Method and equipment for prolonging service life of die casting pressure chamber

Abstract

The invention provides a method and device for prolonging the service life of a pressure chamber and tempering molten metal. The device can be placed on a pressure chamber of a die-casting machine, the impact of molten metal is absorbed during casting, the molten metal is stably conveyed into the pressure chamber, and meanwhile, the molten metal is quenched and tempered so that the molten metal can be die-cast at the temperature lower than the alloy liquidus. The device can greatly prolong the service life of the pressure chamber and improve the mechanical property of the casting.

Description

Grant Statement

[0001] This application is based on a U.S. patent application (Patent Application No.: US 18 / 105,813) filed on February 4, 2023. Field of the Invention

[0002] The present invention belongs to the field of metal die casting, and more specifically, relates to a method and device for transporting and processing liquid metal installed on the pressure chamber of a die casting machine. Background of the Invention

[0003] Die casting, also known as high-pressure die casting, is a widely used casting method that injects liquid metal into the mold cavity under high pressure. Commonly die-cast liquid metals include aluminum alloys, magnesium alloys, and zinc alloys. Other liquid metals include copper alloys and titanium alloys. During the die-casting process, the liquid alloy is transported to the cylindrical cavity of the pressure chamber, and one end of the cavity is connected to the mold cavity. The piston in the pressure chamber pushes the molten metal in the pressure chamber into the mold cavity, causing the molten metal to solidify into a solid casting in the cavity. Die casting is widely regarded as an efficient and low-cost method for manufacturing near-net-shaped castings. Currently, 70% of aluminum castings in the United States are die-castings every year.

[0004] There are currently two die-casting methods: hot-chamber die casting and cold-chamber die casting [1]. Aluminum alloy castings are cast by the cold-chamber die-casting method [2]. During cold-chamber die casting, the pressure chamber connected to the cavity has a pouring hole at one end away from the cavity. The molten metal is poured into the pressure chamber cavity by gravity. The liquid flow impacts the inner surface of the pressure chamber below (or opposite to) the pouring hole at a relatively high flow rate and then fills the pressure chamber. Therefore, the inner surface of the pressure chamber is corroded by the corrosive aluminum alloy liquid. The pressure chamber is usually scrapped due to erosion formed under the pouring gate [3]. These pressure chambers are relatively expensive. In addition, the scrapping of the pressure chamber results in a loss of die-casting machine downtime costs of thousands of dollars per hour.

[0005] When die-casting aluminum alloy castings, the pressure chamber is made of hot-work die steel, such as H13 steel [3]. Each time the aluminum alloy is poured into the pressure chamber, a small amount of the pressure chamber steel is corroded. The hotter the pressure chamber, the faster the corrosion occurs. Since the pressure chamber does not have enough time to cool between two pourings, the corrosion rate of the pressure chamber increases with the increase in production rate and the superheat of the molten metal. Automatic pouring causes the molten metal to repeatedly impact the same position of the pressure chamber, which also increases the corrosion of the pressure chamber under the pouring hole [4 - 7]. Erosion pits gradually form on the inner surface of the pressure chamber under the pouring hole. When the depth of the erosion pits is greater than several millimeters, the pressure chamber is considered to be scrapped due to complete damage.

[0006] Methods for extending the service life of the pressure chamber include: 1) increasing the iron and manganese content in the alloy liquid, 2) using materials resistant to corrosion by molten metal to manufacture the pressure chamber, 3) reducing the flow velocity of the molten metal when it impacts the inner surface of the pressure chamber under the pouring gate, and 4) reducing the pouring temperature of the molten metal.

[0007] The design of die-casting alloys involves minimizing the erosion rate of die-casting tool steel in molten aluminum alloy to minimize production costs. To this end, common aluminum alloys contain high iron and high manganese, making iron supersaturated in the molten aluminum alloy at the pouring temperature. However, the erosion of steel is still the cause of premature damage to die-casting tools, including the shot sleeve and the core rod [4-7]. In recent years, the trend in the automotive industry has been to promote the die-casting industry to use low-iron aluminum alloys to manufacture aluminum alloy structural parts [8-9]. The erosion damage of the shot sleeve under the sprue has become a serious problem in the production of aluminum alloy structural parts. It is estimated that when die-casting these new low-iron aluminum alloys, the service life of the shot sleeve is only 10-20% of that when die-casting traditional high-iron aluminum alloys.

[0008] To improve the service life of the shot sleeve, the industry has begun to experiment with using expensive refractory metals to protect the local area under the sprue of the shot sleeve. The US patent (Patent No. 3,786,552) of Saito et al. discloses a method of using a composite bimetallic shot sleeve to solve the erosion problem of the shot sleeve under the sprue. The shot sleeve consists of an inner layer and an outer layer. The inner layer is a thin layer of refractory metal, such as molybdenum alloy or tungsten alloy. The outer layer is an iron-based alloy prepared by powder metallurgy sintering at high temperature. The US patent (Patent No. 9,114,455) of Donahue et al. discloses a shot sleeve suitable for die-casting low-iron aluminum-silicon alloy and its manufacturing method. The shot sleeve includes a corrosion-resistant bushing as the inner layer assembled into the H13 steel shot sleeve, with a very small tolerance mechanical fit between the two layers. The materials selected for the bushing include refractory alloys such as titanium alloy, tungsten alloy, molybdenum alloy, ruthenium alloy, tantalum alloy, niobium alloy, etc. The US patent application (Application No. 15,463,345) of Han et al. proposes to use refractory alloy to prepare a gooseneck bushing. Using refractory alloy can improve the service life of the shot sleeve but increases the manufacturing cost of the shot sleeve.

