阅读说明：本技术 一种铝合金轮毂的制造工艺 (Manufacturing process of aluminum alloy hub ) 是由 屈发奎 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种铝合金轮毂的制造工艺,包括以下步骤：铝锭检验；溶解:将成份合格的铝锭通熔化为铝液；除气：将溶解后的高温铝液放流至盛汤保温炉中,通入氮气搅拌,除气后铝液温度为700℃±30℃；转汤：将除好气的铝液移转加入低压设备保温密闭溶炉中；氮气加压准备：氮气供气压力调试在4.0kg/cm～(3)-6.0kg/cm～(3)；合模：清除底模杂物启动铸造模具；氮气升压：铝水沿升液管压到模具汤口；氮气加压：铝水进入模具型腔到达轮辋部位；氮气充型：铝水进入模具型腔并且到轮毂后挂；氮气增压：压力继续增大使轮圈当中的缺陷被补充好；氮气保压：保持氮气压力,冷却之后压力减小直至到零；开模：取出铸件。通过上述方式,本发明能够提高效率,增强稳定性,降低报废率。(The invention discloses a manufacturing process of an aluminum alloy hub, which comprises the following steps: inspecting the aluminum ingot; dissolving, namely melting aluminum ingots with qualified components into aluminum liquid; degassing: discharging the dissolved high-temperature aluminum liquid into a soup holding heat preservation furnace, introducing nitrogen gas, stirring, and degassing to obtain the aluminum liquid with the temperature of 700 +/-30 ℃; turning into soup: transferring the degassed aluminum liquid into a low-pressure equipment heat-preservation closed melting furnace; preparing nitrogen pressurization: the nitrogen supply pressure is adjusted to be 4.0kg/cm 3 ‑6.0kg/cm 3 (ii) a Die assembly: removing sundries from the bottom die and starting a casting die; and (3) boosting the pressure of nitrogen: pressing the molten aluminum to the soup port of the mold along the riser; pressurizing with nitrogen: molten aluminum enters a die cavity of the die and reaches a rim part; filling the mold with nitrogen: the molten aluminum enters the die cavity and is hung behind the wheel hub; nitrogen pressurization: the pressure is continuously increased to make the defects in the rim well supplemented; and (3) nitrogen pressure maintaining: maintaining the nitrogen pressure and reducing the pressure to zero after cooling; opening the mold: and taking out the casting. In the above manner, the present invention canThe efficiency is improved, the stability is enhanced, and the rejection rate is reduced.)

1. The manufacturing process of the aluminum alloy hub is characterized by comprising the following steps of:

s1, inspecting the aluminum ingot;

s2, dissolving, namely, melting aluminum ingots with qualified components into aluminum liquid;

s3, degassing: discharging the dissolved high-temperature aluminum liquid into a soup holding heat preservation furnace, introducing nitrogen into a rotary graphite stirrer for stirring, and controlling the temperature of the aluminum liquid to be 700 +/-30 ℃ after degassing;

s4, converting into soup: transferring the degassed aluminum liquid into a low-pressure equipment heat-preservation closed melting furnace;

s5, nitrogen pressurization preparation: the nitrogen supply pressure is adjusted to be 4.0kg/cm³-6.0kg/cm³；

S6, mold closing: removing sundries from the bottom die and starting a casting die;

s7, nitrogen boosting: pressing the molten aluminum to the soup port of the mold along the riser;

s8, pressurizing with nitrogen: molten aluminum enters a die cavity of the die and reaches a rim part;

s9, filling nitrogen gas: the molten aluminum enters the die cavity and is hung behind the wheel hub;

s10, nitrogen pressurization: the pressure is continuously increased to make the defects in the rim well supplemented;

s11, nitrogen pressure maintaining: maintaining the pressure of the nitrogen, and reducing the pressure to zero through a pressure relief valve after cooling;

s12, opening the mould: and taking out the casting from the casting mold.

2. A process for manufacturing an aluminium alloy hub according to claim 1, wherein: in the dissolving step, the aluminum ingot is melted into aluminum liquid at 730 +/-10 ℃ by fuel gas at high temperature.

3. A process for manufacturing an aluminium alloy hub according to claim 1, wherein: the nitrogen pressurization preparation step comprises the following steps:

s5-1, evaporation: gasifying the liquid nitrogen through an evaporator, introducing the gasified nitrogen into a liquid nitrogen tank body, wherein the internal pressure of the liquid nitrogen tank body reaches 5kg/cm³-8 kg/cm³；

S5-2, output: the pressure of the nitrogen output by the pressure output control device of the vaporizer is controlled to be 4.0kg/cm³-6.0kg/cm³。

4. A process for manufacturing an aluminum alloy hub as recited in claim 3, wherein: the vaporizer is an air-temperature vaporizer.

