CN103192027A

CN103192027A - Partial cooling method of cold iron in investment casting

Info

Publication number: CN103192027A
Application number: CN2013101054625A
Authority: CN
Inventors: 吕志刚; 申辰
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2013-03-28
Filing date: 2013-03-28
Publication date: 2013-07-10

Abstract

The invention provides a partial cooling technology of cold iron in investment casting. The partial cooling technology comprises the following steps of: 1, manufacturing a wax model by a general investment casting process; 2, designing the cold iron and a wax block which has the same shape and dimension as the cold iron, according to the shape of the outer surface of a hot spot of a casting, and then manufacturing the cold iron and the wax block, wherein the inner surfaces of the designed cold iron and the wax block are clung to the outer surface of the hot spot of the casting in shape, and the cold iron and the wax block are provided with positioning platforms; 3, fixing the wax block to a part requiring partial chilling on the wax model, and tightly clinging to the surface of the wax model; 4 manufacturing a housing at the surface of the wax model, and exposing part of the positioning platform of the wax block from a model housing; 5, dewaxing the model housing; 6, roasting the model housing at high temperature; 7, fixing the cold ion in an opening of the model housing, and positioning through the positioning platform; and 8, casting after preheating the model housing, wherein the partial chilling effect is realized in the cold iron. By carrying out the steps mentioned above, the heat exchange at the hot spot of the casting can be improved, the chilling effect can be realized, and as a result, the purpose of reducing the defect of dispersed shrinkage of a shrinkage cavity in the casting can be realized.

Description

The local cooling means of a kind of model casting chill

Technical field

The present invention relates to the model casting technical field, be specifically related to the local cooling means of a kind of model casting chill.

Background technology

In casting field, for the intricate casting that has thermal center, be easy to generate quality problems such as shrinkage cavity, shrinkage porosite at the thermal center place.In sand casting, thereby the cooldown rate that can increase the foundry goods part by the mode of placing chill in sand mold reaches control cooling effect in proper order.The application of chill is very ripe in the sand casting, but for model casting, places chill and have certain difficulty, also is not widely used in the actual production.At present, some relevant researchs have appearred in the chill technology of model casting, such as: in shell, preset the effect that the internal densener identical with casting material reaches local Quench.The weak point of this scheme is: chill finally becomes the part of foundry goods, can bring into foundry goods such as impurity, oxide skin; Chill can not reuse in addition.

Summary of the invention

In order to solve above-mentioned the deficiencies in the prior art, the object of the present invention is to provide the local cooling means of a kind of model casting chill, can process the chill that can reuse according to the shape at foundry goods thermal center place, utilize the characteristics of chill good heat conduction effect, reach the effect of the local Quench of foundry goods.

For achieving the above object, the technical solution adopted in the present invention is:

The local cooling means of a kind of model casting chill comprises the steps:

Step 1: at first make wax-pattern according to normal full form casting process;

Step 2: according to the external surface shape at foundry goods thermal center place design chill and with chill shape, measure-alike wax stone, the external surface shape at the chill of design and the inner surface of wax stone and foundry goods thermal center place is fitted, and make chill and wax stone have positioning table, make chill and wax stone then;

Step 3: wax stone is fixed in the position that needs local Quench on the wax-pattern, and fits with the wax-pattern surface is tight;

Step 4: at wax-pattern surface shell processed, the positioning table part on the wax stone is exposed to outside the shell;

Step 5: with the shell dewaxing, wax-pattern and wax stone are removed, form local opening at shell;

Step 6: shell is carried out high-temperature roasting;

Step 7: chill is fixed in the shell opening part, locatees by positioning table;

Step 8: pour into a mould after the shell preheating, the part that chill is exposed to outside the shell is forced cooling.

Step 7 is described to be fixed in the shell opening part with chill, the slit between chill and the shell need be sealed.

The described mode that adopts brushing paint that is sealed into makes the slit between chill and the shell obtain sealing.

The described forced cooling method of step 8 is for blowing or water-cooled.

The local cooling means of model casting chill of the present invention utilizes the chill at foundry goods thermal center place to strengthen local heat exchange, thereby reaches local chill effect; The advantage of this method is: 1, can be according to the shape and size flexible design chill at foundry goods thermal center place, and chill can reuse; 2, with together roasting of shell, the oxide of having avoided producing in the roasting process does not enter foundry goods to chill; 3, can use forced cooling methods such as air blowing or water-cooled to chill, further strengthen local chill effect.

Description of drawings

Fig. 1 is the schematic diagram of chill among the present invention.

Fig. 2 is the schematic diagram that wax stone is fixed in the wax-pattern surface.

Fig. 3 is the schematic diagram (partly cut-away) that chill is fixed in shell.

The specific embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail.

The local cooling means of a kind of model casting chill of the present invention comprises the steps:

Step 1: at first carry out the compacting of wax-pattern and the assembly welding of running gate system according to normal full form casting process;

Step 2: according to the external surface shape at foundry goods thermal center place design chill and with chill shape, measure-alike wax stone, the external surface shape at the chill of design and the inner surface of wax stone and foundry goods thermal center place is fitted, and make chill and wax stone have positioning step, make chill and wax stone then; Be illustrated in figure 1 as the chill schematic diagram of making, should guarantee that the outer wall at chill inner surface and foundry goods thermal center place can fit tightly, reserve positioning table simultaneously, be used for the location of chill on shell, dewaxing back with fixing.

Step 3: wax stone is fixed in the position that needs local Quench on the wax-pattern, and fits with the wax-pattern surface is tight; Be illustrated in figure 2 as the schematic diagram that is fixed in the wax-pattern surface with wax stone, wax stone is fixed in the heat energy-saving position on the wax-pattern, should guarantee fitting tightly of wax stone and wax-pattern;

Step 4: at wax-pattern surface shell processed, the positioning table part of wax stone is exposed to outside the shell; In every layer of shell process processed, pick coating after, carry out stucco after the coating in the wax stone outside wiped, the positioning table part of wax stone outside is exposed to outside the shell;

Step 5: with the shell dewaxing, wax stone removes in shell with wax-pattern, makes shell form opening at the wax stone place, is used for fixedly chill;

Step 6: shell is carried out high-temperature roasting;

Step 7: after the roasting, the chill of making is in advance placed the shell opening part, locate by positioning table; The place, slit of chill and shell seals with bonding with coating;

Step 8: after the shell preheating, pour into a mould; The part that chill is exposed to outside the shell is forced cooling; The heat conductivility of chill is higher than type shell material far away, so can be to the local chill effect that forms of foundry goods, the effect of reach fast cooling, cooling off fast.Present embodiment is blown by the outside to chill in order to strengthen local chill effect, strengthens the heat radiation of chill, reaches bigger cooling rate.

Reclaim chill foundry goods shelling back, can reuse.

Invention has been described by above-described embodiment, can carry out multiple variation, modification, replacement and distortion to embodiment under the situation that does not break away from principle of the present invention and aim, and scope of the present invention is defined by the claims.

Claims

1. the local cooling means of model casting chill is characterized in that: comprise the steps:

Step 6: shell is carried out high-temperature roasting;

2. the local cooling technology of a kind of model casting chill according to claim 1, it is characterized in that: step 7 is described to be fixed in the shell opening part with chill, the slit between chill and the shell need be sealed.

3. the local cooling technology of a kind of model casting chill according to claim 2, it is characterized in that: the described mode that adopts brushing paint that is sealed into makes the slit between chill and the shell obtain sealing.

4. the local cooling technology of a kind of model casting chill according to claim 1, it is characterized in that: the described forced cooling method of step 8 is for blowing or water-cooled.