Adapt 1500 kg level vacuum melting pouring rifled flow control pouring cup

Abstract

The present application provides a kind of borehole type flow state control sprue cup suitable for 1500kg level vacuum melting pouring, belong to the technical field of large precision casting vacuum induction melting pouring equipment, suitable for pouring speed 35-39kg / s, metal liquid temperature 1510-1550℃, including integrally-formed sprue cup body;The upper opening diameter of the sprue cup body is 380-420mm, the lower opening diameter is 120-140mm, the total height is 450-500mm, the inner wall is linear transition from upper end to lower end The transition taper of turning point is 15-18°;The inner wall of the sprue cup body is provided with spiral rifling, the spiral rifling is 3-4, evenly distributed along the inner wall of the sprue cup body, the central angle of adjacent bore is 90°-120°.In the present application, the caliber height of sprue cup is adapted, spiral rifling is used for guiding, and the splashing problem under high flow rate can be solved in the scene of 1500kg level, 37kg / s high flow rate vacuum pouring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum induction melting and pouring equipment for large precision castings, and particularly relates to a pouring cup capable of solving the splashing problem under high flow rate in the scenario of 1500kg level, 37kg / s high flow rate vacuum pouring. BACKGROUND

[0002] In the vacuum induction melting and pouring process of large precision castings (1500kg level), the existing technology has the core contradiction of "large size convergence" and "high speed flow state stability", and this contradiction is particularly prominent under the working condition of 37kg / s high flow rate and 1530℃ metal liquid. The ZG35Cr24Ni7SiN material pouring cup (model: GK-1500) currently used by a certain enterprise needs to be replaced every 3 pouring times due to local temperature concentration on the inner wall caused by turbulence, with a service life of only 5-6 times in 1500kg stainless steel pouring; and the X-ray flaw detection of the castings shows that the turbulence involves air, resulting in a porosity defect rate of 18-22%, and additional detection and repair welding processes are required, increasing the cost of a single casting by about 8000 yuan. The existing technology has no mature flow state regulation scheme and adaptive parameter standard under the scenario of 1500kg level, 37kg / s high flow rate vacuum pouring.

[0003] Therefore, how to solve the splashing problem under high flow rate in the scenario of 1500kg level, 37kg / s high flow rate vacuum pouring is a problem that needs to be solved in the industry. SUMMARY

[0004] One of the main purposes of the present application is to overcome at least one of the above-mentioned defects of the prior art, and to provide a rifling type flow state regulation pouring cup adapted to 1500kg level vacuum melting and pouring, which can solve the splashing problem under high flow rate in the scenario of 1500kg level, 37kg / s high flow rate vacuum pouring.

[0005] To achieve the above-mentioned application purposes, the present application adopts the following technical solutions:

[0006] According to one aspect of the present application, a rifling type flow state regulation pouring cup adapted to 1500kg level vacuum melting and pouring is provided, which is adapted to pouring speed of 35-39kg / s and metal liquid temperature of 1510-1550℃, and comprises an integrally formed pouring cup body; the upper opening diameter of the pouring cup body is 380-420mm, the lower opening diameter is 120-140mm, and the total height is 450-500mm, and the inner wall of the pouring cup body has a linear transition turning taper of 15-18° from the upper end to the lower end; the inner wall of the pouring cup body is provided with spiral rifling, the spiral rifling is 3-4 strips, is uniformly distributed along the circumference of the inner wall of the pouring cup body, and the central angle of adjacent rifling is 90°-120°.

[0007] According to one specific embodiment of the present application, the cross section of the spiral bore is trapezoidal, with the top width W1 being 8-12 mm, the bottom width W2 being 15-20 mm, and the height h being 5-8 mm.

[0008] According to one specific embodiment of the present application, the helix angle β of the spiral bore is a variable angle structure, linearly decreasing from the upper opening side to the lower opening side of the sprue cup body, wherein the helix angle β1 at the entrance end 10-15 mm away from the upper opening edge is 12-15°, and the helix angle β2 at the exit end 20-25 mm away from the lower opening edge is 8-10°.

[0009] According to one specific embodiment of the present application, the length of the linearly decreasing transition section of the helix angle of the spiral bore is 350-400 mm, and the difference in the helix angle at the two ends of the transition section is 4-6°.

[0010] According to one specific embodiment of the present application, in the trapezoidal cross section of the spiral bore, the connecting 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 corners is 1-2 mm.

[0011] According to one specific embodiment of the present application, the material of the sprue cup body is high-chromium heat-resistant cast iron, and the high-chromium heat-resistant cast iron contains 20-25% of Cr element, 2.5-3.0% of C element, 1.0-1.5% of Si element, and the rest is Fe element and impurities.

