CN112620580B

CN112620580B - Shell making process for long hole castings

Info

Publication number: CN112620580B
Application number: CN202011532245.0A
Authority: CN
Inventors: 王家松; 杜应流; 叶小风; 胡存友; 刘正新
Original assignee: Anhui Yingliu Casting Co ltd
Current assignee: Anhui Yingliu Casting Co ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2023-05-26
Anticipated expiration: 2040-12-23
Also published as: CN112620580A

Abstract

The invention discloses a shell making process of a long hole type casting, wherein zircon sand is adopted as a surface layer, mullite sand is adopted as a transition layer, wood strips are inserted into the aperture after 3-4 layers of shell making, conventional shell making, slurry sealing and dewaxing are carried out, and ventilation insertion pipes are inserted into holes after roasting for standby and waiting for pouring; according to the invention, the wood strips are inserted into the long holes after the shell is manufactured, so that long holes are formed after roasting, the heat dissipation condition after the shell is poured is improved, the problem of shrinkage defect of castings is solved, the ventilation insertion pipe is inserted into the holes, the pouring strength of the shell is improved, the heat dissipation effect can be further improved according to ventilation required, the fire running phenomenon can be effectively prevented, the cleaning is convenient, and the production efficiency is high.

Description

Shell making process for long hole castings

Technical Field

The invention relates to the technical field of investment casting, in particular to a shell manufacturing process for long hole castings.

Background

At present, the investment casting production process mainly comprises three working procedures of molding, shell making and mould shell roasting pouring, wherein the shell making working procedure is to form a coating module by a plurality of circulating procedures of coating, sanding, hardening and air drying, and then dewaxing is carried out to form the mould shell, and the cavity in the shell is the part model. In the production process of castings, shell making is a very important process, and the deep long hole castings are difficult to be stained with slurry and sand because of the series of slurry staining, sand spraying and air drying, the shuttering strength is low, the rejection rate is high, the prior machining method is adopted, the casting cost is higher, and for products with slightly larger aperture, the shell making materials in the holes are blocked, heat is difficult to dissipate after pouring, so that shrinkage porosity defect of the castings is caused, and the prior solution method comprises the following steps: 1. immersing the shell into the slurry after the shell is manufactured in 3 layers, filling the slurry into the holes, and after the slurry is dried, manufacturing the next layer of shell, increasing the strength of the shell, and preventing the phenomenon of flame run, wherein the shell is difficult to dry after grouting, and the shell manufacturing period is long; 2. when the ceramic core is molded, the ceramic core which is prefabricated, has certain constant temperature and high temperature strength, small expansion coefficient and chemical stability at high temperature is put into a mold, a wax mold is pressed, then a shell with the ceramic core is manufactured, the ceramic core with an inner cavity is removed after casting, and the ceramic core is difficult to remove after roasting, so that the efficiency is low and the cost of the ceramic core is high.

Disclosure of Invention

The invention mainly aims to provide a shell manufacturing process for long hole castings, which can effectively solve the problems in the background technology.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a shell making process of a long hole casting comprises the following steps: uniformly dipping and plastering surface layer slurry on the surface of a wax mould, uniformly spreading zircon sand, hardening in a hardening pool, then air-drying, dipping and plastering transition layer slurry, and uniformly spreading mullite sand;

step two, inserting battens into the apertures after the transition layer shell making operation in the step one is carried out for 3 to 4 times;

step three, conventional shell making, slurry sealing and dewaxing are carried out;

roasting the dewaxed shell in the third step, and burning out the inserted wood strips to form holes on the shell;

and fifthly, after the ventilation cannula is inserted into the hole in the fourth step, the hole is reserved for standby and is ready for pouring.

Preferably, in the second step, the wood strips are inserted 2-3 hours after the last transition layer is shelled.

Preferably, the size of the wood strip in the second step is consistent with the size of the hole after the wax pattern is used for preparing the shell, and the length of the wood strip is larger than the length of the hole.

Preferably, the ventilation cannula in the fifth step comprises a tube body, a plurality of ventilation openings are formed in the side wall of the tube body, the outer side wall of the tube body is fixedly connected with a support arc plate through an adjusting rod, and the outer port of the tube body is connected with an air inlet pipe.

Preferably, the outer side wall of the end part of the air inlet pipe, which is positioned in the pipe body, is fixedly connected with a sliding sealing plug, and the air inlet pipe is in sliding connection with the end part of the pipe body.

Preferably, the adjusting rod comprises a sleeve and a sliding rod, the sliding rod is connected with the sleeve in a sliding manner, and the end part of the sliding rod is connected with the bottom of the sleeve through a spring.

Preferably, the sleeve is in threaded connection with the fastening bolt near the side wall of the port.

Preferably, the support arc plates are three and are arranged around the annular array of the pipe body, and the outer side walls of the three support arc plates are embedded and connected with a plurality of annular rubber rings at equal intervals.