[0009] To minimize the flow rate of the molten metal when it impacts the inner cavity of the shot sleeve, the die-casting industry tries to keep the ladle spout as close as possible to the sprue of the shot sleeve during pouring. At the same time, the die-casting industry tries to reduce the pouring temperature of the molten metal to reduce the erosion of steel. Since the thick steel shot sleeve absorbs a large amount of heat energy from the molten metal poured into the inner cavity of the shot sleeve, the pouring temperature must be higher than the liquidus temperature of the alloy. Reducing the pouring temperature of the molten metal will cause dendrites formed in the cold shot sleeve to block the ingate of the mold, increasing casting defects [2, 10-11].

[0010] However, metal slurries containing circular solid particles with a certain solid fraction can be cast and die-cast at temperatures significantly lower than their liquidus temperatures [12-13]. The liquid metal can be processed by stirring in a container to form a slurry containing non-dendritic or circular particles

[13] . Such stirring can be achieved by high-intensity ultrasonic vibration [14-16], mechanical stirring [17-18], electromagnetic stirring

[19] , or bubble stirring

[20] . Pouring such a slurry into the cavity of the pressure chamber can significantly reduce the erosion of steel and produce die-castings with higher mechanical properties than those cast from liquid metal.

[0011] Therefore, it is necessary to develop an economical and effective method and device for reducing the impact of the molten metal on the pressure chamber during pouring to delay the formation of erosion pits in the pressure chamber under the pouring hole.

[0012] It is also necessary to develop an economical and effective method and device for generating a slurry containing circular solid particles during pouring and reducing the impact of the molten metal on the pressure chamber. Summary of the Invention

[0013] In one embodiment of the present invention, a method for reducing the impact of molten metal on the pressure chamber under the pouring hole is provided. This method includes the following steps: pouring the molten metal into a device such that when it flows out of the outlet of the device, its flow direction is significantly changed, thereby reducing the impact of the molten metal on the inner surface of the pressure chamber.

[0014] In another embodiment of the present invention, a method for reducing the impact of molten metal on the pressure chamber under the pouring hole is provided. This method includes the following steps: pouring the molten metal into a device such that when it flows out of the outlet of the device, it flows towards the side wall of the pouring hole. The molten metal then flows smoothly along the side wall of the pressure chamber, minimizing the erosion of the working surface of the pressure chamber by the molten metal.

[0015] In another embodiment of the present invention, a method for spreading the molten metal over a larger area under the pouring hole than in the conventional method is provided. This method forms large and shallow erosion pits under the pouring hole, thereby extending the service life of the pressure chamber.

[0016] In another embodiment of the present invention, a method for using a device to partially absorb the impact of the molten metal during pouring is provided. In this method, the bottom wall of the device serves as a sacrificial wall to withstand the impact and protect the pressure chamber.

[0017] In another embodiment of the present invention, a method for treating molten metal to generate a slurry containing circular solid particles with a small solid fraction therein is provided. This method causes the slurry to impact the pressure chamber at a temperature much lower than that of the molten metal. Brief Description of the Drawings

[0018] Figure 1It is a schematic side view of pouring molten metal into the shot sleeve during existing conventional cold chamber die casting.

[0019] Figure 2 It is a schematic view of an embodiment of the present invention.

[0020] Figure 3 It is a schematic view of an embodiment of the present invention.

[0021] Figure 4 It is a schematic view of the splash formed by molten metal during the initial pouring in cold chamber die casting using the prior art.

[0022] Figure 5 It is a schematic view of an embodiment of the present invention.

[0023] Figure 6 It is a schematic view of an embodiment of the present invention.

[0024] Figure 7 It is a schematic view of an embodiment of the present invention.

[0025] Figure 8 It is a schematic view of an embodiment of the present invention. Detailed implementation manners

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.

[0027] Figure 1 Shows the formation process of the erosion pit at the lower part of the pouring hole during existing conventional die casting. Molten metal 140 is poured from the ladle 130 into the shot sleeve 150 through the pouring hole 120. The molten metal 140 directly impacts the bottom inner surface of the shot sleeve 150 and then flows laterally to fill the shot sleeve 150. The flow direction of the liquid during the pouring process is as Figure 1 indicated by the arrows in. After pouring, the molten metal 140 fills the mold cavity 180 under the push of the piston 170. This mold cavity 180 is formed by the fixed die 185 and the moving die 190. After the molten metal solidifies in the mold cavity 180, it is removed from the mold cavity 180. The entire process from pouring the molten metal 140 to removing the solidified casting from the mold cavity 180 is called a cycle or an injection. A shot sleeve often fails and is damaged after being used for many cycles or injections.

[0028] The liquid metal 140 erodes a little of the pressure chamber 150 during each injection period. As the liquid metal 140 impacts the inside of the pressure chamber 150 and fills the pressure chamber 150 at the same position again and again, the erosion pit 160 gradually forms under the pouring hole 120. Since the erosion occurs everywhere on the surface where the pressure chamber 150 contacts the liquid metal 140, the formation of the erosion pit 160 under the pouring hole 120 strongly proves that the erosion rate depends on the flow pattern of the fluid during pouring and the volume of the liquid metal 140 flowing over the surface of the pressure chamber 150. The flow component perpendicular to the surface of the pressure chamber 150 causes more erosion on the surface of the pressure chamber 150 than the flow component parallel to the surface of the pressure chamber 150. Under the condition of a given amount of liquid metal 140 in each pouring cycle, increasing the contact area between the liquid metal 140 and the pressure chamber or reducing the contact time will reduce the formation of erosion pits. However, when the liquid metal 140 is poured into the pouring hole 120 from the ladle 130, it is extremely difficult to increase the contact area between the liquid metal and the pressure chamber.

[0029] Another problem with the prior art as shown in Figure 1 is the splashing of the liquid metal 140 when the molten metal head impacts the bottom surface of the pressure chamber during the initial pouring. This splashing results in the generation of inclusions and the entrapment of gas in the liquid metal 140.

