Reinforced heat generating riser with built-in ceramic tube

Abstract

The present application relates to the technical field of heat generating riser, in particular to a kind of enhanced heat generating riser with built-in ceramic tube, comprising: heat generating riser body, including shell for transferring heat to feeding liquid and heat generating heat preservation body for generating heat by chemical reaction in the interior of shell;Wherein, the upper surface of shell is chamfered surface for limiting the discharge direction of heating gas in the cavity during feeding process of feeding liquid;Ceramic tube is used to transport feeding liquid to hot spot of casting, including flared section for dispersing part of heating gas and reducing the moving range of feeding liquid in horizontal direction, and conveying section for providing feeding channel of feeding liquid;Wherein, quartz sand is filled between heat generating riser body and ceramic tube to limit the horizontal position of ceramic tube;The vertical height of lower surface of ceramic tube is less than the vertical height of lower surface of heat generating riser body.The present application improves the feeding stability of feeding liquid.

Description

Technical Field

[0001] This invention relates to the field of heating riser technology, and more particularly to an enhanced heating riser with an internal ceramic tube. Background Technology

[0002] During the casting process, defects such as shrinkage cavities and porosity are easily generated during the solidification stage of castings. These defects can seriously affect the mechanical properties and reliability of castings. This is especially true for fields such as die casting of high-strength and lightweight structural components, manufacturing of high-quality copper castings, manufacturing of high-quality titanium castings, and manufacturing of high-quality magnesium materials, where the requirements for the internal density and mechanical properties of castings are more stringent. To solve the above problems, exothermic risers are widely used as commonly used feeding devices. Their core principle is to release heat through the chemical reaction of an exothermic agent, which is usually composed of thermite, oxidant, and slag-forming agent, which prolongs the solidification time of the feeding liquid in the riser. This allows the feeding liquid in the riser to solidify later than the casting, thereby using the liquid metal in the riser to compensate for the volume shrinkage generated during the solidification process of the casting, thus achieving the purpose of feeding. Currently, in existing heating riser feeding processes, the feeding process typically includes the following steps: placing the heating riser above the hot spot of the casting; the heating insulation reacts chemically to release heat, insulating the feeding fluid within the riser; the feeding fluid, under gravity, enters the hot spot of the casting through the riser neck to compensate for the solidification shrinkage of the casting. However, in the initial feeding stage, the temperature of the feeding channel within the riser needs time to rise, and a pressure difference exists between the gas pressure in the feeding channel and the gas pressure in the riser cavity. This allows external air to easily enter the feeding channel and contact the casting. Simultaneously, when the feeding fluid enters the riser cavity, it is affected by the impact of the heated gas within the cavity, resulting in increased bubbles and density changes in the feeding fluid. Ultimately, this leads to a decrease in the feeding stability of the feeding process. Therefore, there is an urgent need for an enhanced heating riser with an internal ceramic tube to improve the stability of the feeding process.

[0003] Chinese Patent Publication No. CN121373377A discloses a heating riser for lost foam casting and its usage method, comprising: a riser body, the riser body including two detachable half-risers, and the riser body including a cylindrical part and a conical part; a locking assembly for locking and fixing the two half-risers; the locking assembly including a crossbeam, on which a pair of clamping blocks corresponding to the two half-risers are symmetrically slidably connected; below the crossbeam, a pair of vertically arranged slide rails are fixedly connected by a rod, and a pressing assembly is slidably connected on the slide rails, the pressing assembly contacting the conical part; the present invention, by connecting the locking assembly to the two half-risers, can quickly realize the installation and disassembly of the riser body, which facilitates the removal of the riser from the casting after use and avoids damage to the riser; Therefore, it can be seen that the heating riser for lost foam casting and its usage method have the following problems: before the casting is fed and during the initial feeding stage, the temperature inside the cavity of the riser body needs a certain period of time to increase. Therefore, during the initial feeding stage, the gas pressure inside the ceramic tube cavity is higher than the gas pressure inside the riser body cavity, resulting in a high risk of contact between the casting and air. In addition, when the feeding liquid enters the cavity of the riser body, it is affected by the impact of the preheated gas inside the cavity, which leads to an increase in bubbles and density changes in the feeding liquid, thereby reducing the feeding stability of the feeding liquid. Summary of the Invention

[0004] To address these issues, the present invention provides an enhanced heating riser with an embedded ceramic tube, which overcomes the problems in the prior art where the temperature increase in the cavity of the riser body before and during the initial feeding stage of the casting takes time, resulting in a higher gas pressure in the ceramic tube cavity than in the riser body cavity during the initial feeding stage, leading to a greater risk of contact between the casting and air; and where the feeding fluid entering the riser body cavity is affected by the impact of preheated gas in the cavity, resulting in an increase in bubbles and density changes in the feeding fluid, thus reducing the feeding stability of the feeding fluid.

