A mold ingot mold waterway structure and process based on segmented temperature control-melt feeding coordination

Abstract

This invention belongs to the field of steel ingot casting cooling technology, and discloses an ingot mold water channel structure and cooling process based on segmented temperature control and melt feeding synergy. The water channel structure has 3-5 independent, sealed rectangular cross-section annular water channels along the height direction inside the ingot mold sidewall. The number of annular water channels is adjusted according to the ingot mold height. Each water channel is equipped with independent control and monitoring components, and a high-alumina refractory material insulation layer is installed on the outer side of the top water channel. The supporting cooling process dynamically adjusts the start / stop status and cooling parameters of each water channel according to the four key stages of pouring and solidification, guiding the casting to solidify orderly from bottom to top, while ensuring the continuous unobstructed flow of the top feeding channel. This invention reduces the central shrinkage cavity depth of the casting from 20-50mm to below 5mm, increases material utilization from 80%-85% to over 95%, and reduces the casting crack rate from 3%-5% to below 0.8%. It is suitable for ingot casting production of ultra-thick castings of various steel grades ranging from 50-300 tons without requiring modification of existing production lines.

Description

Technical Field

[0001] This invention belongs to the field of steel casting cooling technology, specifically involving a water channel structure and process for casting ingots based on segmented temperature control and melt feeding synergy, which is suitable for the production of ultra-thick castings (thickness ≥ 450 mm) of carbon steel, alloy steel, stainless steel, heat-resistant steel and other materials with different capacities of 50-300 tons. Background Technology

[0002] Cooling and feeding are interconnected core processes in die casting production, and their synergistic effect directly determines the internal quality and material utilization rate of the casting. Traditional die casting molds often use a single ring structure for cooling water channels, with a fixed cooling water volume and flow rate. This can only achieve uniform cooling of the entire casting and cannot dynamically adjust the cooling intensity according to the solidification process of different areas of the casting. This results in a serious disconnect between cooling and feeding, becoming a key bottleneck restricting the improvement of product quality.

[0003] Specifically, traditional single-channel cooling designs have three major pain points: First, uneven cooling leads to frequent local defects. Insufficient cooling in the bottom area causes slow solidification of the melt, easily forming "bottom shrinkage" defects. Excessive cooling in the top area causes premature formation of the billet shell, easily leading to "top cracking." Meanwhile, the cooling intensity in the middle area cannot meet the core shrinkage requirements, further exacerbating the defect risk. Second, premature closure of the feeding channel results in severe internal shrinkage cavities. Due to the lack of targeted heat preservation and cooling control in the top feeding area, the melt often solidifies prematurely before completing core shrinkage, failing to effectively compensate for core shrinkage. The space constraints result in shrinkage cavities in the center of the casting reaching depths of 20-50mm, requiring subsequent machining to remove the defective area. Material utilization is only 80%-85%, wasting 150-450kg of steel per ton of casting. Thirdly, the mold structure is complex and costly. To alleviate the problem of insufficient feeding, existing technologies often use large feeding risers to achieve feeding. However, the design and manufacturing of risers increase the complexity of the mold, raising the cost of ingot mold manufacturing by 15%-20%. Moreover, the risers themselves consume a large amount of melt, further reducing material utilization and extending the pouring and solidification cycle.

[0004] To improve cooling performance, existing technologies have made preliminary explorations: First, optimizing the water flow parameters of a single water channel to accelerate solidification by increasing the overall cooling water volume has not solved the problem of uneven cooling in different sections, and has instead exacerbated the contradiction between defects at the top and bottom. Second, adding local cooling devices outside the ingot mold can adjust the local cooling intensity in a targeted manner, but the structure is complex, the operation is cumbersome, and it is easy to cause over-cooling and stress cracks. Third, using irregular riser designs to improve the feeding effect has not yet solved the problem of synergistic matching between cooling and feeding, and the risk of feeding failure still exists. In addition, some scholars have tried to use segmented water channel designs, but this only achieves the division of cooling areas and has not established a timing control strategy adapted to the solidification process and melt feeding, thus failing to fundamentally solve the core problem of the disconnect between cooling and feeding.

[0005] With the increasing demands from high-end manufacturing industries for casting material utilization (≥95%) and internal quality (≤5mm depth of central shrinkage cavity), as well as the urgent need for cost reduction and efficiency improvement in industrial production, traditional cooling water circuit designs can no longer meet production requirements. The industry urgently needs to develop a new ingot mold water circuit technology that can achieve "dynamically adjustable cooling intensity and precise coordination between cooling and shrinkage compensation" to fill the existing technological gap. Summary of the Invention

[0006] The core objective of this invention is to provide a water channel structure and process for ingot casting based on segmented temperature control and melt feeding synergy. This is an ingot mold water channel device and supporting process that integrates segmented temperature control and melt feeding synergy design. It is particularly suitable for castings for high-end equipment with stringent requirements for material utilization and internal quality (such as large gear billets, nuclear power pressure vessel billets, and marine engineering steel billets). It can effectively solve problems such as uneven cooling, feeding failure, and material waste in traditional ingot molds, and provide technical support for the high efficiency and high quality of ingot casting production.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A water channel structure for ingot casting based on segmented temperature control and melt feeding synergy is disclosed. This structure comprises 3-5 independent, sealed annular water channels along the height direction inside the sidewall of the ingot mold. Each annular water channel has a rectangular cross-section, with its center 30-50 mm from the inner wall of the mold, a width of 20-30 mm, and a height of 15-25 mm. The ingot mold is made of HT250 or QT400-18 cast iron, with a high temperature resistance ≥1600℃ and a tensile strength ≥400 MPa.

[0008] The number of annular water channels is adjusted according to the total height of the ingot mold: when the total height of the ingot mold is <3m, 3 independent annular water channels are set; when the total height of the ingot mold is 3-5m, 4 independent annular water channels are set; when the total height of the ingot mold is >5m, 5 independent annular water channels are set.

