Rifling type flow regime regulation and control pouring cup adaptive to 1500kg-level vacuum melting and pouring

Abstract

The invention provides a rifling type flow regime regulation and control pouring cup adaptive to 1500kg-level vacuum melting and pouring, and belongs to the technical field of large precision casting vacuum induction melting and pouring equipment, the adaptive pouring speed is 35-39kg / s, the temperature of molten metal is 1510-1550 DEG C, and the rifling type flow regime regulation and control pouring cup comprises an integrally formed pouring cup body; the diameter of an upper opening of the pouring cup body is 380-420 mm, the diameter of a lower opening of the pouring cup body is 120-140 mm, the total height of the pouring cup body is 450-500 mm, and the turning taper of linear transition of the inner wall from the upper end to the lower end is 15-18 degrees; 3-4 spiral riflings are arranged on the inner wall of the pouring cup body, the spiral riflings are uniformly distributed in the circumferential direction of the inner wall of the pouring cup body, and the included angle between the circle centers of the adjacent riflings is 90-120 degrees. According to the invention, the caliber height of the pouring cup is adaptive, and the spiral rifling is adopted for guiding, so that the splashing problem at a high flow speed can be solved in a 1500kg-level 37kg / s high-flow-speed vacuum pouring scene.

Description

Technical Field

[0001] This invention relates to the technical field of vacuum induction melting and casting equipment for large precision castings, and in particular to a pouring cup that can solve the splashing problem at high flow rates in vacuum casting scenarios with a flow rate of 37 kg / s and a flow rate of 1500 kg. Background Technology

[0002] In the vacuum induction melting and casting process of large precision castings (1500kg level), existing technologies suffer from a core contradiction between "large-size flow convergence" and "high-speed flow stability," a contradiction that is particularly pronounced under conditions of high flow rates of 37kg / s and molten metal temperatures of 1530℃. A certain company's current ZG35Cr24Ni7SiN material pouring cup (model: GK-1500) requires replacement on average every 3 pours due to turbulent flow during 1500kg stainless steel casting, resulting in localized temperature concentration on the inner wall and a lifespan of only 5-6 uses. Furthermore, X-ray inspection of the castings reveals that air entrainment during turbulent flow leads to a porosity defect rate of 18-22%, necessitating additional flaw detection and welding processes, increasing the cost per casting by approximately 8000 yuan. Currently, there is no mature flow control scheme or suitable parameter standards for vacuum casting scenarios at the 1500kg level and 37kg / s high flow rate.

[0003] Therefore, how to solve the splashing problem at high flow rates in vacuum casting scenarios with flow rates of 37 kg / s and a flow rate of 1500 kg is an urgent problem for the industry to solve. Summary of the Invention

[0004] A primary objective of this invention is to overcome at least one of the deficiencies of the prior art and to provide a rifling-type flow-controlled pouring cup adapted for 1500kg-level vacuum melting and casting, capable of solving the splashing problem at high flow rates in vacuum casting scenarios at 1500kg level and 37kg / s.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: According to one aspect of the present invention, a rifling-type flow-controlled pouring cup adapted for 1500kg-class vacuum melting and casting is provided, suitable for pouring speeds of 35-39kg / s and molten metal temperatures of 1510-1550℃, comprising an integrally formed pouring cup body; the upper diameter of the pouring cup body is 380-420mm, the lower diameter is 120-140mm, and the total height is 450-500mm, and the inner wall has a linear transition taper of 15-18° from the upper end to the lower end; the inner wall of the pouring cup body is provided with helical rifling, the helical rifling having 3-4 lines, evenly distributed circumferentially along the inner wall of the pouring cup body, and the included angle between the centers of adjacent rifling lines being 90°-120°.

[0006] According to a specific embodiment of the present invention, the cross-section of the helical rifling is trapezoidal, with a top width W1 of 8-12 mm, a bottom width W2 of 15-20 mm, and a height h of 5-8 mm.

[0007] According to a specific embodiment of the present invention, the helix angle β of the spiral rifling is a variable angle structure, which decreases linearly from the upper opening side to the lower opening side of the pouring cup body. The helix angle β1 at the inlet end 10-15mm from the upper edge is 12-15°, and the helix angle β2 at the outlet end 20-25mm from the lower edge is 8-10°.