[0030] The present invention is proposed based on a new idea of delaying the formation of erosion pits under the pouring hole during the die-casting process. Figure 2 Show one of the ideas. Instead of directly pouring the liquid metal 140 into the pressure chamber 150 through the pouring hole 120 as shown in Figure 1 , the liquid metal 140 can be poured into a pouring cup 110 placed above the pouring hole 120 of the pressure chamber 150 through a transfer container (such as a ladle 130, a runner, or a pipe connected to a liquid metal pump). The pouring cup 110 has a shell wall. The opening area at the top of the pouring cup 110 is larger than the area of the pouring hole 120 to facilitate pouring. The liquid metal 140 poured into the pouring cup 110 then flows down along the side wall of the vertical runner 112, impacts the bottom plate or bottom wall 116 connecting the vertical runner 112, and finally flows out from a plurality of lateral outlets or outlets 114. As shown by the arrow in Figure 2 , the vertical runner makes the downward flow smooth and reduces the impact of the liquid metal 140 on the bottom wall 116. The lateral outlets or outlets 114 minimize the flow component perpendicular to the surface of the pressure chamber 150 and increase the flow component parallel to the surface of the pressure chamber as shown by the arrow in Figure 2 . The vertical runner 112 and the bottom plate 116 have shell walls.

[0031] In a preferred embodiment, the present invention relates to a method as shown in Figure 2A method and apparatus for forming a flow channel for molten metal 140 using a vertical runner 112 connected to a pouring cup 110 are shown. The temperature of the pouring cup 110 can be controlled by conventional heating and cooling methods. The flow rate of the molten metal 140 in the flow channel is controlled by the minimum cross-section in the flow channel. This minimum cross-section is either in the vertical runner 112 or at the lateral outlet or outlets 114. The housing wall of this apparatus is constructed of solid materials. The solid materials include steel, cast iron, ceramic materials, refractory materials, or a combination of these materials, and their melting points are often higher than 900 °C. Erosion mainly occurs on the bottom wall or base plate 116 of the vertical channel 112. The entire apparatus, especially the base plate 116 of the vertical channel 112, can be made of steel, making the apparatus a sacrificial device for protecting the shot chamber. The price of such a sacrificial device is much lower than that of the shot chamber. The surfaces of the apparatus in contact with the molten metal 140 can be coated with coatings commonly used in the casting industry. One such coating is boron nitride coating. Coating the surface of the apparatus with boron nitride coating can increase the service life of the apparatus. The parts of the apparatus in contact with the molten metal, especially the local parts of the base plate 116 and the pouring cup 110, can be prepared with refractory materials. These refractory materials include ceramics or refractory metals, such as titanium alloys, tungsten alloys, molybdenum alloys, ruthenium alloys, tantalum alloys, niobium alloys, and so on. Since the base plate 116 of the vertical runner 112 can be made of thin plates, the cost of manufacturing the apparatus of the present invention is much lower than the cost of manufacturing the bushings in the U.S. patents of Saito et al. (Patent No. 3,786,552) or Donahue et al. (Patent No. 9,114,455).

[0032] In another preferred embodiment, the present invention relates to a method and apparatus for extending the service life of a shot chamber as shown Figure 2 The apparatus consists of a pouring cup 110, a vertical runner 112, a base plate 116, and a plurality of lateral outlets or outlets 114, and can be rotated or linearly displaced by physical means such as mechanical equipment or manually. After a predetermined die-casting cycle, whether it is rotation or displacement, any selected movement will cause the molten metal 140 to impact on the surface of the shot chamber 150 that has not been severely eroded in the previous die-casting cycle during the subsequent die-casting cycle. The movement of the apparatus controlled in this way can generate an erosion area much larger than the area of the erosion pit 160 under the pouring hole 120 shown Figure 1 For this reason, any movement of the apparatus will be conducive to delaying the formation of deep erosion pits that lead to the scrapping of the shot chamber. The optimization of the movement of the apparatus can greatly improve the service life of the shot chamber. To ensure stable process control, conventional heating and cooling means can be used to control the temperature of the pouring cup 110 to ensure that the initial temperature is similar during each die-casting cycle. Conventional coatings, such as boron nitride coating, can be applied to the working surface of the apparatus to increase the service life of the apparatus.

[0033] To continuously carry out die-casting cycles, Figure 2The device shown should be lowered into the pressure chamber 150 to receive the molten metal 140. After the molten metal 140 is fed into the pressure chamber 150, the device must be removed from the pressure chamber 150 so that the molten metal 140 can be pushed into the mold cavity 180 by the piston 170. A mechanical device must be used to mechanically drive the device in and out of the pressure chamber 150 to ensure continuous production of die castings one by one. This mechanical method can also be used to rotate the device so that the lateral outlet or outlet 114 guides the molten metal to different parts within the pressure chamber 150. This mechanical method can also be used to position the lateral outlet or outlet 114 at different distances from the bottom of the pressure chamber 150. By rotating or moving Figure 2 the device shown, the molten metal 140 can be distributed over an area much larger than Figure 1 the area under the pouring hole shown. This will help delay the formation of deep erosion pits on the inner surface of the pressure chamber. The formation of erosion pits is the main cause of scrapping the pressure chamber. The mechanical method for rotating or displacing the device according to the present invention can be implemented manually or mechanically, such as using a robot.

[0034] In another preferred embodiment, the present invention relates to a method and device for extending the service life of a pressure chamber as shown in Figure 2 and Figure 3 shown. The end of the vertical runner can be placed in the pouring hole 120 so that when the molten metal 140 flows out of the lateral outlet or outlet 114, it directly impacts the side wall of the pouring hole 120 and then flows along the inner wall of the pressure chamber 150. Since the side wall of the pouring hole 120 is not the working surface of the pressure chamber 150, the erosion of the side wall of the pouring hole 120 will not cause the scrapping of the pressure chamber 150. The flow of the molten metal 140 along the inner wall of the pressure chamber 150 will be smoother than Figure 1 the flow of the molten metal 150 using the prior art as shown. Since the end of the vertical runner 112 and the lateral outlet or outlet 114 are located within the pouring hole, the device of the present invention will not block the movement of the piston 170. Therefore, the device does not have to be moved into or out of the pouring hole 120 in each die casting cycle.