[0012] According to one specific embodiment of the present application, the starting end of the spiral bore is provided with a transition slope, the included angle between the transition slope and the inner wall of the sprue cup body is 30°-45°, and the axial length of the transition slope is 5-8 mm.

[0013] According to one specific embodiment of the present application, the lower opening edge of the sprue cup body is provided with a chamfer, the angle of the chamfer is 45°, the width of the chamfer is 5-8 mm, and the lower opening inner wall is flush with the exit end of the spiral bore.

[0014] According to one specific embodiment of the present application, the inner wall of the sprue cup body and the surface of the spiral bore 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 between the coating and the substrate is ≥30 MPa.

[0015] According to one specific embodiment of the present application, the spiral bore is formed by a five-axis linkage numerical control machine tool, and after processing, the helix angle tolerance of the bore is ±0.2°, the cross-sectional size tolerance is ±0.3 mm, and the surface roughness Ra is ≤1.6 μm.

[0016] From the above technical solutions, the advantages and positive effects of the barrel rifling type flow state regulation nozzle cup adapted to 1500kg level vacuum melting pouring of the present application are that:

[0017] In the present application, the nozzle cup caliber height is adapted, and the spiral rifling guide is adopted, which can solve the splashing problem under high flow rate in the 1500kg level, 37kg / s high flow rate vacuum pouring scene. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the front view structural schematic diagram of the barrel rifling type flow state regulation nozzle cup adapted to 1500kg level vacuum melting pouring of the present application.

[0019] Figure 2 is the top view structural schematic diagram of the barrel rifling type flow state regulation nozzle cup adapted to 1500kg level vacuum melting pouring of the present application.

[0020] Figure 3 is the sectional view structural schematic diagram of the barrel rifling type flow state regulation nozzle cup adapted to 1500kg level vacuum melting pouring of the present application.

[0021] FIG. NO. EXPLANATION:

[0022] 1, barrel rifling one; 2, barrel rifling two; 3, barrel rifling three; 4, composite ceramic coating; R, spiral angle entrance end; Q, spiral angle exit end. DETAILED DESCRIPTION

[0023] Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept of example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the figures, and thus a detailed description of them will not be repeated.

[0024] According to one aspect of the present application, a barrel rifling type flow state regulation nozzle cup adapted to 1500kg level vacuum melting pouring is provided, which is adapted to pouring speed of 35-39kg / s and metal liquid temperature of 1510-1550℃, and comprises an integrally formed nozzle cup body; the upper opening diameter of the nozzle cup body is 380-420mm, the lower opening diameter is 120-140mm, and the total height is 450-500mm, and the inner wall presents a linear transition turning taper of 15-18° from the upper end to the lower end; the inner wall of the nozzle cup body is provided with spiral rifling, the spiral rifling is 3-4, is uniformly distributed along the inner wall of the nozzle cup body in the circumferential direction, and the central angle of adjacent rifling is 90°-120°.

[0025] According to one specific embodiment of the present application, the cross section of the spiral bore is trapezoidal, the top width W1 is 8-12 mm, the bottom width W2 is 15-20 mm, and the height h is 5-8 mm.

[0026] According to one specific embodiment of the present application, the helix angle β of the spiral bore is a variable angle structure, which linearly decreases from the upper opening side to the lower opening side of the sprue cup body, wherein the helix angle β1 at the position 10-15 mm away from the upper opening edge of the entrance end is 12-15°, and the helix angle β2 at the position 20-25 mm away from the lower opening edge of the exit end is 8-10°.

[0027] According to one specific embodiment of the present application, the length of the linearly decreasing transition section of the helix angle of the spiral bore is 350-400 mm, and the difference of the helix angle at both ends of the transition section is 4-6°.

[0028] According to one specific embodiment of the present application, in the trapezoidal cross section of the spiral bore, the connecting 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 corners is 1-2 mm.

[0029] According to one specific embodiment of the present application, the material of the sprue 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.

[0030] According to one specific embodiment of the present application, the starting end of the spiral bore is provided with a transition slope, the included angle between the transition slope and the inner wall of the sprue cup body is 30°-45°, and the axial length of the transition slope is 5-8 mm.

[0031] According to one specific embodiment of the present application, the lower opening edge of the sprue cup body is provided with a chamfer, the angle of the chamfer is 45°, the width of the chamfer is 5-8 mm, and the inner wall of the lower opening is flush with the exit end of the spiral bore.

[0032] According to one specific embodiment of the present application, the inner wall of the sprue cup body and the surface of the spiral bore 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 between the coating and the substrate is ≥30 MPa.

[0033] According to one specific embodiment of the present application, the spiral bore is formed by a five-axis linkage numerical control machine tool, and after processing, the helix angle tolerance of the bore is ±0.2°, the cross section size tolerance is ±0.3 mm, and the surface roughness Ra is ≤1.6 μm.