[0008] According to a specific embodiment of the present invention, the length of the linearly decreasing helix angle transition section of the helical rifling is 350-400 mm, and the difference in helix angle between the two ends of the transition section is 4-6°.

[0009] According to a specific embodiment of the present invention, in the trapezoidal cross-section of the helical rifling, the connection position between the top edge and the side edge, and the bottom edge and the inner wall is provided with a rounded corner, the radius of which is 1-2mm.

[0010] According to a specific embodiment of the present invention, the material of the pouring cup body is high-chromium heat-resistant cast iron, wherein the high-chromium heat-resistant cast iron contains 20-25% Cr, 2.5-3.0% C, 1.0-1.5% Si, and the remainder is Fe and impurities.

[0011] According to a specific embodiment of the present invention, the starting end of the helical rifling is provided with a transition slope, the angle between the transition slope and the inner wall of the pouring cup body is 30°-45°, and the axial length of the transition slope is 5-8mm.

[0012] According to a specific embodiment of the present invention, the lower edge of the pouring cup body is provided with a chamfer, the chamfer angle is 45°, the chamfer width is 5-8mm, and the inner wall of the lower opening is flush with the outlet end of the spiral rifling.

[0013] According to a specific embodiment of the present invention, the inner wall of the pouring cup body and the surface of the spiral rifling are provided with a high-temperature anti-oxidation coating. The coating material is Al2O3-ZrO2 composite ceramic, the coating thickness is 0.1-0.3mm, and the bonding strength between the coating and the substrate is ≥30MPa.

[0014] According to a specific embodiment of the present invention, the helical rifling is machined by a five-axis CNC machine tool, and the helix angle tolerance of the machined rifling is ±0.2°, the cross-sectional dimension tolerance is ±0.3mm, and the surface roughness Ra≤1.6μm.

[0015] As can be seen from the above technical solution, the advantages and positive effects of the rifling-type flow-controlled pouring cup adapted for 1500kg-class vacuum melting and casting of the present invention are as follows: In this invention, the pouring cup has an adapted diameter and height, and uses helical rifling guidance, which can solve the splashing problem at high flow rates in vacuum pouring scenarios with a flow rate of 37 kg / s and a flow rate of 1500 kg. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main structure of the rifling-type flow-regulating pouring cup adapted for 1500kg-class vacuum melting and casting according to the present invention.

[0017] Figure 2 This is a top view schematic diagram of the rifling-type flow-regulating pouring cup adapted for 1500kg-class vacuum melting and casting according to the present invention.

[0018] Figure 3 This is a cross-sectional structural schematic diagram of the rifling-type flow-regulating pouring cup adapted for 1500kg-class vacuum melting and casting according to the present invention.

[0019] Drawing number explanation: 1. Rifling groove one; 2. Rifling groove two; 3. Rifling groove three; 4. Composite ceramic coating; R, helix angle inlet end; Q, helix angle outlet end. Detailed Implementation

[0020] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0021] According to one aspect of the present invention, a rifling-type flow-controlled pouring cup adapted for 1500kg-class vacuum melting and casting is provided, suitable for pouring speeds of 35-39kg / s and molten metal temperatures of 1510-1550℃, comprising an integrally formed pouring cup body; the upper diameter of the pouring cup body is 380-420mm, the lower diameter is 120-140mm, and the total height is 450-500mm, and the inner wall has a linear transition taper of 15-18° from the upper end to the lower end; the inner wall of the pouring cup body is provided with helical rifling, the helical rifling having 3-4 lines, evenly distributed circumferentially along the inner wall of the pouring cup body, and the included angle between the centers of adjacent rifling lines being 90°-120°.

[0022] According to a specific embodiment of the present invention, the cross-section of the helical rifling is trapezoidal, with a top width W1 of 8-12 mm, a bottom width W2 of 15-20 mm, and a height h of 5-8 mm.

[0023] According to a specific embodiment of the present invention, the helix angle β of the spiral rifling is a variable angle structure, which decreases linearly from the upper opening side to the lower opening side of the pouring cup body. The helix angle β1 at the inlet end 10-15mm from the upper edge is 12-15°, and the helix angle β2 at the outlet end 20-25mm from the lower edge is 8-10°.

[0024] According to a specific embodiment of the present invention, the length of the linearly decreasing helix angle transition section of the helical rifling is 350-400 mm, and the difference in helix angle between the two ends of the transition section is 4-6°.