[0009] The distribution ratio of each segment of the annular water channel along the height of the ingot mold is as follows: Three-section annular water channel: the bottom section accounts for 18%-22% of the total height of the ingot mold, the middle section accounts for 28%-32%, and the top section accounts for 48%-52%; Four-section annular water channel: the bottom section accounts for 18%-22% of the total height of the ingot mold, the lower middle section accounts for 23%-27%, the upper middle section accounts for 28%-32%, and the top section accounts for 23%-27%; Five-section annular water channel: the bottom section accounts for 16%-20% of the total height of the ingot mold, the lower middle section accounts for 20%-24%, the middle middle section accounts for 23%-27%, the upper middle section accounts for 20%-24%, and the top section accounts for 11%-15%.

[0010] Each section of the annular water circuit is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor. The inlet valve is an electromagnetic flow control valve with a control accuracy of ±0.5L / min. The flow meter has a measurement range of 0-50L / min, and the temperature sensor has a measurement range of 0-200℃. This allows for independent adjustment of cooling parameters for each section of the water circuit and real-time monitoring of inlet and outlet water temperatures. All water circuit interfaces are sealed with fluororubber gaskets that are resistant to high temperatures ≥200℃ to ensure no cross-contamination or leakage.

[0011] The inner wall of the annular water channel is coated with a Ni-Cr-Al-Y coating with a thickness of 5-8mm using plasma spraying technology. The coating has a thermal conductivity of ≥20W / (m•K), is resistant to long-term corrosion by cooling water, and ensures long-term stable cooling efficiency.

[0012] A 50-80mm thick high-alumina refractory insulation layer is wrapped around the outer side of the top annular water channel. The insulation layer contains ≥85% Al2O3 and has a thermal conductivity ≤0.3W / (m•K) at room temperature. The inner side of the insulation layer is tightly fitted to the outer wall of the water channel, and the outer side is secured with stainless steel plates. This insulation layer effectively prevents heat loss from the top area, maintaining a temperature ≥1450℃ in the top feeding zone even in the later stages of solidification. This ensures good melt fluidity, continuously replenishes the shrinkage space in the core until the core is completely solidified, and completely eliminates central shrinkage cavities.

[0013] A segmented temperature control-melt feeding synergistic cooling process is proposed. The start-up and shutdown of each segment of the annular water channel and the parameters are dynamically adjusted according to the four stages of casting pouring and solidification. This guides the solidification sequence to proceed step by step from bottom to top, while precisely matching the melt feeding process to ensure that the feeding channel remains unobstructed.

[0014] The four stages are divided according to the total pouring volume as follows: the initial pouring stage corresponds to a total pouring volume ≤ 20%, the early solidification stage corresponds to a total pouring volume of 20% < pouring volume ≤ 50%, the middle solidification stage corresponds to a total pouring volume of 50% < pouring volume ≤ 80%, and the late solidification stage corresponds to a total pouring volume of 80% < pouring volume ≤ 100%.

[0015] Based on the number of annular water channels set on the side wall of the ingot mold, the specific process is divided into the following three parallel and independent technical solutions: Option 1: When three independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: Initial stage of casting: This stage is mainly about filling with melt. Only the bottom section of the annular water channel is opened, and the cooling water volume is controlled at 5-10L / min with a flow rate of 0.5-1m / s to slightly cool the bottom melt and avoid solidification delay caused by heat accumulation at the bottom. The other sections of the annular water channel are kept closed to ensure that the melt in the top and middle areas is at a high temperature of ≥1500℃, reduce the melt filling resistance, and ensure that the cavity is completely filled. Pre-solidification stage: Open the bottom and middle annular water channels, increase the water flow rate of the bottom channel to 15-20 L / min and the flow rate to 1-1.5 m / s; control the water flow rate of the middle annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s, and keep the top water channel closed; Mid-stage of solidification: Open all three annular water channels. Keep the flow rate and velocity of the bottom and middle annular water channels unchanged, and adjust the flow rate of the top annular water channel to 15-20 L / min and the velocity to 1-1.5 m / s. During the later stages of solidification: the water flow rate in the top section is controlled at 10-15 L / min and the flow rate is 0.8-1.2 m / s; the water flow rate in the bottom section is reduced to 10-15 L / min and the flow rate is 0.8-1.0 m / s; the water flow rate and flow rate in the middle section are maintained until the surface temperature of the casting drops below 1000℃. Option 2: When four independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: Initial stage of casting: This stage is mainly about filling with melt. Only the bottom section of the annular water channel is opened, and the cooling water volume is controlled at 5-10L / min with a flow rate of 0.5-1m / s to slightly cool the bottom melt and avoid solidification delay caused by heat accumulation at the bottom. The other sections of the annular water channel are kept closed to ensure that the melt in the top and middle areas is at a high temperature of ≥1500℃, reduce the melt filling resistance, and ensure that the cavity is completely filled. Pre-solidification stage: Open the bottom section and lower-middle section annular water channels. Increase the water flow rate in the bottom section to 15-20 L / min and the flow rate to 1-1.5 m / s. Control the water flow rate in the lower-middle section annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s. Keep the other upper sections of the water channels closed. Mid-stage of solidification: Open the bottom, lower-middle, and upper-middle annular water channels. Keep the flow rate and velocity of the bottom and lower-middle annular water channels unchanged. Adjust the flow rate of the upper-middle annular water channel to 15-20 L / min and the velocity to 1-1.5 m / s. Keep the top water channel closed and maintain the top feed channel unobstructed. Later stage of solidification: Open all annular water channels, control the water flow rate of the top section to 10-15L / min and the flow rate to 0.8-1.2m / s; reduce the water flow rate of the bottom section to 10-15L / min and the flow rate to 0.8-1.0m / s; maintain the original water flow rate and flow rate in the lower middle section and the upper middle section until the surface temperature of the casting drops below 1000℃; Option 3: When five independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: Initial stage of casting: This stage is mainly about filling with melt. Only the bottom section of the annular water channel is opened, and the cooling water volume is controlled at 5-10L / min with a flow rate of 0.5-1m / s to slightly cool the bottom melt and avoid solidification delay caused by heat accumulation at the bottom. The other sections of the annular water channel are kept closed to ensure that the melt in the top and middle areas is at a high temperature of ≥1500℃, reduce the melt filling resistance, and ensure that the cavity is completely filled. Pre-solidification stage: Open the bottom section and lower-middle section annular water channels. Increase the water flow rate in the bottom section to 15-20 L / min and the flow rate to 1-1.5 m / s. Control the water flow rate in the lower-middle section annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s. Keep the other upper sections of the water channels closed. Mid-stage of solidification: Open the bottom, lower-middle, middle-middle, and upper-middle annular water channels. Keep the flow rate and velocity of the bottom and lower-middle annular water channels unchanged. Adjust the flow rate of the middle-middle and upper-middle annular water channels to 15-20 L / min and the velocity to 1-1.5 m / s. Keep the top water channel closed and maintain the top feed channel unobstructed. During the later stage of solidification: open all annular water channels, control the water flow rate in the top section to 10-15 L / min and the flow rate to 0.8-1.2 m / s; reduce the water flow rate in the bottom section to 10-15 L / min and the flow rate to 0.8-1.0 m / s; maintain the original water flow rate and flow rate in the lower middle section, middle middle section and upper middle section until the surface temperature of the casting drops below 1000℃.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Constructing a segmented dynamic cooling water circuit and a melt feeding synergy system, the precise synergy of cooling and feeding reduces the center shrinkage cavity depth of castings from 20-50mm in traditional processes to ≤5mm, the center porosity grade from 2.5 to below 1.0, and the material utilization rate from 80%-85% in traditional processes to over 95%. It reduces steel scrap by 150-450kg per ton of castings. Based on an annual production capacity of 100,000 tons, it can save 1,500-4,500 tons of steel per year, resulting in significant direct economic benefits.