5. A process for manufacturing an aluminium alloy hub according to claim 1, wherein: the aluminum ingot is an aluminum ingot with the mark A356.2.

Technical Field

The invention relates to the field of hub manufacturing, in particular to a manufacturing process of an aluminum alloy hub.

Background

At present, the traditional method for casting the aluminum alloy wheel hub at low pressure is to introduce certain dry compressed air into a sealed heat-preservation solution furnace to ensure that liquid aluminum rises along a liquid-lifting pipe under the action of gas pressure and stably enters a mold cavity through a mold pouring gate, and the gas pressure on the liquid surface in the heat-preservation solution furnace is kept until a casting is completely solidified. Then the gas pressure on the liquid surface is relieved, so that the unsolidified aluminum liquid in the liquid lifting pipe flows into the holding furnace along with the action of gravity, and then the casting is opened and pushed out by the oil cylinder. However, in the process of casting the aluminum alloy hub at low pressure, liquid aluminum is not supplemented in time due to volume shrinkage, or hydrogen generated by chemical reaction between water in compressed air and the liquid aluminum cannot be discharged, and aluminum oxide cannot be cleaned in time, so that shrinkage cavities are caused finally. The general pressurizing medium for low-pressure casting is compressed air, and in the low-pressure casting pressurizing process, moisture in the air enters a pressurizing system to react with molten aluminum to generate hydrogen and aluminum oxide, so that the probability of occurrence of shrinkage cavity after processing is increased, the shrinkage cavity is not increased, and the company cost is directly increased.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a manufacturing process of an aluminum alloy hub.

A manufacturing process of an aluminum alloy hub comprises the following steps:

s1, inspecting the aluminum ingot;

s2, dissolving, namely, melting aluminum ingots with qualified components into aluminum liquid;

s3, degassing: discharging the dissolved high-temperature aluminum liquid into a soup holding heat preservation furnace, introducing nitrogen into a rotary graphite stirrer for stirring, and controlling the temperature of the aluminum liquid to be 700 +/-30 ℃ after degassing;

s4, converting into soup: transferring the degassed aluminum liquid into a low-pressure equipment heat-preservation closed melting furnace;

s5, nitrogen pressurization preparation: the nitrogen supply pressure is adjusted to be 4.0kg/cm³-6.0kg/cm³；

S6, mold closing: removing sundries from the bottom die and starting a casting die;

s7, nitrogen boosting: pressing the molten aluminum to the soup port of the mold along the riser;

s8, pressurizing with nitrogen: molten aluminum enters a die cavity of the die and reaches a rim part;

s9, filling nitrogen gas: the molten aluminum enters the die cavity and is hung behind the wheel hub;

s10, nitrogen pressurization: the pressure is continuously increased to make the defects in the rim well supplemented;

s11, nitrogen pressure maintaining: maintaining the pressure of the nitrogen, and reducing the pressure to zero through a pressure relief valve after cooling;

s12, opening the mould: and taking out the casting from the casting mold.

Preferably, in the dissolving step, the aluminum ingot is melted at high temperature into aluminum liquid at 730 ℃ +/-10 ℃ by fuel gas.

Preferably, the nitrogen pressurization preparation step includes the steps of:

s5-1, evaporation: gasifying the liquid nitrogen through an evaporator, introducing the gasified nitrogen into a liquid nitrogen tank body, wherein the internal pressure of the liquid nitrogen tank body reaches 5kg/cm³-8kg/cm³；

S5-2, output: the pressure of the nitrogen output by the pressure output control device of the vaporizer is controlled to be 4.0kg/cm³-6.0kg/cm³。

Preferably, the vaporizer is an air-temperature vaporizer.

Preferably, the aluminum ingot is an aluminum ingot with the grade A356.2.

Due to the application of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) the manufacturing process of the aluminum alloy wheel hub is provided, dry air pressurization is switched to nitrogen pressurization, the speed is high, the operation is simple, nitrogen is inert gas and basically cannot react with high-temperature aluminum liquid, and the safety is high;

(2) the aluminum water has higher and stable density, and the nitrogen pressurization has average density of 2.61kg/cm compared with the original air pressurization³Is increased to 2.64kg/cm³Increased by about 1.3%;

(3) the nitrogen pressurization can reduce and reduce the total rejection rate of production, and the rejection rate of the original air pressurization is reduced from 16.7% to 4.1%, and is reduced by 12.6%.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention, and to clearly and unequivocally define the scope of the present invention.

