CN106493340A - A kind of novel magnesium alloy casting turns liquid system and device - Google Patents

Abstract

The invention specifically relates to a novel magnesium alloy casting and rolling fluid transfer system device, which belongs to the technical field of magnesium alloy plate and strip casting and rolling equipment. Aiming at the existence of magnesium alloy casting and rolling liquid transfer system currently in use: unstable liquid level in the front box, inaccurate system temperature and flow control, difficult maintenance, etc., which can easily cause uneven solidification, segregation, and serious edge cracking of cast-rolled strips and material loss. Invented the system device, including: a servo liquid transfer pump with a tapered lower end cavity, an adaptive thermal expansion liquid transfer pipe, a combined front box and a multifunctional top cover, a precise flow control blocking device, and closed-loop control of liquid level and temperature system etc. The invention provides a safe, economical and easy-to-maintain magnesium alloy cast-roll liquid transfer system device. The system is conveniently connected with a static furnace and an inclined cast-roll machine, and realizes precise control of temperature and flow in the system. It provides guarantee for improving the material quality, yield and cost reduction of cast-rolled magnesium alloy strips, and has broad application prospects.

Description

A new type of magnesium alloy casting and rolling liquid transfer system device

technical field

The invention belongs to the technical field of magnesium alloy strip casting and rolling mill equipment, and in particular relates to a novel magnesium alloy casting and rolling fluid transfer system device.

Background technique

Magnesium alloy casting and rolling is the organic unity of molten alloy solidification and rolling deformation, that is, the alloy liquid undergoes pressure processing and plastic deformation while crystallization and solidification, and completes the entire process from liquid metal to solid strip in a short period of time. It is a near-net forming, short-process magnesium alloy strip production technology. The traditional hot-rolling process is canceled, the production process is simplified, the production cycle is shortened, a large amount of energy is saved, equipment investment is reduced, and production costs are reduced. At the same time, the cast-rolled thin strip can obtain ideal microstructure and good mechanical properties, which has huge Technical and economic development potential.

Germany's Thyssen Corporation, Australia's CSIRO and other units took the lead in developing magnesium alloy twin-roll strip casting equipment. China's Luoyang Copper Processing Group Co., Ltd. and Shanxi Yinguanghua Magnesium Co., Ltd. have successively established production lines for magnesium alloy cast-rolled sheets with a width of 600 mm. However, these production lines have the following outstanding problems to varying degrees: ①The molten pool or the liquid level in the front tank is unstable, causing oxidation, combustion, and even explosion; ②Inaccurate temperature and casting flow control, resulting in uneven solidification of cast-rolled strips and easy formation of segregation quality defects such as serious edge cracks; ③ when the casting is completed or a sudden failure occurs, the molten magnesium in the casting system cannot be recovered, causing great safety hazards and material waste; ④ the front box is an integral structure, which is not easy to clean, and It is inconvenient to repair etc. when its thermal insulation heating device breaks down.

Therefore, the present invention develops a novel magnesium alloy casting and rolling liquid transfer system device for the above-mentioned bottleneck problem in the magnesium alloy casting and rolling process, which provides technical support for the magnesium alloy casting and rolling thin strip feeding link. The device has broad application prospects and great economic and social benefits.

Contents of the invention

The object of the present invention is to provide a safe, economical and easy-to-maintain magnesium alloy cast-roll liquid transfer system device, which provides guarantees for improving the material quality, yield and cost reduction of cast-roll magnesium alloy strips. The liquid transfer system device can be conveniently connected and maintained with the static furnace and the inclined casting and rolling mill under the premise of ensuring safety, and realizes precise control of the liquid level of the static furnace, the liquid level of the head box, the temperature and the flow rate in the system during the liquid transfer process; When the rolling line fails, the magnesium liquid in the front box and liquid transfer system will flow back to the static furnace without loss; the front box liner and shell can be separated, which is convenient for cleaning and maintenance.

