A mold and method for assessing the risk of sand inclusion and sand adhesion defects in castings caused by molding processes.

Abstract

This invention belongs to the field of casting mold technology, and specifically discloses a mold and method for assessing the risk of sand inclusion and sand adhesion defects in castings caused by molding processes. The mold includes an inlet block and a main body block. The inlet block is fixedly connected to the left side of the main body block, and its bottom is sloped, causing its thickness to gradually increase from left to right. The main body block is a stepped structure with several 90° corners, and its sides have several bosses and grooves, while its bottom surface has several grooves. After molding using this invention, the sloped bottom increases the flow rate of the molten metal, and the curved mold body helps increase the impact force of the molten metal on the sand mold wall. The bosses and grooves on the sides and bottom surface represent weak points in the mechanical properties of the sand mold. This invention tests the sand mold's ability to resist external forces during molding, demolding, handling, and the impact of molten metal, enabling rapid and accurate assessment of the risk of sand inclusion and sand adhesion defects in castings caused by molding processes.

Description

Technical Field

[0001] This invention belongs to the field of casting mold technology, and more specifically, relates to a mold and method for assessing the risk of sand inclusion and sand adhesion defects in castings caused by molding processes. Background Technology

[0002] With increasing emphasis on environmental protection and workers' working conditions, environmentally friendly molding sands such as self-hardening alkaline phenolic resin sand and inorganic silicate binder sand are replacing the original high-pollution molding sands, such as furan resin sand and phenol-urea resin sand, which generate a lot of gas and harmful gases. However, in practical applications, the use of environmentally friendly molding sand in casting production is prone to defects such as sand inclusions and sand adhesion. These defects not only reduce the quality of castings but also cause other defects such as cracks. They can even lead to the direct scrapping of castings, thus limiting the further application of environmentally friendly molding sands.

[0003] The main reason for the occurrence of sand inclusion and sand adhesion defects is due to improper molding process (i.e., the type and particle size of the raw sand, the type and amount of binder, the brushing process of the coating, etc.), which weakens the ability of the resin sand mold to resist external wear, collision and impact of molten metal. In actual production, this ability is difficult to assess and must be improved through actual casting production, which is time-consuming and labor-intensive. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a mold and method for assessing the risk of sand inclusion and sand adhesion defects in castings caused by the molding process. The purpose is to achieve a rapid and accurate assessment of the risk of sand inclusion and sand adhesion defects in castings caused by the sand molding process.

[0005] To achieve the above objectives, according to one aspect of the present invention, a mold for assessing the risk of casting defects such as sand inclusions and sand adhesion caused by the molding process is provided, comprising an inlet block and a main body block, wherein:

[0006] The inlet block is fixedly connected to the left side of the main body block, and the bottom of the inlet block is inclined, so that the thickness of the inlet block gradually increases from left to right;

[0007] The main block is a stepped structure with several 90° corners, and the side of the main block has several protrusions and grooves, and the bottom of the main block has several grooves.

[0008] As a further preferred embodiment, the main body block includes a first main body block and a second main body block, wherein the left side of the first main body block is connected to the guide block and the right side is connected to the second main body block; the bottom surface of the first main body block is a slope, and the slope is coplanar with the bottom slope of the guide block to form an integral slope; the thickness of the second main body block remains unchanged, and its thickness is consistent with the thickness of the thickest part on the right side of the first main body block.

[0009] As a further preferred embodiment, the first main body block has several protrusions and grooves on its side, and the second main body block has several grooves on its bottom surface.

[0010] As a further preferred embodiment, the first main body block has two protrusions and two grooves on its side, and the second main body block has two grooves on its bottom surface.

[0011] As a further preferred embodiment, the length and width of the cross-section of the boss or groove on the first main body block are both 12 to 20 mm.

[0012] As a further preferred embodiment, the boss or groove on the first main body block has a square cross-section.

[0013] As a further preferred embodiment, the angle between the front side and the top surface of the inlet block is 100° to 120°.

[0014] As a further preferred embodiment, the main block is a stepped structure with three 90° corners.