[0017] 2. Achieving precise matching between cooling intensity and solidification process, segmented time-sequential temperature control reduces the internal and external temperature gradient of castings from 80-120℃ / cm in traditional processes to 30-50℃ / cm, significantly alleviating thermal stress concentration, reducing the casting crack rate from 3%-5% in traditional processes to ≤0.8%, and narrowing the tensile strength deviation of castings in the same batch to ±5MPa, improving mechanical property stability by more than 25% compared to traditional processes.

[0018] 3. No need to add large feeding risers, greatly simplifying the ingot mold structure and reducing ingot mold manufacturing costs by 15%-20%. At the same time, it reduces melt consumption caused by risers, further reducing raw material costs. The coordinated promotion of cooling and feeding shortens the total casting and solidification cycle by 10%-15%, significantly improves the production efficiency of a single furnace, and can increase the annual production capacity of the production line by 10%-12%.

[0019] 4. The water channel structure can be flexibly adjusted according to ingot molds of different capacities and heights. The cooling parameters can be adapted to the production of various steel grades such as carbon steel, alloy steel, stainless steel, and heat-resistant steel. There is no need to modify the main equipment of the existing mold casting production line. The modification cost of a single production line is ≤800,000 yuan, and the modification cycle is ≤7 days. The operation process is simple and the cooling sequence can be fully automated through the PLC system, reducing the error of manual intervention and having broad industrial application prospects. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the annular water channel structure in the ingot mold of the present invention.

[0021] In the diagram: 1-Flow meter, 2-Inlet valve, 3-Annular water circuit, 4-Ingot mold, 5-Outlet valve. Detailed Implementation

[0022] To further describe the present invention, specific embodiments are provided below, which will more clearly demonstrate the advantages and various effects of the present invention. Those skilled in the art should understand that these specific embodiments are illustrative of the invention and not intended to limit it.

[0023] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0024] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0025] like Figure 1 As shown, a water channel structure for ingot casting based on segmented temperature control and melt feeding synergy is provided. 3-5 independently operating annular water channels 3 are opened inside the side wall of the ingot mold 4. The cross-section of the annular water channel 3 is rectangular, the center of the annular water channel 3 is 30-50mm from the inner wall of the ingot mold 4, and the width of the annular water channel 3 is 20-30mm.

[0026] Cast iron ingot molds are used: the material is HT250 or QT400-18, the temperature resistance is ≥1600℃, and the tensile strength is ≥400MPa.

[0027] The number of annular water channels 3 is adjusted according to the total height of the ingot mold 4: when the total height of the ingot mold 4 is <3m, 3 independent annular water channels 3 are set; when the total height of the ingot mold 4 is 3-5m, 4 independent annular water channels 3 are set; when the total height of the ingot mold 4 is >5m, 5 independent annular water channels 3 are set. Each annular water channel 3 is independently sealed to avoid cross-contamination affecting the cooling effect. The distance from the center of the water channel to the inner wall of the ingot mold is 30-50mm, and the cross-sectional dimensions of the annular water channel 3 are (20-30)mm×(15-25)mm; while ensuring the cooling effect, the wall of the ingot mold 4 is not too thin, resulting in insufficient strength; the height ratio of each annular water channel 3 is strictly adapted to the solidification and shrinkage requirements.

[0028] The distribution ratio of each segment of the annular water channel along the height of the ingot mold is as follows: 3-section annular water channel 3: the bottom section accounts for 18%-22% of the total height of the ingot mold 4, the middle section accounts for 28%-32%, and the top section accounts for 48%-52%; 4-section annular water channel 3: the bottom section accounts for 18%-22% of the total height of the ingot mold 4, the lower middle section accounts for 23%-27%, the upper middle section accounts for 28%-32%, and the top section accounts for 23%-27%; 5-section annular water channel 3: the bottom section accounts for 16%-20% of the total height of the ingot mold 4, the lower middle section accounts for 20%-24%, the middle middle section accounts for 23%-27%, the upper middle section accounts for 20%-24%, and the top section accounts for 11%-15%.

[0029] Each section of the annular water circuit 3 is equipped with an independent inlet valve 2 (electromagnetic flow control valve, control accuracy ±0.5L / min), outlet valve 5, flow meter 1 (measurement range 0-50L / min), and temperature sensor (measurement range 0-200℃). The cooling water volume (5-30L / min) and flow rate (0.5-2m / s) can be adjusted independently, and the temperature difference between the inlet and outlet water can be monitored in real time, providing a basis for adjusting cooling parameters.

