CN105834386A - Continuous casting device of high temperature alloy tubes and continuous casting method of high temperature alloy tubes - Google Patents

Abstract

The invention provides a continuous casting device of high temperature alloy tubes and a continuous casting method of the high temperature alloy tubes. The continuous casting device of the high temperature alloy tubes and the continuous casting method of the high temperature alloy tubes are based on hollow cast-iron tubes, the continuous casting method of the hollow cast-iron tubes and the special equipment of the hollow cast-iron tubes, improve a holding furnace and a crystallizer which are the core components to adapt to the continuous casting production of the high temperature alloy tubes, so that the high temperature alloy tubes can be cast successfully. Molten cast high temperature alloy melt is kept at high temperature and enters the crystallizer through a bottom channel. After cooled by the cooling water which flows in the crystallizer at high speed, the molten cast high temperature alloy melt is solidified from outside to inside on the inner surface of the lining of the crystallizer. A drawing mechanism starts and draws the solidified high temperature alloy tubes out through a crystal leading-out tube. According to the continuous casting device of the high temperature alloy tubes and the continuous casting method of the high temperature alloy tubes, the length of the high temperature alloy tubes can reach tens of meters, the distribution of material is uniform, the high temperature alloy tubes have no welded joints, blowholes and shrinkage cavities, the grain size is small and the circular degree and the straightness accuracy of the inner walls of the tubes are less than 3mm; the production cost is reduced and the production efficiency is improved.

Description

High-temperature alloy pipe continuous casting equipment and continuous casting method

technical field

The invention relates to a high-temperature alloy pipe continuous casting equipment and a continuous casting method thereof, which are specifically applied to the alloy pipe manufacturing industry.

Background technique

In the prior art, high-temperature casting materials are generally directly cast and formed by centrifugal method. Due to the different specific gravity of each element of the high-temperature alloy material, the distribution of the material after forming is uneven, which affects the size and performance of the casting molding. In special occasions, the length of the high-temperature casting alloy pipe profile needs to be Tens of meters long, it can only be welded and assembled by segmental casting, the weld seam needs to be processed, the process is cumbersome, and the strength, performance and service life of the welded profile are affected.

The published publication number is 103706773A for a hollow cast iron pipe and its vertical continuous casting method and special equipment. There is no induction device for casting superalloy pipe continuous casting equipment outside the furnace, and there is no requirement for the size of the furnace at the inlet end of the alloy melt. , the molten iron inlet end of the holding furnace is open, the molten iron is exposed, and the casting temperature of the superalloy is as high as 1600˚C. Compared with the casting temperature of cast iron at 1300˚C, the heat dissipation quickly leads to a sharp deterioration in the fluidity of the melt, and the heat conduction of the superalloy The rate is also worse than that of cast iron, which is not conducive to melt casting; the mold inner sleeve material is graphite, which is very stable when applied to cast iron with high carbon content, but it will dissolve and erode graphite crystals when applied to high-temperature alloys with low carbon content Therefore, this type of equipment can only be used for cast iron continuous casting production, it is difficult to meet the needs of high-temperature alloy continuous casting, and cannot be applied to continuous casting of high-temperature alloy pipes.

Contents of the invention

The technical problem to be solved by the present invention is to improve the existing continuous casting technology and provide a continuous casting equipment and continuous casting method for high-temperature alloy pipes, which can meet the continuous casting production requirements of high-temperature alloy pipe profiles.