[0015] As a further preferred option, for edges in the mold with an angle greater than 180°, a fillet with a radius of 5mm is provided; for edges in the mold with an angle less than 180°, a fillet with a radius of 3mm is provided.

[0016] To achieve the above objectives, according to one aspect of the present invention, a mold for assessing the risk of casting defects such as sand inclusion and sand adhesion caused by the molding process is provided, comprising:

[0017] According to another aspect of the present invention, a method for assessing the risk of casting defects such as sand inclusion and sand adhesion caused by the molding process is provided, which is implemented using the above-mentioned mold and includes the following steps:

[0018] Place the mold into the casting box and fill it with molding sand prepared according to the molding process to be evaluated. After it solidifies and forms a sand mold, remove the mold.

[0019] Molten metal is poured into the sand mold from one side of the inlet block location to form a casting.

[0020] The surface quality of each surface of the casting is analyzed, and the risk of sand inclusion and sand adhesion in the molding sand is assessed based on the ratio of the number of surfaces with sand inclusion and sand adhesion defects to the total number of casting surfaces.

[0021] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0022] 1. This invention, through the design of the guide block and the main body block, enables rapid and accurate assessment of the risk of sand inclusion and sand adhesion defects in castings using miniaturized molds, solving the problem that it is difficult to evaluate the impact and collision resistance of existing casting molding processes; at the same time, it avoids the waste of molding raw materials and molten metal caused by risk assessment, reduces the input of manpower and materials, and the castings after pouring are lightweight, easy to handle and observe, which helps to reduce damage to the surface quality of the castings during handling, and allows for observation from all angles.

[0023] 2. The bottom surface of the mold is provided with a slope of a certain degree. Pouring is carried out from the thinnest side of the mold, which helps to convert more potential energy into kinetic energy and increase the flow rate of molten metal.

[0024] 3. The mold is designed with a stepped main block with a 90° corner. If the angle is too large, the impact force of the molten metal on the mold wall will be insufficient, while if the angle is too small, it will be difficult to remove the mold.

[0025] 4. The mold has grooves and bosses on the sides and grooves on the bottom, which increases the unevenness of the mold surface and can further increase the impact force on the mold wall.

[0026] 5. The angle between the front side and the top surface of the inlet block is set to 100° to 120°, which allows the molten metal to flow into the cavity at a faster speed, thus increasing the impact force on the mold wall and the grooves and bosses. Attached Figure Description

[0027] Figure 1 A schematic diagram of a mold structure used in an embodiment of the present invention to assess the risk of sand inclusion and sand adhesion defects in castings caused by the molding process.

[0028] Figure 2 This is a schematic diagram of the mold dimensions according to an embodiment of the present invention;

[0029] Figure 3 This is a detailed feature diagram of the mold according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the casting scheme according to an embodiment of the present invention.

[0031] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-inlet block, 2-main body block, 3-casting mold, 3-1-bore, 3-2-groove, 3-3-groove, 4-sprue mold, 5-refractory brick, 6-sprue mold, 7-riseer mold. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] This invention provides a mold for assessing the risk of sand inclusion and sand adhesion defects in castings caused by the molding process. This mold is used to assess the risk of sand inclusion and sand adhesion defects in castings caused by the molding process. Therefore, during the design process, the mold needs to be able to increase the metal flow rate and increase the impact force of the molten metal on the sand mold wall, as well as some parts that are prone to sand inclusion and sand adhesion defects. For example... Figure 1 and Figure 3 As shown, the mold includes an inlet block 1 and a main body block 2, wherein:

[0034] The inlet block 1 is fixedly connected to the left side of the main body block 2. The bottom of the inlet block 1 is a slope. The thickness of the inlet block 1 gradually increases from left to right. As the distance to the injection port increases, the internal space of the mold becomes larger, which is conducive to the flow of molten metal and increases the flow speed of molten metal.

[0035] The main body block 2 has a stepped structure with several 90° corners, which increases the impact force of the molten metal on the casting and facilitates inspection. The sides of the main body block 2 have several bosses and grooves, and the bottom surface of the main body block 2 has several grooves. After molding, these parts are the weak points of the sand mold in terms of mechanical properties, and the molten metal will directly impact these parts. This is helpful in testing the ability of the sand mold to resist external collisions, friction and the impact of molten metal during demolding, handling, box closing and pouring.