To achieve the above object, the present invention takes the following design scheme:

A new type of magnesium alloy casting and rolling liquid transfer system device, as shown in Figure 1, includes: a servo liquid transfer pump with a tapered lower end cavity; an adaptive thermal expansion liquid transfer pipe; Tank; with insulation layer, protective gas inlet and outlet holes, liquid level detection device, temperature detection device; pneumatic flow precise control blocking device; and liquid level and temperature closed-loop control system, etc. Concrete invention process is as follows.

The servo liquid transfer pump with a tapered cavity at the lower end is characterized in that: after the casting is completed or when the unit breaks down, the molten magnesium in the system can flow back to the static furnace and avoid feeding the cavity at the lower end of the liquid transfer pump. There is no residual condensation of liquid alloy, and the whole system device is connected to the static furnace and casting nozzle at an inclination angle of 15°, and the bottom of the feeding cavity of the transfer pump is designed as a 160° conical cavity, as shown in Figure 2. The invention overcomes the defect that when the feeding cavity at the lower end of the liquid transfer pump is flat-bottomed, the residual liquid alloy is likely to condense and accumulate, and it is difficult to clean up to cause blockage and fail to work.

The adaptive thermal expansion liquid transfer pipe is characterized in that during the liquid transfer process of magnesium alloy casting and rolling, the temperature in the entire liquid transfer system needs to be kept at 680-700°C, and a certain amount of thermal expansion will inevitably occur in the system components, while the liquid transfer The system is hard-connected with the smelting furnace and the casting and rolling mill, which cannot absorb the thermal expansion, which will cause deformation of the system components, especially the outer surface of the liquid transfer pipe is equipped with insulation devices and insulation layers, and is easy to deform, and there is a potential safety of magnesium liquid leakage Hidden danger. In this regard, the present invention designs an adaptive thermal expansion liquid transfer pipeline, that is, a corrugated compensator is added in the middle of the liquid transfer pipe to absorb the thermal expansion in the entire system, as shown in FIG. 3 .

The combined front box is characterized in that: the front box is composed of an inner tank and an outer shell, the inner tank is fixedly connected with the liquid transfer pipe and the feeding nozzle as a whole, and the inner surface has a SiC anti-oxidation and anti-corrosion coating, and the outer shell is Two halves, made of high temperature resistant stainless steel; the fixed end of the feeding nozzle and the inner tank is round, and the connection end with the casting nozzle is square; there is a heating device and an insulation layer between the inner tank and the outer shell, as shown in Figure 4 Show. The combined front box design is convenient for the disassembly and assembly of the whole system, the maintenance of the heating device and the cleaning of the inner tank.

The precise control system for the liquid level of the front box and the system temperature is characterized in that the height difference between the liquid level of the front box and the nozzle, and the temperature difference when the alloy liquid is transported from the static furnace to the nozzle are the factors that determine the quality of the cast-rolled plate. key factor. The invention adopts the linkage control of the servo liquid transfer pump, the electric caulking device arranged in the front box, and the liquid level detector installed on the top cover of the front box to realize the precise control of the flow rate and the control accuracy of the liquid level in the front box. ±1mm; at the same time, the present invention uses resistance heating to heat the liquid transfer pipe and the front box, and performs linkage detection and closed-loop control of the temperature of the static furnace, liquid transfer pipe, front box and heating components, so that the magnesium liquid is transported from the static furnace to the front box , The temperature change of the magnesium liquid does not exceed 10°C.

Through the invention process, a safe and economical new magnesium alloy cast-roll liquid transfer system device is invented, which can achieve the purpose of improving the material quality, yield and cost reduction of cast-roll magnesium alloy strips.

Advantages and positive effects of the present invention.

1. The present invention can precisely control the head tank liquid level and system temperature, effectively control quality defects such as uneven solidification, segregation and serious edge cracks of the cast-rolled strip, and improve the yield and performance of the plate, thereby greatly reducing production costs and improving production efficiency.

2. The device of the present invention can realize the non-loss return flow of magnesium liquid in the system to the static furnace even if other devices of the casting and rolling line fail, ensuring safety and no loss.