[0025] According to a specific embodiment of the present invention, in the trapezoidal cross-section of the helical rifling, the connection position between the top edge and the side edge, and the bottom edge and the inner wall is provided with a rounded corner, the radius of which is 1-2mm.

[0026] According to a specific embodiment of the present invention, the material of the pouring cup body is high-chromium heat-resistant cast iron, wherein the high-chromium heat-resistant cast iron contains 20-25% Cr, 2.5-3.0% C, 1.0-1.5% Si, and the remainder is Fe and impurities.

[0027] According to a specific embodiment of the present invention, the starting end of the helical rifling is provided with a transition slope, the angle between the transition slope and the inner wall of the pouring cup body is 30°-45°, and the axial length of the transition slope is 5-8mm.

[0028] According to a specific embodiment of the present invention, the lower edge of the pouring cup body is provided with a chamfer, the chamfer angle is 45°, the chamfer width is 5-8mm, and the inner wall of the lower opening is flush with the outlet end of the spiral rifling.

[0029] According to a specific embodiment of the present invention, the inner wall of the pouring cup body and the surface of the spiral rifling are provided with a high-temperature anti-oxidation coating. The coating material is Al2O3-ZrO2 composite ceramic, the coating thickness is 0.1-0.3mm, and the bonding strength between the coating and the substrate is ≥30MPa.

[0030] According to a specific embodiment of the present invention, the helical rifling is machined by a five-axis CNC machine tool, and the helix angle tolerance of the machined rifling is ±0.2°, the cross-sectional dimension tolerance is ±0.3mm, and the surface roughness Ra≤1.6μm.

[0031] As can be seen from the above technical solution, the advantages and positive effects of the rifling-type flow-controlled pouring cup adapted for 1500kg-class vacuum melting and casting of the present invention are as follows: In this invention, the pouring cup has an adapted diameter and height, and uses helical rifling guidance, which can solve the splashing problem at high flow rates in vacuum pouring scenarios with a flow rate of 37 kg / s and a flow rate of 1500 kg.

[0032] In this invention, a pouring cup with spiral rifling is provided for high flow rate conditions of vacuum melting and casting at the 1500kg level. The rifling guides the molten metal to form a stable rotating flow, suppressing turbulence and splashing, while improving the life of the pouring cup and the quality of the casting, without requiring modification of the existing vacuum furnace casting system.

[0033] Parameter name Design Scope Design basis Top opening diameter (D1) 380-420mm Adaptable to steel flow fluctuations with a casting volume of 1500kg, ensuring the catchment area. Bottom diameter (D2) 120-140mm Match standard runner dimensions to avoid sudden changes in flow rate. Total height (H) 450-500mm Balancing buffer space and installation height limitations inside the vacuum furnace Inner wall taper (α) 15-18° Linear transitions avoid sudden increases in flow velocity and reduce the probability of turbulence generation. The core of this invention is the design of variable-parameter helical rifling on the inner wall of the pouring cup, combined with optimization of the body dimensions, to achieve active control of the molten metal flow. The specific structure and parameters are as follows: (1) Core parameters of the pouring cup body (2) Key design parameters of rifling structure (core protection points) 1) Number of rifling grooves (N): 3-4 grooves, evenly distributed along the inner wall circumference (adjacent angles 90° or 120°); Design rationale: fewer than 3 grooves result in insufficient guiding force and unstable rotational flow; more than 4 grooves increase processing difficulty and easily generate additional flow resistance.

[0034] 2) Helical rifling cross-sectional shape: trapezoidal cross-section, with specific dimensions as follows: Top width (W1): 8-12mm (width of the guide surface in contact with the molten metal to ensure guiding effect); Bottom width (W2): 15-20mm (width for connection with the inner wall to ensure structural strength); Height (h): 5-8mm (protrusion height, to avoid excessive height causing turbulent flow and excessive low height having no guiding effect); Auxiliary parameters: The connection points between the top edge and the side edge, and between the bottom edge and the inner wall, should be rounded with a radius of 1-2mm to avoid stress concentration.

[0035] 3) Helix angle (β) of the helical rifling: Variable angle linear decreasing design; Inlet end (10-15mm from the top): 12-15° (to quickly guide the molten metal to start swirling); Outlet end (20-25mm from the bottom): 8-10° (to reduce the rotation speed and avoid impacting the runner and causing secondary turbulence); Transition section length: 350-400mm, with the rise angle difference controlled at 4-6° to ensure a smooth flow transition.