[0036] Furthermore, the main body block 2 includes a first main body block and a second main body block. The first main body block is connected to the import block 1 on the left and to the second main body block on the right. The bottom surface of the first main body block is a slope, and this slope is coplanar with the bottom slope of the import block 1, forming an integral slope. That is, the thickness of the whole composed of the import block 1 and the first main body block gradually increases from left to right. The thickness of the second main body block remains unchanged, and its thickness is consistent with the thickness of the thickest part on the right side of the first main body block.

[0037] Furthermore, the first main block has several protrusions 3-1 and grooves 3-2 on its side, and the second main block has several grooves 3-3 on its bottom surface, in order to test the performance of various casting structures. In this embodiment, the main block 2 is a stepped structure with three 90° corners, and there are two protrusions 3-1, two grooves 3-2, and two grooves 3-3. Preferably, the two grooves 3-1 are located on two opposite sides of the first main block, and the two protrusions 3-2 are also located on two opposite sides of the first main block; the two grooves 3-3 are located on both sides of the bottom surface of the second main block.

[0038] Furthermore, for the cross-section of the boss 3-1 or the groove 3-2, its length and width are both 12-20mm, and the cross-section is preferably a square with equal length and width, so that the mechanical properties of the groove and the boss are moderate, and the applicability of the evaluation molding process scheme is expanded; the height of the boss 3-1 and the groove 3-2 (i.e. the mold thickness direction) is 80% to 100% of the length of the surface on which it is located.

[0039] Furthermore, the angle between the front side and the top surface of the import block 1 is 100° to 120°.

[0040] Furthermore, the mold design includes rounded corners: for edges with angles greater than 180 degrees, the rounded corner radius is set to 5mm; for edges with angles less than 180 degrees, the rounded corner radius is set to 3mm. This facilitates mold release and also helps reduce the vulnerability of the 90° edges of the sand mold to damage from impacts. In particular, for edges with mold angles greater than 180°, the corresponding edges of the sand mold after shaping are less than 90°, so the rounded corners should be set to be larger.

[0041] This invention provides a method for assessing the risk of sand inclusions and sand adhesion defects in castings caused by molding processes. Based on the aforementioned mold, the method includes the following steps:

[0042] Place the mold into the casting box and fill it with the molding sand to be evaluated (i.e., the molding sand prepared according to the molding process to be evaluated). After it solidifies and forms a sand mold, remove the mold.

[0043] Molten metal is poured into the sand mold from one side of the inlet block location to form a casting.

[0044] The surface quality of each surface of the casting is analyzed, and the risk of sand inclusion and sand adhesion in the sand mold is assessed based on the ratio of the number of surfaces with sand inclusion and sand adhesion defects to the total number of casting surfaces.

[0045] More specifically, it includes the following steps:

[0046] S1, Production as follows Figure 2 The dimensions shown indicate the casting mold 3 and other molding molds that assess the risk of sand inclusion and sand adhesion defects in the casting due to the molding process. These include the sprue mold 6, the runner mold 4, and the riser mold 7.

[0047] S2, according to the molding process to be evaluated, the sand is mixed under certain temperature and humidity conditions within the usable time to obtain the mixed molding sand to be evaluated.

[0048] S3, place the casting mold 3 and the runner mold 4 in the lower box. The runner mold is placed at the thinnest part of the longitudinal height of the casting mold. The upper surface of the runner mold and the upper surface of the casting mold are flush with the parting surface. Refractory bricks 5 are placed at the bottom of the runner to reduce the direct impact of the molten metal on the runner and reduce the influence of other factors. Fill in the molding sand mixed in step S1.

[0049] S4. Place the sprue mold 6 and riser mold 7 in the upper box. The bottom of the sprue mold and the upper surface of the sprue are in contact. The upper cross-section of the sprue is large and the lower cross-section is small, which is conducive to pouring and increasing the impact speed of the molten metal. The riser is set at the farthest end from the pouring inlet and filled with the molding sand mixed in step S1.