3. The device of the present invention is safe in use, convenient in maintenance, economical and reliable, and is an advanced liquid transfer device in the middle of a magnesium alloy casting and rolling mill.

Description of drawings

Fig. 1 is a schematic diagram of the device structure of the magnesium alloy casting and rolling fluid transfer system of the present invention.

Fig. 2 is a schematic structural diagram of a servo pump with a tapered lower end cavity in the system device of the present invention.

Fig. 3 is a schematic structural diagram of the self-adaptive thermal expansion liquid transfer pipe in the system device of the present invention.

Fig. 4 is the combined front box in the system device of the present invention.

detailed description

Referring to Fig. 1, at first, open the switch of the protective gas input channel 8 installed at the top cover 6 of the front box, and simultaneously open the switch of the liquid transfer pipe 2 and the heating device 4 and 11 of the front box 5, and the transmission of the protective gas will be passed. Pipeline and headbox are preheated to 680~700°C, casting nozzles and casting rolls are preheated to the set target temperature. After the preheating of the front box system is completed, the outlet plug device 10 in the front box is kept in a sealed state, and under the protective gas, the servo pump 1 with the lower end of the tapered cavity is used to transfer the refined, ventilated slag blowing, The magnesium alloy liquid after standing still is transported to the front box 5 through the liquid transfer pipeline 2, and the temperature detector 7 in the front box in the temperature linkage control described in the above-mentioned invention process reads the real-time temperature, and the temperature of the magnesium alloy liquid is displayed as set. After setting the casting temperature, keep the constant temperature; after the liquid level detector 9 in the current tank shows that the magnesium alloy liquid has reached the predetermined liquid level, open the plug device 10, and the magnesium alloy liquid passes through the launder directly connected with the front tank liner. Passage 12, nozzle, cast-rolling machine realize stable casting and rolling. During the stable casting and rolling process, through the linkage control of the servo liquid transfer pump 1 and the caulking device 10, the liquid level of the front tank is kept at a constant height, ensuring that the liquid enters the casting and rolling machine at a uniform flow rate. Mixed gas (SF ₆ + N ₂ ) is used for the gas protection of the process environment during the entire smelting and conveying and liquid magnesium alloy casting and rolling process, and the flow control of the system must match the speed of the casting and rolling unit.

Claims (5)

1. A new type of magnesium alloy casting and rolling liquid transfer system device, including: a servo liquid transfer pump with a tapered hole at the lower end, an adaptive thermal expansion liquid transfer pipe, a combined front box and a multifunctional top cover, the front box liquid level and the system Precise temperature control system. 2. The servo liquid transfer pump with a tapered lower end cavity according to claim 1, characterized in that: the bottom of the feeding cavity of the servo liquid transfer pump is designed as a 160° conical cavity. 3. The self-adaptive thermal expansion liquid transfer pipe according to claim 1, characterized in that: a corrugated compensator is installed in the middle of the liquid transfer pipe to eliminate the thermal expansion in the whole system. 4. According to the combined front box and multifunctional top cover described in claim 1, it is characterized in that: the front box is composed of an inner tank and an outer shell, the inner tank is fixedly connected with the liquid transfer pipe and the feeding nozzle as a whole, and The inner surface has a SiC anti-oxidation and anti-corrosion coating, and the shell is in two halves, and the material is high-temperature resistant stainless steel; the fixed end of the feeding nozzle and the inner tank is round, and the connection end with the casting nozzle is square; the gap between the inner tank and the outer shell is It is equipped with heating device and insulation layer; the multifunctional top cover is composed of high temperature resistant stainless steel and insulation layer, and is equipped with protective gas inlet valve, liquid level detection device, temperature detection device, and electric impaction device. 5. According to the precise control system of the liquid level of the front tank and the system temperature in claim 1, it is characterized in that: a servo transfer pump, an electric impacting device arranged in the front tank and a liquid pump installed on the top cover of the front tank are adopted. The linkage control of the position detector realizes the precise control of the flow rate, so that the control accuracy of the liquid level in the front box is ±1mm; Transported from the static furnace to the front box, the temperature change of the molten magnesium does not exceed 10°C.