Patent Application
20210310101
The present disclosure relates to a technology in the field of alloy manufacturing, and in particular to a method and an apparatus for synchronously melting and preparing alloy.
Generally, aluminum alloys contain a variety of alloying elements, and corresponding alloy components need to be added to the raw molten aluminum during the preparation process. The alloy components can be added in the form of pure metals (such as Mg, Zn, Cu and Si, among others) or master alloys (such as Al—Fe, Al—Ni, Al—Zr and Al—Sr, among others). In actual production, all the alloys are often added in the holding furnace, melted and left to stand before the casting process. The existing major problem is that due to the different densities of different types of added elements, adding alloying elements is likely to cause specific gravity segregation in a large holding furnace. For instance, Cu and Zn, which are elements with higher density, concentrate at the lower part of the holding furnace, while elements with lower density such as Mg and Li concentrate at the upper part of the holding furnace. Strong stirring is required to keep the melt uniform. Notwithstanding, it is still highly likely that the substandard chemical composition or uneven composition takes place, resulting in the alloy after melting and preparing with unqualified quality.
In light of the current problems that specific gravity segregation and uneven distribution of elements is highly likely to occur in the alloy after melting and preparing in the large holding furnace, the present disclosure proposes a method and an apparatus for synchronously melting and preparing alloy, which is able to avoid specific gravity segregation caused by the long-term standing of melt, and thus realize the preparation of gradient materials while significantly improving the alloying efficiency.
The present disclosure is realized through the following technical solutions.
The present disclosure relates to a method for synchronously melting and preparing alloy. The alloy to be added is made into wire in advance, and the wire feeding speed required for the preparation of the alloy with a specific composition is calculated according to the flow rate of raw molten aluminum in the launder. In the continuous ingot casting process, the wire is continuously and stably fed into the launder of the raw molten aluminum at the wire feeding speed, thereby real-time forming the alloy preparation.
The wire is alloy wire or pure metal wire.
As for the wire feeding speed, the wire feeding speed Vwire is determined according to the flow rate V1 of the molten aluminum in the launder, i.e., Vwire=kV1, where k is a fixed constant.
The real-time forming refers to: in order to make the wire quickly be dissolved into the raw molten aluminum, the method of high-frequency instantaneous heating is applied to melt the alloy with high melting point while the wire is being fed, so that the melted alloy can be guided and diverted into the molten aluminum to enable rapid mixing to realize the required concentration of the alloying elements.
The alloy with high melting point refers to an alloy with a melting point higher than that of pure aluminum, such as Al—Mn, Al—Fe, Al—Cr and the like.
The present disclosure relates to an apparatus for realizing the above method, comprising: a launder for molten aluminum and at least one guiding tube having a wire feeding device disposed in the launder for molten aluminum, wherein the wire feeding device is disposed at the inlet end of the guiding tube and is connected with a movement control device, so as to adjust the feeding speed of the wire, and a temperature control device is disposed at the outlet end of the guiding tube, so as to adjust the temperature of the wire when the wire enters the launder for molten aluminum.
The guiding tube is a hollow curved tube, with the wire arranged inside, and the bending direction of the guiding tube is the same as the flow direction of the molten aluminum in the launder for molten aluminum.
The depth of the guiding tube inside the launder for molten aluminum is determined according to the depth of the launder, and is preferably ½˜⅔ of the depth of the launder.
The movement control device comprises: a movement controller module, and a driver module, an execution module and a feedback sensor module, which are connected to the movement controller module, respectively, wherein the driver module converts the control command from the movement controller into a current or voltage to control electrical level, and the feedback sensor module outputs the position of the execution module to the movement controller.
The temperature control device comprises: an electric temperature transmitter module, an electronic potentiometer module, an electric controller module and a silicon controlled rectifier voltage regulator module, wherein the temperature change is measured by a thermocouple, and converted into 0-10 mA of DC current signal, which is standard signal of model meter, through the electric temperature transmitter; then the DC current signal is transmitted to the electronic potentiometer for recording, and at the same time transmitted to the electric controller, wherein the controller outputs a 0˜10 mA of DC current signal and transmits the same to the silicon controlled rectifier voltage regulator after a calculation, which is according to the magnitude and direction of the bias and pursuant to the predetermined control rule. Then AC voltage is adjusted to realize automatic control.
where 1 wire feeding device, 2 wire, 3 ceramic guiding tube, 4 high frequency induction coil, 5 launder, 6 movement control device, 7 temperature control device, 8 molten drop, 9 raw molten aluminum.
