CN116117124A

CN116117124A - Slag mixing-in prevention technology for molten metal intelligent magnetic suspension continuous casting waste heat blank

Info

Publication number: CN116117124A
Application number: CN202310047200.1A
Authority: CN
Inventors: 刘巍
Original assignee: Chengdu Lihua Strong Maglev Continuous Casting Technology Co ltd
Current assignee: Chengdu Lihua Strong Maglev Continuous Casting Technology Co ltd
Priority date: 2023-01-30
Filing date: 2023-01-30
Publication date: 2023-05-16

Abstract

The invention discloses a technology for preventing slag from being mixed into molten metal in an intelligent magnetic suspension continuous casting waste heat billet of molten metal, and belongs to the field of production of metal materials in the metallurgical industry. In order to prevent slag generated by the covering agent from being mixed into the molten metal magnetic suspension continuous casting waste heat casting blank, a slag baffle plate is arranged on the molten metal outflow side in a ladle (or a furnace, the same shall apply hereinafter). So that the flowing molten metal is close to the ladle bottom. The specific gravity of the covering agent is far smaller than that of the molten metal, so that the covering agent is covered on the upper part and does not mix into the molten metal. Otherwise, the metal product becomes a waste product once mixed. The slag trap made of refractory material is installed by being embedded into the molten metal outflow side of the refractory brick wall and bonded outside the wall by high temperature adhesive. The size of the interval between the lowest end of the slag baffle and the upper surface of the refractory brick with the bottom is positively correlated with the viscosity of molten metal.

Description

Slag mixing-in prevention technology for molten metal intelligent magnetic suspension continuous casting waste heat blank

[ field of technology ]

The technology of slag mixing into molten metal for intelligent magnetic suspension continuous casting waste heat blank belongs to the field of metallurgical technology.

[ background Art ]

The main working procedures of the production flow of the metal materials of steel, aluminum, copper, zinc, titanium, lead, magnesium and the like are as follows: 1. the preparation method comprises the steps of material preparation (including mining and ore dressing.) →2. Smelting→3. Casting blank→4. Heating→5. Hot working→6. Cold working (including intermediate annealing) →7. Finishing, checking, packaging, warehousing and the like.

In the production processes, the process 3, the technological principle of casting blanks and semi-finished products thereof influence the simplicity and reproduction of the production processes of the

subsequent processes

4, 5 and 6; the energy consumption of unit products, the improvement of product quality, cost reduction and income increase are restricted.

The current production technology of casting blank working procedures of metal materials at home and abroad mainly adopts continuous casting of a water-cooled mould (DCC for short).

DCC principle: the molten metal flows into the crystallizer to contact with the inner shell wall of the crystallizer, so that the molten metal is cooled to form a solid phase and forms a crust, and the crust strength reaches the friction force generated by friction with the inner shell wall of the crystallizer when the molten metal is pulled and moved, so that the molten metal is continuously pulled and moved out of the crystallizer, and a metal casting blank is continuously cast.

Speed of casting blank of DCC: the steel ingot (billet) is 2.7-5 m/min, and the copper billet is 0.1-0.5 m/min.

Temperature of the cast slab of DCC: the temperature of the steel ingot (blank) is less than or equal to 900 ℃, and the temperature of the copper and aluminum blank is room temperature.

The speed of the casting blank of the DCC cannot be too high and the temperature cannot be too high, otherwise, the casting blank is broken due to insufficient strength of the casting blank shell, and the metal liquid gushes out to form a major accident.

Major drawbacks of DCC: the crystallizer and a large amount of high-pressure cooling water are consumed, excessive waste heat in the molten metal is dissipated, a steel ingot with the temperature less than or equal to 900 ℃ is cast, and the steel ingot hot rolling temperature is 1050-1250 ℃ and needs to be heated for the second time. Some steel ingots with the temperature less than or equal to 900 ℃ are directly rolled into materials, which is illegal operation and causes a plurality of problems.

DCC can only cast copper blanks with the subsequent cold working amount accounting for more than 80 percent of the total production workload of products in the copper field, and the large production workload is reserved for cold working (including intermediate annealing) with a large amount of energy and object consumption.