[0030] The inner wall of the annular water channel 3 is coated with a Ni-Cr-Al-Y coating with a thickness of 5-8mm using plasma spraying technology. The coating has a thermal conductivity of ≥20W / (m•K). It has strong corrosion resistance and high thermal conductivity, preventing the cooling water from corroding the water channel. The interfaces of each section of the water channel are sealed with fluororubber gaskets (high temperature resistant ≥200℃) to ensure no water leakage.

[0031] To ensure the top melt retains its feeding capacity during the later stages of solidification, a 50-80mm thick high-alumina refractory insulation layer (Al2O3 content ≥85%, thermal conductivity at room temperature ≤0.3W / (m•K)) is wrapped around the outside of the annular water channel in the top section. The inner side of the insulation layer is tightly fitted to the outer wall of the water channel, and the outer side is fixed with a stainless steel plate. This insulation layer effectively prevents heat loss from the top area, maintaining a temperature of ≥1450℃ in the top feeding zone even during the later stages of solidification. This ensures good melt fluidity, continuously replenishing the shrinkage space in the core until the core is completely solidified, thus completely eliminating central shrinkage cavities.

[0032] A segmented temperature control-melt feeding synergistic cooling process is proposed. The start-up and shutdown of each segment of the annular water channel and the parameters are dynamically adjusted according to the four stages of casting pouring and solidification. This guides the solidification sequence to proceed step by step from bottom to top, while precisely matching the melt feeding process to ensure that the feeding channel remains unobstructed.

[0033] The four stages are divided according to the total pouring volume as follows: the initial pouring stage corresponds to a total pouring volume ≤ 20%, the early solidification stage corresponds to a total pouring volume of 20% < pouring volume ≤ 50%, the middle solidification stage corresponds to a total pouring volume of 50% < pouring volume ≤ 80%, and the late solidification stage corresponds to a total pouring volume of 80% < pouring volume ≤ 100%.

[0034] Based on the number of annular water channels set on the side wall of the ingot mold, the specific process is divided into the following three parallel and independent technical solutions: Option 1: When three independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: Initial stage of casting: This stage is mainly about filling with melt. Only the bottom section of the annular water channel is opened, and the cooling water volume is controlled at 5-10L / min with a flow rate of 0.5-1m / s to slightly cool the bottom melt and avoid solidification delay caused by heat accumulation at the bottom. The other sections of the annular water channel are kept closed to ensure that the melt in the top and middle areas is at a high temperature of ≥1500℃, reduce the melt filling resistance, and ensure that the cavity is completely filled. Pre-solidification stage: Open the bottom and middle annular water channels, increase the water flow rate of the bottom channel to 15-20 L / min and the flow rate to 1-1.5 m / s; control the water flow rate of the middle annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s, and keep the top water channel closed; Mid-stage of solidification: Open all three annular water channels. Keep the flow rate and velocity of the bottom and middle annular water channels unchanged, and adjust the flow rate of the top annular water channel to 15-20 L / min and the velocity to 1-1.5 m / s. During the later stages of solidification: the water flow rate in the top section is controlled at 10-15 L / min and the flow rate is 0.8-1.2 m / s; the water flow rate in the bottom section is reduced to 10-15 L / min and the flow rate is 0.8-1.0 m / s; the water flow rate and flow rate in the middle section are maintained until the surface temperature of the casting drops below 1000℃. Option 2: When four independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: Initial stage of casting: This stage is mainly about filling with melt. Only the bottom section of the annular water channel is opened, and the cooling water volume is controlled at 5-10L / min with a flow rate of 0.5-1m / s to slightly cool the bottom melt and avoid solidification delay caused by heat accumulation at the bottom. The other sections of the annular water channel are kept closed to ensure that the melt in the top and middle areas is at a high temperature of ≥1500℃, reduce the melt filling resistance, and ensure that the cavity is completely filled. Pre-solidification stage: Open the bottom section and lower-middle section annular water channels. Increase the water flow rate in the bottom section to 15-20 L / min and the flow rate to 1-1.5 m / s. Control the water flow rate in the lower-middle section annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s. Keep the other upper sections of the water channels closed. Mid-stage of solidification: Open the bottom, lower-middle, and upper-middle annular water channels. Keep the flow rate and velocity of the bottom and lower-middle annular water channels unchanged. Adjust the flow rate of the upper-middle annular water channel to 15-20 L / min and the velocity to 1-1.5 m / s. Keep the top water channel closed and maintain the top feed channel unobstructed. Later stage of solidification: Open all annular water channels, control the water flow rate of the top section to 10-15L / min and the flow rate to 0.8-1.2m / s; reduce the water flow rate of the bottom section to 10-15L / min and the flow rate to 0.8-1.0m / s; maintain the original water flow rate and flow rate in the lower middle section and the upper middle section until the surface temperature of the casting drops below 1000℃; Option 3: When five independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: Initial stage of casting: This stage is mainly about filling with melt. Only the bottom section of the annular water channel is opened, and the cooling water volume is controlled at 5-10L / min with a flow rate of 0.5-1m / s to slightly cool the bottom melt and avoid solidification delay caused by heat accumulation at the bottom. The other sections of the annular water channel are kept closed to ensure that the melt in the top and middle areas is at a high temperature of ≥1500℃, reduce the melt filling resistance, and ensure that the cavity is completely filled. Pre-solidification stage: Open the bottom section and lower-middle section annular water channels. Increase the water flow rate in the bottom section to 15-20 L / min and the flow rate to 1-1.5 m / s. Control the water flow rate in the lower-middle section annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s. Keep the other upper sections of the water channels closed. Mid-stage of solidification: Open the bottom, lower-middle, middle-middle, and upper-middle annular water channels. Keep the flow rate and velocity of the bottom and lower-middle annular water channels unchanged. Adjust the flow rate of the middle-middle and upper-middle annular water channels to 15-20 L / min and the velocity to 1-1.5 m / s. Keep the top water channel closed and maintain the top feed channel unobstructed. During the later stage of solidification: open all annular water channels, control the water flow rate in the top section to 10-15 L / min and the flow rate to 0.8-1.2 m / s; reduce the water flow rate in the bottom section to 10-15 L / min and the flow rate to 0.8-1.0 m / s; maintain the original water flow rate and flow rate in the lower middle section, middle middle section and upper middle section until the surface temperature of the casting drops below 1000℃.

