阅读说明：本技术 一种镁锂合金铸件的砂型铸造工艺 (Sand mold casting process of magnesium-lithium alloy casting ) 是由 刘俊峰 赵华军 陈琨 许朝安 程宝林 于 2018-08-16 设计创作，主要内容包括：本发明公开了一种镁锂合金铸件的砂型铸造工艺,属于金属材料铸造技术领域,它包括以下步骤：S1、制作模具,所述模具由非磁性材料制成；S2、将100重量份的金属砂、2～4重量份的磷酸盐粘结剂混匀制得型砂；S3、将所述模具置于砂箱中,再充入型砂至满箱,形成铸型；S4、设置浇口、冒口,合箱；S5、对所述砂箱进行加热；S6、向铸型中注入镁锂合金金属液,待其凝固形成铸件后,进行落砂及抛丸处理。本发明采用金属砂铸型和倾斜浇注,型腔稳定性高,充型平稳,能够减少夹渣的发生,且便于铸型排气,降低气孔缺陷,铸件的机械性能高。(The invention discloses a sand casting process of a magnesium-lithium alloy casting, belonging to the technical field of metal material casting, and comprising the following steps of: s1, manufacturing a mold, wherein the mold is made of a non-magnetic material; s2, uniformly mixing 100 parts by weight of metal sand and 2-4 parts by weight of phosphate binder to prepare molding sand; s3, placing the mould in a sand box, and filling the sand box with molding sand to full extent to form a casting mould; s4, arranging a pouring gate and a riser, and closing the box; s5, heating the sand box; and S6, injecting magnesium-lithium alloy molten metal into the casting mould, and performing sand falling and shot blasting treatment after the magnesium-lithium alloy molten metal is solidified to form a casting. The invention adopts the metal sand casting mold and the inclined pouring, has high stability of the cavity and stable mold filling, can reduce the occurrence of slag inclusion, is convenient for the exhaust of the casting mold, reduces the defect of air holes, and has high mechanical property of the casting.)

1. A sand casting process of a magnesium-lithium alloy casting is characterized by comprising the following steps:

s1, manufacturing a mold, wherein the mold is made of a non-magnetic material;

s2, uniformly mixing 100 parts by weight of metal sand and 2-4 parts by weight of phosphate binder to prepare molding sand;

s3, placing the mould in a sand box, and filling the sand box with molding sand to full extent to form a casting mould;

s4, arranging a pouring gate and a riser, and closing the box;

s5, heating the sand box;

and S6, injecting magnesium-lithium alloy molten metal into the casting mould, and performing sand falling and shot blasting treatment after the magnesium-lithium alloy molten metal is solidified to form a casting.

2. A sand casting process for magnesium-lithium alloy castings according to claim 1, wherein in step S1, the mold is made of silicon carbide ceramic.

3. A sand casting process of magnesium-lithium alloy castings according to claim 1, wherein the step S5 is heating by irradiating far infrared rays to the sand box.

4. A sand casting process of magnesium-lithium alloy castings according to claim 1, wherein in step S6, the sand box is tilted first, the magnesium-lithium alloy molten metal is poured from the pouring gate, the sand box is leveled when the liquid level reaches the riser 1/3, and then the magnesium-lithium alloy molten metal is poured from the riser until the casting is full.

5. A sand casting process of magnesium-lithium alloy castings according to claim 1, further comprising a step S3' after the step S3, of coating a high temperature resistant coating on the surface of the cavity of the mold.

6. A sand casting process of magnesium lithium alloy castings according to claim 5, characterized in that the high temperature resistant coating is composed of the following components: 40-60 parts of quartz powder, 40-60 parts of alcohol-based zircon powder, 1-5 parts of activated bentonite, 3-7 parts of water glass, 2-6 parts of phenolic resin and a proper amount of water.

Technical Field

The invention relates to the technical field of metal material casting, in particular to a sand casting process of a magnesium-lithium alloy casting.