[0034] From the above technical solutions, the advantages and positive effects of the barrel rifling type flow state regulation sprue cup adapted to 1500 kg level vacuum melting and pouring are that:

[0035] In the present application, the sprue cup caliber height is adapted, and spiral rifling guidance is adopted, which can solve the splashing problem under high flow rate in the 1500 kg level, 37 kg / s high flow rate vacuum pouring scene.

[0036] In the present application, for the high flow rate working condition of 1500 kg level vacuum melting and pouring, a sprue cup with spiral rifling is provided, which forms a stable rotating flow state of metal liquid through rifling guidance, suppresses turbulence and splashing, and improves the service life of the sprue cup and the quality of the casting, without the need to modify the existing vacuum furnace pouring system.

[0037] Parameter name Design range Design basis Upper opening diameter (D1) 380-420mm Adapt to 1500kg pouring capacity steel flow fluctuation, ensure the convergence area Lower opening diameter (D2) 120-140mm Match the conventional runner size, avoid flow rate sudden change Total height (H) 450-500mm Balance the buffer space and the installation height limit in vacuum furnace Inner wall transition taper (a) 15-18° Linear transition to avoid flow rate sudden increase, reduce the probability of turbulence generation

[0038] The core of the present application is to design a variable parameter spiral rifling on the inner wall of the sprue cup, combined with the optimization of the body size, to realize active regulation of the metal liquid flow state, and the specific structure and parameters are as follows:

[0039] (1) Core parameters of sprue cup body

[0040] (2) Key design parameters of rifling structure (core protection point)

[0041] 1) Number of spiral rifling (N): 3-4, evenly distributed along the inner wall (adjacent angle 90° or 120°); design reason: less than 3 guiding force is insufficient, rotating flow state is unstable; more than 4 processing difficulty increases, easy to produce additional flow resistance.

[0042] 2) Cross-sectional shape of spiral rifling: trapezoidal cross-section, specific dimensions are:

[0043] Top width (W1): 8-12mm (width of the guiding surface in contact with the metal liquid, to ensure the guiding effect);

[0044] Bottom width (W2): 15-20mm (width connected with the inner wall, to ensure the structural strength);

[0045] Height (h): 5-8mm (convex height, to avoid excessive turbulent flow state and no guiding effect);

[0046] Auxiliary parameters: R1-2mm round corners are provided at the connection positions of the top edge and the side edge, and the bottom edge and the inner wall, to avoid stress concentration.

[0047] 3) Spiral angle of spiral rifling (β): variable angle linearly decreasing design;

[0048] Inlet end (10-15mm from the upper opening): 12-15° (rapidly guide the metal liquid to rotate);

[0049] Outlet end (20-25mm from the lower mouth): 8-10° (slow down the rotation speed to avoid secondary turbulence caused by impact on the pouring gate);

[0050] Transition length: 350-400mm, the difference in the angle of ascent is controlled at 4-6° to ensure smooth transition of flow state.

[0051] 4) Number of turns N estimation:

[0052] The definition of helix angle α is "the angle between the helix and the axial direction", and the pitch P (the axial advancement distance of the helix for one turn) is calculated as: P=πD×tanα

[0053] D: the inner wall diameter of the pouring cup at the position of the helix (mm);

[0054] α: the helix angle at the corresponding position (°);

[0055] Since the angle of ascent linearly changes from the inlet α1 to the outlet α2, the "average pitch" is used to calculate the number of turns. The diameter D1 at the inlet end and the diameter D2 at the outlet end are brought into the formula to obtain the inlet pitch P1 and the outlet pitch P2, and the average pitch Pavg is calculated as: Pavg= (P1+P2) / 2;

[0056] The effective helix length (transition length) L of the helix and the number of turns N are calculated as: N=L / Pavg.

[0057] 5) Design of helix starting and ending:

[0058] A 30-45° transition slope (5-8mm in axial length) is provided at the starting end to guide the smooth entry of the metal liquid into the helix;

[0059] The ending end is flush with the inner wall of the lower mouth, and a 45° chamfer (5-8mm in width) is provided at the edge of the lower mouth to avoid vortex formation.

[0060] (3) Material and surface treatment

[0061] The 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 temperatures above 1600°C;

[0062] Surface treatment: Al2O3-ZrO2 composite ceramic high-temperature oxidation-resistant coating is provided on the inner wall and the helix surface, with a thickness of 0.1-0.3mm and a bonding strength of ≥30MPa, improving the high-temperature wear resistance.

[0063] (4) Processing technology requirements

[0064] The helix is formed by a five-axis linkage numerical control machine tool, with a helix angle tolerance of ±0.2°, a cross-sectional size tolerance of ±0.3mm, and a surface roughness Ra≤1.6μm, ensuring the guiding accuracy.