[0005] To achieve the above objectives, the present invention provides an enhanced heating riser with an embedded ceramic tube, comprising: A heating riser body for insulating the replenishing fluid includes a shell for transferring heat to the replenishing fluid and a heating insulation body disposed inside the shell that generates heat through a chemical reaction. The upper surface of the shell is a slanted surface used to define the discharge direction of the heated gas in the cavity during the replenishment process of the replenishing fluid. A ceramic tube, disposed within the cavity formed by the heating riser body, is used to deliver the feeding fluid to the hot spot of the casting. It includes a flared section for dispersing part of the heating gas and reducing the range of movement of the feeding fluid in the horizontal direction, and a conveying section fixedly connected below the flared section for providing a feeding channel for the feeding fluid. The space between the heating riser body and the ceramic tube is filled with quartz sand to define the horizontal position of the ceramic tube; the upper surface of the quartz sand is on the same horizontal plane as the upper edge of the flared section; the vertical height of the lower surface of the ceramic tube is less than the vertical height of the lower surface of the heating riser body.

[0006] Furthermore, the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is greater than or equal to 1.5 and less than or equal to 3.0.

[0007] Furthermore, the quartz sand is also used to expel some of the gas in the casting to the outside of the casting, and to reduce heat loss at hot spots.

[0008] Furthermore, the flared section is shaped like a hollow frustum.

[0009] Furthermore, the angle between the generatrix of the hollow frustum and the axis is greater than the angle of the oblique sectional surface.

[0010] Furthermore, the vertical height of the outer edge of the beveled surface is greater than the vertical height of the inner edge, so as to expand the horizontal diffusion range of the heated gas in the cavity during the replenishment process.

[0011] Furthermore, the axial centerline of the heating riser body is on the same straight line as the axial centerline of the ceramic tube.

[0012] Furthermore, a coating is provided on the inner wall of the ceramic tube to reduce the roughness of the inner wall of the ceramic tube.

[0013] Furthermore, the material of the heating and heat-insulating body is a mixture of heating agent, heat-insulating material and binder, which is then pressed into shape.

[0014] Furthermore, the molding density of the heating and heat-insulating body is 1.2 g / L. Up to 1.6g / .

[0015] Compared with the prior art, the beneficial effect of the present invention is that, by setting the vertical height of the lower surface of the ceramic tube to be less than the vertical height of the lower surface of the heating riser body, the present invention solves the problem that the gas pressure inside the ceramic tube is greater than the gas pressure inside the cavity of the heating riser body before the casting is fed. Since the ceramic tube directly receives the heat conducted from the casting, and the volume of the ceramic tube cavity is small, the concentrated heat causes the gas inside the ceramic tube cavity to heat up and expand. However, the heating and insulation body of the heating riser body requires a certain chemical reaction time to self-heat, and the cavity volume is large, resulting in a lag effect in the heat conduction to the air in the cavity and its heating. Therefore, in the initial stage of feeding, a pressure difference is formed where the gas pressure inside the tube is greater than the gas pressure in the cavity. At this point, the air pressure inside the ceramic tube cavity is greater than the air pressure inside the cavity. Then, by using the shape of a hollow frustum in the flared section and extending the ceramic tube downwards towards the casting, the volume of the ceramic tube cavity is increased. The increased cavity volume also reduces the heat absorbed per unit volume, thereby lowering the steady-state value of the air pressure inside the ceramic tube cavity. Thus, the difference between the air pressure inside the ceramic tube cavity and the air pressure inside the cavity is minimized. As the heating and insulation body continues to react and release heat, the air temperature inside the cavity rises. By continuously increasing the air pressure inside the cavity, external air is prevented from entering the cavity, thereby reducing the contact area between the molten metal on the upper surface of the casting and the air inside the ceramic tube, thus improving the feeding effect of the feeding fluid.

[0016] Furthermore, the present invention utilizes a flared section of a hollow frustum-shaped ceramic tube to reduce the horizontal movement range of the replenishing fluid during its initial entry. Simultaneously, the flared section disperses the heating gas entering the ceramic tube from the cavity, resulting in more gas entering the ceramic tube during the initial replenishing process and relatively less heating gas exiting the tube. This reduces the impact force on the replenishing fluid, minimizes the risk of contact between the heating gas and the replenishing fluid within the ceramic tube cavity, and further reduces bubbles generated by the heating gas above the casting entering the replenishing fluid, thereby improving the replenishing stability of the replenishing fluid.