[0050] S5. After the sand mold has solidified, remove the casting mold 3, the horizontal runner mold 4, the vertical runner mold 6, and the riser mold 7. Keep the refractory brick 5 fixed in the sand mold.

[0051] S6. Apply paint to the horizontal runner, sprue, riser, and the contact area between the upper box and the casting mold to reduce the impact of these parts on the result. Do not apply paint to the other parts where the casting mold is used to complete the shape.

[0052] S7, pour molten metal, wait for the casting to solidify, remove the casting and cool it, then perform sand removal and shot blasting treatment; the casting weighs more than 6kg (cast steel parts) after pouring, which is conducive to molding and observation, and consumes less molten metal and molding materials.

[0053] S8. Observe typical parts of the casting, including the plane and inclined surface of the bottom surface, the three surfaces of the two bosses on the side, the four surfaces of the two grooves on the side, the four surfaces of the two grooves on the bottom surface, and a total of 24 surfaces on both sides to analyze the roughness of the casting, sand inclusion, and sand adhesion defects, and record the number of surfaces with sand inclusion and sand adhesion defects among the 24 surfaces.

[0054] S9, the percentage of the number of faces with sand inclusion or sand adhesion defects divided by the total number of faces (24) is used to assess the risk of sand inclusion or sand adhesion caused by the modified process.

[0055] In summary, the mold and risk assessment method provided by this invention not only solve the problem of being unable to assess the risk of sand inclusion and sand adhesion defects caused by the molding process, which in turn leads to actual defects in the casting, but also make the mold miniaturized and easy to operate, thus making it particularly suitable for applications involving risk assessment of sand inclusion and sand adhesion defects caused by sand casting molding process.

[0056] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A mold for assessing the risk of sand inclusion and sand adhesion defects in castings caused by molding processes, characterized in that, Includes an import block (1) and a main block (2), wherein: The inlet block (1) is fixedly connected to the left side of the main body block (2). The bottom of the inlet block (1) is a slope, so that the thickness of the inlet block (1) gradually increases from left to right. The angle between the front side and the top side of the inlet block (1) is 100° to 120°. The main block (2) is a stepped structure with three 90° corners, and the main block (2) has several protrusions and grooves on its side and several grooves on its bottom surface. The main body block (2) includes a first main body block and a second main body block. The first main body block is connected to the guide block (1) on the left and to the second main body block on the right. The bottom surface of the first main body block is a slope, and the slope is coplanar with the bottom slope of the guide block (1) to form an integral slope. The thickness of the second main body block remains unchanged, and its thickness is consistent with the thickness of the thickest part on the right side of the first main body block. The first main body block has several protrusions and grooves on its side, and the second main body block has several grooves on its bottom surface; For edges in the mold with an angle greater than 180°, set a fillet with a radius of 5 mm; for edges in the mold with an angle less than 180°, set a fillet with a radius of 3 mm.

2. The mold for assessing the risk of sand inclusions and sand adhesion defects in castings caused by the molding process, as described in claim 1, is characterized in that... The first main block has two protrusions and two grooves on its side, and the second main block has two grooves on its bottom surface.

3. The mold for assessing the risk of sand inclusions and sand adhesion defects in castings caused by the molding process, as described in claim 1, is characterized in that... For the bosses or grooves on the first main body block, the length and width of their cross-sections are both 12 to 20 mm.

4. The mold for assessing the risk of sand inclusions and sand adhesion defects in castings caused by the molding process, as described in claim 1, is characterized in that... For the boss or groove on the first main block, its cross-section is square.

5. A method for assessing the risk of sand inclusions and sand adhesion defects in castings caused by molding processes, implemented using a mold as described in any one of claims 1-4, characterized in that, Includes the following steps: Place the mold into the casting box and fill it with molding sand prepared according to the molding process to be evaluated. After it solidifies to form a sand mold, remove the mold. Molten metal is poured into the sand mold from one side of the inlet block location to form a casting. The surface quality of each side of the casting is analyzed, and the risk of sand inclusion and sand adhesion in the molding sand is assessed based on the ratio of the number of surfaces with sand inclusion and sand adhesion defects to the total number of casting surfaces.

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