阅读说明：本技术 一种消失模烧空壳型铸造工艺 (Lost foam sintering empty shell mold casting process ) 是由 丁宇 刘家宝 于 2020-05-19 设计创作，主要内容包括：本发明涉及铸件成型和铸造技术领域,具体涉及一种消失模烧空壳型铸造工艺,主要工艺流程为制模,粘贴冒口、浇道,涂料,烘干,烧空,埋箱,浇注,清理、打磨、机加,采用本发明铸造工艺生产的铸件具有表面光洁度高,尺寸精度高等优点,不仅能够满足对铸件精度的要求,还能够大大降低生产成本和生产污染,能够满足高档、复杂结构、精密铸件的要求,制壳过程绿色环保。(The invention relates to the technical field of casting forming and casting, in particular to a lost foam hollow shell burning casting process, which comprises the main process flows of molding, riser head pasting, pouring, coating, drying, burning, box burying, pouring, cleaning, polishing and machining.)

1. A lost foam burning empty shell mold casting process is characterized in that: the method mainly comprises the following steps:

s1: selecting polystyrene to manufacture a foam white mold consistent with a casting entity;

s2: sticking a riser and a pouring gate to the white mold prepared in the step S1 according to the process;

s3: sequentially carrying out surface layer coating and back layer coating on the die prepared in the step S2 and drying, wherein the drying thickness of the surface layer coating is 0.5-1 mm, the drying temperature is 51-60 ℃, the humidity is 60-70%, the drying time is 2-3 hours, the back layer coating is coated for 2-5 times, the coating thickness of each time is 1.0-1.5 mm, the total thickness of the coating is 3-7.5 mm, the drying time of each time of coating the back layer coating is one time, the drying temperature of the back layer coating is 65 ℃, the humidity is 60-70%, the drying time is 1.5 hours, and a black die is obtained after drying;

s4: burning and roasting the dried black mold in the step S3 by using a heating furnace, preserving heat and cooling to obtain a cavity shell mold, and embedding and pouring the cavity shell mold within 4 hours;

s5: the shell mold that completed the casting process in S4 was cleaned, ground, and machined.

2. The lost foam pattern casting process of claim 1, wherein: in step S2, the mold is reinforced at the position where the mold is easily deformed, specifically, the mold is placed on a flat plate or a jig, and bonded, corrected and reinforced with a fiber rod, a refractory cloth, a ceramic block, or the like.

3. The lost foam pattern casting process of claim 1, wherein: in step S3, the coating is applied by dipping the small pieces, flow coating the large pieces, flow coating the production line, and brushing the local patch.

4. The lost foam pattern casting process of claim 1, wherein: in step S3, selecting corresponding coating according to the material requirement and the casting characteristics, adding powder while stirring liquid in the mixing process, stirring for 30 minutes after mixing, storing the mixed coating in an environment of 10-40 ℃, sealing and not exposing to the sun, ensuring the white mold surface to be clean before coating the surface layer coating, uniformly smearing the marks and the fine parts to prevent bubbles, and ensuring the coating to be uniform after coating the surface layer.

5. The lost foam pattern casting process of claim 1, wherein: in step S3, when the degree of drying after the top coating is applied is 70 to 80%, a back coating is applied on the outside of the top coating, the surface of the top coating is kept clean before the back coating is applied, and the back coating is soaked on the top coating for 1 to 4 minutes when the back coating is applied for the first time.

6. The lost foam pattern casting process of claim 1, wherein: after the drying process in step S3 is completed, the shell-type paint is dried integrally, and the mold is placed in a high-temperature high-wind-speed low-humidity drying chamber to be dried for 6 hours.

7. The lost foam pattern casting process of claim 1, wherein: in step S4, the coating of the shell type dope on the casting head of the black mold is cut, and exhaust holes with a diameter of 10mm are drilled in the upper and lower parts of the mold, and the black mold is fired empty and baked in a heating furnace.

8. The lost foam pattern casting process of claim 7, wherein: after the temperature of the shell mold had dropped to room temperature, the casting head was tightly sealed with a plastic bag.

9. The lost foam pattern casting process of claim 1, wherein: in step S4, the drain hole drilled at the time of shell mold firing is attached with a fire-resistant cloth and a paint before potting, and the gate is tightly sealed with a plastic film.

10. The lost foam pattern casting process of claim 1, wherein: in step S4, the molten steel is poured in an intermediate frequency furnace, and after the pouring is finished, the temperature is kept for more than 8 hours, and the molten steel is cooled to below 600 ℃ and taken out of the box.

Technical Field

The invention relates to the technical field of casting forming and casting, in particular to a lost foam hollow shell mold burning casting process.