The invention patent ZL200510021740.4 (metal liquid magnetic suspension continuous casting near final type waste heat hot rolling blank technology) (hereinafter called MFCC for short) can subvert and eliminate water cooling die continuous casting.

Principle of MFCC: the molten metal is restrained by casting mould (outflow pipe) at the mouth of ladle (or furnace, the same shall apply below) to form final-shaped liquid column (liquid sheet) with heat and cold working allowance section size, and is drawn to flow into 5-30 KHz alternating magnetic field, and the molten metal is repelled by electromagnetic induction and suspended (simultaneously by electromagnetic stirring) in continuous movement to hot working machine, and is moderately cooled to form final-shaped waste heat casting blank with the optimum hot working temperature of the brand metal, and immediately hot-worked on line, so that the molten metal can be made into steel material on line in one step according with technological requirements, or made into copper material blank, aluminium material blank and mechanical part blank with the subsequent cold working quantity less than 20%.

Magnetic levitation continuous casting and on-line hot working advantages:

1. greatly optimizing the casting blank tissue (electromagnetic stirring effect) to improve the strength of the casting blank, thereby improving the strength of the material;

2. greatly simplifying the production flow, ensuring the minimum hot and cold working passes required by the strength of the product, thereby reducing the energy consumption, the metal loss and various consumption, and achieving the purposes of energy saving, carbon emission reduction, product quality improvement, cost reduction and income increase.

3. The magnetic levitation continuous casting and on-line hot working into a material or a net refined blank, and the subsequent cold working amount and the intermediate annealing pass are greatly reduced, so that 1/3-2/3 equipment (except a melting furnace) is idle at the same yield.

4. The principle of the magnetic levitation continuous casting is simple, the operation is simple, the regulation and control are simple, main equipment of a newly-built magnetic levitation continuous casting production line is an alternating power supply, a plurality of domestic manufacturers and newly-added auxiliary machines are simple.

From the above, the magnetic levitation continuous casting is necessary to subvert and eliminate the water-cooled die continuous casting.

The magnetic levitation continuous casting is to suspend and cool down the molten metal in direct current flowing into an alternating magnetic field, and the intelligent control is needed, so that stable and safe production is achieved.

[ invention ]

The invention is further developed on the basis of the invention patent application of patent application No. 202111382250.2 (published in 2022, 04 and 12 of 38 volume 1501) to prevent slag (generated by covering agent, see 4 in figure 1 of the specification) from being mixed into molten metal. Because once slag is mixed into molten metal, the quality of the metal product is seriously deteriorated to be a waste product.

The method for preventing slag from being mixed into molten metal is to add a slag baffle in a bag (or furnace, hereinafter the same) with the patent application number 202111382250.2, namely 8 in the figure 1 of the specification.

Principle of preventing slag from mixing into molten metal: the specific gravity of the covering agent 4 in the attached figure 1 of the specification is far lower than that of the molten metal, so that the covering agent floats on the molten metal for a long time, and after the slag baffle 8 is additionally arranged, the molten metal can only flow out from the bottom of the ladle, so that the covering agent which can form slag cannot be mixed into the molten metal.

The distance between the end of the slag trap 8 and the upper surface of the refractory brick 19, i.e. the value of dimension A in the specification of figure 1, is directly related to the viscosity of the molten metal of the brand, and the value of dimension A ranges from 20mm to 50mm.

The production process after the combination of patent application number 202111382250.2 and the present application is described.

The principle that molten metal must flow out at a constant speed and an online hot processing production line in the process of carrying out the intelligent magnetic suspension continuous casting of molten metal waste heat casting blank is shown in the attached figure 1 of the specification. The intelligent control targets of the molten metal magnetic suspension continuous casting waste heat casting blank and the online hot working production line are five:

1. in order to meet the requirements of the production and smooth operation of the production line, it is necessary to make the molten metal flow out of the water outlet 18 at a constant flow rate;

2. the method of constant-speed outflow of molten metal is composed of a molten metal depth measurement system (application number 202111382250.2, written in application number [ 0015 ]) consisting of 6 (cesium 137) and 22 (radiation absorption sensor) in fig. 1 of the specification, the radiation method, the programmable controller (PLC, application number 202111382250.2, written in application number "electronic computer", PLC) of the control system 15, and the

actuators

24 and 21.