A manufacturing process of an aluminum alloy hub comprises the following steps:

s1, aluminum ingot inspection: using an aluminum ingot conforming to the marked A356.1 mark;

s2, dissolving, namely melting the aluminum ingots with qualified components into 730 ℃ aluminum liquid through fuel gas at high temperature;

s3, degassing: discharging the dissolved high-temperature aluminum liquid into a soup holding heat preservation furnace, introducing nitrogen into a rotary graphite stirrer for stirring, so that the aluminum liquid achieves the purposes of hydrogen removal, purification and temperature reduction, and the temperature of the aluminum liquid is 700 ℃ after degassing;

s4, converting into soup: transferring the degassed aluminum liquid into a low-pressure equipment heat-preservation closed melting furnace. The existing equipment is rectified: a pipeline can be added at the door of the existing nitrogen tank air outlet valve, the pipeline extends to the pipeline of the air inlet of low-pressure equipment which needs to be modified, and a manual valve is added between the nitrogen pipeline of the low-pressure machine and the machine table connecting port.

S5, nitrogen pressurization preparation:

s5-1, evaporation: the normal pressure of a liquid nitrogen tank is 1.6Mpa, enough liquid nitrogen is stored, the liquid nitrogen is discharged through a pipeline under the action of gravity, and is gasified through an evaporator, so that gasified gas enters the top of the liquid nitrogen tank, and the pressure in the liquid nitrogen tank is provided to achieve the self-pressurization effect. The pressure control system of the liquid nitrogen tank is used for providing safety alarm for the pressurized liquid nitrogen, stabilizing and controlling the internal pressure of the liquid nitrogen tank to reach 5kg/cm³-8kg/cm³。

S5-2, output: the pressure of the nitrogen output by the pressure output control device of the vaporizer is controlled to be 4.0kg/cm³-6.0kg/cm³。

S6, mold closing: and removing impurities from the bottom die, and starting the casting die to close the upper die, the lower die and the side dies.

S7, nitrogen boosting: the molten aluminum is pressed to the die soup port along the riser, but does not enter the die cavity.

S8, pressurizing with nitrogen: molten aluminum enters the die cavity of the die and reaches the rim part.

S9, filling nitrogen gas: molten aluminum enters a die cavity and hangs behind a hub, but the inside of the rim has a plurality of shrinkage cavity defects.

S10, nitrogen pressurization: the pressure continues to increase causing the defects in the rim to be compensated.

S11, nitrogen pressure maintaining: keeping the pressure of the nitrogen, and driving a battery valve by a pressure system according to preset time after cooling to reduce the pressure to zero through a pressure release valve;

s12, opening the mould: and the model opening oil cylinder automatically opens the model and takes out the casting.

In the process, the pressure setting parameters of the low-pressure casting machine are as follows:

pressure velocity	0.5PSI/SEC	0.10PSI/SEC	0.15PSI/SEC	0.20PSI/SEC	1.0PSI/SEC
						Pressure of	3.0PSI	4.0PSI	5.0PSI	7.0PSI	14.0PSI
Effect of pressure	Step-up	Applying pressure	Filling type	Pressurized feeding	Pressure maintaining/relieving

The aluminum soup with the same weight is pressurized by nitrogen and air respectively, and is sampled for three times every day, and the sampling data for three days are shown in table 1:

TABLE 1

As is clear from Table 1, the molten aluminum had a high and stable density, and the average density of the pressurized nitrogen gas was 2.61kg/cm³Is increased to 2.64kg/cm³And the improvement is about 1.3 percent.

The aluminum soup with the same weight is pressurized by nitrogen and air respectively, and is sampled twice every day, and the sampling data in three days are shown in table 2:

TABLE 2

As can be seen from Table 2, the amount of aluminum dross in the closed heat-preserving furnace of the low-pressure machine is reduced more, and the average amount of aluminum dross is reduced from 5.53 KG/boiler to 1.84 KG/boiler under the original air pressure, which is reduced by about 66%.

The same weight of aluminum soup was pressurized by nitrogen and air, and sampled once a day, and the data for three days are shown in table 3. Wherein, the K-mode cleanliness is equal to the sum of poor quantity/(5 samples x 4 fracture openings), and the K-mode cleanliness is qualified when being below 0.1; the sum of the undesirable amounts is equal to the amount of impurities per unit area.

TABLE 3

As can be seen from Table 3, the cleanliness of the molten aluminum residue K-die was reduced from 0.08 by the original air pressurization to 0.05 by the nitrogen pressurization, which was improved by about 40%.

TABLE 4

Table 4 shows the total rejection rate of two types of hubs produced by nitrogen pressurization and air pressurization, respectively, in one month. As can be seen from Table 4, the total rejection rate of the type 216 hub prepared by nitrogen pressurization is reduced to 4.1% from 16.7% of the original air pressurization, and is reduced by 12.6%; the total rejection rate of the model 356 hub prepared by nitrogen pressurization is reduced to 11.7% from 18.0% of the original air pressurization, and is reduced by 6.3%.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, or direct or indirect applications in other related fields, which are made by the contents of the present specification, are included in the scope of the present invention.