[0017] Furthermore, by setting the vertical height of the outer edge of the beveled surface of the heating riser body to be greater than the vertical height of the inner edge, the larger the inclination angle of the beveled surface formed on the upper surface of the shell, the stronger the guiding effect of the heating gas discharged along the beveled surface toward the upper outer wall, which can reduce the downward disturbance of the heating gas to the replenishing liquid or direct contact with the replenishing liquid, reduce the interference of the heating gas on the downward flow of the replenishing liquid and the generation of bubbles inside the replenishing liquid, thereby improving the replenishing stability of the replenishing liquid. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the heating riser body and the ceramic tube of the enhanced heating riser with built-in ceramic tube in an embodiment of the present invention; Figure 2 This is a vertical cross-sectional view of the enhanced heating riser with a built-in ceramic tube in an embodiment of the present invention; Figure 3 This is a vertical cross-sectional view of the ceramic tube with an enhanced heating riser and built-in ceramic tube in an embodiment of the present invention. Figure 4 This is a schematic diagram showing the installation position of the enhanced heating riser with built-in ceramic tube on the casting according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1-Upper surface of the shell, 2-Ceramic tube, 3-Quartz sand, 4-Shell, 5-Flanged section, 6-Conveying section, 7-Heating insulation body, 8-Heating riser body. Detailed Implementation

[0020] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0021] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0023] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Please see Figure 1 As shown, it is a structural schematic diagram of the heating riser body and the ceramic tube of the enhanced heating riser with built-in ceramic tube in an embodiment of the present invention. Embodiment 1 of the present invention provides an enhanced heating riser with a built-in ceramic tube, comprising: The heating riser body 8 is used to keep the replenishing fluid warm, including a shell 4 for transferring heat to the replenishing fluid and a heating insulation body 7 disposed inside the shell to generate heat through a chemical reaction; The upper surface 1 of the shell is a beveled surface used to define the discharge direction of the heated gas in the cavity during the feeding process of the feeding fluid; the feeding fluid is molten metal with the same composition as the casting being fed. The ceramic tube 2 is disposed in the cavity formed by the heating riser body to deliver the feeding fluid to the hot spot of the casting. It includes a flared section 5 for dispersing part of the heating gas and reducing the range of movement of the feeding fluid in the horizontal direction, and a conveying section 6 fixedly connected below the flared section to provide a feeding channel for the feeding fluid. The space between the heating riser body and the ceramic tube is filled with quartz sand 3 to define the horizontal position of the ceramic tube; the vertical height of the lower surface of the ceramic tube is less than the vertical height of the lower surface of the heating riser body.

[0025] Please see Figure 2 As shown, it is a vertical cross-sectional view of the enhanced heating riser with built-in ceramic tube in an embodiment of the present invention, wherein the upper surface of the quartz sand and the upper edge of the flared section are on the same horizontal plane.

[0026] In this embodiment, the upper surface of the quartz sand is on the same horizontal plane as the upper edge of the flared section, so as to prevent the quartz sand from entering the interior of the flared section and blocking the feeding channel, while ensuring that the upper edge of the flared section is fully exposed in the cavity to facilitate the dispersion of the heating gas.

[0027] In this embodiment, the relative positional relationship between the ceramic tube and the heating riser body is a preferred embodiment. Under the condition of increasing the cavity volume of the ceramic tube and shortening the feeding channel, those skilled in the art can make adaptive adjustments to the length of the ceramic tube, the distance between the ceramic tube and the heating riser body according to different feeding requirements, which are not limited here.

[0028] Please continue reading. Figure 2 As shown, the vertical height of the lower surface of the ceramic tube is less than the vertical height of the lower surface of the heating riser body. This is to reduce the pressure difference between the gas pressure inside the ceramic tube cavity and the gas pressure inside the heating riser body cavity before feeding, thereby reducing the time and volume of outside air entering the cavity before feeding, and reducing the risk of contact between outside air and casting before the feeding liquid enters the ceramic tube.

[0029] It is understandable that, since the ceramic tube directly receives the heat conducted by the casting and the volume of the ceramic tube cavity is small, the heat concentration causes the gas inside the ceramic tube cavity to heat up and expand; while the heating and insulation body of the heating riser body requires a certain chemical reaction time to heat up, and the cavity volume is large, so there is a lag effect in the heat conduction to the air in the cavity and its heating. Therefore, in the initial stage of feeding, a pressure difference is formed where the gas pressure inside the tube is greater than the gas pressure in the cavity.