The high-temperature alloy pipe continuous casting equipment of the present invention includes a maintenance furnace and a crystallizer. The maintenance furnace has a large furnace cavity and a small furnace cavity located at the bottom of the crystallizer. The inside of the large furnace cavity can hold the casting melt. There are passages at the bottom that communicate with each other. The inner liner of the crystallizer has a protruding end that is inserted into the small furnace cavity of the maintenance furnace. The crystallizer is connected with a pulling mechanism for pulling the cast-molded profiles, and a cutting device is arranged above the pulling structure , which is characterized in that: the mouth of the large furnace cavity has a top cover, the center of the top cover has an opening for the melt to pour into the large furnace cavity, the diameter of the top cover opening is less than 1/2 of the diameter of the large furnace cavity, and the periphery of the large furnace cavity is provided with Induction heating device;

The ratio of the volume of the large furnace chamber to the sum of the volume of the small furnace chamber and the bottom channel is 10:1;

The crystallizer includes a tubular shell, an inner liner lining the inside of the shell, a baffle plate with a hole in the center above the shell and the inner liner; a cooling water channel is arranged in the outer shell 2 of the crystallizer, and the inner liner is made of corundum material. The inner hole is an inner conical surface with a taper of 1 to 2 degrees, and the inner surface finish is not lower than △8 grade;

The upper part of the crystallizer is provided with a seeder, the lower end of the seeder is inserted into half the height of the crystallizer, the inner surface of the lower end of the seeder has a spiral inner groove, and the outer diameter of the seeder is 0.5mm smaller than the inner diameter of the crystallizer.

The method for continuous casting of high-temperature alloy pipes of the present invention adopts the above-mentioned continuous casting equipment for high-temperature alloy pipes, and comprises the following steps:

a. Preheat and maintain the furnace chamber by flame-spraying and burning method, and maintain the temperature of the bottom surface of the furnace chamber not lower than 1050°C ;

b. The lower end of the seed tube is inserted into the half height of the crystallizer;

c. Inject cooling water into the shell of the crystallizer; and ensure that the temperature of the water outlet of the crystallizer is not higher than 35°C;

d. The melted HP40 superalloy melt is poured into the sustaining furnace from the inlet end of the sustaining furnace, and the temperature of the melt leaving the melting furnace is not lower than 1700°C;

e. Start the induction heating device on the maintenance furnace to heat and keep the high-temperature alloy melt in the maintenance furnace to ensure that the temperature of the alloy melt in the maintenance furnace is not lower than 1500°C;

f. After the superalloy melt enters the inner bushing of the crystallizer, it stays for a period of time according to the thickness of the superalloy pipe. When the thickness of the superalloy pipe is 8mm, the residence time is 80s; when the thickness is 10mm, the residence time is 100s; When the thickness is 12mm, the residence time is 120s. The smaller the thickness, the shorter the residence time; the superalloy melt enters the spiral inner groove on the inner surface of the lower end of the seeding tube, and after solidification, it is integrated with the seeder, and the pulling mechanism is activated to pass through the seeder. Pull out the superalloy pipe at a constant speed, and determine the drawing speed of the drawing mechanism according to the thickness of the pipe, so that the drawing mechanism can smoothly pull out the solidified and formed superalloy pipe; the drawing speed of the superalloy pipe with a wall thickness of 8mm is 0.4mm/ s, the drawing speed of the superalloy pipe with a wall thickness of 10mm is 0.3mm/s, and the drawing speed of a high temperature alloy pipe with a wall thickness of 12mm is 0.2mm/s, the smaller the wall thickness of the superalloy pipe, the faster the drawing speed;

g. The drawing mechanism continues to draw, and the melt is continuously replenished into the maintenance furnace, so that the liquid level of the alloy melt in the maintenance furnace remains unchanged; the liquid level in the furnace melt entrance of the maintenance furnace is 10% higher than the upper surface of the crystallizer ~20mm;

h. After the drawing length of the pipe meets the product requirements, it is cut off by the cutting device and then unloaded, transported and put into storage;

i. After the drawing is finished, turn off the induction heating device and cooling water.