[0035] The present invention will be described in detail below through six specific embodiments. These embodiments are only used to illustrate the present invention and do not constitute a limitation on the scope of protection.

[0036] Example 1: 50 tons of Q235 carbon steel ultra-thick castings (thickness 450mm); Ingot mold parameters: capacity 50 tons, total height 2.8m, adopts a 3-section annular water channel; the bottom section accounts for 20% of the ingot mold height, the middle section accounts for 30%, and the top section accounts for 50%; the annular water channel cross-section is 20mm×15mm, and the center distance of the water channel from the inner wall of the ingot mold is 30mm; the outer side of the top section of the water channel is wrapped with a 50mm thick high-alumina refractory material insulation layer with an Al2O3 content of 85%; the ingot mold body is made of HT250 cast iron; the inner wall of the annular water channel is coated with a 5mm thick Ni-Cr-Al-Y coating using plasma spraying technology; each section of the water channel is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

[0037] Application process: Pouring temperature 1520-1550℃; Initial stage of pouring (0-20% of total pouring volume): Only open the bottom section water passage, water flow rate 5L / min, flow rate 0.5m / s; Early stage of solidification (20%-50% of total pouring volume): Open the bottom and middle sections of the water passage, bottom section water flow rate 15L / min, flow rate 1.0m / s, middle section water flow rate 10L / min, flow rate 0.8m / s, the top section water passage remains closed; Mid-stage of solidification (total (Pouring volume 50%-80%): Open all three water channels, keep the parameters of the bottom and middle sections unchanged, and set the water flow rate of the top section to 15L / min and the flow rate to 1.0m / s; (Later solidification stage, total pouring volume 80%-100%): Adjust the water flow rate of the top section to 10L / min and the flow rate to 0.8m / s, reduce the water flow rate of the bottom section to 10L / min and the flow rate to 0.8m / s, and maintain the original parameters of the middle section until the surface temperature of the casting drops below 1000℃.

[0038] Implementation results: The central shrinkage cavity depth of the casting is 3mm, and the material utilization rate is 95.2%; the internal and external temperature gradient of the casting is 30℃ / cm, and the crack rate is 0.5%; the manufacturing cost of the ingot mold is reduced by 15% compared with the traditional ingot mold, and the solidification cycle of the casting is shortened by 10%; the measured tensile strength of the casting body is 420MPa, the yield strength is 235MPa, and the mechanical property deviation of the same batch is ±3MPa, which fully meets the requirements for use in heavy machinery frames.

[0039] Example 2: 120 tons of 42CrMo alloy steel ultra-thick casting (thickness 600mm); Ingot mold parameters: capacity 120 tons, total height 3.5m, adopts a 4-section annular water channel; the bottom section accounts for 20% of the ingot mold height, the lower middle section accounts for 25%, the upper middle section accounts for 30%, and the top section accounts for 25%; the annular water channel cross-section is 25mm×20mm, and the center distance of the water channel from the inner wall of the ingot mold is 35mm; the outer side of the top section water channel is wrapped with a 60mm thick high-alumina refractory material insulation layer with an Al2O3 content of 88%; the ingot mold body is made of QT400-18 ductile iron; the inner wall of the annular water channel is coated with a 6mm thick Ni-Cr-Al-Y coating using plasma spraying technology; each section of the water channel is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

[0040] Application Process: Pouring temperature 1540-1570℃; Initial pouring stage (0-20% of total pouring volume): Only open the bottom section water channel, water flow rate 8L / min, flow rate 0.8m / s; Early setting stage (20%-50% of total pouring volume): Open the bottom section and lower-middle section water channels, bottom section water flow rate 18L / min, flow rate 1.2m / s, lower-middle section water flow rate 12L / min, flow rate 1.0m / s, keep the upper-middle and top section water channels closed; Mid-setting stage (50%-80% of total pouring volume) Open the bottom section, lower middle section, and upper middle section water channels. Keep the parameters of the bottom section and lower middle section unchanged. The water flow rate of the upper middle section is 18L / min and the flow rate is 1.2m / s. Keep the top section water channel closed. In the later stage of solidification (80%-100% of the total casting volume): Open all four water channels. The water flow rate of the top section is 12L / min and the flow rate is 1.0m / s. The water flow rate of the bottom section is reduced to 12L / min and the flow rate is 0.9m / s. The lower middle section and upper middle section maintain the original parameters until the surface temperature of the casting drops below 1000℃.

[0041] Implementation results: The central shrinkage cavity depth of the casting is 4mm, and the material utilization rate is 95.8%; the internal and external temperature gradient of the casting is 35℃ / cm, and the crack rate is 0.6%; the manufacturing cost of the ingot mold is reduced by 18% compared with the traditional ingot mold, and the solidification cycle of the casting is shortened by 12%; the measured tensile strength of the casting body is 985MPa, the yield strength is 855MPa, and the mechanical property deviation of the same batch is ±4MPa, which fully meets the performance requirements of the wind turbine main shaft.