Preferably, the annular rubber ring is made of heat-resistant materials and slightly protrudes out of the outer side wall of the supporting arc plate.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, the wood strips are inserted into the long holes after the shell is manufactured, so that long holes are formed after roasting, the heat dissipation condition after the shell is poured is improved, the problem of shrinkage defect of castings is solved, the ventilation insertion pipe is inserted into the holes, the pouring strength of the shell is improved, the heat dissipation effect can be further improved according to ventilation required, the fire running phenomenon can be effectively prevented, the cleaning is convenient, and the production efficiency is high.

Drawings

FIG. 1 is a schematic view of the ventilation cannula of the present invention;

fig. 2 is a schematic view of the structure of the adjusting lever of the present invention.

In the figure: 1. a tube body; 2. a vent; 3. an adjusting rod; 31. a sleeve; 32. a slide bar; 33. a spring; 34. a fastening bolt; 4. supporting an arc plate; 5. an air inlet pipe; 6. sliding the sealing plug; 7. an annular rubber ring.

Detailed Description

The invention is further described in connection with the following detailed description, in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the invention easy to understand.

A shell making process of a long hole casting comprises the following steps: uniformly dipping and plastering surface layer slurry on the surface of a wax mould, uniformly spreading zircon sand, hardening in a hardening pool, then air-drying, dipping and plastering transition layer slurry, and uniformly spreading mullite sand;

In this embodiment, the wood strips are inserted 2-3 hours after the last transition layer in the second step is provided.

In this embodiment, the size of the wood strip in the second step is identical to the size of the hole after the wax pattern is used to prepare the shell, and the length of the wood strip is greater than the length of the hole.

In this embodiment, as shown in fig. 1-2, the ventilation cannula in the fifth step includes a tube body 1, a plurality of ventilation openings 2 are provided on the side wall of the tube body 1, the outer side wall of the tube body 1 is fixedly connected with a support arc plate 4 through an adjusting rod 3, and the outer port of the tube body 1 is connected with an air inlet pipe 5.

In this embodiment, the outer side wall of the end portion of the air inlet pipe 5 located in the pipe body 1 is fixedly connected with the sliding sealing plug 6, and the air inlet pipe 5 is slidably connected with the end portion of the pipe body 1.

In this embodiment, the adjusting rod 3 includes a sleeve 31 and a slide rod 32, the slide rod 32 is slidably connected with the sleeve 31, and an end of the slide rod 32 is connected with the bottom of the sleeve 31 through a spring 33.

In this embodiment, the sleeve 31 is screwed to the fastening bolt 34 near the side wall of the port.

In this embodiment, the support arc plates 4 are three and are arranged in an annular array around the pipe body 1, and the outer side walls of the three support arc plates 4 are embedded and connected with a plurality of annular rubber rings 7 at equal intervals.

In this embodiment, the annular rubber ring 7 is made of heat-resistant material, and the annular rubber ring 7 slightly protrudes from the outer side wall of the support arc plate 4.

While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that modifications may be made to the described embodiments in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive of the scope of the invention, which is defined by the appended claims.

Claims

1. A shell making process for long hole castings is characterized in that: the method comprises the following steps:

uniformly dipping and plastering surface layer slurry on the surface of a wax mould, uniformly spreading zircon sand, hardening in a hardening pool, then air-drying, dipping and plastering transition layer slurry, and uniformly spreading mullite sand;

step five, after the ventilation insertion pipe is inserted into the hole in the step four, the ventilation insertion pipe is reserved for standby and is ready for pouring;

the ventilation intubate includes the body, the lateral wall of body is equipped with a plurality of vents, the lateral wall of body is through adjusting pole fixed connection support arc board, the outer port connection air-supply line of body, the tip lateral wall fixed connection sliding seal plug that the air-supply line is located the body, air-supply line and body tip sliding connection, adjust pole including sleeve pipe and slide bar, slide bar and sleeve pipe sliding connection and the tip and the sleeve pipe bottom of slide bar pass through spring coupling.

2. The process for manufacturing the shell of the long hole castings according to claim 1, wherein the process is characterized in that: and in the second step, the wood strips are inserted 2-3 hours after the last transition layer is used for making the shell.

3. The process for manufacturing the shell of the long hole castings according to claim 1, wherein the process is characterized in that: the size of the wood strip in the second step is consistent with the size of the hole after the wax pattern is used for preparing the shell, and the length of the wood strip is larger than that of the hole.

4. The process for manufacturing the shell of the long hole castings according to claim 1, wherein the process is characterized in that: the side wall of the sleeve close to the port is in threaded connection with a fastening bolt.

5. The process for manufacturing the shell of the long hole castings according to claim 1, wherein the process is characterized in that: the support arc plates are three and are arranged around the annular array of the pipe body, and the outer side walls of the three support arc plates are embedded and connected with a plurality of annular rubber rings at equal intervals.

6. The process for manufacturing the shell of the long hole castings, according to claim 5, is characterized in that: the annular rubber ring is made of heat-resistant materials and protrudes out of the outer side wall of the supporting arc plate.