[0065] Advantages of the present application

[0066] (1) Significant flow control effect: Spiral rifling guides the metal liquid to form a stable "spiral descending flow state", reducing splashing by more than 90% compared to existing technologies, and completely solving the problem of splashing at high flow rates.

[0067] (2) Significant improvement in casting quality: The rotating flow state gathers small inclusions towards the center by centrifugal force, and enters the sprue with the metal liquid, reducing the defect rate of casting porosity and slag inclusion by more than 60%.

[0068] (3) Strong adaptability and economy: The parameters cover a pouring speed of 35-39 kg / s and a metal liquid fluctuation range of 1510-1550°C, which can be directly integrated into existing vacuum furnace systems; the service life of the sprue cup is more than 15 times, which is 3 times longer than conventional products, reducing replacement costs.

[0069] (4) High structural stability: The trapezoidal cross-section spiral rifling has no stress concentration points, and the combination of high-chromium cast iron material and ceramic coating can withstand long-term erosion of 1530°C metal liquid without cracking or rapid wear.

[0070] The present application will be described below with reference to specific examples, it should be noted that the examples are merely descriptive and do not limit the present application in any way.

[0071] 1. Implementation parameters

[0072] As shown in Figure 1 to Figure 3 , in this example, the sprue cup body has an upper diameter of 400 mm, a lower diameter of 130 mm, a total height of 480 mm, and an inner wall turning taper of 16°.

[0073] The spiral rifling includes rifling one 1, rifling two 2, and rifling three 3, a total of three. The three spiral riflings are evenly distributed circumferentially (with adjacent angles of 120°), have a trapezoidal cross-section (top width 10 mm, bottom width 18 mm, height 6 mm, and round corner R1.5 mm), have a spiral angle inlet end R of 14° and a spiral angle outlet end Q of 9°, have a transition segment length of 380 mm, have a starting transition slope of 40°, have a lower corner of 45 degrees, and have 2 turns.

[0074] Material: High-chromium heat-resistant cast iron with Cr22%, C2.8%, and Si1.2%.

[0075] Surface treatment: Al2O3-ZrO2 composite ceramic coating 4, thickness 0.2 mm, bonding strength 35 MPa.

[0076] Processing technology: Five-axis linkage numerical control machine tool processing, spiral angle tolerance ±0.2°, cross-sectional size tolerance ±0.3 mm, surface roughness Ra1.2 μm.

[0077] 2. Implementation process

[0078] (1) Installation preparation: install the pouring cup of the application above the gate inlet of the pouring system of a 10-ton vacuum induction furnace through positioning tooling, ensure that the coaxiality of the lower opening and the gate is ≤0.5mm, and the vacuum degree in the vacuum furnace is extracted to ≤5Pa;

[0079] (2) Pouring operation: start the vacuum furnace overturning mechanism, and the 1530℃ stainless steel liquid flows out from the furnace mouth at a speed of 37kg / s and enters the upper opening of the pouring cup;

[0080] (3) Flow state guiding: after the metal liquid contacts the starting transition slope of the rifling, the clockwise rotating flow state is formed under the guidance of the 14° lift angle, and with the decrease of the inner wall taper, the helix lift angle linearly decreases to 9°, and the flow state gradually stabilizes;

[0081] (4) Stable pouring: the metal liquid of the rotating flow state enters the gate from the lower opening (45° chamfer transition) without splashing and turbulence, and the pouring of 1500kg of metal liquid is completed, and the whole process takes about 40 seconds;

[0082] (5) Effect verification: after the pouring is completed, the collected splashing material is only 16.5kg (splashing amount 1.1%); the X-ray flaw detection of the casting shows that the defect rate is only 6.3%; after the pouring cup is used continuously for 16 times, the height of the rifling is worn only by 1.8mm, which still meets the use requirements.

[0083] Those skilled in the art to which the present application pertains should understand that the specific structures and process shown in the above detailed implementation part are only exemplary and not limiting. Moreover, those skilled in the art can combine the various technical features shown above in various possible ways to form new technical solutions, or make other modifications, which all belong to the scope of the present application.

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, 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°; 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; 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°.

2. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 1, 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°.

3. The 1500 kg class vacuum induction melted, die cast, rifled flow control nozzle cup of claim 1, wherein: In the trapezoidal cross section of the spiral rifling, the connecting positions of the top side and the side, and the bottom side and the inner wall are provided with round corners, and the radius of the round corner is 1-2 mm.

4. 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.

5. The rifling-type flow-regulating pouring cup adapted for 1500kg-class vacuum melting and casting as described in claim 1, characterized in that: 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.

6. The 1500 kg class vacuum induction melted, die cored, flow regime control nozzle cup adapter of claim 5, 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.

7. 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.

8. 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-sectional size tolerance is ±0.3 mm, and the surface roughness Ra is ≤1.6 μm.

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