[0035] In another preferred embodiment, the present invention relates to a method and device for extending the service life of a pressure chamber and a method and device for conditioning the molten metal flowing into the device. As shown in Figure 3As shown, the pouring cup 110 is equipped with a stirrer 100. The stirrer 100 is driven by physical fields, including ultrasonic fields, mechanical fields, electric fields, magnetic fields, or combinations of these fields. The molten metal 140 input into the pouring cup 110 through a ladle, launder, or pipe is conditioned by the stirrer 100. The residence time of the molten metal in the pouring cup 110 can be controlled by the geometry of the vertical sprue 112 and the lateral outlet or outlets 114. The conditioning of the molten metal 140 within a controlled time is for 1) forming a large number of fine, round solid grains 118 with a solid-phase weight fraction less than 0.2 in the molten metal 140, and 2) reducing the temperature of the molten metal 140. The presence of a large number of fine, round solid grains 118 hinders dendrite formation in the shot sleeve 150. When the molten metal is driven by a piston 170 to fill the cavity 180 formed by the mold 185 and 190, the dendrites formed in the shot sleeve 150 tend to block the flow of the molten metal. To ensure stable process control, conventional heating and cooling means can be used to control the temperature of the pouring cup 110 to ensure that the initial temperature and the degree of conditioning of the molten metal are similar for each die-casting cycle.

[0036] Figure 3 The optimized operating state of the stirrer 100 in [reference] can be achieved by the controlled cooling of the molten metal 140 in the pouring cup 110. The combination of the external field emitted by the stirrer 100 and cooling will more effectively promote the formation of spherical solid grains 118 in the molten metal 140 than using only the external field alone [15 - 16]. The molten metal 140 containing spherical solid grains 118 can be die-cast at a temperature much lower than the liquidus temperature of the alloy, thereby reducing the tendency to form pits in the shot sleeve 150 and the tendency to form mold sticking on the mold 185 and 190 [1, 5, 7]. Castings made from slurries containing spherical solid grains generally have higher toughness and internal density than castings made from liquid metal

[13] .

[0037] It must be noted that Figure 3 the stirrer 100 shown is only symbolic. The stirrer 100 can be a physical device attached to the pouring cup 110 that applies a physical field to the pouring cup 110 for stirring the molten metal

[0038] The present invention also provides an example of a technique for extending the service life of a shot sleeve. The examples provided below are merely for illustrative purposes of several embodiments and should not be construed as limiting the scope of the claims, which is defined only by the specification.

[0039] Example 1.

[0040] Figure 4 Describes the turbulence when molten metal is poured into the cavity of the shot sleeve during the initial pouring process of a conventional die casting ( Figure 4 Only the part of the shot sleeve near the pouring hole is shown). There are two problems with conventional die casting: 1) splashing and 2) the molten metal impacting the local bottom surface of the shot sleeve under the pouring hole.

[0041] When the molten metal is poured into the shot sleeve under the action of gravity, the leading edge of its flow impacts the bottom surface of the shot sleeve cavity, forming splashing. This splashing increases the oxide film formed on the free surface of the molten metal. This splashing also tends to entrap the oxide film and gas by the molten metal. These oxide films and bubbles entrapped by the molten metal reduce the mechanical properties of the casting. This impact increases the local erosion of the shot sleeve under the pouring hole. The repeated impacts during die casting gradually form erosion pits locally. The size of the erosion pits is proportional to the size of the pouring hole. The depth of the erosion pits is proportional to the impact strength and the number of pourings.

[0042] Example 2.

[0043] Reducing the impact of the molten metal on the bottom surface of the shot sleeve cavity reduces the splashing of the molten metal and delays the formation of deep erosion pits under the pouring hole. Figure 5 Shows an example of the present invention for reducing the splashing of the molten metal and delaying the formation of deep erosion pits on the inner surface of the shot sleeve under the pouring hole. Figure 5 In it, α is the angle between the axis of the shot sleeve and the axis of the molten metal outlet. θ is the angle between the axis of the pouring cup and the normal of the side wall of the pouring hole. The device of the present invention includes a pouring cup, a vertical runner located at the pouring hole, a plurality of lateral outlets or outlets located at the end of the vertical runner, and a mechanical device for driving the movement of the device. The device can be rotated by any angle of α and can also be vertically moved into or out of the pouring hole. The vertical cross-sections of the pouring cup, the vertical runner, and the outlets can be any geometric shape that allows the molten metal to flow through to fill the cavity of the shot sleeve. Before each pouring, the temperature of the pouring cup is controlled at a selected temperature using conventional heating and cooling techniques. The surface of the device is coated with a conventional coating, such as boron nitride coating, which can improve the service life of the device.

[0044] Figure 5Show a pouring cup placed above the pressure chamber. A vertical sprue extends the pouring cup into the pouring hole of the pressure chamber. The vertical sprue does not extend into the cavity of the pressure chamber so that the presence of this device does not affect the movement of the piston pushing the molten metal in the pressure chamber. This device can also be moved into or out of the pouring hole manually or mechanically. The pouring hole is specially machined so that the included angle θ of its side wall is less than 90 degrees ( Figure 4 in the prior art shown, this included angle is greater than 90 degrees). When the included angle θ is less than 90 degrees, the upper opening of the pouring hole is relatively small and can be used to support the pouring cup; the lower opening of the pouring hole is relatively large and can provide space for the molten metal to flow out of the vertical runner. In this way, the molten metal flowing out of the outlet impacts the side wall of the pouring hole and then flows along the side wall of the pressure chamber to the bottom of the cavity of the pressure chamber. Such a flow, for example Figure 4 is smoother than the flow of pouring the molten metal outside the pouring hole as shown.