[0030] The pressure difference between the gas pressure inside the ceramic tube cavity and the gas pressure inside the cavity of the heating riser body is determined based on the difference between the gas pressure inside the cavity and the gas pressure inside the ceramic tube cavity. The gas pressure inside the cavity is determined based on the cavity volume, air temperature, and amount of gas in the cavity. Under the condition that the amount of gas and air temperature remain constant, the larger the cavity volume, the lower the gas pressure inside the cavity. Similarly, the gas pressure inside the ceramic tube cavity is determined based on the cavity volume, air temperature, and amount of gas in the cavity. Under the condition that the amount of gas and air temperature remain constant, the larger the cavity volume, the lower the gas pressure inside the cavity.

[0031] In this embodiment, the vertical height relationship between the ceramic tube and the heating riser body is a preferred embodiment of the present invention. Under the condition of increasing the volume of the ceramic tube cavity and shortening the feeding channel, those skilled in the art can make adaptive adjustments to the thickness of the ceramic tube and the size of the heating riser body according to the specific feeding requirements.

[0032] Preferably, the ceramic tube is made of alumina with a thermal conductivity ≤1.5W / (m·K) and a refractoriness ≥1700℃.

[0033] The heating and insulation body is also used to heat the air inside the cavity to increase the air pressure inside the cavity to a level greater than the air pressure inside the ceramic tube cavity, thereby increasing the resistance of outside air entering the ceramic tube cavity and reducing the risk of outside air contacting the casting.

[0034] In this embodiment, the upper surface of the quartz sand is on the same horizontal plane as the upper edge of the flared section. The quartz sand is also used to expel some of the gas in the casting to the outside of the casting, and to reduce heat loss at hot spots. Preferably, the particle size of the quartz sand is 20 to 40 mesh, and the filling density is 1.5 g / L. Up to 1.7g / .

[0035] Specifically, quartz sand has low thermal conductivity and high permeability, so the heat in the hot spot diffuses slowly to the surrounding area through the quartz sand, and the gas in the casting can be absorbed and discharged as much as possible through the quartz sand, thereby reducing the risk of porosity in the casting.

[0036] In this embodiment, the casting is a mixture of molten metal and solid metal in the solidification process. Preferred embodiments of the casting include low alloy steel castings, carbon steel castings, high manganese steel castings, ductile iron castings, and heat-resistant steel castings.

[0037] Specifically, the flared section is shaped like a hollow frustum.

[0038] Please see Figure 3 As shown, it is a vertical cross-sectional view of the ceramic tube of the enhanced heating riser with built-in ceramic tube in an embodiment of the present invention. The ratio of the upper edge diameter of the flared section to the diameter of the conveying section is greater than or equal to 1.5 and less than or equal to 3.0. It is understandable that by dispersing the heating gas entering the ceramic tube from the cavity through the flared section, more gas enters the ceramic tube during the feeding process, and relatively less heating gas rushes out of the ceramic tube. Consequently, the impact force on the feeding fluid is smaller, the risk of contact between the heating gas and the feeding fluid in the ceramic tube cavity is smaller, and the number of bubbles generated by the heating gas above the casting entering the feeding fluid is reduced.

[0039] Please see Figure 4The diagram shows the installation position of the enhanced heating riser with a built-in ceramic tube on the casting according to an embodiment of the present invention. In this embodiment, the heating gas flushed out of the ceramic tube during the initial entry of the feeding fluid is determined based on the difference in the amount of heating gas entering the ceramic tube from the cavity and the amount of heating gas flushed out of the ceramic tube. The amount of heating gas entering the ceramic tube from the cavity is determined based on the diameter of the upper edge of the flared section and the pressure difference between the cavity and the tube. Under the condition of constant pressure difference, the larger the diameter of the upper edge of the flared section, the more heating gas enters the ceramic tube from the cavity. The amount of heating gas flushed out of the ceramic tube is determined based on the amount of heating gas entering the ceramic tube from the cavity. Under the condition that the total amount of gas in the tube remains basically constant, the more heating gas enters the ceramic tube from the cavity, the less heating gas flushed out of the ceramic tube, and thus the smaller the impact force on the feeding fluid. The risk of contact between the heating gas in the tube cavity and the feeding fluid is smaller, and the effect of suppressing bubble generation is more significant.

[0040] In this embodiment, based on Bernoulli's equation and continuity equation in fluid mechanics, and combined with the structural strength requirements of ceramic tubes at high temperatures, theoretical calculations and experimental verification show that when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is less than 1.5, the flaring effect of the flared section is insufficient and cannot effectively disperse the heating gas; when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is greater than 3.0, the upper edge diameter of the flared section is too large, which occupies the effective volume of the cavity and weakens the constraint of the quartz sand on the horizontal position of the ceramic tube. In addition, the radial diffusion distance of the gas in the flared section is too long, which easily causes backflow, and the dispersion benefit tends to saturate.