Background

Sand casting refers to a casting method for producing castings in sand molds, and a casting mold used for sand casting is generally formed by combining an outer sand mold and a core; steel, iron and most nonferrous castings can be obtained by sand casting of magnesium lithium alloy castings. The molding material used for sand casting is cheap and easy to obtain, the casting mould is simple and convenient to manufacture, and the casting mould can adapt to single-piece production, batch production and mass production of castings, and is a basic process in casting production for a long time. At present, 60-70% of castings are produced by sand molds internationally. However, because the molding material in sand casting is sand, the whole body of the molding material is soft and porous, the stability of the sand mold formed by the molding material is poor, the molding material is easy to collapse and deform, the pouring process needs to be very careful, and the sand mold can be damaged by a little attention to cause the pouring failure, and particularly under the conditions of large and long casting size and high casting precision requirement, the traditional sand mold casting process has certain difficulty; and secondly, the heat conductivity coefficient of the sand mold is small, so that the defects of large crystal grains, loose structure, sand holes, air holes and the like of the casting are easily caused, and the mechanical property of the casting is lower.

Disclosure of Invention

The invention aims to provide a sand casting process of a magnesium-lithium alloy casting, which aims at overcoming the defects of the prior art, adopts a metal sand casting mold and inclined casting, has high stability of a cavity, is stable in mold filling, can reduce slag inclusion, is convenient for exhaust of the casting mold, reduces the defect of air holes, and has high mechanical property of the casting.

The technical scheme adopted by the invention is as follows:

a sand casting process of a magnesium-lithium alloy casting comprises the following steps:

s1, manufacturing a mold, wherein the mold is made of a non-magnetic material;

s2, uniformly mixing 100 parts by weight of metal sand and 2-4 parts by weight of phosphate binder to prepare molding sand;

s3, placing the mould in a sand box, and filling the sand box with molding sand to full extent to form a casting mould;

s4, arranging a pouring gate and a riser, and closing the box;

s5, heating the sand box;

and S6, injecting magnesium-lithium alloy molten metal into the casting mould, and performing sand falling and shot blasting treatment after the magnesium-lithium alloy molten metal is solidified to form a casting.

In step S1, the mold is made of silicon carbide ceramic.

Further, in the step S5, the flask is irradiated with far infrared rays to be heated.

Further, in step S6, the sand box is tilted, the magnesium-lithium alloy molten metal is poured from the pouring gate, the sand box is leveled when the liquid level reaches the riser 1/3, and then the magnesium-lithium alloy molten metal is poured from the riser until the sand box is full.

Further, step S3' is included after step S3, in which a high temperature resistant paint is coated on the surface of the cavity of the mold.

Further, the high-temperature resistant coating is composed of the following components: 40-60 parts of quartz powder, 40-60 parts of alcohol-based zircon powder, 1-5 parts of activated bentonite, 3-7 parts of water glass, 2-6 parts of phenolic resin and a proper amount of water.

Compared with the prior art, the invention has the following remarkable advantages and beneficial effects:

1. the metal sand has high mechanical strength and is not easy to break, mineral sand dust is not generated in the production process, and the pollution to the production environment is avoided; in addition, because the metal sand has large dead weight and round appearance, a clear and stable cavity can be formed without large external force during molding, and therefore, the metal sand can be assembled for production only by simple equipment, thereby saving a large amount of electric power, reducing noise during molding and cleaning equipment operation, and improving the working environment of a production site.

2. The sand box is heated by far infrared rays, so that the temperature of the casting mold is also increased; after the magnesium-lithium alloy molten metal enters the casting mold, the temperature difference between the casting mold and the magnesium-lithium alloy molten metal is small, the heat absorbed by the casting mold from the magnesium-lithium alloy molten metal is small, the cooling gradient of the magnesium-lithium alloy molten metal is mild, the time for keeping the magnesium-lithium alloy molten metal in a liquid state in the cavity is prolonged, the fluidity is good, the mold filling capacity is obviously improved, the casting mold is convenient to exhaust, the defect of air holes is reduced, and the improvement of the mechanical performance of a casting is facilitated.

3. The inclined pouring is performed, so that the stability is better, and the impact on a sand mold is small; the method for pouring the magnesium-lithium alloy molten metal from the pouring gate after tilting the sand box is creatively adopted, and then the sand box is flatly placed to perform the supplementary pouring of the rest magnesium-lithium alloy molten metal from the riser has the advantages of stable mold filling, capability of reducing slag inclusion, convenience for exhaust of a casting mold, reduction of pore defects, improvement of riser feeding effect and reduction of shrinkage porosity defects.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.