Casting process method of rudder horn for large ship

Abstract

The invention relates to a casting process method of a large marine rudder horn, which comprises the following steps of: producing a casting stereogram through SolidWorks software, carrying out Magama casting simulation analysis, designing a casting scheme of a stepped sand core of a rudder horn casting, matching a foot plate and supporting and positioning a multi-point cylindrical blank, designing a special sand box, setting a reverse deformation amount, thickening and widening a box belt at a stress point, and casting the rudder horn by using a large-scale marine rudder horn. The method has the beneficial effects that the influence of buoyancy on the wall thickness is effectively controlled, the strength of the large sand mold is improved, the deformation problem of the rudder horn casting in the high-temperature process is solved, the deformation of the casting is controlled, the size of the casting is ensured, the quality of the casting is improved, the service life of the casting is prolonged, and the size precision condition of the casting is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of casting of marine rudder carrier arms, and particularly to a casting process method for large marine rudder carrier arms. Background Art

[0002] Since 2021, Chinese shipbuilding enterprises have received new orders for 965 ships with 22.8 million tons of castings, ranking first in the world with a market share of nearly 60%, and the future market for marine components is huge. Among them, the rudder carrier arm casting is one of the main components of container ships. Its casting belongs to an ultra-long cavity structure, with high precision requirements for the finished wall thickness size, dimensional accuracy requirements, and strict flaw detection requirements.

[0003] The casting process of large marine rudder carrier arm castings is complex. Usually, the casting work of large marine rudder carrier arms is completed by manual experience and manual grinding of castings. The manual workload is huge, the casting time is long, the difficulty is high, and the manual technical requirements are high, which seriously restricts the quantity of castings produced in batches. Therefore, formulating the optimal casting new process and control method has great milestone significance for improving the overall quality of large marine castings, enhancing the market competitiveness and production share of marine castings. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a casting process method for large marine rudder carrier arms. By producing a three-dimensional drawing of the casting with 3D software and conducting casting simulation analysis with casting simulation software, a stepped core head is designed, a forming core iron is set in the middle large core, and at the same time, it is supported and positioned with large square solid weights and cylindrical blank hard points, thereby improving the strength of the large sand mold and effectively controlling the influence of buoyancy on the wall thickness; by designing a special sand box and thickening and widening the force-bearing points of the box straps to improve the strength of the sand box; controlling the sand mixture ratio of the middle large core during core making and the continuity of core making; setting the anti-deformation amount of the rudder carrier arm casting process and controlling the heat treatment process, thereby reducing the deformation problem of the rudder carrier arm casting during the high-temperature process, controlling the deformation of the casting, ensuring the dimensions of the casting, and improving the quality, service life, and dimensional accuracy of the casting.

[0005] In order to achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] A casting process method for large marine rudder carrier arms, the casting process method includes the following contents:

[0007] S1: Generate a three-dimensional drawing of the casting with 3D software, and optimize the shape of the riser subsidy and integrate the number of risers by calculating the sizes of the hot spot circles of the rudder carrier arm casting;

[0008] S2: Conduct casting process simulation analysis through casting software, conduct simulation of the casting process plan, simulate filling, solidification, and stress deformation, and finally determine the casting process plan;

[0009] S3: Design the core head part of the large middle core for the rudder carrier casting into a stepped positioning core head, set up shaping core iron for the large middle core, and at the same time, place square solid weights at the bottom of the stepped positioning core head when ramming the rudder carrier;

[0010] S4: Set up cylindrical blank hard point supports, and at the same time, design using the force-bearing points of the upper box straps and the load-bearing ribs of the shaping core iron;

[0011] S5: Design a special casting sand box according to the casting analysis and simulation of the pouring deformation results; set the process reverse deformation amount of the rudder carrier according to the casting process, and confirm the best force-bearing points in the vertical direction according to the 3D model digital model measurement, and design the force-bearing point box straps to be thickened and widened;

[0012] S6: Control the molding sand ratio for ramming the large middle core, that is, use chromite sand for the facing sand and all use ester-hardened recycled sand for the backing sand;

[0013] S7: Place a shaping steel blank in the hollow part of the rudder carrier during the heat treatment process as a support for preventing heat treatment deformation, and at the same time, design a follow-up pad iron according to the outer shape structure of the rudder carrier;

[0014] S8: During the finishing process, use an angular outer shape template in combination with a total station to accurately position and control the overall streamline outer shape;

[0015] S9: After the rudder carrier casting is poured and the whole mold is removed and finished, mark the first-piece rudder carrier casting, check the dimensions, and perform non-destructive magnetic particle flaw detection on all surfaces of the rudder carrier casting, and repair the internal defects of the sand box.