The working principle is as follows:

the depth of the molten metal from the level of the molten metal in the ladle, i.e., the depth from 6 (cesium 137) to 22 (radiation absorption sensor) in fig. 1 of the specification, decreases with continuous outflow and increases with replenishment of the bath by the melting furnace.

The metal flow rate is dependent on a number of factors, but is primarily determined by the depth of 6 to 22. The molten metal can flow out at a constant speed by maintaining the depth of 6 to 22 within the range of the initial setting at any time.

The method for maintaining the depth of 6 to 22 within the range of the initial setting at any time is as follows: in the measuring system consisting of 6 and 22 in fig. 1, the measured metal liquid depth value is input into 15 (PLC) at any time, after the calculation is performed between 15 and the preset value, an instruction is sent to instruct the

executing mechanisms

24 and 21 to lift (rotate) the inclusion and lift (rotate) the inclusion as a whole, so that the metal liquid flows out at a constant speed and a constant height (the height difference between the lowest outflow point of the outflow pipe 18 and the plane on the leftmost end of the alternating magnetic field 17 is the outflow height).

3. The accident of production line is even, so that the molten metal is stopped as soon as possible, and the accident is prevented from expanding.

4. When the hot working production is needed, the functions of the metal liquid flow rate, the magnetic suspension continuous casting parameters, the hot working parameters and the like can be adjusted on line.

5. After the slag baffle 8 is added, the covering agent 4 cannot be mixed into molten metal in a slag-forming manner.

[ description of the drawings ]

Description fig. 1 is a drawing of the present invention, in which the numbers correspond to the following numbers.

1. Pack (oven) shell: is made of steel plate or glass fiber plate.

2. An insulation blanket.

3. Refractory bricks.

4. And (3) a covering agent.

5. And (3) molten metal.

6. Cesium 137.

7. And (5) a heat-insulating cover plate. The movable plate (lifted when molten metal is added) and the fixed plate are respectively composed of a heat insulating material and a steel frame.

8. Slag baffle. Made of refractory material.

9. Slag trap binder. And (3) a high-temperature binder.

10. And (5) spraying water particles and a water mist recovery system.

11. And (5) waste heat casting blank.

12. A thermal processing system. Can be a rolling mill, an extruder or a die casting machine.

13. And (5) thermally processing the product.

14. A post-heat treatment system.

15. A programmable controller (PLC).

16. A traction system. Consists of a traction head, a traction rope, a bracket and a traction machine.

17. An alternating magnetic field. Consists of alternating power supply and copper pipe.

18. And the metal liquid flows out of the pipe. Made of refractory material.

19. And (5) wrapping the bottom refractory bricks.

20. And a furnace body supporting and rotating system.

21. And the whole lifting executing mechanism.

22. Cesium 137 radiation absorption sensor.

23. And (5) integrally supporting and rotating the system.

24. Furnace body lifting actuating mechanism

[ detailed description ] of the invention

The slag trap 8 is installed by embedding and bonding. Embedded in the refractory brick wall at the side of the molten metal outlet, and bonded at the contact position with the wall body by using high-temperature bonding materials.

The embodiment of the metal liquid outflow pipe 18 is as follows.

1. The cross section size of the inner cavity of the outflow pipe 18 must meet the requirements of the product size, strength, hot and cold working allowance and the like because the metal liquid flows into the alternating magnetic field after filling the cross section of the inner cavity and is cast into the waste heat continuous casting blank.

2. The matching and installation of the outflow pipe 18 are respectively processed according to the casting temperatures of different molten metals:

2.1 the casting temperature of the molten steel is more than or equal to 1530 ℃, the service life of the refractory bricks of the inner wall is limited, and the service life of the outflow pipe 18 can be the same as that of the furnace wall bricks. When the furnace wall bricks are changed, the outflow pipes 18 are changed, so that the outflow pipes 18 are embedded together with the furnace wall bricks for building.