[0045] Using the present invention as shown in Figure 5 has many advantages over using the prior art as shown in Figure 4 . First, when the molten metal flows out of the outlet, it is a lateral flow and only impacts the side wall of the pouring hole. The impact force of such a lateral flow is lower than the Figure 4 vertical impact shown. Second, due to the use of multiple lateral outlets or outlets, the volume of the molten metal impacting a single position during each pouring is much smaller than that using the prior art, reducing the erosion at this position. Third, the molten metal only impacts the bottom plate of the vertical runner and the side wall of the pouring hole. These surfaces are not the working surfaces of the pressure chamber. The vertical runner is inexpensive and can be used as a sacrificial device to protect the pressure chamber. And the erosion on the side wall of the pouring hole will not affect the operation of the die-casting machine. Fourth, the rotating pouring cup can change the included angle α, thereby changing the impact position of the molten metal on the side wall of the pouring hole. In this way, by simply rotating the device, the side wall of the pouring hole can be eroded evenly. Finally, the molten metal flowing past the side wall of the pressure chamber causes erosion. The erosion generated in this way is much smaller than the erosion generated by the impact of the molten metal. In addition, the rotating device can make the molten metal flow past a larger side wall of the pressure chamber than using the prior art. Therefore, the erosion of the working surface of the pressure chamber can be significantly reduced.

[0046] Example 3.

[0047] Figure 6 Show that the present invention uses a stirrer to temper the molten metal in the pouring cup. In Figure 6Among them, α is the angle between the axis of the shot sleeve and the axis of the molten metal outlet. θ is the angle between the axis of the pouring cup and the normal line of the side wall of the pouring hole. The device of the present invention includes a pouring cup, a stirrer attached to the pouring cup, a vertical runner located at the pouring hole, a mechanical device for operating the movement of the device, and a plurality of lateral outlets or outlets located at the end of the vertical runner. The device can be rotated at any α angle and can also be vertically moved into or out of the pouring hole. The vertical cross-sections of the pouring cup, the vertical runner and the outlet can be of any geometric shape that allows the molten metal to flow through and fill the cavity of the shot sleeve. The stirrer is driven by a physical field. Such physical fields include high-intensity ultrasonic vibration, mechanical or acoustic vibration, alternating electromagnetic field, pulsed current, pulsed magnetic oscillation, or any combination of these fields. Conventional cooling means can be used to assist stirring to condition the molten metal. Conventional heating and cooling means can be used to control the temperature of the pouring cup before each pouring. Conventional coatings, such as boron nitride coatings, can be applied to the working surface of the device to increase the service life of the device.

[0048] Figure 6 It shows a pouring cup placed above the shot sleeve. A vertical runner extends the pouring cup into the pouring hole of the shot sleeve. The vertical runner does not extend into the cavity of the shot sleeve so that the presence of the device does not affect the movement of the piston pushing the molten metal in the shot sleeve. This device can also be driven into or out of the pouring hole manually or by a mechanical device. The pouring hole is specially processed so that the included angle θ of its side wall is less than 90 degrees ( Figure 4 In the prior art shown, this included angle is greater than 90 degrees). When the included angle θ is less than 90 degrees, the upper opening of the pouring hole is relatively small and can be used to support the pouring cup; the lower opening of the pouring hole is relatively large and can provide space for the molten metal to flow out of the vertical runner. In this way, the molten metal flowing out of the outlet impacts the side wall of the pouring hole and then flows along the side wall of the shot sleeve to the bottom of the cavity of the shot sleeve. Such a flow is more stable than, for example, Figure 4 the flow of pouring the molten metal from outside the pouring hole as shown.

[0049] The purpose of using the stirrer is to generate circular solid-phase grains in the molten metal. For this purpose, the molten metal must stay in the pouring cup under physical stirring for a certain period of time. When a certain amount of molten metal is fed into the pouring cup, the residence time of the molten metal in the pouring cup is controlled by the minimum of the cross-sectional areas of the outlet or the vertical runner. By designing the outlet or the vertical runner, it can be ensured that most of the molten metal delivered to the pouring cup stays in the pouring cup for a longer time than the critical time when flowing into the cavity of the shot sleeve. The solid-phase dendrites formed in the molten metal in the pouring cup need a certain amount of time to be broken and matured into circular particles under the stirring of the stirrer. The molten metal containing circular grains can be die-cast at a temperature much lower than the liquidus of the alloy.

[0050] The physical fields driving the stirrer include high-intensity ultrasonic vibration, mechanical or acoustic vibration, alternating electromagnetic field, pulsed current, pulsed magnetic oscillation, or any combination of these fields. The stirrer can also be a stirrer inserted into the molten metal in the pouring cup to stir the molten metal. The stirrer can also be a tube inserted into the molten metal in the pouring cup for blowing inert gas such as argon or nitrogen into the molten metal. Turning the cold inert gas in the tube into bubbles to stir and rapidly cool the molten metal can produce circular solid grains in the molten metal in the pouring cup.