Background

In the technical field of the prior casting forming and casting, the processes mainly comprise a sand casting method, a lost foam casting method and the like, but the methods have the defects of low precision, large casting defects and the like. The casting produced by the traditional lost foam casting process is easy to deform, the precision is difficult to guarantee, and the defects of giving away, air holes and the like can be caused.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a lost foam burning empty shell type casting process, and aims to solve the technical problem of improving the casting forming and production process, so that the produced casting has higher surface smoothness and better quality, and meanwhile, the production cost can be saved.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: a lost foam burning empty shell mold casting process mainly comprises the following steps:

s1: selecting polystyrene to manufacture a foam white mold consistent with a casting entity;

s2: pasting a riser and a pouring gate on the white mold prepared in the step S1;

s3: sequentially carrying out surface layer coating and back layer coating on the die prepared in the step S2 and drying, wherein the drying thickness of the surface layer coating is 0.5-1 mm, the drying temperature is 51-60 ℃, the humidity is 60-70%, the drying time is 2-3 hours, the back layer coating is coated for 2-5 times, the coating thickness of each time is 1.0-1.5 mm, the total thickness of the coating is 3-7.5 mm, the drying time of each time of coating the back layer coating is one time, the drying temperature of the back layer coating is 65 ℃, the humidity is 60-70%, the drying time is 1.5 hours, and a black die is obtained after drying;

s4: burning and roasting the dried black mold in the step S3 by using a heating furnace, preserving heat and cooling to obtain a cavity shell mold, and embedding and pouring the cavity shell mold within 4 hours;

s5: and cleaning, grinding, machining and the like are carried out on the casting blank which is poured in the step S4, and a finished product is finished.

Further, in step S2, the mold is reinforced at the position where the mold is easily deformed, specifically, the mold is placed on a flat plate or a jig, and bonded, corrected and reinforced by a fiber rod, a refractory cloth, a ceramic block, or the like.

Further, in step S3, the coating is applied by dipping the small pieces, flow coating the large pieces on the production line, and brushing the local patch.

Further, in step S3, a corresponding coating is selected according to the requirements of the material and the characteristics of the casting, the coating is prepared by adding powder while stirring the liquid, rapidly stirring for 30 minutes after uniformly mixing, storing the mixed coating in an environment of 10-40 ℃, sealing and not exposing to the sun, ensuring the surface of the mold to be clean before coating the surface coating, uniformly smearing the marks and the fine parts to prevent bubbles, and ensuring the coating to be uniform after coating the surface coating.

Further, in step S3, when the degree of drying after the top coating is applied is 70 to 80%, a back coating is applied to the outside of the top coating, the top coating is kept clean before the back coating is applied, and the back coating is soaked on the top coating for 1 to 4 minutes when the back coating is applied for the first time.

Further, after the drying process is finished in step S3, the shell-shaped paint is dried as a whole, and the black mold is placed in a high-temperature high-wind-speed low-humidity drying chamber to be dried for 6 hours.

Further, in step S4, the coating of the shell type dope is cut off from the casting head of the black mold, and exhaust holes with a diameter of 10mm are drilled in the upper and lower portions of the mold, and the black mold is fired and baked by a heating furnace.

Further, after the temperature of the shell mold was lowered to room temperature, the casting head was tightly sealed with a plastic bag.

Further, in step S4, before the casing is buried, the drain hole drilled at the time of firing the shell is attached with a refractory cloth and a paint, and the gate is tightly sealed with a plastic film.

Further, in step S4, the molten steel is poured by an intermediate frequency furnace, and after the pouring is finished, the molten steel is kept warm for more than 8 hours and cooled to below 600 ℃ and then taken out of the box.

The beneficial effect that this technical scheme brought is: the casting surface and the near surface produced by the process have no defects of sand holes, air holes, slag inclusion and the like, so that the subsequent welding repair and polishing workload of the casting is greatly reduced, particularly the welding repair and polishing workload of high-alloy steel castings such as heat-resistant steel and the like can be reduced by about 60%, the labor intensity is reduced, the appearance of the casting is attractive, the production cost is greatly reduced, the pollution is reduced, and the quality of high-grade castings with magnetic powder inspection requirements on the surface is easier to ensure. Meanwhile, the process can also enable the size of the casting blank to be more accurate, reduce the machining allowance, save the raw material cost, and also has a series of advantages of reducing the recarburization of the casting and the like. Specifically, the process has the advantages of convenience in production, high efficiency, less material consumption, less pollution, low noise and the like, and the produced casting has high surface smoothness and high dimensional precision.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a process flow diagram of an evaporative pattern sintering empty shell mold casting process according to an embodiment of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are merely for purposes of illustration and explanation, and are not intended to limit the present invention.