CN101406932B - Precision-investment casting method - Google Patents

Abstract

The invention provides a method for casting a fusible pattern precisely, which comprises the following steps: manufacturing a wax pattern in accordance with a cast product, wherein the wax pattern comprises a casting head and a core print corresponding to structures of an internal chill or an external chill; manufacturing a silicasol fusible pattern according to the wax pattern, and performing dewaxing and solidifying processes to obtain a shuttering which contains a reserved opening corresponding to the core print; placing the external chill or the internal chill which is designed well according to a dispersed thermal centre of the cast product into the shuttering from the reserved opening; pouring molten metal into a die cavity in the shuttering to obtain the cast product; cutting and separating the casting head of the cast product after the mould is opened, and removing the external chill or finishing a protruding part of the internal chill to obtain the finished product. The method is applicable in the field of casting high-precision parts.

Description

A kind of precision-investment casting method

Technical field

The present invention relates to a kind of metal casting method, particularly a kind of precision-investment casting method.

Background technology

On March 12nd, 2008, the Chinese patent CN101138781A of bulletin disclosed a kind of investment casting formwork and manufacture method thereof, this investment casting formwork comprises several aspect layer fireproof coating and several layers of back-up coat fireproof coating and is positioned at sanding material between the adjacent two layers fireproof coating, described back-up coat fireproof coating comprises the wollastonite powder, can increase the intensity of investment casting formwork by the wollastonite powder, reduce the number of plies that the formwork manufacturing applies and reduce the quantity of tying up iron wire.As seen, obtaining cast member by the method for model casting is a known technology, but for part with a plurality of dispersion thermal centers, because the less liquid that causes casting of material cooled contraction of being cast and the wall thickness between the adjacent thermal center of cast member itself is filled abundant inadequately, the inherent dense structure's property of prepared cast member is poor, structural strength is inhomogeneous, and bearing capacity is poor.Can cause the following process amount big again if on investment casting formwork, increase the quantity of dead head, increase energy consumption.

Summary of the invention

The purpose of this invention is to provide a kind of precision-investment casting method, it is the energy energy savings on the one hand, and prepared on the other hand workpiece can satisfy requirement of strength again.

The technical solution adopted in the present invention is such: a kind of precision-investment casting method comprises the steps:

1), making is consistent with cast member and comprise the wax-pattern of dead head, on the thermal center of the corresponding cast member of described wax-pattern away from dead head core print is set, described core print and wax-pattern are one-body molded;

2), make the Ludox fusible pattern, and guarantee that the end of core print is positioned at the outside of Ludox fusible pattern according to described wax-pattern;

3), the Ludox fusible pattern of being produced placed carries out dewax under 110 ℃～120 ℃ temperature and handle and to make formwork, contain the reserved opening of corresponding core print structure on the described formwork;

4), the formwork of being produced is placed carry out roasting under 1100 ℃～1200 ℃ temperature and solidify to handle;

5), will insert in the formwork from reserved opening according to external chill or internal densener that cast member disperses thermal center to design;

6), the die cavity that molten metal liquid is poured in the formwork makes cast member;

7), the dead head to cast member after the die sinking carries out cutting and separating, and remove external chill or the internal densener projection repaired and make finished product.

By adopting the aforementioned techniques scheme, the invention has the beneficial effects as follows: by core print is set on wax-pattern, the position of corresponding core print forms reserved opening on the formwork that makes like this, thereby chill can be inserted die cavity by this reserved opening, like this for cast member with a plurality of dispersion thermal centers, by placing compactness that suitable chill can guarantee cast member integral body to satisfy requirement of strength, cast member need not complicated back processing after the moulding in die cavity simultaneously, uses manpower and material resources sparingly.

Description of drawings

Fig. 1 is the stereogram of embodiment cast member;

Fig. 2 is another visual angle stereogram of embodiment cast member;

The specific embodiment

With reference to figure 1 and Fig. 2, embodiment discloses a kind of precision-investment casting method, comprises the steps:

1, making is consistent with cast member and comprise the wax-pattern of dead head 1, on the thermal center 2 of the corresponding cast member of described wax-pattern away from dead head 1 core print is set, and this core print and wax-pattern are one-body molded;

2, make the Ludox fusible pattern according to described wax-pattern, and the floating sand of the core print end of after completing, erasing and guarantee that it is positioned at the outside of Ludox fusible pattern; Putting before this, the process of producing the Ludox fusible pattern is a known technology, and it obtains open fully in the file that background technology is mentioned;

3, the Ludox fusible pattern of being produced is placed carry out dewax under 110 ℃～120 ℃ temperature and handle and to make formwork, contain the reserved opening of corresponding core print structure on the described formwork;

4, the formwork of being produced is placed carry out roasting under 1100 ℃～1200 ℃ temperature and solidify to handle, preferred sintering temperature is controlled at about 1150 ℃;

5, characteristics according to this cast member thermal center 2, wall thickness is thicker in the middle of the thermal center 2 relative cast members, it is loose easily to occur shrinkage cavity during cast on thermal center 2, influence the safety in utilization of part, should set up rising head at this from the common process analysis, because of accessory size bigger, consider the complexity that running gate system is provided with, embodiment adopts the mode of internal densener to insert a chill 3 in advance in the position of thermal center 2, for guarantee chill 3 when the high temperature smoothly safety put into, the material of requirement chill 3 and the material of cast member are just the same, and control the high temperature fit clearance of chill 3 and formwork well, simultaneously chill 3 one ends extend near the barb outer face of cast member thermal center 2 positions, and the other end of chill 3 is positioned at the reserved opening of formwork and roughly concordant with the formwork lateral surface;

6, the die cavity that molten metal liquid is poured in the formwork makes cast member;

7, the dead head 1 to cast member carries out cutting and separating after the die sinking, and excision internal densener 3 unnecessary parts make finished product.

In the foregoing description, some cast member is not suitable for or need not adopting internal densener, can adopt the mode at the built-in external chill of die cavity this moment, in specific operation process, when producing the Ludox fusible pattern, the position that will place external chill in advance on the dispersion thermal center away from dead head is the forming core print in advance, this core print and wax-pattern are one-body molded, thereby the formwork that described Ludox fusible pattern dewax makes after handling is formed with reserved opening, and the die cavity of formwork comprises the die cavity of cast member and the die cavity of external chill, at this moment, can insert external chill in the die cavity by reserved opening, pour into a mould then, other process procedure and previous embodiment are similar, and it can realize purpose of the present invention equally.

Claims (1)

1. a precision-investment casting method is characterized in that comprising the steps:

1), making is consistent with cast member and comprise the wax-pattern of dead head, on the thermal center of the corresponding cast member of described wax-pattern away from dead head core print is set, described core print and wax-pattern are one-body molded;

2), make the Ludox fusible pattern, and guarantee that the end of core print is positioned at the outside of Ludox fusible pattern according to described wax-pattern;

3), the Ludox fusible pattern of being produced placed carries out dewax under 110 ℃～120 ℃ temperature and handle and to make formwork, contain the reserved opening of corresponding core print structure on the described formwork;

4), the formwork of being produced is placed carry out roasting under 1100 ℃～1200 ℃ temperature and solidify to handle;

5), will insert in the formwork from reserved opening according to external chill or internal densener that cast member disperses thermal center to design;

6), the die cavity that molten metal liquid is poured in the formwork makes cast member;

7), the dead head to cast member after the die sinking carries out cutting and separating, and remove external chill or the internal densener projection repaired and make finished product.

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