[0016] Furthermore, the shape of the riser subsidy in step S1 is a subsidy shape with a herringbone machining allowance set in the machining hole, which effectively compensates for shrinkage at the bottom of the rudder carrier.

[0017] Furthermore, the riser in step S1 is set at the part of the rudder carrier casting with high flaw detection requirements, and the shape of the riser is an elliptical open riser.

[0018] Furthermore, the number of cylindrical blank hard point supports in step S4 is several, and the cylindrical blank hard point supports are simultaneously supported between the upper box, the lower box and the shaping core iron.

[0019] Furthermore, the reverse deformation amount of the upper plane of the special sand box in step S5: +5 to +20 mm; the reverse deformation amount of the lower plane: 0 to +5 mm.

[0020] Furthermore, the force-bearing point box straps in step S5 are thickened and widened up to 150 mm × 150 mm at most.

[0021] Furthermore, the thickness of the chromite sand used for the facing sand in step S6 is 10 to 15 mm.

[0022] Furthermore, an exhaust cord is placed in the middle of the large core in step S6, and the exhaust is led out from the core head part.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1) A casting scheme of a stepped core + formed core iron for the rudder arm casting, combined with a square solid iron weight + multi-point cylindrical blank support positioning, is designed to improve the strength of the core, effectively prevent problems caused by excessive buoyancy, solve the problems of wall thickness deviation and deformation of large marine rudder arms, avoid the appearance of unqualified products or core lifting resulting in scrap, thereby improving the finished product rate and casting capacity.

[0025] 2) In the casting process design, an anti-deformation amount is set for the rudder arm, a special sand box is set to improve the strength of the sand box, and round blanks are placed in the inner cavity of the rudder arm to reduce the deformation problem of the rudder arm casting during the high-temperature process, control the deformation of the casting, ensure the dimensions of the casting, and improve the quality, service life, and dimensional accuracy of the casting.

[0026] 3) The process of making the mold is simplified, the size of the sand mold is controllable, the size of core setting during mold closing is more controllable and accurate, the accuracy of the marine rudder arm casting is higher, the subsequent finishing and grinding are reduced, the manual workload is reduced, and the overall production time is shortened.

[0027] 4) A casting process scheme for large marine rudder arm castings is provided, which reduces the technical requirements for casting workers, improves production efficiency, reduces the casting difficulty, increases the quantity of castings produced in batches, improves the overall quality of large marine castings, and enhances the market competitiveness of marine castings. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the casting scheme described in the present invention.

[0029] Figure 2 It is a schematic diagram of the formed core iron of the core described in the present invention.

[0030] Figure 3 It is a riser diagram of the new casting process of the rudder arm casting described in the present invention.

[0031] Figure 4 It is a riser diagram of the traditional casting process of the rudder arm casting described in the present invention.

[0032] Figure 5 It is a schematic diagram of the shape of the riser pad described in the present invention.

[0033] In the figure: 1, upper box; 2, upper sand mold; 3, lower sand mold; 4, iron weight; 5, wall thickness; 6, core; 7, formed core iron; 8, hard point support; 9, open riser; 10, blind riser; 11, round hole; 12, herringbone machining allowance. Specific Embodiments

[0034] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings:

[0035] As Figures 1 - 5 shown, a casting process method for a large marine rudder stock includes the following contents:

[0036] S1: Use SolidWorks software to generate a three-dimensional solid model of the casting. According to the three-dimensional structural characteristics and size of the casting, divide the rudder stock into several parts. By calculating the size of each hot spot circle of the rudder stock casting, optimize the shape of the riser pad and integrate the number of risers, cancel the point-fed riser, increase the safety of casting pouring, reduce molten steel, overcome the price increase of raw materials and electricity, and comprehensively reduce the casting cost. Integrate the 11 blind risers 10 in the original process plan into 3 blind risers 10. At the same time, set multiple vent risers with a diameter of 30 mm. The original 2 oval open risers 9 remain unchanged, and cooperate with the heat preservation covering agent to achieve the best feeding effect and ensure the internal quality of the rudder stock;

[0037] S2: Through Magama casting process simulation analysis, conduct casting process plan simulation, simulate filling, solidification, stress and deformation, and finally determine the casting process plan for the full-scale pattern molding;

[0038] S3: Through Magama simulation analysis, design the core head part of the middle sand core 6 of the rudder stock casting into a stepped positioning core head, and independently design and manufacture the forming core iron 7 of the middle sand core 6 according to the casting structure, so as to ensure the core strength and prevent the sand core from being damaged during mold turnover. At the same time, place square solid pressure irons at the bottom of the stepped positioning core head during ramming of the rudder stock to improve the mold strength and prevent the middle sand core 6 from sinking, which may cause the deviation of the position of the middle sand core 6 of the rudder stock casting, ensure the convenience of core setting operation and casting size control during mold making, effectively control the influence of buoyancy on the wall thickness, and thus improve the strength of the large mold;

[0039] S4: Based on the calculation of the buoyancy of the sand core 6 and its structural characteristics, set 6 cylindrical blank hard point supports 8. The cylindrical blank hard point supports are simultaneously supported between the upper mold, the lower mold and the forming core iron. Utilize the force-bearing point of the ribband on the upper mold 1 and the load-bearing rib of the forming core iron 7, and set the pressure iron 4 for pressing the mold on the upper mold, effectively preventing the problem of wall thickness 5 deviation or core lifting caused by excessive buoyancy and avoiding the floating core of the middle sand core 6 of the rudder stock;

[0040] S5: According to the pouring deformation results simulated by Magama casting analysis, a special molding sand box is designed uniformly, which can reduce the sand consumption of the upper sand mold 2 and the lower sand mold 3, and facilitate the precise control of the core setting and the dimensional positioning of the combination of the upper box 1 and the lower box; set the anti-deformation amount of the rudder stock arm box body according to the casting process plan, and the anti-deformation amount is set as +5 to +20 mm for the upper plane; 0 to +5 mm for the lower plane; measure and confirm the best stress point in the vertical direction according to the solidwork digital model to ensure the position and height of the back point, and thicken and widen the box straps at the stress point to 150 mm × 150 mm; the designed special sand box improves the strength of the sand box;

[0041] S6: Strictly control the sand ratio of the core 6 during core making, that is, use chromite sand for the facing sand and all use ester-hardened recycled sand for the backing sand, so as to ensure the finishing collapsibility of the core 6; at the same time, ensure the continuity of core making to prevent the loose connection and reduced strength of the core sand due to discontinuity;

[0042] S7: According to the structural characteristics of the rudder stock arm casting, analyze the deformation trend at high temperature, and design the kiln loading and heat treatment methods, that is, place a formed steel billet in the hollow part of the rudder stock arm as a support for preventing heat treatment deformation, and at the same time design a follow-up pad iron according to the outer shape structure of the rudder stock arm to reduce the deformation problem of the rudder stock arm during the high-temperature process;

[0043] S8: During the finishing process, use an angular-shaped outer template in cooperation with a total station to accurately position the overall streamline outer shape control to meet the overall dimensional control requirements of the shipyard for the rudder stock arm casting;

[0044] S9: After the rudder stock arm casting is poured and then undergoes overall shakeout and finishing, mark the first-piece rudder stock arm casting, check the dimensions, and perform non-destructive magnetic particle flaw detection on all surfaces of the rudder stock arm casting.

[0045] Furthermore, the shape of the optimized riser pad in step S1 is optimized from the round hole 11 + follow-up annular machining allowance to the shape of the pad with a herringbone machining allowance 12 set in the casting round hole 11, and the bottom of the machining hole of the rudder stock arm is compensated by this riser pad shape.

