阅读说明：本技术 一种扇形叶轮的熔模铸造工艺 (Investment casting process of fan-shaped impeller ) 是由 许四冈 于 2019-11-06 设计创作，主要内容包括：本发明公开了一种扇形叶轮的熔模铸造工艺,涉及材料成型技术,用于解决铸件容易产生锈蚀的问题,包括以下步骤：先按照扇形叶轮的尺寸和形状,制造型腔与其一致的模壳；然后将金属熔融后注入模壳内,待金属完全冷却凝固后,获得扇形叶轮铸件；之后将扇形叶轮从模壳内取出后,放入窑炉内,以720~760℃的火焰对其进行烘烤,以炉内冷却的方式静置12h,重复两遍之后取出,对其进行二次抗锈处理；本发明具有以下优点和效果：烘烤处理能够让扇形叶轮以再结晶的形式形成铁素体晶格,以铁素体对抗液体对扇形叶轮的腐蚀,减缓其氧化锈蚀的速度,从而达到提升其力学性能保持性的目的。(The invention discloses a fired mold casting process of a fan-shaped impeller, which relates to the material forming technology and is used for solving the problem that a casting is easy to rust.)

1. An investment casting process of a fan-shaped impeller is characterized by comprising the following steps:

s1 molding, namely manufacturing a mold shell with a mold cavity consistent with the fan-shaped impeller according to the size and the shape of the fan-shaped impeller;

s2, pouring, namely melting the metal and injecting the molten metal into the mould shell, and obtaining a fan-shaped impeller casting after the metal is completely cooled and solidified;

s3 anti-rust treatment, taking the fan-shaped impeller out of the mould shell, putting the impeller into a kiln, baking the impeller with flame at 720 ~ 760 ℃, standing the impeller for 12 hours in a manner of cooling in the kiln, taking out the impeller after repeating twice, and carrying out secondary anti-rust treatment on the impeller.

2. The investment casting process of a sector impeller of claim 1, wherein: the method for the secondary anti-rust treatment comprises the following steps: the method comprises the steps of firstly coating natural plant paint on the whole surface of a fan-shaped impeller, then placing the fan-shaped impeller into a kiln for baking, taking out the fan-shaped impeller after cooling, roasting the fan-shaped impeller by flame, then brushing the surface of one side, opposite to the flame, of the fan-shaped impeller by using the natural plant paint, continuously rotating the fan-shaped impeller in the brushing process until the natural plant paint is coated on the whole surface of the fan-shaped impeller, and roasting the fan-shaped impeller until the surface is reddish brown.

3. The investment casting process of a sector impeller of claim 2, wherein: the preparation method of the natural plant paint comprises the following steps: grinding green herba Zosterae Marinae, fresh folium Camelliae sinensis and tuber of Polygoni Multiflori radix, standing for 24 hr, filtering with gauze to remove residue, and filtering to obtain mixed juice as natural plant lacquer.

4. The investment casting process of a sector impeller of claim 3, wherein: the addition ratio of the green kelp to the fresh tea leaves to the tuber of the polygonum multiflorum is 3:1: 2.

5. The investment casting process of a sector impeller of claim 1, wherein: the specific steps of the molding are as follows: firstly putting a fan-shaped impeller into an original mould, pouring rubber into a gap between the fan-shaped impeller and the original mould, dividing the mould to take out the fan-shaped impeller after the rubber is completely solidified, then peeling off a formed rubber reverse mould from the fan-shaped impeller to obtain an outer mould of the fan-shaped impeller, then pouring molten wax liquid into the outer mould, completely cooling and solidifying the wax liquid to obtain a wax mould with the shape and the size consistent with those of the fan-shaped impeller, then manufacturing the wax mould into a wax tree, immersing the wax tree into slurry, taking out the wax tree, wrapping refractory sand, preparing a mould shell, and repeating the process of dip-dyeing the slurry and wrapping the refractory sand at least three times to increase the thickness of the mould shell.

6. The investment casting process of a sector impeller of claim 5, wherein: the wax tree is prepared by the following steps: firstly, wax is used as a raw material to manufacture a wax seat, then a spray gun is used for roasting the surface of the wax seat to melt the surface of the wax seat, then a wax pattern is quickly pressed to the melting part of the wax seat, and then a plurality of wax patterns are welded on the wax seat according to the same method to form the wax tree.

7. The investment casting process of a sector impeller of claim 5, wherein: the formwork is required to be cured after being manufactured, and the specific curing method comprises the following steps: placing the mould shell in a burning furnace upside down, roasting the mould shell by flame, solidifying the slurry in the mould shell by burning completely, and pouring the mould shell when the mould shell is taken out from the furnace after burning.

8. The investment casting process of a sector impeller of claim 1, wherein: the fan-shaped impeller is required to be corrected before being cast and molded and subjected to anti-embroidery treatment, and the specific method of the correction treatment comprises the following steps: cutting off a sprue gate on the fan-shaped impeller, wherein a sprue gate is required to be remained for 0.3mm when the sprue gate is cut, then polishing by using an abrasive belt machine to ensure that the cut of a product is smooth, and the surface of the product is prevented from being damaged in the cutting and polishing processes.