[0051] Using the present invention as shown in Figure 6 has numerous advantages over using the prior art as shown in Figure 4 . First, when the molten metal flows out of the outlet, it is a lateral flow and only impacts the side wall of the pouring hole. The impact force of such a lateral flow is lower than the Figure 4 vertical impact shown. Second, due to the use of multiple lateral outlets or exits, the volume of molten metal impacting a single position during each pouring is greatly reduced compared to using the prior art, reducing the erosion at this position. Third, the molten metal only impacts the bottom plate of the vertical runner and the side wall of the pouring hole. These surfaces are not the working surfaces of the pressure chamber. The vertical runner is inexpensive and can be used as a sacrificial device to protect the pressure chamber. And the erosion on the side wall of the pouring hole does not affect the operation of the die-casting machine. Fourth, the rotating pouring cup can change the angle α, thereby changing the impact position of the molten metal on the side wall of the pouring hole. In this way, by simply rotating the device, the side wall of the pouring hole can be evenly eroded. Fifth, the molten metal flowing past the side wall of the pressure chamber causes erosion. The erosion generated in this way is much smaller than the erosion generated by the impact of the molten metal. In addition, the rotating device can make the molten metal flow past a larger side wall of the pressure chamber than using the prior art. Therefore, the erosion of the working surface of the pressure chamber can be significantly reduced. Finally, combining the use of a stirrer and cooling the pouring cup using conventional techniques can reduce the temperature of the molten metal entering the pressure chamber. Reducing the pouring temperature of the molten metal or metal slurry can significantly reduce the erosion of the pressure chamber and the die-casting tool. Figure 6 Another advantage of the present invention as shown in

[0052] is that semi-solid slurry suitable for die-casting can be prepared in the pouring cup. Components made of semi-solid materials have better strength and toughness than components made of non-semi-solid materials.

[0052] Example 4.

[0053] Figure 7 Shows an example of the present invention being used to reduce the splashing of molten metal and delay the formation of deep erosion pits on the inner surface of the pressure chamber under the pouring hole. Figure 7 In Figure 7The device of the present invention shown includes a pouring cup, a vertical runner located at the pouring hole with its end about H away from the bottom surface of the cavity of the pressure chamber, and a plurality of lateral outlets or outlets located at the end of the vertical runner. Before each pouring, the value of H can be any value from zero to the diameter of the cavity of the pressure chamber. The device can be rotated by any angle α, and can also be vertically moved into or out of the pouring hole. The vertical cross-sections of the pouring cup, the vertical runner and the outlets can be of any geometric shape that allows the molten metal to flow through and fill the cavity of the pressure chamber. Before each pouring, the temperature of the pouring cup is controlled at a selected temperature by conventional heating and cooling techniques. The surface of the device is coated with a conventional coating, such as boron nitride coating, which can improve the service life of the device.

[0054] Figure 7 Show a pouring cup placed above the pressure chamber. A vertical runner extends the pouring cup into the cavity of the pressure chamber. The pouring hole is specially machined so that the included angle θ of its side wall is less than 90 degrees ( Figure 4 In the prior art shown, this included angle is greater than 90 degrees). When the included angle θ is less than 90 degrees, the upper opening of the pouring hole is relatively small and can be used to support the pouring cup. The molten metal flowing out of the outlet enters the die-casting cavity near the bottom of the cavity of the pressure chamber. Such a flow is, for example, Figure 4 more stable than the flow of pouring the molten metal outside the pouring hole as shown.

[0055] Using the present invention as shown in Figure 7 has many advantages over using the prior art as shown in Figure 4 First, when the molten metal flows out of the outlet, it is a lateral flow and only impacts the side wall of the pouring hole. The impact force of such a lateral flow is lower than the Figure 4 vertical impact shown. Second, due to the use of multiple lateral outlets or outlets, the volume of the molten metal impacting a single position during each pouring is much smaller than that using the prior art, reducing the erosion at this position. Third, the molten metal only impacts the bottom plate of the vertical runner. The vertical runner is inexpensive and can be used as a sacrificial device to protect the pressure chamber. When using the present invention as shown in Figure 7 the impact of the molten metal on the pressure chamber is much smaller than when using the prior art as shown in Figure 4 Finally, the rotating pouring cup device can change the included angle α, thus changing the impact position of the molten metal in the pressure chamber. Changing H can also change the impact position of the molten metal in the pressure chamber. Conservatively assume that the number of pourings required to form a deep erosion pit when using the present invention and when using the prior art is both N. Changing α or H to make the molten metal impact another new position allows another N pourings before forming a new deep erosion pit. In this way, the service life of the pressure chamber when using the present invention can be increased many times compared to the service life of the pressure chamber when using the prior art as shown in the figure.

[0056] Example 5.

[0057] Figure 8 Show that the present invention uses a stirrer to temper the molten metal in the pouring cup. InFigure 8 In this case, α is the angle between the axis of the shot sleeve and the axis of the molten metal outlet. θ is the angle between the axis of the pouring cup and the normal of the side wall of the pouring hole. The device of the present invention includes a pouring cup, a stirrer attached to the pouring cup, a vertical runner located at the pouring hole with its end about H away from the bottom surface of the shot sleeve cavity, and a plurality of outlets located at the end of the vertical runner. Before each pouring, the value of H can be any value from zero to the diameter of the shot sleeve cavity. The device can be rotated by any angle α and can also be vertically moved into or out of the pouring hole. The vertical cross-sections of the pouring cup, the vertical runner and the outlets can be of any geometric shape that allows the molten metal to flow through and fill the shot sleeve cavity. The stirrer is driven by a physical field. Such physical fields include high-intensity ultrasonic vibration, mechanical or acoustic vibration, alternating electromagnetic field, pulsed current, pulsed magnetic oscillation, or any combination of these fields. Conventional cooling means can be used to assist stirring to condition the molten metal. Conventional heating and cooling means can be used to control the temperature of the pouring cup before each pouring.

[0058] Figure 8 Show a pouring cup placed above the shot sleeve. A vertical runner extends the pouring cup into the shot sleeve cavity. The pouring hole is specially machined so that the angle θ of its side wall is less than 90 degrees ( Figure 4 In the prior art shown, this angle is greater than 90 degrees). When the angle θ is less than 90 degrees, the upper opening of the pouring hole is relatively small and can be used to support the pouring cup. The molten metal flowing out from the side outlet or outlets enters the die-casting cavity near the bottom of the shot sleeve cavity. Such a flow is Figure 4 more stable than the flow of pouring the molten metal outside the pouring hole as shown.

