at the end of the vermicular graphite cast iron exhaust pipe is frequently subjected to shrinkage porosity and other defects during casting, and a chill is required to be added to eliminate the defects. However, the exhaust pipe castings are thin-wall pipeline castings, core heads are arranged at the ends of the exhaust pipe castings to interfere with each other, and chill is inconvenient to place.

Disclosure of Invention

In view of the problem that the chill is inconvenient to place when the shrinkage cavity defect of the flange surface is assembled in the casting process of the exhaust pipe casting, the sand core of the exhaust pipe casting is necessary to be provided, and the sand core of the exhaust pipe casting is provided with the core head through reasonably arranging the core separating surface of the sand core of the exhaust pipe and the core head on the pipeline core of the sand core of the exhaust pipe, so that the chill can be arranged on the core head of the pipeline sand core, the integral casting of the pipeline part of the exhaust pipe casting is realized, and the casting quality is improved.

A sand core of an exhaust pipe casting, comprising a bottom core, a middle core and a cover core, wherein the bottom core and the cover core are used for forming the outer contour of the exhaust pipe casting, and the middle core is used for forming an inner cavity structure of the exhaust pipe casting; the bottom core, the middle core and the cover core are printed by a 3DP printing technology, so that the surface quality and the dimensional accuracy of the exhaust pipe casting are improved.

Further, the middle core is provided with a main pipeline sand core and a branch pipeline sand core, core heads are arranged at two ends of the main pipeline sand core, and chill is arranged on the core heads and used for chilling, so that the main pipeline is made of more compact materials, shrinkage porosity defects which possibly occur are avoided, and the exhaust pipe casting is lifted to a military grade from a civil grade.

Furthermore, as the pipeline wall of the exhaust pipe casting is thinner, the chill is set to be a sand-isolating chill, so that the chilling effect of the chill becomes softer, and the defects of premature coagulation and the like caused by overstimulation are avoided.

The sand core of the exhaust pipe casting further comprises a first core separating surface and a second core separating surface, the first core separating surface is parallel to the second core separating surface, the first core separating surface passes through the highest line of the sand core of the main pipeline, and the second core separating surface passes through the lowest line of the sand core of the main pipeline, so that the middle core can form a complete inner cavity structure of the exhaust pipe casting.

The technical scheme of the invention has the beneficial effects that: the upper and lower mold closing modeling no-chill direct production process of the wood mold process in the prior art is improved into the mode of integrally casting the inner cavity structure of the exhaust pipe in the technical scheme, namely, the inner cavity structure of the exhaust pipe is integrally formed by the middle layer, so that the cloak on the inner cavity is avoided, and the surface quality and the dimensional accuracy of the inner cavity of the exhaust pipe are improved through the 3DP printing technology. Meanwhile, the chilling blocks are arranged on the end faces of the flanges at the two ends of the main pipeline of the exhaust pipe, so that the compactness of the pipeline wall is improved, and the use level of the exhaust pipe is from civil level to military level.

Drawings

FIG. 1 is a schematic view of an exhaust pipe structure;

FIG. 2 is a schematic diagram of the sand core structure of the exhaust pipe;

FIG. 3 is a schematic diagram of a split core explosion;

FIG. 4 is a schematic view of an intermediate core;

wherein, 1-exhaust pipe casting; 2-a main pipeline sand core; 3-supporting a pipeline sand core; 4-chill; 5-a cover core; 6-an intermediate core; 7-a bottom core; 8-core baffle.

Detailed Description

In order to more clearly illustrate the technical solution of the present invention, it is obvious that the following description is a few exemplary embodiments of the present invention, and other solutions can be obtained according to these embodiments without inventive effort for a person skilled in the art.

In order to minimize the sand-iron ratio of the casting of the exhaust pipe, the casting process is designed by adopting a flat casting one-box two-piece mode, and the technical scheme according to the invention is shown in fig. 1 to 4, and the concrete implementation mode is as follows.

In the diagram, a first core dividing surface and a second core dividing surface are arranged on two parallel lines along the highest point and the lowest point of the flange of the main pipeline, the first core dividing surface and the second core dividing surface are parallel to each other, and the inner cavity structure of the exhaust pipe casting is entirely arranged between the first core dividing surface and the second core dividing surface. As shown in fig. 1, in order to achieve the minimum sand-iron ratio, two exhaust pipes are arranged in one production, and the two exhaust pipes are arranged in an L shape with branch pipes located on the inner side of the L shape. By the arrangement mode, the lowest sand-iron ratio of the casting of the exhaust pipe casting is realized.