[0042] Example 3: 200 tons of 304 stainless steel ultra-thick castings (750mm thick); Ingot mold parameters: capacity 200 tons, total height 4.0m, adopts a 4-section annular water channel; the bottom section accounts for 20% of the ingot mold height, the lower middle section accounts for 25%, the upper middle section accounts for 30%, and the top section accounts for 25%; the annular water channel cross-section is 28mm×22mm, and the center distance of the water channel from the inner wall of the ingot mold is 40mm; the outer side of the top section water channel is wrapped with a 70mm thick high-alumina refractory material insulation layer with an Al2O3 content of 86%; the ingot mold body is made of QT400-18 ductile iron; the inner wall of the annular water channel is coated with a 7mm thick Ni-Cr-Al-Y coating using plasma spraying technology; each section of the water channel is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

[0043] Application Process: Pouring temperature 1530-1560℃; Initial stage of pouring (0-20% of total pouring volume): Only open the bottom section water passage, water flow rate 10L / min, flow rate 1.0m / s; Early stage of solidification (20%-50% of total pouring volume): Open the bottom section and lower middle section water passages, bottom section water flow rate 20L / min, flow rate 1.5m / s, lower middle section water flow rate 15L / min, flow rate 1.2m / s, keep the upper middle section and top section water passages closed; Mid-stage of solidification (50%-80% of total pouring volume) Open the bottom section, lower middle section, and upper middle section water channels. Keep the parameters of the bottom section and lower middle section unchanged. The water flow rate of the upper middle section is 20L / min and the flow rate is 1.5m / s. Keep the top section water channel closed. In the later stage of solidification (80%-100% of the total casting volume): open all four water channels. The water flow rate of the top section is 15L / min and the flow rate is 1.2m / s. The water flow rate of the bottom section is reduced to 15L / min and the flow rate is 1.0m / s. The lower middle section and upper middle section maintain their original parameters until the surface temperature of the casting drops below 1000℃.

[0044] Implementation results: The central shrinkage cavity depth of the casting is 4.5mm, and the material utilization rate is 96.1%; the internal and external temperature gradient of the casting is 40℃ / cm, and the crack rate is 0.7%; the manufacturing cost of the ingot mold is reduced by 17% compared with the traditional ingot mold, and the solidification cycle of the casting is shortened by 13%; no rust was found after 2000 hours of testing with 5% NaCl solution and 35℃ neutral salt spray, which fully meets the requirements for use in marine engineering equipment.

[0045] Example 4: 80 tons of 12Cr1MoV heat-resistant steel ultra-thick castings (900mm thick); Ingot mold parameters: capacity 80 tons, total height 2.2m, adopts a 3-section annular water channel; the bottom section accounts for 20% of the ingot mold height, the middle section accounts for 30%, and the top section accounts for 50%; the annular water channel cross-section is 22mm×18mm, and the center distance of the water channel from the inner wall of the ingot mold is 32mm; the outer side of the top section of the water channel is wrapped with a 55mm thick high-alumina refractory material insulation layer with an Al2O3 content of 87%; the ingot mold body is made of HT250 cast iron; the inner wall of the annular water channel is coated with a 6mm thick Ni-Cr-Al-Y coating using plasma spraying technology; each section of the water channel is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

[0046] Application process: Pouring temperature 1550-1580℃; Initial stage of pouring (0-20% of total pouring volume): Only open the bottom section water passage, water flow rate 7L / min, flow rate 0.7m / s; Early stage of solidification (20%-50% of total pouring volume): Open the bottom and middle sections of the water passage, bottom section water flow rate 16L / min, flow rate 1.1m / s, middle section water flow rate 11L / min, flow rate 0.9m / s, the top section water passage remains closed; Mid-stage of solidification (total (Pouring volume 50%-80%): Open all three water channels, keep the parameters of the bottom and middle sections unchanged, and set the water flow rate of the top section to 16L / min and the flow rate to 1.1m / s; (Later solidification stage, total pouring volume 80%-100%): Adjust the water flow rate of the top section to 11L / min and the flow rate to 0.9m / s, reduce the water flow rate of the bottom section to 11L / min and the flow rate to 0.9m / s, and maintain the original parameters of the middle section until the surface temperature of the casting drops below 1000℃.

[0047] Implementation results: The central shrinkage cavity depth of the casting is 3.5mm, and the material utilization rate is 95.5%; the internal and external temperature gradient of the casting is 32℃ / cm, and the crack rate is 0.4%; the manufacturing cost of the ingot mold is reduced by 16% compared with the traditional ingot mold, and the solidification cycle of the casting is shortened by 11%; the high-temperature creep strength at 550℃ and 1000h is 185MPa, which fully meets the technical requirements of thermal power equipment shells.

[0048] Example 5: 150 tons of Q345B low-alloy high-strength steel ultra-thick castings (thickness 500mm); Ingot mold parameters: capacity 150 tons, total height 5.2m, adopts a 5-section annular water channel; the bottom section accounts for 18% of the ingot mold height, the lower middle section 22%, the middle middle section 25%, the upper middle section 22%, and the top section 13%; the annular water channel cross-section is 26mm×21mm, and the center distance of the water channel from the inner wall of the ingot mold is 38mm; the outer side of the top section water channel is wrapped with a 65mm thick high-alumina refractory material insulation layer with an Al2O3 content of 85%; the ingot mold body is made of QT400-18 ductile iron; the inner wall of the annular water channel is coated with a 7mm thick Ni-Cr-Al-Y coating using plasma spraying technology; each section of the water channel is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

[0049] Application process: Pouring temperature 1510-1540℃; Initial stage of pouring (0-20% of total pouring volume): Only open the bottom section water passage, water flow rate 6L / min, flow rate 0.6m / s; Early stage of solidification (20%-50% of total pouring volume): Open the bottom section + lower middle section water passages, bottom section water flow rate 17L / min, flow rate 1.3m / s, lower middle section water flow rate 13L / min, flow rate 1.1m / s, keep the middle-middle section, upper-middle section and top section water passages closed; Mid-stage of solidification (50%-80% of total pouring volume): Open the bottom section + lower middle section water passages. +Middle-middle section +Upper-middle section water passages, bottom and lower middle section parameters remain unchanged, middle-middle section water flow rate 17L / min, flow rate 1.3m / s, upper-middle section water flow rate 15L / min, flow rate 1.2m / s, top section water passage remains closed; late solidification stage (total casting volume 80%-100%): open all five water passages, top section water flow rate 10L / min, flow rate 0.8m / s, bottom section water flow rate reduced to 13L / min, flow rate 0.9m / s, the remaining middle sections maintain the original parameters until the casting surface temperature drops below 1000℃.