[0059] The purpose of using the stirrer is to generate circular solid-phase grains in the molten metal. For this purpose, the molten metal must stay in the pouring cup under physical stirring for a certain period of time. When a certain amount of molten metal is fed into the pouring cup, the residence time of the molten metal in the pouring cup is controlled by the cross-sectional area of the outlet or the vertical runner, whichever is the smallest. By designing the outlet or the vertical runner, it can be ensured that most of the molten metal transferred to the pouring cup stays in the pouring cup for a longer time than the critical time when flowing into the shot sleeve cavity. The solid-phase dendrites formed in the molten metal in the pouring cup need a certain time to be broken and matured into circular particles under the stirring of the stirrer. The molten metal containing circular grains can be die-cast at a temperature much lower than the liquidus of the alloy.

[0060] The physical fields driving the stirrer include high-intensity ultrasonic vibration, mechanical or acoustic vibration, alternating electromagnetic field, pulsed current, pulsed magnetic oscillation, or any combination of these fields. The stirrer can also be a stirrer inserted into the molten metal in the pouring cup to stir the molten metal. The stirrer can also be a tube inserted into the molten metal in the pouring cup for blowing inert gas such as argon or nitrogen into the molten metal. Turning the cold inert gas in the tube into bubbles to stir and rapidly cool the molten metal can generate circular solid grains in the molten metal in the pouring cup.

[0061] Using the present invention as shown in Figure 8 has numerous advantages over using the prior art as shown in Figure 4 . First, when the molten metal flows out of the outlet, it is a lateral flow. The impact force of such a lateral flow is lower than the Figure 4 vertical impact shown in Figure 8 . Second, since multiple outlets are used, the volume of the molten metal impacting a single position during each pouring is much smaller than that of using the prior art, reducing the erosion at this position. Third, the molten metal only impacts the bottom plate of the vertical runner. The vertical runner is inexpensive and can be used as a sacrificial device to protect the pressure chamber. When using the present invention as shown in Figure 4 , the impact of the molten metal on the pressure chamber is much smaller than that when using the prior art as shown in Figure 8 . Fourth, the rotating pouring cup device can change the included angle α, thereby changing the impact position of the molten metal in the pressure chamber. Changing H can also change the impact position of the molten metal in the pressure chamber. Assuming conservatively that the number of pourings required to form a deep erosion pit when using the present invention and the number of pourings required when using the prior art are both N, changing α or H to make the molten metal impact another new position allows for N more pourings before a new deep erosion pit is formed. In this way, the service life of the pressure chamber when using the present invention can be increased many times compared to the service life of the pressure chamber when using the prior art shown in the figure. Finally, combining the use of a stirrer and cooling the pouring cup using conventional techniques can reduce the temperature of the molten metal entering the pressure chamber. Reducing the pouring temperature of the molten metal or metal slurry can significantly reduce the erosion of the pressure chamber and the die-casting tool.

[0062] Although the present invention has been described in connection with specific embodiments, it should be understood that the method of the present invention can be further modified. This patent application is intended to cover any variations, uses, or modifications of the present invention. The principles of the present invention, including departures from the present disclosure within the scope of the art to which the present invention pertains and within the scope of known or customary practices, as well as the basic features that may be applicable to the present invention, are as follows within the scope of the appended claims. References 1.Q.Han, C.Vian, and J.Good, “Application of Refractory Metals to Facilitate Hot Changer Aluminum Die Casting,” International Journal of Metalcasting, 15(2021)411 - 416. 2. Q. Han, and J. Zhang, “Fluidity of Alloys under High-Pressure Die Casting Conditions: Flow-Choking Mechanisms,” Metallurgical and Materials Transactions B, 51(4)(2020) 1795-1804. 3. A. B. William, and S. Midson, Shot System Components User’s Guide, NADCA Publication: 525, NADCA 2016. 4. J. Song, T. Den Ouden, and Q. Han, “Mechanisms of Soldering Formation on Coated Core Pins”, Metalurgical and Materials Transactions A, 43A(2012) 415-421. 5. Q. Han, and S. Viswanathan, “Analysis of the Mechanism of Die Soldering in Aluminum Die Casting”, Metallurgical and Materials Transaction A, 34A, (2003) 139-146. 6. Y. Chu, P. Cheng, and R. Shivpuri “A Study of Erosive Wear in Die Casting Dies: Surface Treatments and Coatings,” NADCA Transactions 1993, pp. 361-371. 7. Q. Han, “Mechanism of Die Soldering during Aluminum Die Casting,” China Foundry, 12(2)(2015) 136-143. 8. R. Donahue, “Avoiding Washout in Shot Sleeve When Used with Low Iron, Structural Aluminum Die Casting Alloys”, NADCA Transactions 2013, T13-051. 9. R. Donahue, S. Knickel, P. Schneider, M. Witzel, J. Melius, and A. Monroe, “Performance of Shot Sleeve with Different Refractory Metal Liners in Casting of Structural Aluminum Die Casting Alloy 362”, NADCA Transactions 2014, T14-011. 10. Q. Han, “A Model Correlating Fluidity to Alloy Variables in HyPoeutectic Alloys,” Acta Materialia, 228(2022)117587. 11. Q·Han, H. Xu, “Fluidity of Alloys under High Pressure Die Casting Conditions,” Scripta Materialia, 53(2011)7-10. 12. Q. Han, S. Viswanathan, “The Use of Thermodynamic Simulation for the Selection of HyPoeutectic Aluminum-Silicon Alloys for Semi-Solid Metal Processing”, Materials Science and Engineering A, 364(2004)48-54. 13. M.C. Flemings, “Behavior of Metal Alloys in the Semisolid State,” Metallurgical Transaction B, 22B(1991)269-293. 14.X. Jian, H. Xu, T. T. Meek, Q. Han, “Effect of Ultrasound on Solidification of Aluminum A356 Alloy”, Materials Letters, 59(2005)190 - 193. 15.C. Vian, C. Kibbey, C. Kurtz, Q. Han, “Cooling - Assisted Ultrasonic Grain Refining of Aluminum E380 Die Cast Alloy”, International Journal of Metalcasting, 16(2)(2022)842 - 852. 16.Q. Han, “Ultrasonic Processing of Materials”, Metallurgical and Materials Transactions B, 46B(2015)1603 - 1614. 17.R. Martinez, A. Figueredo, J. A. Yurko, M. C. Flemings, “Efficient Formation of Structures Suitable for Semisolid Forming”, NADCA Transactions 2001, 47 - 54. 18.M. C. Flemings, R. G. Riek, K. P. Young, “Rheocasting”, Materials Science and Engineering, 25(1976)103 - 107. 19.D. H. Kirkwood, “Semisolid Metal Processing”, International Materials Reviews, 39(1994)173 - 189. 20.J. Wannasin, R. A. Martinez, M. C. Flemings, “Grain Refinement of an Aluminum Alloy by Introducing Gas Bubbles during Solidification”, Scripta Materialia, 55(2006)115 - 118。