[0041] In this embodiment, the formula for calculating the gas flow rate entering the conveying section is: ; Where c is the flow coefficient, which is the ratio of the actual flow rate to the theoretical flow rate at the contraction section of the flared section; This is the gas expansion correction factor, which is calculated according to the theoretical formula in the international standard ISO 5167; The pressure difference between the cavity and the tube is ρ; the gas density is ρ. It is the ratio of the diameter of the conveying section to the diameter of the upper edge of the flared section.

[0042] In one specific embodiment, the upper edge diameter of the flared section is 60mm, and the diameter of the conveying section is 30mm.

[0043] In this embodiment, the flared section with the shape of a hollow frustum is a preferred embodiment of the present invention. Under the condition of reducing the range of movement of the replenishing fluid in the horizontal direction and dispersing the heating gas, those skilled in the art can make adaptive adjustments to the wall thickness of the hollow frustum, the inner surface coating of the flared section, and the material of the ceramic tube according to the specific replenishing requirements, which are not limited here.

[0044] Please continue reading. Figure 2 As shown, the angle between the generatrix of the hollow frustum and the axis is greater than the angle of the oblique surface. This is used to direct the heated gas ejected from the ceramic tube along the direction of the generatrix of the flared section towards the lower edge of the oblique surface during the replenishment process of the replenishing fluid, thereby promoting the subsequent discharge of heated gas along the oblique surface towards the upper part of the outer wall.

[0045] Whether the heating gas ejected from the ceramic tube points towards the lower edge of the beveled surface along the generatrix of the flared section is determined based on the relationship between the angle between the generatrix and the axis of the hollow frustum and the angle of the beveled surface. When the angle is greater than the angle of the beveled surface, the heating gas ejected from the ceramic tube points towards the lower edge of the beveled surface along the generatrix, thereby promoting the subsequent heating gas to be discharged towards the upper outer wall along the beveled surface.

[0046] Please continue reading. Figure 2 As shown, the vertical height of the outer edge of the beveled surface is greater than the vertical height of the inner edge, so as to expand the horizontal diffusion range of the heated gas in the cavity during the replenishment process.

[0047] The horizontal diffusion range is determined by the projected area of ​​the three-dimensional escape region of the heated gas escaping from the cavity to the top of the heating riser body during the feeding process on the horizontal plane. It is used to determine the collision risk between the heated gas in the cavity and the feeding fluid during the feeding process. The larger the horizontal diffusion range, the lower the collision risk between the heated gas in the cavity and the feeding fluid during the feeding process.

[0048] It is understandable that the greater the difference between the vertical height of the outer edge and the vertical height of the inner edge of the beveled surface, the larger the bevel angle. This results in a larger three-dimensional movement space for the heated gas in the cavity when the replenishing liquid begins to enter the cavity, thus reducing the degree of impact contact between the heated gas and the replenishing liquid in the cavity.

[0049] Specifically, the oblique angle of the oblique cut is the acute angle between the oblique cut and the horizontal plane.

[0050] In this embodiment, the relative positional relationship between the outer wall and the inner wall of the shell of the heating riser body is a preferred embodiment of the present invention. Under the condition of expanding the horizontal diffusion range of the heated gas in the cavity to be squeezed and pushed back to the outside of the heating riser body during the feeding process, those skilled in the art can make adaptive adjustments to the thickness of the shell, the height of the outer wall of the shell and the height of the inner wall of the shell according to the specific feeding requirements, which will not be elaborated here.

[0051] In this embodiment, the material and wall thickness of the shell of the heating riser body are not limited. It is only necessary to transfer the heat generated by the heating insulation body through chemical reaction to the shrinkage fluid. Those skilled in the art can make adaptive adjustments to the material and wall thickness of the shell of the heating riser body according to actual application or production needs.

[0052] Preferably, the shell of the heating riser body is a steel shell.

[0053] Specifically, the axial centerline of the heating riser body is on the same straight line as the axial centerline of the ceramic tube.

[0054] In this embodiment, by setting the axial centerline of the heating riser body and the axial centerline of the ceramic tube on the same straight line, the feeding liquid is ensured to flow vertically downward along the axis of the ceramic tube, avoiding uneven feeding caused by the deviation of the feeding liquid. At the same time, the dispersion effect of the flared section on the heating gas is axially symmetrical, improving the feeding stability.

[0055] Specifically, the inner wall of the ceramic tube is provided with a coating to reduce the roughness of the inner wall of the ceramic tube.

[0056] Preferably, the coating is boron nitride, the coating thickness is 0.1 mm to 0.3 mm, and the coating is formed by spraying.