The high-temperature alloy pipe continuous casting equipment and continuous casting method of the present invention are based on the hollow cast iron pipe and its continuous casting method and special equipment, and the core component holding furnace and crystallizer are improved to adapt to the continuous casting production of high-temperature alloy pipe profiles. The high-temperature alloy pipe is successfully cast; the molten cast high-temperature alloy melt maintains high temperature and enters the crystallizer through the bottom channel, and is cooled by the cooling water flowing through the mold at high speed, and then solidifies from the outside to the inside on the inner surface of the mold lining , the drawing mechanism starts to pull out the solidified superalloy pipe through the seed tube, the length can reach tens of meters, the material is evenly distributed and there is no weld seam, the grain is small, there is no air hole and shrinkage cavity, the roundness and straightness of the inner wall of the pipe Less than 3mm; reduce production cost and improve production efficiency.

Description of drawings

Fig. 1 is a schematic structural view of a high temperature alloy pipe continuous casting equipment according to an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a crystallization furnace according to an embodiment of the present invention.

detailed description

As shown in the figure, a high-temperature alloy pipe continuous casting equipment includes a maintenance furnace 1 and a crystallizer 8. The maintenance furnace 1 has a large furnace cavity and a small furnace cavity at the bottom of the crystallizer 8. The inside of the large furnace cavity can hold the casting melt , the bottom of the large furnace cavity and the small furnace cavity are connected with each other through passages, the inner liner 11 of the crystallizer 8 has a protruding end inserted into the small furnace cavity of the maintenance furnace 1, and the crystallizer 8 is connected with a pulling mechanism 6 for pulling and casting The formed profile is provided with a cutting device above the pulling structure 6, which is characterized in that: the mouth of the large furnace cavity has a top cover 5, and the center of the top cover 5 has an opening for the melt to pour into the inside of the large furnace cavity, and the top cover 5 opens The diameter is less than 1/2 of the diameter of the large furnace cavity, and the periphery of the large furnace cavity is provided with an induction heating device 3; the ratio of the volume of the large furnace cavity, the volume of the small furnace cavity and the bottom channel is 10:1; the crystallizer 8 includes a tubular shell 10. The inner bushing 11 lining the inside of the shell 10, the baffle plate 9 with a hole in the center above the shell 10 and the inner bushing 11; the outer shell 10 of the crystallizer 8 is provided with a cooling water channel, and the inner bushing 11 is corundum material, the inner hole is an inner conical surface, the taper is 1-2 degrees, and the inner surface finish is not lower than △8 grade; the upper part of the crystallizer 8 is provided with a seeder 7, and the lower end of the seeder 7 is inserted into the crystallizer at half the height of 8 , the inner surface of the lower end of the seeder 7 has a spiral inner groove, and the outer diameter of the seeder 7 is 0.5 mm smaller than the inner diameter of the crystallizer 8 .

The specific steps of the continuous casting preparation work are as follows: first, the crystallizer 8 is assembled, one end of the inner bush 11 of the mold 8 is pressed into the steel shell 2, and the step is matched with the groove of the steel shell 2 to limit the position, and a baffle is also provided 9 is fixedly connected with the steel shell 2, and the other end of the inner bush 11 is a protruding end extending out of the steel shell 2, and the protruding length is about 100mm. The cooling water channel in the steel shell 2 is connected to the external water inlet and water outlet Then the assembled crystallizer 8 is placed on the small furnace chamber of the maintenance furnace 1, and the contact surface of the lower end surface of the crystallizer 8 and the maintenance furnace 1 is cushioned with refractory mud to prevent the molten superalloy melt from leaking from the gap of the contact end surface , the lower end of the crystallizer 8 is fixedly connected to the maintenance furnace 1 by bolts, and the protruding end of the inner liner 11 is inserted into the small furnace cavity of the maintenance furnace 1; finally, the melt is prepared, and the melt material is HP40 superalloy steel, which is passed through induction After the heating furnace is melted, it is ready for use.