[0050] Implementation results: The center shrinkage cavity depth of the casting is 2.8mm, and the material utilization rate is 96.3%; the internal and external temperature gradient of the casting is 38℃ / cm, and the crack rate is 0.5%; the manufacturing cost of the ingot mold is reduced by 20% compared with the traditional ingot mold, and the solidification cycle of the casting is shortened by 14%; the impact energy at -20℃ is 68J, which fully meets the requirements of heavy-duty use of engineering machinery.

[0051] Example 6: 250 tons of S30408 ​​stainless steel ultra-thick castings (thickness 800mm); Ingot mold parameters: capacity 250 tons, total height 5.5m, adopts a 5-section annular water channel; bottom section accounts for 18% of the ingot mold height, lower middle section 22%, middle middle section 25%, upper middle section 22%, and top section 13%; the annular water channel cross-section is 30mm×25mm, and the center distance of the water channel from the inner wall of the ingot mold is 45mm; the outer side of the top section water channel is wrapped with an 80mm thick high-alumina refractory material insulation layer with an Al2O3 content of 90%; the ingot mold body is made of QT400-18 ductile iron; the inner wall of the annular water channel is coated with an 8mm thick Ni-Cr-Al-Y coating using plasma spraying technology; each section of the water channel is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

[0052] Application process: Pouring temperature 1540-1570℃; Initial stage of pouring (0-20% of total pouring volume): Only open the bottom section water passage, water flow rate 9L / min, flow rate 0.9m / s; Early stage of solidification (20%-50% of total pouring volume): Open the bottom section + lower middle section water passages, bottom section water flow rate 19L / min, flow rate 1.4m / s, lower middle section water flow rate 14L / min, flow rate 1.2m / s, keep the middle-middle section, upper-middle section and top section water passages closed; Mid-stage of solidification (50%-80% of total pouring volume): Open the bottom section + lower middle section water passages. +Middle-middle section +Upper-middle section water passages, bottom and lower-middle section parameters remain unchanged, middle-middle section water flow rate 19L / min, flow rate 1.4m / s, upper-middle section water flow rate 15L / min, flow rate 1.2m / s, top section water passage remains closed; late solidification stage (total casting volume 80%-100%): open all five water passages, top section water flow rate 13L / min, flow rate 1.0m / s, bottom section water flow rate reduced to 14L / min, flow rate 1.0m / s, the remaining middle sections maintain the original parameters until the casting surface temperature drops below 1000℃.

[0053] Implementation results: The central shrinkage cavity depth of the casting is 4.8mm, and the material utilization rate is 95.9%; the internal and external temperature gradient of the casting is 45℃ / cm, and the crack rate is 0.8%; the manufacturing cost of the ingot mold is reduced by 19% compared with the traditional ingot mold, and the solidification cycle of the casting is shortened by 15%; no rust was found after 2500 hours of testing in 5% NaCl solution and 35℃ neutral salt spray, and the uniform corrosion resistance is improved by 28% compared with the parts produced by the traditional process, which fully meets the stringent requirements of marine engineering equipment.

[0054] The above embodiments demonstrate that the segmented temperature control-melt feeding synergistic ingot mold water circuit device and process of the present invention can play a stable role in the production of ultra-thick castings of different capacities and materials. Through structural innovation and process synergy, it achieves precise matching of cooling and feeding, and has advantages in quality, cost and efficiency, and has significant industrial application value and promotion prospects.

[0055] This invention designs an independently sealed annular water channel based on the ingot mold height, with each section's height precisely matched to the solidification and feeding requirements. Each water channel is equipped with an independent electromagnetic flow control valve, flow meter, and temperature sensor, allowing for individual adjustment of cooling water volume and flow rate. This enables regional dynamic adjustment of cooling intensity, solving the core problem of uneven cooling in traditional technologies. Through a four-stage timing control logic—"initial casting stage - early solidification stage - mid-solidification stage - late solidification stage"—the solidification sequence is guided to progress gradually from bottom to top. By dynamically adjusting the start / stop status and parameters of each water channel section, the cooling process is precisely matched to the melt feeding requirements, preventing premature closure of the feeding channels. This completely solves the key problem of disconnect between cooling and feeding in traditional technologies, achieving a synergistic effect of "cooling guiding solidification and feeding following shrinkage." This invention adds a high-alumina refractory insulation layer to the outside of the top water channel section, maintaining the temperature of the top feeding area at ≥1450℃. This design eliminates the need for large feeding risers, ensuring that the melt retains good fluidity during the later stages of solidification and continuously replenishes the core shrinkage space. This simplifies the mold structure and avoids material waste and increased costs associated with risers.

[0056] Those skilled in the art should recognize that the above embodiments are merely illustrative of the invention and not intended to limit it, but are similarly limited to the scope of the invention. Variations and modifications to the above embodiments will fall within the protection scope of the claims. It should be understood that the endpoints and values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of various ranges, the endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0057] It should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone.

[0058] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A mold ingot mold waterway structure based on segmented temperature control-melt feeding cooperation, characterized in that, Three to five independent, sealed annular water channels are formed along the height direction inside the side wall of the ingot mold. The cross-section of the annular water channel is rectangular, the distance from the center of the water channel to the inner wall of the ingot mold is 30-50mm, the width of the annular water channel is 20-30mm, and the height of the cross-section is 15-25mm.

2. A mold ingot mold waterway structure based on segmented temperature control-melt feeding coordination according to claim 1, characterized in that, The number of annular water channels is adjusted according to the total height of the ingot mold: when the total height of the ingot mold is <3m, 3 independent annular water channels are set; when the total height of the ingot mold is 3-5m, 4 independent annular water channels are set; when the total height of the ingot mold is >5m, 5 independent annular water channels are set.