[0036] 4) Estimation of the number of laps N: The helix angle α is defined as "the angle between the helix and the axis of rotation". The lead P (the axial distance the helix travels in one revolution) is calculated using the formula: P = πD × tanα D: Diameter of the inner wall of the pouring cup at the location of the rifling (mm); α: The helix angle (°) at the corresponding position; Since the rise angle gradually changes linearly from the inlet α1 to the outlet α2, the number of turns needs to be calculated using the "average lead". The inlet diameter is D1 and the outlet diameter is D2. Substitute them into the formula to obtain the inlet lead P1 and the outlet lead P2. Calculate the average lead: Pavg = (P1 + P2) / 2. Effective helix length (transition section length) L of helical rifling, number of turns: N=L / Pavg.

[0037] 5) Rifling start and end design: A 30-45° transition slope (5-8mm axial length) is provided at the starting end to guide the molten metal smoothly into the rifling. The termination end is flush with the inner wall of the lower opening, and the lower edge is chamfered at 45° (5-8mm wide) to avoid the formation of vortices.

[0038] (3) Material and surface treatment Body material: High chromium heat-resistant cast iron with Cr content of 20-25%, C content of 2.5-3.0%, and Si content of 1.0-1.5%, resistant to high temperatures above 1600℃; Surface treatment: The inner wall and rifling surface are coated with an Al2O3-ZrO2 composite ceramic high-temperature anti-oxidation coating with a thickness of 0.1-0.3mm and a bonding strength of ≥30MPa, which improves the high-temperature wear resistance.

[0039] (4) Processing technology requirements The helical rifling is machined using a five-axis CNC machine tool with a helix angle tolerance of ±0.2°, a cross-sectional dimension tolerance of ±0.3mm, and a surface roughness Ra≤1.6μm to ensure guiding accuracy.

[0040] Advantages and effects of this invention (1) Significant flow control effect: The spiral rifling guides the molten metal to form a stable "spiral downward flow state", reducing the amount of splashing by more than 90% compared with the existing technology, and completely solving the splashing problem at high flow rates.

[0041] (2) The quality of castings is greatly improved: the rotating flow state carries tiny inclusions to the center through centrifugal force and enters the gating with the molten metal, reducing the porosity and slag inclusion defect rate of castings by more than 60%.

[0042] (3) Strong adaptability and economy: The parameters cover the pouring speed of 35-39kg / s and the fluctuation range of molten metal of 1510-1550℃, which can be directly integrated into the existing vacuum furnace system; the life of the pouring cup is more than 15 times, which is 3 times longer than conventional products, reducing replacement costs.

[0043] (4) High structural stability: The trapezoidal cross section helical rifling has no stress concentration points. The combination of high chromium cast iron material and ceramic coating can withstand long-term scouring by molten metal at 1530℃ without cracking or excessive wear.

[0044] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0045] 1. Implementation parameters like Figures 1 to 3 As shown, in this embodiment, the pouring cup body has an upper diameter of 400mm, a lower diameter of 130mm, a total height of 480mm, and an inner wall taper of 16°.

[0046] The rifling consists of three grooves: groove 1, groove 2, and groove 3. These three grooves are evenly distributed circumferentially (with an adjacent angle of 120°), have a trapezoidal cross-section (top width 10mm, bottom width 18mm, height 6mm, and a fillet radius of 1.5mm), a helix angle of 14° at the inlet, and 9° at the outlet. The transition section is 380mm long, with a 40° initial transition slope and a 45° chamfer at the bottom. There are two rifling revolutions.

[0047] Material: High-chromium heat-resistant cast iron with Cr 22%, C 2.8%, and Si 1.2%.

[0048] Surface treatment: Al2O3-ZrO2 composite ceramic coating 4, thickness 0.2mm, bonding strength 35MPa.

[0049] Machining process: Five-axis CNC machine tool processing, helix angle tolerance ±0.2°, cross-sectional dimension tolerance ±0.3mm, surface roughness Ra1.2μm.