[0057] Specifically, the material of the heating and heat-insulating body is a mixture of heating agent, heat-insulating material and binder, which is then pressed into shape; In one specific embodiment, the heating agent of the heating and insulation body includes 20 to 30 parts by weight of aluminum powder, 50 to 70 parts by weight of iron oxide powder, and 5 to 10 parts by weight of potassium nitrate; the components of the insulation material include 10 to 20 parts by weight of expanded perlite and 5 to 15 parts by weight of aluminum silicate fiber; and the binder is 3 to 8 parts by weight of phenolic resin.

[0058] Specifically, the molding density of the heating and heat-insulating body is 1.2 g / L. Up to 1.6g / Molding density is less than 1.2g / L. At that time, the mechanical strength of the heating and insulation element was insufficient, making it prone to breakage during transportation and installation; the molding density was higher than 1.6g / L. If the porosity of the heating insulation body is too low, the gas produced by the chemical reaction will be difficult to escape, which may lead to an abnormal increase in pressure inside the riser.

[0059] Specifically, the initial reaction temperature of the heating insulation body is 900℃ to 1000℃, and the maximum reaction temperature is 1400℃ to 1600℃.

[0060] Working process: The heating riser body is placed above the hot spot of the casting that needs to be fed. As the heating insulation undergoes a chemical reaction, it continuously releases heat, causing the air temperature inside the cavity to gradually rise and the air pressure inside the cavity to continuously increase. During the feeding process, the feeding fluid inside the heating riser body, driven by gravity and the air pressure difference, flows downwards through the flared section and conveying section of the ceramic tube, entering the hot spot of the casting for feeding. When the feeding fluid flows through the flared section, the hollow frustum shape of the flared section, on the one hand, reduces the horizontal movement range of the feeding fluid, causing it to concentrate and flow downwards; on the other hand, through the expansion... The heating gas is dispersed in the cavity of the ceramic tube, which reduces the risk of contact between the heating gas and the feeding fluid, thereby reducing the risk of bubble formation in the feeding fluid. During the feeding process, the heated gas in the cavity and the heated gas escaping from above the casting move upward. Since the upper surface of the shell is a beveled surface, and the vertical height of the outer edge of the beveled surface is greater than that of the inner edge, the heated gas is discharged along the beveled surface towards the upper outer wall, expanding the horizontal diffusion range. The heated gas is guided along the beveled surface to the upper outer wall, avoiding the downward backflow of heated gas that impacts the feeding fluid, thereby reducing the disturbance inside the feeding fluid and completing the feeding of the molten metal. Example 1

[0061] The difference between Example 2 and Example 1 is that the upper edge diameter of the flared section is adjusted from 60mm to 45mm, while the diameter of the conveying section remains unchanged at 30mm, so that the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 1.5. Example 2

[0062] The difference between Example 3 and Example 1 is that the upper edge diameter of the flared section is adjusted from 60mm to 90mm, while the diameter of the conveying section remains unchanged at 30mm, so that the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 3.0. Example 3

[0063] Based on Example 1, Example 4 adjusts the upper edge diameter of the flared section from 60mm to 72mm, while keeping the conveying section diameter unchanged at 30mm, so that the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 2.4. Example 4

[0064] In this embodiment 5, based on embodiment 1, the downward probing distance of the ceramic tube is adjusted from 15mm to 8mm. Example 5

[0065] In this embodiment 6, based on embodiment 1, the downward probing distance of the ceramic tube is adjusted from 15mm to 25mm.

[0066] Comparative Example 1 Based on Example 1, Comparative Example 1 adjusts the upper edge diameter of the flared section from 60mm to 36mm, while keeping the conveying section diameter unchanged at 30mm, so that the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 1.2.

[0067] Comparative Example 2 Based on Example 1, Comparative Example 2 adjusts the upper edge diameter of the flared section from 60mm to 105mm, while keeping the conveying section diameter unchanged at 30mm, so that the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 3.5.

[0068] Comparative Example 3 In Comparative Example 3, based on Example 1, the lower surface of the ceramic tube is adjusted to be flush with the lower surface of the heating riser body.

[0069] Comparative Example 4 Based on Example 1, Comparative Example 4 sets the angle between the generatrix of the hollow frustum and the axis to be the same as the angle of the oblique tangent.

[0070] To verify the technical effect of the above ratio range and positional relationship limitation, a test platform was used to test a carbon steel stepped test block with a cross section of 60mm×60mm at the hot spot and a casting temperature of 1540±10℃. Three test blocks were cast for each scheme and the average value was taken.