3. A mold casting ingot mold waterway structure based on segmented temperature control-melt feeding coordination according to claim 2, characterized in that, The distribution ratio of each segment of the annular water channel along the height of the ingot mold is as follows: Three-section annular water channel: the bottom section accounts for 18%-22% of the total height of the ingot mold, the middle section accounts for 28%-32%, and the top section accounts for 48%-52%; Four-section annular water channel: the bottom section accounts for 18%-22% of the total height of the ingot mold, the lower middle section accounts for 23%-27%, the upper middle section accounts for 28%-32%, and the top section accounts for 23%-27%; Five-section annular water channel: the bottom section accounts for 16%-20% of the total height of the ingot mold, the lower middle section accounts for 20%-24%, the middle middle section accounts for 23%-27%, the upper middle section accounts for 20%-24%, and the top section accounts for 11%-15%.

4. The water channel structure of the segmented temperature control-melt feeding coordination based mold ingot mold according to claim 1, characterized in that, Each section of the circular waterway is equipped with an independent inlet valve, outlet valve, flow meter, and temperature sensor.

5. The water channel structure of the segmented temperature control-melt feeding coordination based mold ingot mold according to claim 1, characterized in that, The inner wall of the annular water channel is coated with a Ni-Cr-Al-Y coating with a thickness of 5-8mm using plasma spraying technology. The coating has a thermal conductivity of ≥20W / (m•K).

6. A mold casting ingot mold waterway structure based on segmented temperature control-melt feeding coordination according to claim 1, characterized in that, A 50-80mm thick high-alumina refractory insulation layer is wrapped around the outer side of the top section of the annular water channel. The insulation layer contains ≥85% Al2O3 and has a thermal conductivity of ≤0.3W / (m•K) at room temperature. The inner side of the insulation layer is tightly fitted to the outer wall of the water channel, and the outer side is fixed with stainless steel plates.

7. A process based on segmented temperature control-melt feeding and synergistic cooling, characterized in that, The ingot mold water channel structure based on segmented temperature control and melt feeding synergy, as described in any one of claims 1-6, is adopted. The start-up, shutdown, and parameters of each segment of the annular water channel are dynamically adjusted according to the four stages of casting pouring and solidification. The specific process, based on the number of annular water channels set on the ingot mold sidewall, is divided into the following three parallel and independent technical solutions: Option 1: When three independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: During the initial stage of pouring: only open the bottom section of the annular water channel, control the cooling water volume at 5-10L / min and the flow rate at 0.5-1m / s, and keep the other sections of the annular water channel closed; Pre-solidification stage: Open the bottom and middle annular water channels, increase the water flow rate of the bottom channel to 15-20 L / min and the flow rate to 1-1.5 m / s; control the water flow rate of the middle annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s, and keep the top water channel closed; Mid-stage of solidification: Open all three annular water channels. Keep the flow rate and velocity of the bottom and middle annular water channels unchanged, and adjust the flow rate of the top annular water channel to 15-20 L / min and the velocity to 1-1.5 m / s. During the later stages of solidification: the water flow rate in the top section is controlled at 10-15 L / min and the flow rate is 0.8-1.2 m / s; the water flow rate in the bottom section is reduced to 10-15 L / min and the flow rate is 0.8-1.0 m / s; the water flow rate and flow rate in the middle section are maintained until the surface temperature of the casting drops below 1000℃. Option 2: When four independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: During the initial stage of pouring: only open the bottom section of the annular water channel, control the cooling water volume at 5-10L / min and the flow rate at 0.5-1m / s, and keep the other sections of the annular water channel closed; Pre-solidification stage: Open the bottom section and lower-middle section annular water channels. Increase the water flow rate in the bottom section to 15-20 L / min and the flow rate to 1-1.5 m / s. Control the water flow rate in the lower-middle section annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s. Keep the other upper sections of the water channels closed. Mid-stage of solidification: Open the bottom, lower-middle, and upper-middle annular water channels. Keep the flow rate and velocity of the bottom and lower-middle annular water channels unchanged. Adjust the flow rate of the upper-middle annular water channel to 15-20 L / min and the velocity to 1-1.5 m / s. Keep the top water channel closed and maintain the top feed channel unobstructed. Later stage of solidification: Open all annular water channels, control the water flow rate of the top section to 10-15L / min and the flow rate to 0.8-1.2m / s; reduce the water flow rate of the bottom section to 10-15L / min and the flow rate to 0.8-1.0m / s; maintain the original water flow rate and flow rate in the lower middle section and the upper middle section until the surface temperature of the casting drops below 1000℃; Option 3: When five independently operating annular water channels are opened inside the side wall of the ingot mold, the process at each stage is as follows: During the initial stage of pouring: only open the bottom section of the annular water channel, control the cooling water volume at 5-10L / min and the flow rate at 0.5-1m / s, and keep the other sections of the annular water channel closed; Pre-solidification stage: Open the bottom section and lower-middle section annular water channels. Increase the water flow rate in the bottom section to 15-20 L / min and the flow rate to 1-1.5 m / s. Control the water flow rate in the lower-middle section annular water channel to 10-15 L / min and the flow rate to 0.8-1.2 m / s. Keep the other upper sections of the water channels closed. Mid-stage of solidification: Open the bottom, lower-middle, middle-middle, and upper-middle annular water channels. Keep the flow rate and velocity of the bottom and lower-middle annular water channels unchanged. Adjust the flow rate of the middle-middle and upper-middle annular water channels to 15-20 L / min and the velocity to 1-1.5 m / s. Keep the top water channel closed and maintain the top feed channel unobstructed. During the later stage of solidification: open all annular water channels, control the water flow rate in the top section to 10-15 L / min and the flow rate to 0.8-1.2 m / s; reduce the water flow rate in the bottom section to 10-15 L / min and the flow rate to 0.8-1.0 m / s; maintain the original water flow rate and flow rate in the lower middle section, middle middle section and upper middle section until the surface temperature of the casting drops below 1000℃.

8. A process based on segmented temperature control-melt feeding and synergic cooling according to claim 7, characterized in that, The four stages are divided according to the total pouring volume as follows: the initial pouring stage corresponds to a total pouring volume ≤ 20%, the early solidification stage corresponds to a total pouring volume of 20% < pouring volume ≤ 50%, the middle solidification stage corresponds to a total pouring volume of 50% < pouring volume ≤ 80%, and the late solidification stage corresponds to a total pouring volume of 80% < pouring volume ≤ 100%.

Images