[0050] 2. Implementation Process (1) Installation preparation: Install the pouring cup of the present invention directly above the inlet of the pouring channel of the 10-ton vacuum induction furnace pouring system using positioning fixtures, ensuring that the coaxiality between the lower opening and the pouring channel is ≤0.5mm, and the vacuum degree in the vacuum furnace is evacuated to ≤5Pa; (2) Pouring operation: Start the vacuum furnace turning mechanism, and the 1530℃ stainless steel liquid flows out from the furnace mouth at a speed of 37kg / s and enters the upper part of the pouring cup; (3) Flow pattern guidance: After the molten metal contacts the initial transition slope of the rifling, it forms a clockwise rotating flow pattern under the guidance of a 14° rise angle. As the inner wall taper decreases, the helical rise angle decreases linearly to 9°, and the flow pattern gradually stabilizes. (4) Stable pouring: The rotating molten metal enters the gating from the bottom (45° chamfer transition), without splashing or turbulence, and the 1500kg molten metal is poured continuously. The whole process takes about 40 seconds. (5) Effect verification: After the casting was completed, the mass of the collected spatter was only 16.5 kg (spatter amount 1.1%); X-ray inspection of the casting showed that the defect rate was only 6.3%; after the casting cup was used continuously for 16 times, the rifling height wear was only 1.8 mm, which still met the usage requirements.

[0051] Those skilled in the art should understand that the specific structures and processes shown in the above detailed embodiments are merely exemplary and not restrictive. Furthermore, those skilled in the art can combine the various technical features described above in various possible ways to form new technical solutions or make other modifications, all of which fall within the scope of this invention.

Claims

1. A rifled flow state control sprue bushing for 1500 kg class vacuum induction melting and pouring, suitable for pouring speed of 35-39 kg / s, and metal temperature of 1510-1550 °C, characterized in that: The gate cup body is integrally formed; the upper opening diameter of the gate cup body is 380-420 mm, the lower opening diameter is 120-140 mm, the total height is 450-500 mm, and the inner wall linearly transitions from the upper end to the lower end with a transition taper of 15-18°; the inner wall of the gate cup body is provided with spiral rifling, the spiral rifling is 3-4, uniformly distributed along the inner wall of the gate cup body, and the central angle of adjacent rifling is 90°-120°.

2. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 1, wherein: The cross section of the spiral rifling is trapezoidal, the top width W1 of the trapezoidal is 8-12 mm, the bottom width W2 is 15-20 mm, and the height h is 5-8 mm.

3. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 2, wherein: The helix angle β of the spiral rifling is a variable angle structure, which linearly decreases from the upper opening side to the lower opening side of the gate cup body, wherein the helix angle β1 at the position 10-15 mm away from the upper opening edge of the inlet end is 12-15°, and the helix angle β2 at the position 20-25 mm away from the lower opening edge of the outlet end is 8-10°.

4. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 3, wherein: The length of the linearly decreasing transition section of the helix angle of the spiral rifling is 350-400 mm, and the angle difference at both ends of the transition section is 4-6°.

5. The rifling-type flow-regulating pouring cup adapted for 1500kg-class vacuum melting and casting as described in claim 2, characterized in that: In the trapezoidal cross section of the spiral rifling, the connection positions of the top edge and the side edge, and the bottom edge and the inner wall are provided with round corners, and the radius of the round corner is 1-2 mm.

6. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 1, wherein: The material of the gate cup body is high-chromium heat-resistant cast iron, the content of Cr element in the high-chromium heat-resistant cast iron is 20-25%, the content of C element is 2.5-3.0%, the content of Si element is 1.0-1.5%, and the rest is Fe element and impurities.

7. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup adapter of claim 3, wherein: The starting end of the spiral rifling is provided with a transition slope, the included angle between the transition slope and the inner wall of the gate cup body is 30°-45°, and the axial length of the transition slope is 5-8 mm.

8. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 7, wherein: The lower opening edge of the gate cup body is provided with a chamfer, the angle of the chamfer is 45°, the chamfer width is 5-8 mm, and the lower opening inner wall is flush with the outlet end of the spiral rifling.

9. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 1 wherein: The inner wall of the gate cup body and the surface of the spiral rifling are both provided with a high-temperature oxidation-resistant coating, the coating material is Al2O3-ZrO2 composite ceramic, the coating thickness is 0.1-0.3 mm, and the bonding strength of the coating and the substrate is ≥30 MPa.

10. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 1 wherein: The spiral rifling is formed by a five-axis linkage numerical control machine tool, and after processing, the helix angle tolerance of the rifling is ±0.2°, the cross section size tolerance is ±0.3 mm, and the surface roughness Ra is ≤1.6 μm.

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