Technical Field

The invention relates to a material forming technology, in particular to an investment casting process of a fan-shaped impeller.

Background

The material forming method mainly includes casting, forging, powder metallurgy, extrusion, rolling, drawing and the like, wherein casting and forging are the forming methods which are most applied. Forging is plastic by hammering, so that dimensional accuracy is difficult to grasp, and casting is industrially more widely used because a finished product is identical to a mold and dimensional accuracy is better grasped.

At present, the chinese patent with application publication number CN109175305A discloses an impeller casting process and an impeller thereof, wherein the process comprises the following steps: adopting a core to perform investment casting on an impeller shell; using the cores of all investment casting steps as cores of an impeller shell when the impeller is cast; the impeller shell forms the impeller in a low pressure casting process.

The casting process as described above requires frequent contact with liquid because the impeller is usually applied to a compressor, a pump, etc., and the product produced by the casting method is usually not enough in terms of anti-corrosion performance, so that the impeller is easily corroded during use, thereby resulting in a reduction in mechanical properties of the impeller.

Disclosure of Invention

The invention aims to provide a fired mold casting process of a fan-shaped impeller, which can improve the anti-corrosion performance of the fan-shaped impeller so as to achieve the aim of improving the mechanical property durability of the fan-shaped impeller.

The technical purpose of the invention is realized by the following technical scheme: an investment casting process of a fan-shaped impeller comprises the following steps:

s1 molding, namely manufacturing a mold shell with a mold cavity consistent with the fan-shaped impeller according to the size and the shape of the fan-shaped impeller;

s2, pouring, namely melting the metal and injecting the molten metal into the mould shell, and obtaining a fan-shaped impeller casting after the metal is completely cooled and solidified;

s3, carrying out rust resistance treatment, taking the fan-shaped impeller out of the formwork, putting the impeller into a kiln, baking the impeller by flame at 720-760 ℃, standing the impeller for 12 hours in a cooling mode in the kiln, repeating the steps for two times, taking the impeller out, and carrying out secondary rust resistance treatment on the impeller.

By adopting the scheme, 720-760 ℃ is a temperature interval in which ferrite is easily formed in the steel recrystallization process, and the ferrite is a eutectoid solid solution of carbon and alpha-Fe, so that compared with steel in other forms, the rust resistance of the fan-shaped impeller can be improved after baking treatment, and the secondary rust resistance in the later period is supplemented, so that the rust resistance of the fan-shaped impeller can be greatly improved, the fan-shaped impeller has longer mechanical property retentivity, and the service life of the fan-shaped impeller is prolonged.

The invention is further provided with: the method for the secondary anti-rust treatment comprises the following steps: the method comprises the steps of firstly coating natural plant paint on the whole surface of a fan-shaped impeller, then placing the fan-shaped impeller into a kiln for baking, taking out the fan-shaped impeller after cooling, roasting the fan-shaped impeller by flame, then brushing the surface of one side, opposite to the flame, of the fan-shaped impeller by using the natural plant paint, continuously rotating the fan-shaped impeller in the brushing process until the natural plant paint is coated on the whole surface of the fan-shaped impeller, and roasting the fan-shaped impeller until the surface is reddish brown.

By adopting the scheme, the natural plant paint is coated firstly and then baked, so that the natural plant paint can gradually permeate into the fan-shaped impeller in the baking process, and the mineral components contained in the natural plant paint can improve the anti-rusting performance and the mechanical property of the natural plant paint; on one hand, the later-stage roasted painting of the plant paint can enhance the penetration of mineral elements in the plant paint to the fan-shaped impeller, and simultaneously can promote the surface passivation of the plant paint, so that the plant paint has better anti-rusting capability.

The invention is further provided with: the preparation method of the natural plant paint comprises the following steps: grinding green herba Zosterae Marinae, fresh folium Camelliae sinensis and tuber of Polygoni Multiflori radix, standing for 24 hr, filtering with gauze to remove residue, and filtering to obtain mixed juice as natural plant lacquer.

By adopting the scheme, the green kelp contains rich phosphorus elements, so that the iron elements in the fan-shaped impeller can be phosphated, the phosphated iron is stable in property, and a layer of protective film can be formed on the surface of the fan-shaped impeller to prevent the fan-shaped impeller from being oxidized and rusted; the tea leaves and the tuber of the polygonum multiflorum contain rich nickel and chromium which are inert elements, and the oxidation resistance of steel can be effectively improved after the chromium and the nickel penetrate into the fan-shaped impeller, so that the fan-shaped impeller has better anti-rusting capability; meanwhile, the quenching mode of the plant juice can ensure that the content of heavy metals in the cost cannot exceed the standard, so that the fan-shaped impeller has better safety when being used for a drinking water pump.

The invention is further provided with: the addition ratio of the green kelp to the fresh tea leaves to the tuber of the polygonum multiflorum is 3:1: 2.