Pour the molten superalloy melt into the furnace cavity of the continuous casting equipment consisting of the maintenance furnace 1, induction heating device 3, crystallizer 8 and seeder 7, and the superalloy melt is cooled and solidified in the crystallizer 8 to a thickness of To meet the requirements of the high-temperature alloy pipe, start the drawing mechanism 6, and pull the solidified pipe shell out of the crystallizer at a constant speed according to the thickness of the pipe size. When the length of the drawn pipe reaches the required size , cut off by the cut-off device above the crystal, and then the profiles are unloaded, transported and put into storage through the loading and unloading mechanism.

The method for continuous casting of high-temperature alloy pipes of the present invention adopts the above-mentioned continuous casting equipment for high-temperature alloy pipes, and comprises the following steps:

a. Preheat and maintain the furnace chamber by flame-spraying and burning method, and maintain the temperature of the bottom surface of the furnace chamber not lower than 1050°C ;

b. The lower end of the seed tube is inserted into the half height of the crystallizer;

c. Inject cooling water into the shell of the crystallizer; and ensure that the temperature of the water outlet of the crystallizer is not higher than 35°C;

d. The melted HP40 superalloy melt is poured into the sustaining furnace from the inlet end of the sustaining furnace, and the temperature of the melt leaving the melting furnace is not lower than 1700°C;

e. Start the induction heating device on the maintenance furnace to heat and keep the high-temperature alloy melt in the maintenance furnace to ensure that the temperature of the alloy melt in the maintenance furnace is not lower than 1500°C;

f. After the superalloy melt enters the inner bushing of the crystallizer, it stays for a period of time according to the thickness of the superalloy pipe. When the thickness of the superalloy pipe is 8mm, the residence time is 80s; when the thickness is 10mm, the residence time is 100s; When the thickness is 12mm, the residence time is 120s. The smaller the thickness, the shorter the residence time; the superalloy melt enters the spiral inner groove on the inner surface of the lower end of the seeding tube, and after solidification, it is integrated with the seeder, and the pulling mechanism is activated to pass through the seeder. Pull out the superalloy pipe at a constant speed, and determine the drawing speed of the drawing mechanism according to the thickness of the pipe, so that the drawing mechanism can smoothly pull out the solidified and formed superalloy pipe; the drawing speed of the superalloy pipe with a wall thickness of 8mm is 0.4mm/ s, the drawing speed of the superalloy pipe with a wall thickness of 10mm is 0.3mm/s, and the drawing speed of a high temperature alloy pipe with a wall thickness of 12mm is 0.2mm/s, the smaller the wall thickness of the superalloy pipe, the faster the drawing speed;

g. The drawing mechanism continues to draw, and the melt is continuously replenished into the maintenance furnace, so that the liquid level of the alloy melt in the maintenance furnace remains unchanged; the liquid level in the furnace melt entrance of the maintenance furnace is 10% higher than the upper surface of the crystallizer ~20mm;

h. After the drawing length of the pipe meets the product requirements, it is cut off by the cutting device and then unloaded, transported and put into storage;

i. After the drawing is finished, turn off the induction heating device and cooling water.

The HP40 high-temperature alloy steel pipe prepared by the above method has fine grains, no pores and shrinkage cavities, and the roundness and straightness of the inner wall of the pipe are less than 3mm; the smoothness of the outer surface of the pipe is greater than ▽6, and the roundness and straightness of the outer surface are less than 1.5 mm.

Claims (10)