[0046] Furthermore, the riser in step S1 is set at the part of the rudder stock arm casting with high flaw detection requirements, and the shape of the riser is an oval open riser.

[0047] Furthermore, the box straps at the stress point in step S5 are thickened and widened up to 150 mm × 150 mm at most.

[0048] Furthermore, the chromite sand used for the facing sand in step S6 has a thickness of 10 to 15 mm.

[0049] Furthermore, an exhaust rope is placed in the middle of the core 6 in step S6, and the exhaust is led out from the core head part.

[0050] As described above, it is only the preferred specific implementation manner of the present invention. However, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and concept of the present invention, making equivalent replacements or changes should be covered within the protection scope of the present invention.

Claims

1. A casting process method for a large marine rudder carrier, characterized in that, The described casting process method includes the following: S1: Generate a three-dimensional solid model of the casting using 3D software. By calculating the sizes of the hot spot circles of the rudder carrier casting, optimize the shape of the feeder pad and integrate the number of feeders. S2: Conduct casting process simulation analysis through casting software, perform simulation of the casting process plan, simulate filling, solidification, stress and deformation, and finally determine the casting process plan. S3: Design the core head part of the large middle core for the rudder carrier casting as a stepped positioning core head, set up a core iron in the large middle core, and at the same time place a square solid iron weight at the bottom of the stepped positioning core head when ramming the rudder carrier. S4: Set up cylindrical blank hard point supports, and at the same time utilize the force-bearing points of the upper box straps and the load-bearing ribs of the formed core iron for design. S5: Design a special casting sand box according to the casting analysis simulation pouring deformation results; set the process reverse deformation amount of the rudder carrier according to the casting process, and measure and confirm the best force-bearing points in the vertical direction based on the 3D model digital model, and design the force-bearing point box straps to be thickened and widened. S6: Control the molding sand ratio for ramming the large middle core, that is, use chromite sand for the facing sand and all use ester-hardened recycled sand for the backing sand. S7: Place a formed steel blank in the hollow part of the rudder carrier during the heat treatment process as a support for preventing heat treatment deformation, and at the same time design a conforming pad iron according to the outer shape structure of the rudder carrier. S8: During the finishing process, use an angular outer shape template in combination with a total station to accurately position and control the overall streamline outer shape. S9: After the rudder carrier casting is poured and the whole mold is removed and finished, mark the first-piece rudder carrier casting, check the dimensions, and perform non-destructive magnetic particle flaw detection on all surfaces of the rudder carrier casting, and repair the internal defects of the sand box.

2. The casting process method of a large marine rudder stock according to claim 1, characterized in that, The shape of the feeder pad in step S1 is a shape with a herringbone machining allowance set in the machining hole, which effectively compensates for shrinkage at the bottom of the rudder carrier.

3. The casting process method of a large marine rudder carrier according to claim 1, characterized in that, The feeder in step S1 is set at the part of the rudder carrier casting with high flaw detection requirements, and the shape of the feeder is an elliptical open feeder.

4. The casting process method of a large marine rudder carrier according to claim 1, characterized in that, The number of cylindrical blank hard point supports in step S4 is several, and the cylindrical blank hard point supports are simultaneously supported between the upper box, the lower box and the formed core iron.

5. The casting process method of a large marine rudder carrier according to claim 1, characterized in that, The reverse deformation amount of the upper plane of the special sand box in step S5: +5 to +20 mm; the reverse deformation amount of the lower plane: 0 to +5 mm.

6. The casting process method of a large marine rudder carrier according to claim 1, characterized in that, The force-bearing point box straps in step S5 are thickened and widened up to 150 mm × 150 mm at most.

7. The casting process method of a large marine rudder carrier according to claim 1, characterized in that, The thickness of the chromite sand used for the facing sand in step S6 is 10 to 15 mm.

8. The casting process method of a large marine rudder carrier according to claim 1, characterized in that, An exhaust rope is placed in the middle of the large core in step S6, and the exhaust is led out from the core head part.

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