[0071] Specifically, miniature pressure sensors are pre-embedded in the ceramic tube cavity and the heating riser body cavity respectively. After the casting is poured, the pressure difference between the ceramic tube cavity and the heating riser body cavity is continuously recorded from 0 to 60 seconds. After the filling is completed, the average value of the time interval from 30 to 60 seconds after the reaction is exothermic is taken as the steady-state pressure difference between the tube cavity and the cavity. The shrinkage porosity of hot joints was determined according to GB / T 5677 "Radiographic Inspection of Castings"; Specifically, after the shrinkage was completed, a sample with a size of approximately 30mm×30mm×30mm was cut from the self-heating joint. After X-ray inspection, the volume percentage of shrinkage porosity was calculated using stereoscopic image analysis software. The gas content of the replenishing fluid was determined according to the liquid balance method specified in GB / T 3850; Specifically, a sample is taken from the solidification section of the self-compensating channel, the actual density is measured and compared with the theoretical density of the same material, and the gas volume fraction is calculated based on the volume difference. The number of falling bubbles was determined using high-speed imaging. Specifically, a high-speed camera is placed in the observation window of the feeding channel to count the number of heated gas bubbles that fall back into the feeding liquid within 0 to 60 seconds after pouring, in units per second; Table 1: Comparative Experiment Data Table ; As can be seen from Example 1, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 2.0, and the ceramic tube extends 15mm downward, the shrinkage rate of the hot section shrinkage hole is 0.7%, the gas content of the replenishing liquid is 1.2‰, the steady-state pressure difference between the tube cavity and the cavity is 110Pa, and the number of falling bubbles is 3 per second. All indicators are at a relatively good level and can be regarded as the preferred parameter combination of the present invention.

[0072] As shown in Example 2, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 1.5, the shrinkage rate of the hot section shrinkage cavity increases to 1.4%, the gas content of the replenishing liquid increases to 2.3‰, and the number of falling bubbles increases to 5 per second, which are 2.0 times, 1.9 times, and 1.7 times that of Example 1, respectively. This indicates that when the ratio is close to the lower limit, the flared section's ability to disperse the heated gas weakens, the impact suppression of the gushing gas on the replenishing liquid is insufficient, and the risk of bubbles and shrinkage cavities increases accordingly.

[0073] As can be seen from Example 3, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 3.0, the shrinkage rate of the hot section shrinkage hole is 0.5%, the gas content of the replenishing liquid is 0.9‰, and the number of falling bubbles is 2 per second, which is a further decrease compared to Example 1.

[0074] As can be seen from Example 4, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 2.4, the shrinkage rate of the hot section shrinkage hole is 0.55%, the gas content of the replenishing liquid is 1.0‰, and the number of falling bubbles is 2 per second. These indicators are between those of Example 1 and Example 3.

[0075] As shown in Example 5, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section remains unchanged at 2.0, reducing the downward probe distance from 15mm to 8mm increases the steady-state pressure difference between the tube cavity and the cavity from 110Pa to 180Pa. The shrinkage rate of the hot section shrinkage cavity and the gas content of the replenishing liquid increase to 0.9% and 1.5‰, respectively, and the number of falling bubbles increases to 4 per second. This indicates that reducing the downward probe distance will reduce the volume of the ceramic tube cavity, increase the steady-state pressure difference, reduce the resistance of outside air entering the cavity before replenishment, and slightly increase the number of bubbles and shrinkage cavities.

[0076] As shown in Example 6, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section remains unchanged at 2.0, increasing the downward probe distance to 25 mm reduces the steady-state pressure difference between the tube and the cavity to 70 Pa. The shrinkage rate of the hot section shrinkage hole is 0.7%, the gas content of the replenishing fluid is 1.1‰, and the number of falling bubbles is 3 per second. Compared with Example 1, the pressure difference is further reduced, indicating that increasing the downward probe distance can continue to reduce the steady-state gas pressure of the tube and reduce the pressure difference with the cavity. However, excessive downward probe will prolong the replenishing channel and increase the consumption of ceramic tube materials and the heat loss of the hot section. Usually, 15 mm is a compromise value that takes into account both pressure difference control and replenishing efficiency.

[0077] As shown in Comparative Example 1, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 1.2, the shrinkage rate of the hot section is 2.6%, the gas content of the replenishing liquid is 4.1‰, and the number of falling bubbles is 12 per second, the increase in shrinkage cavities and bubbles indicates that the dispersion ability of the flared section is insufficient when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is less than 1.5.