1. A high-temperature alloy pipe continuous casting equipment, including a maintenance furnace (1) and a crystallizer (8). The maintenance furnace (1) has a large furnace cavity and a small furnace cavity located at the bottom of the crystallizer (8). Inside the large furnace cavity It can contain the casting melt, the bottom of the large furnace chamber and the small furnace chamber have channels connected with each other, the inner bushing (11) of the crystallizer (8) has a protruding end inserted into the small furnace chamber of the maintenance furnace (1), and the crystallizer ( 8) It is connected with a pulling mechanism (6) for pulling and pulling the cast-molded profiles, and a cutting device is arranged above the pulling structure (6), which is characterized in that the mouth of the large furnace cavity has a top cover (5), and (5) There is an opening in the center for pouring melt into the inside of the large furnace chamber, the opening diameter of the top cover (5) is less than 1/2 of the diameter of the large furnace chamber, and an induction heating device (3) is arranged on the periphery of the large furnace chamber. 2. The high-temperature alloy pipe continuous casting equipment according to claim 1, characterized in that the ratio of the volume of the large furnace cavity to the sum of the volumes of the small furnace cavity and the bottom channel is 10:1. 3. The high-temperature alloy pipe continuous casting equipment according to claim 1, characterized in that: the crystallizer (8) includes a tubular shell (10), an inner bushing (11) lining the inside of the shell (10), The baffle plate (9) with a hole in the center is located above the shell (10) and inner bushing (11), the upper part of the crystallizer (8) is provided with a seeder (7), and the lower end of the seeder (7) is inserted into the crystallizer Inside (8) at half the height. 4. The high-temperature alloy pipe continuous casting equipment according to claim 3, characterized in that: the shell (10) of the crystallizer (8) is provided with a cooling water channel, the inner bushing (11) is made of corundum material, and the inner The hole is an inner tapered surface with a taper of 1 to 2 degrees, and the inner surface finish is not lower than △8. 5. The high-temperature alloy pipe continuous casting equipment according to claim 3, characterized in that: the inner surface of the lower end of the seeder (7) has a spiral inner groove, and the outer diameter of the seeder (7) is smaller than that of the crystallizer ( 8) The inner diameter is 0.5mm smaller. 6. A method for continuous casting of high-temperature alloy pipes, using the continuous casting equipment for high-temperature alloy pipes according to one of claims 1 to 5, comprising the following steps: a. Preheat and maintain the furnace cavity by flame-spraying method; b. The lower end of the seed tube is inserted into the half height of the crystallizer; c. Inject cooling water into the shell of the crystallizer; d. The melted HP40 superalloy melt is poured into the maintenance furnace from the inlet end of the maintenance furnace; e. Start the induction heating device on the maintenance furnace to heat and keep the high temperature alloy melt in the maintenance furnace; f. After the superalloy melt enters the inner bushing of the crystallizer, it stays for a period of time according to the thickness of the superalloy pipe; the superalloy melt enters the spiral inner groove on the inner surface of the lower end of the seeding tube, and is integrated with the seeding device after solidification , start the drawing mechanism, pull out the superalloy pipe at a constant speed through the seeder, and determine the drawing speed of the drawing mechanism according to the thickness of the pipe, so that the drawing mechanism can smoothly pull out the solidified and formed superalloy pipe; g. The drawing mechanism continues to draw, and the superalloy melt is continuously replenished into the maintenance furnace to maintain the liquid level of the superalloy melt in the furnace to remain unchanged; h. After the drawing length of the pipe meets the product requirements, it is cut off by the cutting device and then unloaded, transported and put into storage; i. After the drawing is finished, turn off the induction heating device and cooling water. 7. The method for continuous casting of superalloy pipes according to claim 6, characterized in that: the preheating temperature of the bottom surface of the maintenance furnace cavity is not lower than 1050°C. 8. The method for continuous casting of superalloy pipes according to claim 6, characterized in that: the temperature of the cooling water outlet of the shell of the crystallizer is not higher than 35°C. 9. The method for continuous casting of superalloy pipes according to claim 6, characterized in that: said, the temperature of the superalloy melt out of the smelting furnace is not lower than 1700°C, and the temperature of the superalloy melt in the furnace is maintained not lower than 1500°C. 10. The method for continuous casting of superalloy pipes according to claim 6, characterized in that: the liquid level in the furnace melt inlet chamber of the maintenance furnace is kept 10-20 mm higher than the upper surface of the crystallizer.