By adopting the scheme, the green kelp contains more water, the fresh tea leaves and the tuber of the polygonum multiflorum contain less water, the natural plant paint can be conveniently smeared only by certain fluidity, the juice cannot be too diluted, or the pulp cannot be easily formed on the surface of the fan-shaped impeller, and the green kelp, the fresh tea leaves and the tuber of the polygonum multiflorum are blended in a ratio of 3:1:2, so that the squeezed juice can exist in a thicker form, the squeezed juice is not easy to overflow after being smeared on the fan-shaped impeller, and mineral elements in the natural plant paint can be more uniformly permeated into the fan-shaped impeller after the fan-shaped impeller is heated.

The invention is further provided with: the specific steps of the molding are as follows: firstly putting a fan-shaped impeller into an original mould, pouring rubber into a gap between the fan-shaped impeller and the original mould, dividing the mould to take out the fan-shaped impeller after the rubber is completely solidified, then peeling off a formed rubber reverse mould from the fan-shaped impeller to obtain an outer mould of the fan-shaped impeller, then pouring molten wax liquid into the outer mould, completely cooling and solidifying the wax liquid to obtain a wax mould with the shape and the size consistent with those of the fan-shaped impeller, then manufacturing the wax mould into a wax tree, immersing the wax tree into slurry, taking out the wax tree, wrapping refractory sand, preparing a mould shell, and repeating the process of dip-dyeing the slurry and wrapping the refractory sand at least three times to increase the thickness of the mould shell.

By adopting the scheme, the shape and the size of the cavity of the mould shell can be almost consistent with those of the fan-shaped impeller by the mode of firstly preparing the wax mould and then sleeving the mould shell, so that the preparation precision of the mould can be improved, and the aim of improving the casting precision of a product is fulfilled; the quantity of products produced in a single production process can be increased by manufacturing the wax trees, and the more wax molds compounded on the wax trees means that the more fan-shaped impellers are obtained after a casting is demoulded, so that the production efficiency of the products can be greatly improved under the condition of batch production.

The invention is further provided with: the wax tree is prepared by the following steps: firstly, wax is used as a raw material to manufacture a wax seat, then a spray gun is used for roasting the surface of the wax seat to melt the surface of the wax seat, then a wax pattern is quickly pressed to the melting part of the wax seat, and then a plurality of wax patterns are welded on the wax seat according to the same method to form the wax tree.

By adopting the scheme, the wax has good self-adhesion, the wax seat is roasted by the spray gun and melted, and then the wax mould is pressed and attached, so that the wax mould and the wax seat can be well combined together to form a wax tree, the wax tree is not easy to break when being soaked in slurry, and the formwork can be better manufactured.

The invention is further provided with: the formwork is required to be cured after being manufactured, and the specific curing method comprises the following steps: placing the mould shell in a burning furnace upside down, roasting the mould shell by flame, completely burning and solidifying the slurry in the membrane shell, and pouring the membrane shell when the membrane shell is taken out from the furnace after burning.

By adopting the scheme, the mould shell is inverted and then sintered, so that the molten wax mould in the mould shell can conveniently flow out from the pouring gate in the heating process, the wax can be removed while the mould shell is sintered, the waste of energy is reduced, and the production efficiency of the mould shell is improved; and the temperature difference between the mould shell and the molten metal can be reduced by adopting a hot pouring mode, so that the defects of shrinkage porosity and the like in the metal condensation forming process are reduced, and the quality of the finished product of the casting is improved.

The invention is further provided with: the fan-shaped impeller is required to be corrected before being cast and molded and subjected to anti-embroidery treatment, and the specific method of the correction treatment comprises the following steps: cutting off a sprue gate on the fan-shaped impeller, wherein a sprue gate is required to be remained for 0.3mm when the sprue gate is cut, then polishing by using an abrasive belt machine to ensure that the cut of a product is smooth, and the surface of the product is prevented from being damaged in the cutting and polishing processes.

Any foundry goods all can leave the waste material that is formed by watering in pouring gate department after the casting shaping, and this part waste material need be amputated, through adopting above-mentioned scheme, reserves 0.3 mm's runner and gets rid of with the form of polishing when the cutting, can conveniently control the size of foundry goods, and the mode of polishing simultaneously also can be repaired as far as possible and removed flaw such as compound die line and burr that the product casting process produced to make the finished product have better size precision and appearance quality.

In conclusion, the invention has the following beneficial effects:

1. the baking treatment can enable the fan-shaped impeller to form ferrite lattices in a recrystallization mode, so that the ferrite resists the corrosion of liquid to the fan-shaped impeller and slows down the oxidation and corrosion speed of the fan-shaped impeller, thereby achieving the purpose of improving the mechanical property retentivity of the fan-shaped impeller;

2. on one hand, the secondary quenching treatment can permeate inert elements into the fan-shaped impeller to improve the anti-corrosion capability of the fan-shaped impeller, and simultaneously can form a protective film on the surface of the fan-shaped impeller in a phosphorization and passivation mode, so that the anti-corrosion capability of the fan-shaped impeller is further improved;

3. the mode of making the mould shell on the basis of the wax mould can ensure that the mould cavity of the mould shell has higher dimensional accuracy, thereby improving the forming quality of products.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.