[0078] As shown in Comparative Example 2, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section is 3.5, the gas content of the replenishing liquid is 1.0‰, the shrinkage rate of the hot section shrinkage hole is 0.6%, and the number of falling bubbles is 2 per second, and the dispersion effect is not significantly improved. However, the measured eccentricity of the hot section shrinkage hole is 0.41, indicating that the replenishing is eccentric. This shows that when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section exceeds 3.0, the upper edge of the flared section expands excessively, squeezing the cavity and weakening the constraint of the quartz sand on the horizontal position of the ceramic tube.

[0079] As shown in Comparative Example 3, when the lower surface of the ceramic tube is flush with the lower surface of the body, the steady-state pressure difference between the tube cavity and the cavity rises to 260 Pa. The shrinkage rate of the hot section is 1.8%, the gas content of the replenishing liquid is 3.0‰, and the number of falling bubbles is 8 per second. This indicates that when the ceramic tube is not extended downwards, the tube cavity volume is too small and the steady-state pressure difference is too large. In the initial stage of replenishment, the pressure difference between the air pressure inside the tube and the air pressure in the cavity is not effectively reduced, and the risk of outside air entering the cavity increases.

[0080] As shown in Comparative Example 4, when the ratio of the upper edge diameter of the flared section to the diameter of the conveying section remains at 2.0, but the angle between the generatrix of the hollow frustum and the axis is the same as the angle of the oblique section, the shrinkage rate of the hot section shrinkage hole is 1.9%, the gas content of the replenishing liquid is 3.2‰, and the number of falling bubbles is 18 per second. This indicates that when the ratio is within the range but the angle condition is missing, the gas guidance fails and the falling intrusion increases.

[0081] Based on Examples 1 to 6 and Comparative Examples 1 to 4, it can be seen that limiting the ratio of the upper edge diameter of the flared section to the diameter of the conveying section to 1.5 to 3.0, and making the vertical height of the lower surface of the ceramic tube lower than the lower surface of the heating riser body, can improve the impact suppression rate of bubbles, and result in lower shrinkage rate, gas content, number of falling bubbles, and smaller steady-state pressure difference between the tube and the cavity.

[0082] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A reinforced heating riser with an embedded ceramic tube, characterized in that, include: A heating riser body for insulating the replenishing fluid includes a shell for transferring heat to the replenishing fluid and a heating insulation body disposed inside the shell that generates heat through a chemical reaction. The upper surface of the shell is a slanted surface used to define the discharge direction of the heated gas in the cavity during the replenishment process of the replenishing fluid. A ceramic tube, disposed within the cavity formed by the heating riser body, is used to deliver the feeding fluid to the hot spot of the casting. It includes a flared section for dispersing part of the heating gas and reducing the range of movement of the feeding fluid in the horizontal direction, and a conveying section fixedly connected below the flared section for providing a feeding channel for the feeding fluid. The space between the heating riser body and the ceramic tube is filled with quartz sand to define the horizontal position of the ceramic tube. The upper surface of the quartz sand is on the same horizontal plane as the upper edge of the flared section. The vertical height of the lower surface of the ceramic tube is less than the vertical height of the lower surface of the heating riser body.

2. The reinforced heating riser with an embedded ceramic tube according to claim 1, characterized in that, The ratio of the upper edge diameter of the flared section to the diameter of the conveying section is greater than or equal to 1.5 and less than or equal to 3.

0.

3. The reinforced heating riser with an embedded ceramic tube according to claim 2, characterized in that, The quartz sand is also used to expel some of the gas in the casting to the outside of the casting, and to reduce heat loss in hot spots.

4. The reinforced heating riser with an embedded ceramic tube according to claim 3, characterized in that, The flared section is shaped like a hollow frustum.

5. The reinforced heating riser with an embedded ceramic tube according to claim 4, characterized in that, The angle between the generatrix of the hollow frustum and the axis is greater than the angle of the oblique tangent.

6. The enhanced heating riser with an embedded ceramic tube according to claim 5, characterized in that, The vertical height of the outer edge of the beveled surface is greater than that of the inner edge, so as to expand the horizontal diffusion range of the heated gas in the cavity during the replenishment process.

7. The enhanced heating riser with an embedded ceramic tube according to claim 6, characterized in that, The axial centerline of the heating riser body is on the same straight line as the axial centerline of the ceramic tube.

8. The reinforced heating riser with an embedded ceramic tube according to claim 7, characterized in that, The inner wall of the ceramic tube is provided with a coating to reduce the roughness of the inner wall of the ceramic tube.

9. The reinforced heating riser with an embedded ceramic tube according to claim 8, characterized in that, The material of the heating and heat-insulating body is a mixture of heating agent, heat-insulating material and binder, which is then pressed into shape.

10. The reinforced heating riser with an embedded ceramic tube according to claim 9, characterized in that, The molding density of the heating and heat-insulating body is 1.2 g / L. Up to 1.6g / .

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