As indicated in
The guiding tubes 3 are immersed in the raw molten aluminum 9.
During the alloying process, the raw molten aluminum flows stably in the launder at the speed of vL (<3 m/s); the alloy wire required to be added, which has a diameter of d1, d2, d3 (<30 mm), respectively, is fed into the ceramic guiding tubes through the wire feeding devices at the speed of v1, v2, v3 (<5 m/s), respectively. The wire feeding speed is correlated with the concentration level of this element in the ingot to be prepared, and is controlled by the movement control device. Driven by the wire feeding device, the alloy wire moves downward in the ceramic guiding tube. The high frequency induction coils are controlled by the temperature control device to heat the corresponding local areas up to the temperatures of T1, T2, T3 (>melting point of the alloy wire), respectively, such that the alloy wire is rapidly melted to form molten drops, and the formed molten drops continue to enter into the raw molten aluminum along the ceramic guiding tubes, thereby achieving the alloying and uniform distribution along with the movement of the raw molten aluminum.
The guiding tube 3 having the wire feeding device 1 may be determined according to the number of elements to be added, and multiple sets can work simultaneously to achieve the online alloying of multiple alloying elements at the same time. After the alloying is completed, the alloy melt can enter the casting apparatus for casting to form an ingot.
In this embodiment, the Al—Mg—Si alloy was prepared by the above-mentioned apparatus: the raw molten aluminum was controlled to flow stably in the launder at the speed of 0.22 m/s, and the pure magnesium wire with a diameter of 1.8 mm and the Al-20Si alloy wire with a diameter of 3.0 mm were fed into the ceramic guiding tubes by the wire feeding devices at speeds of 1.8 cm/s and 2.6 cm/s, respectively. Driven by the wire feeding devices, the alloy wire moved downward in the ceramic guiding tubes. The high frequency induction coils were controlled by the temperature control device to heat the corresponding local areas up to the temperatures of 700° C. and 720° C., respectively, such that the alloy wire was rapidly melted to form molten drops, and the formed molten drops continued to enter into the raw molten aluminum along the ceramic guiding tubes, thereby achieving the alloying and uniform distribution along with the movement of the raw molten aluminum. The alloy melt entered the casting apparatus for casting to form Al—Mg—Si alloy ingot.
In this embodiment, the Al—Zn—Mg—Cu alloy with composition gradient was prepared by the above-mentioned apparatus: the raw molten aluminum was controlled to flow stably in the launder at the speed of 0.28 m/s, and pure zinc wire with a diameter of 4.0mm, pure magnesium wire with a diameter of 1.8mm, and an Al-20 Cu alloy wire with a diameter of 1.5 mm were fed into the ceramic guiding tubes by the wire feeding devices at speeds of 2.2 cm/s, 2.5 cm/s and 1.8 mm/s, respectively. Driven by the wire feeding devices, the alloy wire moved downward in the ceramic guiding tubes. The high frequency induction coils were controlled by the temperature control device to heat the corresponding local areas up to the temperatures of 460° C., 700° C. and 740° C., respectively, such that the alloy wire was rapidly melted to form molten drops, and the formed molten drops continued to enter into the raw molten aluminum along the ceramic guiding tubes, thereby achieving the alloying and uniform distribution along with the movement of the raw molten aluminum. The alloy melt entered the casting apparatus for casting to form Al—Zn—Mg—Cu alloy ingot. During the preparation process, the wire feeding speed of the pure zinc wire was uniformly reduced (wherein the wire feeding speed is reduced by 0.1 cm/s every 5 minutes), and the wire feeding speed of the pure zinc wire was reduced to 1.0 cm/s after the casting was completed. Tests indicate that the zinc content of the prepared alloy was 6.5% at the head of the ingot and 3% at the tail of the ingot, with a uniform gradient change from the head to the tail of the ingot.
The specific embodiments above may be partially adjusted by those skilled in the art in different ways without departing from the principle and purpose of the present disclosure. The protection scope of the present disclosure should be subject to the claims and is not limited by the specific embodiments above. All implementation solutions within the scope thereof are bound by the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201910513397.7 | Jun 2019 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2019/112402 | 10/22/2019 | WO | 00 |