Claims

1. A method for receiving molten metal from a container, conditioning the molten metal, and delivering the molten metal through a pouring hole on a shot chamber of a die casting machine into the shot chamber to manufacture a metal collar component, comprising the following steps: S1) Maintaining the molten metal at a selected temperature; S2) Preparing a device, which comprises a pouring cup for receiving molten metal, a vertical runner for guiding the molten metal to flow downward from the pouring cup, a buffer plate for absorbing the impact of the molten metal during pouring and changing the flow direction of the molten metal, and a plurality of lateral outlets provided at the end of the vertical runner for the molten metal to flow out of the vertical runner and flow along the inner wall of the shot chamber, wherein the flow rate of the molten metal in the device is controlled by the size of the vertical runner or the size of the plurality of lateral outlets; S3) Placing the device above the pouring hole of the shot chamber and controlling the pouring cup at the selected temperature by a cooling or heating method; S4) Preparing mechanical equipment for positioning and rotating the device so that the plurality of lateral outlets are located at selected positions and in selected directions in the shot chamber cavity or the pouring hole and / or coordinating the movement of the piston of the device and the die casting machine, including lowering the lateral outlets of the device into the shot chamber cavity before receiving molten metal and immediately lifting the lateral outlets of the device out of the shot chamber after completion of pouring; S5) Pouring the molten metal into the device at the selected position and orientation so that the molten metal flows into the shot chamber cavity; The molten metal is conditioned in the pouring cup at a given temperature and then flows into the shot chamber along the inner wall of the shot chamber, thereby reducing the erosion of the shot chamber under the pouring hole.

2. The method according to claim 1, characterized in that, The device claimed in the claims has a shell wall made of a material with a melting point higher than 900 °C, and these materials include steel, cast iron, refractory metal alloys or ceramic materials.

3. The method according to claim 1, characterized in that, The molten metal in the pouring cup is stirred by a stirrer for a certain period of time, and the time is controlled by the size of the vertical runner or the plurality of lateral outlets to obtain a certain fraction of non-dendritic round solid phase grains.

4. The method according to claim 3, wherein The stirrer is combined with the pouring cup and driven by a physical field or a mechanical field, including high-intensity ultrasonic vibration, alternating electric field or magnetic field, mechanical vibration, pulsed electric field or magnetic field, or a combination of several fields.

5. A device for receiving molten metal from a container, conditioning the molten metal, and delivering the molten metal through a pouring hole on a shot chamber of a die casting machine into the shot chamber to manufacture a metal collar component, comprising: A pouring cup located above the pouring hole of the shot chamber for receiving molten metal from the container and controlling the pouring cup at the selected temperature by a cooling or heating method; A buffer plate for absorbing the impact of the molten metal during pouring and changing the flow direction of the molten metal; A vertical runner for guiding the molten metal to flow downward from the pouring cup, with its top connected to the pouring cup and its end connected to the buffer plate; A plurality of lateral outlets located at the end of the vertical runner for the molten metal to flow laterally out of the vertical runner under the control of the flow rate of the molten metal by the size of the vertical runner or the plurality of lateral outlets; A mechanical equipment for positioning and rotating the plurality of lateral outlets to be placed in the pouring port of the shot chamber or the cavity of the shot chamber and / or coordinating the movement of the piston of the device and the die casting machine, including lowering the lateral outlets of the device into the shot chamber cavity before receiving molten metal and immediately lifting the lateral outlets of the device out of the shot chamber after completion of pouring. The molten metal is conditioned in a pouring cup at a given temperature, and the buffer plate absorbs the impact of the molten metal during pouring.

6. The device according to claim 5, wherein, The device claimed in the right has a shell wall made of materials with a melting point higher than 900 °C, including steel, cast iron, refractory metal alloys or ceramic materials.

7. The device according to claim 5, characterized in that The surface of the device in contact with the molten metal is coated with a layer of coating including boron nitride coating.

8. The device according to claim 5, characterized in that, The upper opening of the pouring hole in the pressure chamber is smaller than its lower opening.

9. The device according to claim 5, characterized in that, The molten metal in the pouring cup is stirred by a stirrer for a certain time, and the time is controlled by the size of the vertical runner or many lateral outlets to obtain a certain fraction of non-dendritic round solid phase grains.

10. The device according to claim 9, characterized in that, The stirrer is combined with the pouring cup and driven by a physical field or a mechanical field, including high-intensity ultrasonic vibration, alternating electric field or magnetic field, mechanical vibration, pulsed electric field or magnetic field, or a combination of several fields.

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