2.2 casting temperature of copper (copper alloy containing) solution is less than or equal to 1250 ℃, and service life of refractory bricks on the inner wall of the heat preservation furnace is long, so that a crystallizer and a crystallizer seat (door surface rotation, the same applies below) combined method of the prior casting blank DCC technology can be adopted. Namely, the crystallizer seat is built and embedded on a furnace wall during furnace building, and when the size of a casting blank is changed, the crystallizer is pulled out and a new crystallizer is inserted.

The matching method of the crystallizer and the crystallizer seat comprises the operations of the respective size of the combined part, the gap blocking of the low-strength adhesive, and the like according to the existing copper production operation.

2.3 casting temperature of Nickel liquid approximately 1500 ℃ the assembly of the outflow pipe is carried out according to 2.1 molten steel.

2.4 assembly of outflow tube for aluminium liquid, according to 2.2 copper liquid

3. The structure of the outflow pipe can be an upper piece and a lower piece. The cross sections of the two inner cavities are U-shaped and inverted U-shaped, and the lower transverse dimension and the upper transverse dimension of the two inner cavities are the width of a casting blank; the sum of the heights between the two left and right vertical strokes is the thickness of the casting blank. The two sheets are bonded into a whole by using a high-temperature bonding agent (such as aluminum dihydrogen phosphate and 200 meshes corundum powder).

4. The gap between the outflow pipe and the outflow pipe seat is blocked by the low-strength adhesive for the inserted outflow pipe, and the outlet end of the outflow pipe is coated with a heat insulating agent (commodity) and clamped by a clamp to prevent the outflow pipe from falling off. The pressing plate of the fixture needs to be a glass fiber plate which can not generate electromagnetic induction.

The metal liquid depth measuring system comprising 6 to 22 metal liquid flow rates, 6 to 22 metal liquid depths, and 6 and 22 metal liquid flow rates is determined by debugging the output of metal materials in unit time, and is stored in a PLC as original data, the measured metal liquid depth information is input into the PLC at any time, and after calculation of the PLC and the original data, instructions are sent to enable 24 and 21 to lift and enable the metal liquid to flow into an alternating magnetic field at a constant flow rate and a constant height.

The furnace body lifting actuator 24 and the integral lifting actuator 21 can be hydraulic, electric or pneumatic. Each actuating mechanism is composed of a respective structure and a plurality of assemblies.

In a three-dimensional space of 300mm at the leftmost end point of the alternating magnetic field, no metal material capable of generating electromagnetic induction can be arranged. The glass fiber board and other materials which do not generate electromagnetic induction can be used for replacing metal materials.

The cross-sectional dimensions of the internal cavity of the metal outflow tube 18 are determined by a combination of multiple data, such as product size, strength, and hot and cold working margins. The molten metal must be filled in the outflow pipe and flow out. If the cross-sectional size of the new product is larger than the existing product, the outflow tube must be replaced; if smaller than the existing product, it may be adjusted in the thermal processing system 12, and if the adjustment is not required, the outflow tube may need to be replaced.

The cesium 137 ray absorption sensor is made of refractory and heat-insulating materials.

The constant-height outflow is aimed at preventing impact on an alternating magnetic field due to the change of the height reduction or elevation of the outflow of the molten metal, and affecting the stability of magnetic suspension.

Claims

1. In order to prevent slag generated by covering agent from being mixed into molten metal flowing out of continuous casting ladle (or furnace, if the molten metal is mixed, the quality of metal products is reduced to waste), a refractory brick wall on the side of molten metal flowing out of ladle is used for embedding and bonding a slag baffle plate, so that molten metal flows out from the position close to ladle bottom, and the molten metal can be only covered on the molten metal because the specific gravity of the covering agent is far smaller than that of the molten metal, thereby preventing slag forming of the covering agent from being mixed into the molten metal;

the method is characterized in that: on the refractory brick wall of the continuous casting ladle, slag baffle is embedded and adhered to make the molten metal flow out from the ladle, and the covering agent has specific gravity far lower than that of the molten metal and can only cover the molten metal to prevent slag from mixing into the molten metal.