The utility model provides a sand core of blast pipe foundry goods, includes lid core 5, middle core 6 and end core 7, lid core 5 with end core 7 is used for forming the external profile of blast pipe foundry goods, middle core 6 is used for forming the inner chamber structure of blast pipe foundry goods, just lid core 5, middle core 6 and end core 7 are by 3DP technique printing to further promoted the surface quality of blast pipe foundry goods sand core, and then guaranteed the quality and the dimensional accuracy of the surface of blast pipe foundry goods.

The middle core 6 is provided with two exhaust pipe sand cores which are distributed in an L shape, and the branch pipeline sand core 3 is positioned on the inner side of the L shape, so that the other pipe orifice of the main pipeline sand core 2 is positioned on the edge of the middle core 6, the outer contour of the middle core 6 is a rectangular frame, and the edge of the rectangular frame is the minimum sand consumption limit for casting of the two exhaust pipe sand cores which are distributed in the L shape. And a core head is arranged on the end face of the flange plate of the sand core of the main pipeline, and a sand-separating chill is placed at the position of the core head so as to adjust the temperature field of the metal liquid in the cavity of the main pipeline, so that the metal liquid in the cavity of the main pipeline can be uniformly solidified, and the main pipeline with uniform and compact texture is obtained. Because of the core print, the space occupied by the main pipe sand core is enlarged, and under the condition of not changing the size and the minimum sand consumption of the outer outline rectangular frame of the middle core 6, the two core print positioned at the two top ends of the L shape are lapped on the edge of the rectangular frame, and core sand lapped on the edge of the corresponding part of the core print on the rectangular frame edge of the middle core 6 is hollowed out, namely, even if the two core print positioned at the two top ends of the L shape are exposed to the rectangular frame of the middle core 6, namely, are not wrapped by the rectangular frame, or the edge of the outer outline rectangular frame of the middle core 6 is discontinuous, and the two top ends of the L shape are disconnected. The rectangular frame of the bottom core 7 is provided with a core head baffle 8, the position of the core head baffle 8 corresponds to the disconnection position of the middle core 6, and the thickness and the height of the core head baffle 8 are just matched with the frame and the core head of the middle core 6. Two core baffles 8 are arranged on the bottom core 7 corresponding to the two exhaust pipes of one box.

The casting method of the exhaust pipe casting comprises the following steps:

1) Drawing a three-dimensional model of the exhaust pipe castings according to the patterns of the exhaust pipe castings, arranging the three-dimensional models of the two exhaust pipe castings into an L shape, and arranging a pouring system;

2) Embedding the three-dimensional model with the pouring system in a cube with minimum sand consumption, and then performing shell extraction treatment to obtain a core package of the exhaust pipe casting;

3) Dividing the core package into a cover core, a middle core and a bottom core according to the positions of the first core dividing surface and the second core dividing surface;

4) The generated slice data of the cover core, the middle core and the bottom core are issued to 3DP printing equipment, and the cover core, the middle core and the bottom core are printed out through the 3DP printing equipment;

5) Cleaning and coating the cover core, the middle core and the bottom core, and then matching, namely, recombining the cover core, the middle core and the bottom core into an integral cube;

6) And (5) casting after the pouring gate is configured, and obtaining the exhaust pipe casting after condensation.

The above embodiment is only a description of a typical application of the technical scheme of the present invention, and can be reasonably expanded on the basis of reasonable design and no need of creative labor.

Claims

1. The sand core of the exhaust pipe casting is characterized by comprising a bottom core, a middle core and a cover core, wherein the bottom core and the cover core are used for forming the outer contour of the exhaust pipe casting, and the middle core is used for forming the inner cavity structure of the exhaust pipe casting; the bottom core, the middle core and the cover core are printed by a 3DP printing technology;

the middle core is provided with a main pipeline sand core and a branch pipeline sand core, core heads are arranged at two ends of the main pipeline sand core, chill is arranged on the core heads, two core heads of the main pipeline sand core positioned at two top ends of the L shape are lapped on the edge of a rectangular frame of the middle core, and the edge of the rectangular frame at the lap joint is disconnected;

the sand core device further comprises a first core separating surface and a second core separating surface, wherein the first core separating surface is parallel to the second core separating surface, the first core separating surface passes through the highest line of the sand core of the main pipeline, and the second core separating surface passes through the lowest line of the sand core of the main pipeline;

the bottom core is also provided with a core head baffle plate, and the core head baffle plate is matched with the disconnection part of the middle core, so that the middle core is complete.

2. The sand core of an exhaust pipe casting of claim 1 wherein the chill is a sand-blocking chill.